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From: John De Armond
Newsgroups: alt.energy.homepower,misc.rural
Subject: Re: Micro Nukes - a prediction comes true
Date: Thu, 20 Dec 2007 19:06:14 -0500
Message-ID: <01vlm3502i9jr93blsq2sq98hqsnvvng4o@4ax.com>

On Fri, 21 Dec 2007 00:13:16 +0100, Trygve Lillefosse <news@lillefosse.NOSPAM.org>
wrote:


>BTW: What happened to the "pebble bed" reactors? There was supposed to
>pop up quite a few of them, especialy in China. Have not heard of any
>actualy beeing produced and commissioned..

In the present climate, there is too much business risk in trying anything nuclear
that is totally new.  "Intrinsically safe" is a buzzword that the politicians and
informed members of the public want to hear.  Undoubtedly a PBR could be made
intrinsically safe with some work but that work costs money and lots of it.  As in a
lot of other areas, good enough is the enemy of perfection.  More conventional
reactor geometries are good enough for now.

For low quality heat applications (district heating, low pressure steam, etc) I like
the liquid fueled reactor a lot.  This consists of a solution of uranium salt that is
pumped into a critically favorable vessel, usually a sphere, where the reaction takes
place.  Either the fuel solution is circulated out or coils immersed in the fuel
bring the heat out.  Fission products are removed continuously and new fuel is added
as needed.

This reactor is extremely safe.  Because of the huge negative temperature and void
coefficients of reactivity, it is impossible for the reactor to over-power for more
than a few milliseconds.  No large inventory of fission products is allowed to build
up so there is no concern with decay heat after shutdown.  In an emergency the
reactor can be instantly scrammed by simply opening a dump valve that lets the fuel
drain to a critically safe container.

Los Alamos did a lot of work on the liquid reactor in the 50s and 60s.  They worked
out the material compatibility issues among others.  To me, this would be a perfect
design for a micro-nuke.  Refueling per se would not exist as a separate process.  At
periodic intervals, the fission product concentrate would removed for disposal and
new liquid fuel added to a reservoir.

District heating is another one of those practices that has gone the full circle and
is returning to interest.  In case you don't know, this is the form of heating
practiced in large cities such as NYC where a central boiler plant makes hot water
and/or steam that is piped around the district and sold to consumers.  Low pressure
steam (<15psi) is the typical form the energy arrives at the consumer.

A neighborhood nuke would be wonderful for this application.  Supplying heat directly
to the consumer avoids all the multiple levels of conversion inefficiency involved in
making and transporting electricity to the end-user.  Fifteen psi steam is hot enough
for many things including cooking.  100 psi is hot enough for baking, radiant heat,
drying, etc.  I had a steam jacketed kettle in my restaurant and would kill for one
in my house.  Imagine an oven that could not get any hotter than its setpoint.
Imagine a radiant heater that could not start a fire because it could not get hot
enough.

By avoiding the conversion losses involved in central power generation, absorption or
Stirling-driven air conditioning and refrigeration becomes practical and economical.
Once the steam infrastructure is in place, the demand for electricity drops greatly.
Basically lighting, entertainment and the odd heating application.  And if BEVs ever
become a reality, what better place to generate the electricity to charge the
batteries than right there alongside your garage?  A small steam turbogenerator would
do the job.

On the reactor side, dropping the operating pressure from the current practice of
something in the 2300 psi range to say, 100 psi tremendously reduces the cost while
increasing the safety margin.  With little stored energy to deal with, the plant can
be designed lightweight and compact.

This is, of course, futurethink.  But all it would take in the near future is for
some forwardlooking, courageous and politically well-connected developer to design a
community around a neighborhood nuke.  Once the total cost of living were published,
I bet people would be fighting to buy a house in a place like that.

John


From: John De Armond
Newsgroups: alt.energy.homepower,misc.rural
Subject: Re: Micro Nukes - a prediction comes true
Date: Sun, 23 Dec 2007 00:20:16 -0500
Message-ID: <mukrm3pdpt208p54dmt5t0uvm4ojreoefs@4ax.com>

On Sat, 22 Dec 2007 21:01:18 -0500, "daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com>
wrote:


>"Neon John" <no@never.com> wrote in message
>news:01vlm3502i9jr93blsq2sq98hqsnvvng4o@4ax.com...

>> For low quality heat applications (district heating, low pressure
>> steam, etc) I like the liquid fueled reactor a lot.  This consists of a
>> solution of uranium salt that is pumped into a critically favorable
>> vessel, usually a sphere, where the reaction takes place.  Either the
>> fuel solution is circulated out or coils immersed in the fuel bring the
>> heat out.  Fission products are removed continuously and new fuel is
>> added as needed.
>
>What does any of that have to do with district heating?  Are you suggesting
>the reactor temperature be kept low enough to drive such heating directly
>without a steam cycle?  That would be incredibly dumb.

Really?  Care to expand on that?  Considering how many district heating hot water
systems there are out there, I want to hear this definition of "dumb".

In case it whooshed by, I addressed three different concepts in one post: 1) hot
water district heating, 2) low pressure steam district heating, 3) medium pressure
district steam.  Hot water heating would require the least capital investment but
would also do the least - basically comfort heating.  The others do progressively
more until with 100 to say, 150 psi, the steam can be the home's only energy source.

>Such 'multiple levels of conversion' don't exist in homes that use NG,
>propane, oil, solar, wood or other biomass for heat already.... (i.e. folks
>that live in cold climates that need a lot of heating usually don't use
>electric heat, it's too expensive for the very reason you cite)  If you
>could supply district heating steam at a price comparable to even as low as
>$2 per Therm (after paying for heat losses, district piping, and condensate
>reprocessing), I'd be surprised.

If you can't step outside your box then at least cut a teeny tiny hole in the side
and look out.  Try to see beyond the end of your nose.  The objective of a nuclear
district heating system >IS< to >replace< those fuel-based heating methods.  D'oh!

Also, instead of looking over your shoulder at what used to be, perhaps you should
inform yourself of what is being done now.  Polymer is replacing steel in low
pressure steam applications just like it is in most other forms of utility
transmission.  Neither does district heating over a small to medium sized community
mean massive digs.  HDDB and push piping are two of the new technologies that are
obsoleting the old way.  One of the advantages of reading over a hundred trade rags a
month is that one CAN remain informed in multiple fields in a way that sitting behind
a computer screen just can't do.

When I talk about this stuff I'm looking forward toward the short term future,
extrapolating a few years forward from what the state of the art in construction
practices are today.

>If you only cook with 250 degF, yes.  So heating up veggies, or some soup
>will work at that.  But I couldn't even cook some fudge with that.

OH MY GAWD!!!!  The man can't cook fudge.  Guess we'll have to scrap the whole
concept then.  After all, doesn't everyone eat fudge for every meal?

Sheesh, dude. Guess you might have to get out your electric fudge cooker, eh.  How
often do you make fudge compared to making soup, casseroles, roasts and other such
dishes.  OK, so you're the odd one.  How often do you think the average guy makes
fudge compared to cooking conventional foods?

Ya know what?  I can't make fudge in my crock pot either but it's cooking something
most of the time.  If I ever need to make fudge or anything else that requires that
kind of temperature then I'll just get out my hotplate, my induction range or
whatever seems most suitable.  The right tool for the job, eh?

>
>> 100 psi is hot enough for baking, radiant heat,
>> drying, etc.
>
>The 15 psi is plenty hot enough for space heating but 100 psi will get you
>only about 340 degF.  Fair enough for some baking, but you can't cook pizza
>or fry chicken with that.  I'll keep my gas oven thanks.

Well good for you.  There's always an odd one in the crowd.  350 deg is certainly
enough for baking.  It is also enough for frying.  I run my fryers, both commercial
and at home, at 350 degrees.  The result is slower but oh so much more tasty than
when fried at higher "fast food" temperatures.  The french fries are crisp through
and through.  Chicken is cooked thoroughly without the breading getting even the
least bit scorched.  Breaded veggies such as mushrooms lose enough moisture that they
firm up nicely and are no longer soggy.

If I find myself needing a higher temperature then my steam fryer or oven is simply
equipped with aux electrical heating elements.  Here's a little secret.  The high
temperature is needed only for a short portion of the cook cycle.  Deep frying
involves mostly boiling out excess moisture from the food.  Only the last part,
involved in browning, requires anything higher than the boiling point of water.  Same
with baking.  Similar with roasting.  In that case, most of the time is spent
permeating the meat with heat to reach the proper temperature.  Only at the end when
the moisture in the outside of the meat has reduced sufficiently does browning occur.

If you've ever stuck a thermocouple in a deep fryer and run a data log (somehow I'm
thinking that you haven't), you'll see that when a mass of frozen food is added, the
grease immediately (over less than a minute) drops to below 250 degrees.  There is
sits as the high heat of vaporization carries off all the heat the burner/heating
element is inputting.  As the moisture content drops, the temperature starts rising
as the heat input outstrips the heat of vaporization.  Only during the last part of
the cycle (30 sec to a minute in a commercial fryer) does the grease return to a
temperature high enough to cause browning.

In the event someone decides he needs more heat that the steam supplies then the
solution is simple.  A small aux electrical or gas heater, a finishing heater, will
do the job.  It wouldn't operate but for a few minutes at the end.  The energy
consumption would be minimal.

Steam heat is the rule in both commercial and industrial food service.  We cooked
caramel with steam at M&M Mars on the Twix line.  We cooked chocolate and roasted
peanuts with steam.  Only for baking wafers on the old Summit line did we use gas,
for reasons other than it was the best heat source.

Once one cooks with steam, he'll go back to other sources only kicking and screaming.
I LOVED my steam kettles and my steam oven in my restaurant.  The best feature is
that it is practically impossible to burn something in a steam kettle.  Set the
pressure regulator to whatever steam pressure you desire and there it stays,
regardless of the heat load.  Set it to 12-13 psi and that batch of thick rich soup
will boil vigorously but never burn.

I used to make 80 gallon batches of my Jalapeno cream cheese soup.  The raw
ingredient cost was well over $1000.  I'd never even think about making such a large
batch in anything else, considering how easy cheese, milk protein and sugar are to
burn.  Even a small scorching fouls the whole batch.  Previously we made it in 10
gallon batches and even with an employee dedicated to that batch, standing there
stirring constantly, scorching happened way too often.  The steam kettle neatly
solved that problem and the problem of having to have an employee fully occupied
babysitting the process.

When you ridicule steam cooking, you're doing so out of ignorance.


>Dream on.  Running a small turbogenerator on 100 psi steam means for every
>kWhr you get out you have to buy about 5 - 6 kWhr worth of steam.
>TANSTAAFL, you can make electricity with about 33% efficiency in a high
>pressure/high temperature reactor system, or you can make low pressure
>process steam and get less than 20% efficiency in your home 'small steam
>turbogenerator'.  Guess which one costs you more in the long run.
>
>Don't have a high vacuum surface condenser for your turbogenerator to
>exhaust to? then the efficiency drops even further and you might need to buy
>10-15 kWhr of steam for every kWhr of electricity you generate with this.

Faulty analysis based on just enough knowledge to be dangerous.  First off, the
efficiency of the generator becomes less an issue as the cost of energy drops.  Such
as will be the case for a neighborhood nuke.

Fuel cost is an insignificant portion of operating cost in a nuke, especially a high
burnup nuke.  Construction and maintenance costs dominate, mainly regulation-induced
needless construction costs.  Maintenance costs don't scale linearly.  That is, it
takes much less maintenance to maintain a small low pressure plant than a large one.

Let's do some figurin'.  The Browns Ferry Plant Units 1 and 2 were built in the 60s
at a cost of $300,000,000 per unit.  1000MWe units.  That's $300,000 per MW. BFNP was
the last of GE's turn-key jobs, the style of construction where the costs are least.
Both the regulatory environment and the union problems were mild.  A great example of
a plant that was built in a timely and straightforward manner.

OK, assuming that the scale remains the same, a 0.5MW micro nuke would cost $150,000
to build.  The scale won't remain the same on many things - site prep will be
proportionally higher with a small unit while piping and apparatus for low pressure
operation is cheaper.  Let's round WAY up to half a million to make the plant.

Let's say the plant costs $0.5 million to construct and $50,000 to fuel.  Forty year
life.  0.5MW * 24hours * 365days * 40years = 175,200 MWh or 175,200,000 kWh over the
life of the plant.  Dividing $550,000/175MkWh = $0031 per MWh or 0.31 cents/kWh. That
seems like a reasonable number but feel free to toss in whatever numbers you like.
Assign whatever cost you'd like for running steam through a few thousand feet of pipe
to the end-users.

Let's say this small steam turbine only achieves 10% efficiency.  That makes the cost
of the power it generates for the EV 3.1 cents/kWh.  Less than half what I'm paying
right now and I live in a low cost power region.

But it's a lot better than that.  The exhaust from the steam turbine has a number of
uses.  Comfort heating, water heating, absorption refrigeration, heating the swimming
pool, thawing the driveway and walks.  The possibilities to use essentially free
waste heat are enormous.

And it may be that a steam-heated Stirling engine or a compound turbine/Stirling
combo will be the thermodynamically optimal architecture.  It took the power industry
a few decades to figure out and perfect the multi-stage extraction steam heated
feedwater system used in today's power plants.  I'm sure that wasn't obvious to the
pioneers.  It'll take the thermo-heads awhile to figure this one out too.

And since charging the EV will be only a part of the house's full energy load, its
efficiency will have an even smaller effect on the home's efficiency than the above
calculation predicts.

Indeed, it might work out that it is more economical overall for each house generate
all its own electricity since the amount the house would need would be minimal once
all the heating and AC is supplied by steam.  It might not make economic sense to run
transmission lines AND steam lines.  Especially since the waste heat from the
generator can be used on-site.

>Reactor pressure would have to be a few hundred psi if you hope to supply
>100 psi to customers.  Say, about 500 psi for plenty of margin.  Yes, the
>vessel and piping would be much lighter and cheaper for such an operating
>pressure.  But the primary water would still be about 350 to 400 degF and
>that's only about 100 to 120 degF cooler than a modern PWR.  I wouldn't call
>that 'little stored energy'.  Depending on containment size you would still
>see peak containment pressures after a LOCA similar to those of existing
>PWR's (if you build a 'compact' containment, the peak pressures could
>actually be *higher* than those of a PWR).
>
>For example, if you take something like 5000 gals of primary water at 340
>degF/100 psi and release it into a 40x40x40 ft containment (quite a bit
>larger than your 'compact' idea), you get a pressure of about 10 psig
>assuming you started with a vacuum in the containment to begin with.  A
>40x40 wall that could hold back 1152 *tons* of force is not what most people
>call 'lightweight'.  Physics says if you use a smaller coolant system but
>release it into a smaller containment, the peak pressure stays about the
>same..

Man, your head is REALLY stuck inside the box.  Or the box is stuck on your head. You
don't REALLY think that any micronuke engineer worth his weight in Pu is going to
copy the mistakes of the past and allow any significant inventory of hot pressurized
water in the "containment", do you?  That kinda defeats the whole purpose of
intrinsically safe reactor design principles.

Since I haven't seen prints for any of the proposed micronukes, I don't know any
details but I'll just bet that the primary coolant will be molten salt or molten
metal, in any event, operating at atmospheric pressure, plus or minus.  I'm betting
on molten salts.

C'mon daestrom.  We're trying to look forward to the near future and not back over
our shoulders.  Get with the program.

John


From: John De Armond
Newsgroups: alt.energy.homepower
Subject: Re: Micro Nukes - a prediction comes true
Date: Sun, 23 Dec 2007 02:05:37 -0500
Message-ID: <opsrm3d21eug23mvhn5ussf05au4mcmv9k@4ax.com>

On Sat, 22 Dec 2007 19:49:41 -0500, "daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com>
wrote:

>Well NJ, you seem to have been in the nuclear field at one time (Navy
>perhaps?), why don't *you* think about this a bit.  How much uranium do you
>need to run at about 600 kWth for 40 years (to get about 200 kWe)?

Depends.  What fuel enrichment, geometry, physical form do you want?  Fast or
thermal?  What burnup?  If thermal, what moderator?  With high enrichment, I can make
half a kWt in a can that two guys can carry around.  If we want to go natural fueled
and heavy water or graphite moderated, then it gets a little larger.


>Where do
>all those fission product gasses go?  Well, of course they should stay right
>there in the fuel assembly.  And maintaining a critical configuration as
>those neutron-loving fission products build up?

Why do I want to keep fission gases in the fuel?  That's so high pressure light water
cooled yesterday-think.  I want fission gasses out as quickly as possible.  I avoid
the xenon well and since I'm not burning xenon, I avoid so much iodine buildup.

I want to pull the nobles and iodine out and store them for decay.  Modern materials
such as molecular sieves make this a trivial task.  It's even possible to segregate
elements.  After a few weeks of decay, only Kr85 remains in any quantity.  Kr85 is a
valuable industrial and medical isotope so "disposing" of it consists of selling it.

I'm not going to be running a micronuke at the very high energy densities that large
LWRs do so I have much more freedom of design for my fuel and encapsulation. Sintered
metal or mixed metal fuel is practical and is porous enough to let those nasty nobles
out quickly.  And I won't be dealing with tens of thousands of individual rods so
plumbing each fuel element into a gas recovery system is perfectly feasible.

>
>Now let's talk about a containment structure.  Even a low power unit such as
>this requires *some* amount of containment around it don't you think?  True,
>a release from such a plant would be smaller, but if your 'neighborhood' has
>houses within 100 ft of the plant, don't you think some of those neighbors
>are going to want some containment around the thing?  Is this thing water
>cooled?  That would mean a strong containment wall is required.  Gas-cooled
>is easier to contain, but still requires a containment.  How strong does the
>containment need to be to resist some credible threats like a tornado,
>earthquake, or flooding?  Not to mention the paranoia about suicide
>terrorist attacks.

All the neighborhood nuke proposals I've read have one thing in common.  The reactor
goes underground.  Dig a pit, pour some concrete, plop down the shop-fabricated
reactor and containment, cover that with some more concrete and dirt and there you
are.

Now the "credible threats" from outside factors mostly evaporate.  No tornados.  NO
missiles.  No terrorists, unless they happen to have an earth penetrating bomb.
Making something as small as a typical house earthquake-proof is fairly trivial.

I'm going to allow essentially no stored energy in the containment.  Either molten
salt or molten metal as coolant, operating at atmospheric pressure, more or less.  No
chemically stored energy either.  If the coolant is Na or NaK then no water is
allowed inside the containment and the free space is severely limited to preclude the
buildup of hydrogen.  More likely I'm going to use a salt or something like lead as
my coolant.

AEC built some lead-cooled research reactors that performed exquisitely.  Lead has a
very high boiling point and a very low vapor pressure at typical operating
temperatures.  It's inert. It doesn't make any long-lived isotopes.  It does double
duty of cooling and shielding the core.  Gamma radiant energy that is normally lost
to the thermal shield in a conventional reactor is now captured as useful heat in the
lead.

Now the containment only has to be large enough and thick enough to support itself. A
design-basis accident would probably have to include the accidental introduction of
some water into the containment but with minimal free space around the reactor, the
containment mass necessary to contain moderate pressure is small.  Or maybe not.  I
can visualize designs that absolutely preclude water entering the containment.

>
>Assuming 33% efficiency, 200 kWe means you need to reject 400 kW thermal to
>*somewhere*.  Even Alaska doesn't need district heating in the summer time.
>How many neighborhoods want a cooling tower at the end of the block?  or
>have access to cooling water at about 100 gpm all day/night?  If efficiency
>is a lot lower (you say you don't care about efficiency, but here is one
>reason why you should), you might need 500 to 1000 gpm all day/night for an
>open cycle heat sink.  Of course a cooling tower could cut this way down,
>but then you need to build that instead.  Assuming the neighbors don't rise
>up in arms about the 'drift' from such a tower staining all their laundry
>and car windshields (and spoiling the view).

There's historical precedent for how people react.  Middletown, PA, home of TMI.  The
residents were whipped into an anti-nuke frenzy when TMI was first proposed.  Met-Ed
did a brilliant and very forward-looking thing.  The offered Middletown a 99 year
fixed rate contract for electricity at 1 cents/kWh.

Ya know what happened?  Middletown couldn't wait sign on the dotted line.  The
outside agitators were run out of town instantly.

Though Met-Ed's successors have tried to break that contract, it is still in effect.
It's interesting to see the town and see the effects.  People haven't had to waste
their money on silly conservation crap.  Just use whatever appliance is most
convenient and go on about their lives.  Lots of window units.  Lots of all-electric
houses.  Electric radiant heaters on back porches.  LOT higher standard of living
than say, Royalton which is right across the creek but missed out on the deal.

But hey, you know, micronukes might not be for everyone, at least in the beginning.
Those who want to continue paying the man can.  What is it Kalifornicators are paying
now?  25 cent/kWh?  That's fine.  Let 'em keep paying.  I bet they won't for
long..... :-)

As I stated earlier, I predict that the first micronukes will most likely be in the
form of planned communities built around the things.  Everyone who buys into the
community will be there because they WANT to be there.  The prospect of almost free
energy will be powerfully appealing.

Most likely the community will be near a body of water that can supply the necessary
cooling water.  Or in a place where the water table is high and shallow geothermal
wells can do the job.

As for cooling towers?  In my neighborhood growing up, there was an HVAC cooling
tower in nearly every back yard.  Power was cheap but labor was cheaper back then so
they made sense. Nobody paid any attention at all to the towers, just as nobody pays
attention to the ugly condensing units sitting outside most houses today.  Or the
ugly power poles on the street.  People quickly get used to things that benefit them.

The water cooled AC was incredibly efficient.  One of my grammar school science fair
projects (my dad's idea) was to measure the sub-cooling achieved in the tower from
evaporation.  In clearing out some of my late father's papers awhile back I found
some old power bills.  It was remarkable how few kWh that house used even though it
was fairly large and by today's standards, poorly insulated.

People "put up with" whatever is necessary to better their lives once they're
educated (or led by the noses).

>Ever know of a simple thing like a pump to last five years without
>maintenance?  How about a couple of dozen pumps, valves, and a generator?
>Even routine maintenance means skilled technicians, training programs and
>requalification programs to prove they know what they are doing, quality
>assurance programs to check that they didn't just blow it off, oversight and
>licensing compliance folks to make sure you're not violating the law and a
>host of others.  All that takes people, and people cost money.  The highest
>O&M cost in traditional nucs is *payroll*.  Even if the neighborhood co-op
>just leases one of these from Toshiba, *somebody* is doing the maintenance,
>and *somebody* is paying for it.

Man, you ARE stuck in the past.

Well, I suppose the operators could do the same thing that many small factories and
the water system from back home does now.  They use a contract maintenance service to
do what is needed.  With automated controls, advanced vibration and acoustical
monitoring instruments and wireless and internet communications, there is no longer
any need for the daily walk-around.  A central monitoring station can monitor one or
several plants and dispatch maintenance as needed.

In fact, there may be another business opportunity.  Centralized operations and
monitoring.  Given a sufficiently intrinsically safe design and favorable regulatory
conditions, there will be no need for a micronuke to be manned.  Many could be
monitored from a central location.  Similar to burglar alarm services, only on a much
higher skill and training level, of course.

>You think the government should just let someone buy/lease one of these and
>set it up and then the government won't want to inspect it once in a while?
>Maybe look over some records, see who did the last maintenance on the safety
>systems?  What kind of background checks were done on the people allowed
>access to the thing?  Are any of those people psychotic? drug addicts?  What
>kind of security is required of the fuel?  Even though it's not 'bomb
>grade', it's still subject to tight controls isn't it?

Oldthink again.  If the reactor is buried underground and is fueled for life, who
needs to access the thing?  If it's intrinsically safe then no active engineered
safeguards are present so there is nothing to surveillance.  Multiply redundant
self-calibrating and self-healing instrument systems obviate the need for frequent
instrument surveillance.  Or perhaps ANY human surveillance.  Such systems calibrate
themselves, fix themselves as much as possible and report out orders for replacements
for the defective components.

This is nothing new.  Stratus Computers was doing that stuff over 20 years ago. These
are the computers that ran (probably still do) most of financial networks where
100.000% uptime is required.   The tested themselves, fixed problems by cutting in
redundant hardware as needed and automatically phoned home for replacement parts.  I
was surprised more than once when the Stratus service engineer showed up with a
replacement board that I didn't realize one of my machines needed.

If you had kept up to date at all on the instrument and controls industry, you'd know
just how far this self-diagnosing, self-healing, self-calibrating technology has been
taken.  The old I&C man is becoming as obsolete as the village blacksmith.

For another example, if you get the opportunity, talk to an electronic flight
controls engineer sometime.  Find out what is considered old technology in that
industry.  I have a friend who was one of the architects of the fly by wire system on
the JSF.  Even though I try to stay up to date on that kind of stuff, he regularly
makes my jaw drop.  Controlling an intrinsically safe small reactor is child's play
compared to controlling a high performance, inherently unstable military aircraft.

>
>Funny thing, all my Googling for information about this all leads back to
>that same article at www.nextenergynews.com.  Not even Toshiba Nuclear's web
>site mention any of this 'breakthrough'.  I'm beginning to think it's some
>hoax or 'cyber-legend' by nextenergynews.

Perhaps.  I've written Toshiba to find out.  Sometimes people who know just enough to
be dangerous write up hoaxes that are amazingly possible to the informed.

But even if it is a hoax right now it won't be in the near future.  I don't see any
technological nor materials impediment to making and deploying micro-nukes.  Only the
political climate has to change and that is currently happening at blinding speed.

Let's look at this another way.  Twenty five years ago, in 1982, would you have ever
in your wildest imagination have dreamed of this Internet thingie?  I certainly
didn't and I was in the thick of the computer revolution back then.

I wired my company and equipped my road warriors with CP/M computers and 2400 baud
modems plus custom software back when that wasn't even a dream in most people's
minds.  One of my site managers could write a proposal to the client, send it to me
or my partner for approval or modification, get it back and print it out all in one
day.  My nuclear clients, deeply tethered in the mainframe and typing pool worlds
were stunned.  I'm proud to have caused a wildcat strike of the steno pool union at
Three Mile Island :-)  How DARE engineers do their own typing!?!?!

Even when I got on the ARPAnet in the mid 80s, I still would have never dreamed of
anything like we have today.  Even when in the 90s I operated dixie.com, one of the
first commercial ISPs in the country, I still didn't see it coming.  Few did.  I
won't make that mistake again.

So now, with a nuclear career behind me and aware of what can be done today with
today's materials and technologies, how could I possibly NOT predict micro-nukes in
the future?  The only impediment has been political and I see that changing at an
exponentially accelerating rate.

John


From: John De Armond
Newsgroups: alt.energy.homepower
Subject: Re: Micro Nukes - a prediction comes true
Date: Sun, 23 Dec 2007 14:06:51 -0500
Message-ID: <o2ctm35o9fscbufre3cq49s7shlr27fkvg@4ax.com>

On 23 Dec 2007 07:40:57 -0500, nicksanspam@ece.villanova.edu wrote:

>"daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote:
>
>>Assuming 33% efficiency, 200 kWe means you need to reject 400 kW thermal to
>>*somewhere*.  Even Alaska doesn't need district heating in the summer time.
>>How many neighborhoods want a cooling tower at the end of the block?
>
>We might turn off the nukes in summertime, or store heat underground...

Or more likely, run the AC and refrigeration from the heat.  Absorption (available
now) or stirling (available when there is a market)

>
>James Lovelock of Gaia fame (and amazing spectroscopic techniques) has been
>advocating nukes to reduce CO2 for a long time. He has a standing offer to
>store all of the nuclear waste created in the UK in a year in a 1 meter cube
>in his back yard, which he would use to heat his house.

I was aware of his advocacy but not of his offer.  I'll make the same offer here.  In
fact, I'd LOVE to have a few gigacuries of high level "waste".  I could become
totally energy self-sufficient.  I could do what my Mom always yelled at me not to do
- run the AC with the windows open :-)

You know, I bet that if the government got out of the way, there'd be a market for
HLW.  There are surely enough of us sufficiently educated types out there that the
demand would outstrip the supply.  There's the solution to the "nuclear waste"
problem.

John


From: John De Armond
Newsgroups: alt.energy.homepower
Subject: Re: Micro Nukes - a prediction comes true
Date: Sun, 23 Dec 2007 15:21:01 -0500
Message-ID: <dcftm31pm613op26bo7vvki4l5ftdakjll@4ax.com>

On Sun, 23 Dec 2007 12:07:30 -0500, "daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com>
wrote:


>> Depends.  What fuel enrichment, geometry, physical form do you want?
>> Fast or thermal?  What burnup?  If thermal, what moderator?  With high
>> enrichment, I can make half a kWt in a can that two guys can carry
>> around.  If we want to go natural fueled and heavy water or graphite
>> moderated, then it gets a little larger.
>>
>
>You missed the point.  Do it for 40 years without refueling and no fuel
>assembly failures.  The total energy produced is simply 24000kW-years.  The
>amount of fission products produced for that energy production doesn't vary
>much between fast/thermal so take your choice.  After calculating the
>neutron absorption of that amount of fission product poisons, add enough
>fuel to overcome that negative reactivity and maintain criticality at
>end-of-life.  If you want to add a burnable poison to help beginning of life
>shutdown margins, don't forget the gasses produced when they 'burn'.  Now
>design a fuel assembly that will contain all of this during the same forty
>years of irradiation / corrosion.

No, I didn't miss your point.  I simply have a wider experience base than just
utility LWRs.  LWRs were designed for a set of circumstances that never quite
materialized, the assumption being that the fuel would stay in the core for 3 cycles,
then out and reprocessed.  Low enrichment to limit fuel costs.  Extremely high energy
density (better than 20kW/foot) was more important than extended fuel residency.  A
rather extreme amount of shutdown margin was also thought to be necessary
politically.

Have you ever taken a look at a CANDU reactor?  IMO, a much more intelligent design
for civilian power than what the US has.  We were shacked with the "Rickhover
effect".  Natural uranium fueled, heavy water moderated, capable of being refueled
online, capable of other uses such as isotope manufacture.  Canada has become the
world's supplier for medical isotopes.

There is a world outside of US LWRs, believe it or not.

Have you ever seen a sub reactor?  "Greater than 50MWt", as the official statement
goes, in a pot that one can almost wrap his arms around.  ">90% enriched" uranium
metal fuel.  Warm shutdown to full power in "> 1 minute".  Refueling interval >20
years.  The actual values are classified but those are good enough to work with.
That's what the Navy did with a different set of design and operating parameters.  A
very long refueling interval was a prime consideration.

Have you ever seen any research power reactors?  AEC, Los Alamos, Sandia, Oak Ridge
and others did a yeoman's amount of work in that area.  Much of it has been
declassified.  Many of the LASL papers are available here:

http://www.sciencemadness.org/lanldocs.html
or
http://www.fas.org/sgp/othergov/doe/lanl/index.html

The original source of these reports, the Las Alamos Technical Library's "Library
without walls initiative" was an early victim of the post-9/11 hysteria.  Lots of
good reading there that might expand your horizons beyond existing PWR techniques and
designs.

John


From: John De Armond
Newsgroups: alt.energy.homepower
Subject: Re: Micro Nukes - a prediction comes true
Date: Sun, 23 Dec 2007 16:10:56 -0500
Message-ID: <mqgtm3d953o6hcc4lo4ao2hajjrirn3ki7@4ax.com>

On Sun, 23 Dec 2007 13:50:23 -0500, "daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com>
wrote:

<massive snippity>

Do you REALLY have to quote EVERYTHING.

>
>Man, you string together a lot of ideas, but you don't connect very many
>dots.  Here let's see...
>
>You bury it underground and build it in an area with a high water table for
>cooling water wells.  Then you want to exclude all water from the
>containment?  Ever see a concrete sailboat?

Well, yes, yes I have.  I've also seen underground bunkers and missile silo and any
number of underground structures that are designed NOT to float.  Besides, "high
water table" is relative.  At 50 ft down, the water table here is considered high but
my basement hasn't floated away yet.

Are you asserting that engineers, geologists and others involved in site selection
aren't capable of avoiding this simple problem?  Really?

>
>You're self-diagnosing, self-healing instruments are great as long as they
>last, but they don't last 40 years.  If they did, satellites wouldn't have
>the failures rates they do.

Ya mean like Viking?  Any idea what kind of radiation field exists in synchronous
orbit?

>Put electronics anywhere near a radiation
>source like the reactor or primary piping and you have some very real
>radiation dose issues.
>
>They may 'phone home' for repair parts, but since you won't let anyone
>access them, what's the point in calling for a repair part that can't be
>installed?  Your Stratus still had failures didn't it?  How long would the
>computer complex have continued if no repair parts were ever installed?
>That's what you're proposing with your 'no access' policy, some number of
>components that continue for 40 years with enough redundancy to deal with
>all failures.  Drives the price up.

Are you being intentionally dense or are you really that ignorant?  What knucklehead
would even consider placing the instrumentation in a high radiation field?  Do you
have any idea how long industrial instrumentation actually lasts?  "life of the
plant" isn't unusual.  Do you have any idea how long ordinary industrial
instrumentation in the containment of TMI-2 lasted, even when immersed in fuel-laden
water?  The field around these instruments was STILL several hundred thousand R/hr
when we (I say "we" cuz I was there) entered the containment a couple of years later.

Is it conceivable to you to hermetically seal the reactor but not the instrumentation
and controls?

You're either being silly or dumb as a rock.

>You want to extract the fission product gasses and store them for decay?
>Okay....  So you're storing them somewhere outside the reactor, sounds like
>separate tanks with some plumbing and valves and blowers/pumps.

Nope, I'm thinking about a few cylinders of molecular sieve located outside the
thermally hot area but still inside the containment.  No pumps or other active
hardware necessary.  Not even any active valves unless one wants to harvest the Kr85.

Do you by any chance know how a molecular sieve works?  Do you know how the MS pump
that holds the vacuum in a liquefied gas dewar works?  Are you surprised to learn
that these things last the life of the dewar?

>Molecular sieves can work well when you're trying to separate two or three
>components from one and other.  But the mess of things that come off of
>fuel?  Do you remember just how many different fission products are likely
>to come by your sieves?

Well yeah, as a matter of fact I do.  Several isotopes of Xe and a few Kr.  Probably
only a trace of I, as it combines with Cs, another fission product to make a
non-volatile solid.  There is quite a bit of He but it's not radioactive so we really
don't care about that and besides, the sieve pretty much ignores He.  If air is
allowed within neutron range, they'll be some N12 activation product but with a 12
second half-life, we can ignore that one.  Air probably won't be allowed in anyway. A
nitrogen blanket would produce some O16 (I think, not sure of the isotope number) but
with a few seconds' half-life, again, not a concern.

Basically, we'll be dealing with Xe and Kr and maybe a slight trace of I that can be
absorbed in a silver pre-trap.

A routine part of my day to day business at Radiation Measurement Systems, Inc (the
company I founded) involved handling multi-kilocurie quantities of both Xe and Kr,
both of which were stored in sieves when not in use. I designed the gas handling
apparatus and the means of storage.  But hey, what the hell do I know about handling
noble gas compared to you?

>
>Ever hear of eroson/corrosion?  You got a moving liquid in a pipe, you need
>to monitor for pipe-wall thinning.  I'd predict that after just 15 years, we
>will have learned some 'new things' about liquid metal flowing in pipes that
>has never been seen before.  Oops, can't access it so we can't fix the
>problem though.  Even 40 years *after* the first LWR's, we're still learning
>new things about water in pipes and problems in prolonging pipe life
>(crevice corrosion, flow-accelerated corrosion are a couple).  But you think
>liquid metal pipes/pumps is more mature technology than water pipes??  Dream
>on...  Even if you design based on the best predictions of today, investors
>and regulators are going to want to *know* how performance matches
>prediction.  That's how we learn and refine future predictions.  You got a
>number of ultrasonic instruments that can calibrate themselves for 40 years
>stuck all over the piping systems?  Drives cost up.

Why do you remain stuck in LWR-think.  OK, I understand.  That's all you've been
exposed to and that's all you're comfortable with.

Might I suggest that you take a look at designs for intrinsically safe reactors
sometime?  You might discover that these designs avoid the problems of the past by
avoiding high velocity fluids.  And avoiding water, one of the more corrosive
substances used in industry.

Liquid metals have been very well characterized, ranging from the research labs to
full scale production such as at SuperPhoenix.

Do you have any idea how long liquid lead has been pumped around in non-nuclear
applications?  It IS pretty well characterized.

Back to LWR for a moment, you DO realize, don't you that all those corrosion problems
you're getting so lathered up about were the result of the ill-conceived push for
excessively pure water that originated in the late 80s.  The goal, to reduce
activation product concentration in the primary water, was questionable in itself.
Had the plant specs been left as they were originally designed, water purity the same
as conventional steam plants, then this would not have been a problem.  This is what
happens when too many unqualified people get to tamper with things.

The corrosion wasn't really much of a surprise to many folks.  The literature
predicted such problems when the push for ultrapure water began.  They were ignored,
of course.

I'm not sure why you keep suggesting that micronukes will operate at the same
intensity level and have all the same problems associated with LWRs.  A micronuke of
less than 1MWt output may have a core a quarter the size and a fraction of the volume
of an LWR core, yet the power output will be less than 1/1000 that of the LWR. Energy
density, fluid velocity, fission product concentration - all important parameters
will be lower.  The design will be optimized for reliability and longevity rather
than high performance.

I'm being serious now, you really ought to try to think outside the box just a
little, the way us engineers and scientists do.  It really isn't that difficult.

>I'm not so much 'stuck in the past' as being more realistic.  You're like a
>lot of 'arm-chair engineers'.  They take a hodge-podge of ideas and string
>them together and say, "Gee, I'm so smart I ought to patent this."  Never
>mind that many of the ideas are mutually exclusive, or that there are some
>serious flaws in them (like the cost of xx number of redundancies).  Some
>things like mechanical failures and material science, you just gloss over
>because you don't understand the issues involved.

Sounds to me like engineer penis envy.  There IS a remedy for that.

So what is your association with nuclear power?  You sound like an ARO or instrument
or chemlab tech to me.  You know, the kind that sits around in the shop or lab making
fun of "those ignorant engineers", thereby personifying that old saying about not
knowing enough to know what you don't know.

Your behavior in this thread is like someone popping into a discussion about advanced
multi-processor computers to protest because no one has mentioned how to manage chad
buildup in the paper tape punch.  You shouldn't be surprised at the looks and the
rolled eyes you're getting.

John


From: John De Armond
Newsgroups: alt.energy.homepower
Subject: Re: Micro Nukes - a prediction comes true
Date: Sun, 23 Dec 2007 19:50:00 -0500
Message-ID: <va0um3947u28itb3jrhf87a7cmph6n8vsl@4ax.com>

On 23 Dec 2007 16:29:18 -0500, nicksanspam@ece.villanova.edu wrote:

>Neon John  <no@never.com> wrote:
>
>>You know, I bet that if the government got out of the way, there'd be
>>a market for HLW.  There are surely enough of us sufficiently educated
>>types out there that the demand would outstrip the supply.  There's
>>the solution to the "nuclear waste" problem.
>
>It might end up in inexpensive Chinese handwarmers for outdoor workers :-)

I want one!  Two, actually.  I was just thinking about that after I posted.  A few
kilocuries of Sr90 would make an excellent handwarmer and with no radiation emission.

When I was out there in the 80s, there was a huge pool at Hanford, larger than an
olympic swimming pool, where canisters of Sr90 were merrily boiling away.  It was
separated out from the Pu production waste stream for some project that got
cancelled.  I begged'n'pleaded for a canister, alas, to no avail :-)

Maybe someday.

John


From: John De Armond
Newsgroups: alt.energy.homepower
Subject: Re: Micro Nukes - a prediction comes true
Date: Mon, 24 Dec 2007 14:55:14 -0500
Message-ID: <fv20n31ua1rrt3qc8iqn3raffda3kt1gd3@4ax.com>

On Mon, 24 Dec 2007 12:48:04 -0500, "daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com>
wrote:


>You want to keep all the water out, that means active pumps.  Either inside
>to control in-leakage, or outside to maintain the local water table outside
>the structure below a critical level.  Do you really think you can just dig
>a forty or fifty foot hole, line it with concrete and leave it?  Talk to a
>civil engineer for a few minutes.  Do you have any idea what happens when
>you even do something little like empty an in-ground pool in many parts of
>the country?

You do know that nuclear plant concrete structures are a bit more substantial than a
couple of inches of Gunnite, don't you?

So that's your theory, eh?  One counter example negates a theory.  Let's see.
Consider my first nuclear plant, Sequoyah in Chattanooga.  Ground elevation is 706
ft.  The sub-basement is 662 (we use elevation instead of floor numbers in nuke
plants).  That's (mumble mumble) 44 ft below ground level.  The river is elevation
685 at that point (can you believe I remember these numbers from when I worked there
in the 70s?) which pretty much defines the water table close to the river.  The
basement is 23 ft below the water table.

Yet somehow, contrary to your theory, there is no inleakage and no routinely operated
sump pumps.  (There are pumps but they're there to catch accidental leakage from the
equipment.)  How the heck did they do that?  Clue: knowing what they were doing.

Another counter-example.  The reactor sump at Sequoyah is about 200 feet below
ground.  Yet not a drop leaks in.  In fact, the containment is periodically tested
for hermeticity.  Ya know how they did that?  Why they poured a 35 ft thick
foundation, poured the walls and then lined the concrete with steel plate.  IOW, they
built a tank inside the concrete.  Very sophisticated technology, circa probably
1930s or whenever they started welding pressure vessels.

Seriously now, why are you making such crazy assertions?  Certainly you know better.

John


From: John De Armond
Newsgroups: alt.energy.homepower
Subject: Re: Micro Nukes - a prediction comes true
Date: Mon, 24 Dec 2007 18:32:14 -0500
Message-ID: <6m30n3h5tnmd2f5io417vbiqhvbcloqdc4@4ax.com>

[Hang in there guys, this is a long 'un.  But like they say, it takes 100 hours of
truth to counter 1 hour of BS.]

On Mon, 24 Dec 2007 12:48:04 -0500, "daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com>
wrote:

>> Ya mean like Viking?  Any idea what kind of radiation field exists in
>> synchronous
>> orbit?
>
>Much less than inside the containment of a reactor at power.

Wrong.  I've never seen a refueling deck area radiation monitor go over 10mR/hr
during normal operations.  IOW, barely a radiologically controlled area.

If you want to assert anything higher then I must insist that you produce your
plant's biological shield survey map (if you even work at a plant).  That survey is
conducted for every plant during startup and is usually found in the FSAR as amended.

Here's a paper discussing geosynchronous orbit radiation levels

http://www.aero.org/publications/crosslink/summer2003/07.html

The subject is complex because of the broad spectrum of particles involved and their
energies, and what the sun is doing at the moment but to toss out a number picked
from one of the graphs, the surface dose from energetic electrons ranges an order of
magnitude either side of 10,000 rad/hr.  The internal bremsstrahlung x-radiation
generated from stopping these energetic particles is probably a couple orders of
magnitude less.  Still, 10 to 100 R/hour ain't "much less than inside the containment
of a reactor."

Let's see if you'll admit your error.

>
>>
><snip>
>>
>> Are you being intentionally dense or are you really that ignorant?
>> What knucklehead would even consider placing the instrumentation in a
>> high radiation field? Do you have any idea how long industrial
>> instrumentation actually lasts?  "life of the plant" isn't unusual.  Do
>> you have any idea how long ordinary industrial instrumentation in the
>> containment of TMI-2 lasted, even when immersed in fuel-laden water?
>> The field around these instruments was STILL several hundred thousand
>> R/hr when we (I say "we" cuz I was there) entered the containment a
>> couple of years later.
>>
>
>Maybe you're talking about something really simple like an RTD.  A chunk of
>wire.  How about a more complex instrument like a differential pressure cell
>or capacitance probe for level detection?

Actually I was referring specifically to the pressurizer level transmitter, a
conventional differential pressure transmitter.  Bailey brand if memory serves.

>A lot of  compounds have a pretty
>low tolerance for rad exposure, a few tens of thousand rads cumulative and
>they crumble and lose their elasticity.  If you really were at TMI, you
>might have noticed some things didn't stand up to the dose levels.  Why do
>you think a lot of instruments are located outside of LWR containments and a
>lot of instruments inside LWR containments are routinely replaced?

"If you really were at TMI"?  *chuckle*. My name is in the public record as the
responsible engineer for several systems, including the RegGuide 1.97 post accident
radiation monitoring system for Unit 1.  Is that the only kind of crap you can come
up with to argue about?  Perhaps you'd enjoy some photos:

http://www.neon-john.com/Nuke/TMI/TMI_Index.htm

Re: your allegation that total integrated dose is responsible for instrument failure,
do you have any credible evidence to back up that claim?  It's certainly something
that I've never seen asserted and nuclear I&C is my specialty.  The only instruments
that I've heard of failing due to radiation were those immersed in sump water at
TMI2.  The instruments hadn't been recovered when my involvement ended and AFIK they
were never recovered so the failure mode is open to conjecture.  It could just as
well been moisture infiltration.

I have a copy of every TDR (technical data report - engineering reports for internal
consumption) that GPU issued - several filing cabinets full - through the end of my
stay and the only thing I ever saw was some speculation about failure mode and
theoretical calculations regarding same.

Radiation dose isn't an issue with in-containment instruments simply because they're
located behind the biological shield.  You'd know that if you'd ever actually been in
a containment.  I can probably dig up some photos if you'd like to learn something of
what you're talking about.

This is again old-PWR-speak and has nothing to do with a micro-nuke.

>
>Would I 'really put it in a high radiation field'?  What sort of knucklehead
>are you to think you can instrument all around a reactor and *not* be in a
>high radiation area?

Must be a lot of knuckleheads out there since every single power reactor design
places the instrumentation (in-core and ex-core instrumentation excepted for obvious
reasons) behind the biological shield.  But we're not interested in LWR technology in
this thread.  Let's think a bit about how we'd do a 0.5MWt micro-nuke.

First let's set a size scale.  A low enriched core would easily fit inside a 55
gallon drum.  Let's double that and make it a 100 gallon drum.  A hermetically sealed
drum.  The reactor operates on natural circulation of the liquid metal (my choice is
still lead) so no pumps are necessary. (Natural circ means that normal convection
currents in a heated liquid cause enough flow to transport the heat.)  No in-core
instruments are needed for obvious reason so the only thing in the pot is the core
and the heat exchanger that conducts the heat out of the pot.  I'm going to design
the core to be self regulating so the only control rods necessary are shutdown rods.
Or maybe rod.  Or maybe no rods if I choose to go with external moderators and/or
poisons.  This is all old-tech.

The pot operates at atmospheric pressure so it doesn't need to be a pressure vessel.
I'm going to set this pot inside a tightly conforming secondary containment.  Then
I'm going to set that tank inside a tertiary containment just for good measure. These
tanks are hermetically sealed but of course they contain bolted or welded manways for
access.

I'm going to set this assembly inside one compartment of a two compartment steel
lined concrete box that serves as the 4th containment and the biological shield.  The
divider wall in the box will be heavy concrete* designed for radiation shielding. The
other side is the instrumentation vault.

* "heavy concrete" is a special high density concrete designed for radiation
shielding.  It is loaded with very dense aggregate and/or lead to increase its
density over conventional concrete.

So what instruments will we need?  We'll need an ex-core neutron monitor to determine
reactor power. One would do but since we want to seal this thing up for life, let's
include a dozen.  Fiber-optic coupled neutron scintillator glass will work fine.
Fiber-optics using the proper glass are practically radiation proof.

We won't need level indication during normal operation but let's include some
indications to detect potential leaks.  Fiber-optic laser range finders get the job
done.  Off the shelf instruments that cost in the $200-1000 range.

We'll want pressure indication so I'm going to include a pressure diaphragm at the
top of the reactor pot and measure its deflection with another fiber-optic laser
range finder.  Or an alternative design that isn't quite off the shelf involves
wrapping the pot with numerous turns of optical fiber and measuring the
temperature-compensated elongation as the pot expands under pressure.

We'll want core inlet and outlet temperature indication, of course.  Platinum RTDs
are proven technology for high radiation fields.  The only problem is that electrical
signals must be brought through the shield wall.  Fiber optic thermal detectors,
though not as old as RTDs are as reliable. (These use the changing refractive index
vs temperature of special glasses.)  I'll also include a fiber optic infrared
pyrometer that looks at the inner pot's surface.

I'll include gas sampling plumbing to sample the gas between each sets of
containments to detect developing leaks.

I'll feed all this instrumentation into a multiply redundant integrated reactor
management system that runs on multiple, redundant processors and executes software
written using provably correct methods.  This is a description of the large reactor
control systems that outfits like GE and Westinghouse/Toshiba currently offer for
backfitting LWRs.  It is simply scaled down for this application.

Other than the heat exchanger inlet and outlet and the control rod drive if used,
this design has no penetrations capable of conducting fluid connecting to the primary
containment/reactor pot.  And with the possible exception of the RTDs if used, there
are no electrical connections going into the reactor compartment.  This is to
preclude the ignition of any improbable hydrogen buildup.  There are no polymers or
other radiation-affected materials in the high radiation area.  Only metal, ceramic
and glass.  The instrumentation is located in the shielded instrument vault that may
be entered if necessary.

This whole affair may consume no more than 1500 sq ft of floor space which will be
the inside dimension of the concrete cube.  I'm going to bury this cube at sufficient
depth to shield it from missile or other impact damage and reduce the surface
radiation exposure to ambient.  I'm going to provide access via redundant water-tight
hatches - standard submarine fare.  I'm going to inert the whole affair with helium
and then pull a shallow vacuum on the cube and the space between the doors.  My
instrumentation is going to monitor the absolute pressure in both spaces to detect
any inleakage, indicative of a fault in the hermetic seal.

I'm going to cover the whole affair with a concrete weight/shield of about 100 ton
mass.  This precludes access to the reactor by "terrorists" or whatever the bogeyman
of the moment is, or anyone else without access to heavy cranes. The weight also
provides impervious missile shielding.  Again, old-tech, what was used to shield
underground missile silos and yet provide ready access.

This is a simple design that is the result of oh, a whole hour of thought.  Turn 'em
loose and I'll just bet that engineers who do this for a living will package the
thing in something that'll fit inside a dump truck.

>Certainly any LWR operator knows about N-16.

Yep.  Remind me again of what that has to do with a micro-nuke.  Or of conventional
power reactor instrumentation for that matter.

>Of
>course you want a liquid metal, but do you know what happens to prolonged
>operation with liquid sodium, say 40 years?  I doubt it since nobodies done
>it.  Of course you can keep dreaming about liquid lead I suppose...

Really?  I'm looking now at a book titled "The Nuclear Age".  A very nice large
format book with gorgeous photography, it was published by the French "Electricite'
de France".  It was presented to me by a French colleague of that agency when he
visited the US for a conference in the 90s.

Anyway, there's a nice timeline in there for French work with sodium cooled reactors.
They ARE the world leaders in that area.

1957-1983, 26 years - Rhaposidie - the first sodium cooled power reactor, 40MWe
1965-1980, 15 years - Phenix - sodium pool reactor*, 250MWe
1971-???, still operating as of the book's publishing - SuperPhenix - sodium pool
reactor, 1200MWe

* "pool reactor" means that all the primary system components - reactor, coolant
pumps and primary heat exchange are contained in a large pool of liquid sodium. Quite
similar to the more popular intrinsically safe designs.

>You brought up the whole idea of a 'sealed reactor containment' as a way to
>avoid needing some of the safeguards and maintenance controls I mentioned
>before.  If technicians are allowed near the reactor to perform maintenance
>during outages, then you need all that security and QA that you previously
>tried to avoid by saying there wouldn't be any access to the reactor.  Can't
>have it both ways.

Really?  Can you point out to me in that simplistic and unrefined design that I just
outlined exactly when and where access to the hot side will be needed?  There is no
actively powered equipment in the hot side.  Nor are there any moving parts other
than the control rod drive.  With some clever engineering I could probably eliminate
that.

I should remind you that all micro-nuke designs including mine are fueled for the
life of the plant.  No "refueling outages" will occur.  That's LWR-think again.

>Better go brush up on your activation products.  N12 has an 11 millisecond
>half-life.  N-16 is about 7 seconds, maybe that's what you're thinking of,
>but that comes from a chain of events involving O.  How would a neutron flux
>produce N-12?

My most humblest apology for that typo.  Satisfied?

>
>BTW, if you want the coolant to be about 350 degF, the centerline
>temperature of the fuel will obviously be higher than that.  Ceramic fuels
>would have a centerline that is at least a few hundred degrees higher than
>clad surface (assuming a really low power density).  If you check your
>nuclide chart, you'll find there are several more fission products that are
>volital enough to come off the fuel at those temperatures.  Xe and Kr come
>off when cold, but you'll be getting quite a few more from 'hot' fuel.

You just can't get your head out of LWR-think, can you?  Why would I ever even dream
of using solid ceramic fuel?  Totally inappropriate for a reactor of this size and
power level.  I have neither the temperature, the pressure, the flow velocity nor the
power density of a PWR.  In fact, all are orders of magnitude less.

After suitable materials R&D of course, I may choose a thin wall ceramic or metal
matrix.  Or I may use a large particle sintered mass with pore size large enough to
allow free coolant flow and the escape of fission gases.  Sintered porous fuel is
old-tech, as you'd see if you read some of those LASL papers I referenced earlier. IN
any event, I'm certainly not going to allow a "few hundred degree rise" in fuel
temperature.

See, in engineering we formulate an engineering goal and then do the work necessary
to achieve that goal.  My first-cut goal would be a temperature rise of no more than
100 deg.

Let's call it 500 deg just to make a good round number.  Now I want YOU to consult
YOUR nuclide chart and tell me what isotopes are volatile at that temperature.  If
you figure out any, now tell me how many are volatile enough not to condense out on
the cooler metal surrounding the core and on the gas containment structures.

Take your time, I'll wait.  I can't come up with any despite this being part of my
specialty but hey, maybe you're smarter than I am.

>
>You mean like APW1000, EBWR, or ESBWR??  Hint, the 'W' in each of those
>stands for water.  MPBR are nice and have some real nice features, just have
>to make sure the fuel-handling equipment works better than Germany's.
>Molten salts have some interesting features (high actinide burnup), but are
>far less mature.

*sigh*. What can I say?  Can you REALLY not think outside the large scale LWR box?
Those guys are looking at making hundreds to thousands of megawatts.  I'm looking at
a fraction of one.

This does raise an obvious question.  Have you ever seen or even read about any type
of reactor other than the LWR varieties?


>> Back to LWR for a moment, you DO realize, don't you that all those
>> corrosion problems you're getting so lathered up about were the result
>> of the ill-conceived push for excessively pure water that originated in
>> the late 80s.  The goal, to reduce activation product concentration in
>> the primary water, was questionable in itself. Had the plant specs been
>> left as they were originally designed, water purity the same as
>> conventional steam plants, then this would not have been a problem.
>> This is what happens when too many unqualified people get to tamper
>> with things.
>
>LOL, now you really have gone round the deep end.  Listen to yourself, "It's
>those unqualified engineers and chemists that wanted to lower dose levels
>that messed up all the water quality.  If it hadn't been for them, corrosion
>would be about the same as conventional steam plants."

Actually it was the unqualified regulators and the ALARA-at-any-cost crowd.

>Sure, you *could* design a reactor core that operates with the parameters
>you suggest.  Do you think it will produce at 5 cents / kWhr?  I don't.  You
>take an open-ended budget, some very major over-designing and you could
>build a nice little nuk.  But it would cost you more like $1 / kWhr.
>
>Ever stop to think why the fluid velocities in heat exchangers and piping
>are what they currently are?  It's not because some engineer wanted to waste
>a lot of pumping power for no reason.  Seriously, before you try to go
>'outside the box', you ought to consider why the 'box' is there at all in
>the first place.  Maybe you'd realize that there are some pretty good
>reasons for the way mechanical engineers do the things they currently do.
>Cut the velocity way down and the temperature rise going through the reactor
>goes up.  Now you got large differential temperature effects along the fuel
>assembly to deal with.  And what will that do for your fission product
>migration within the fuel pin?  Now you have to figure out how your ex-core
>instruments are going to be affected as well.  Just a couple of 'off the
>cuff' issues that would have to be addressed.  Gonna drop velocities down to
>laminar flow conditions?  What would that do to the temperature profile
>across the coolant channel?  Dumb, dumb, dumb...

What a silly argument.  You do realize, don't you, that the latest navy sub reactors
can make almost full power using natural circulation only?  That's "well over 50MWt"
(the actual classified value is significantly larger than that) - 100X what I predict
- from a pot not much larger than a 55 gallon drum.  Natural circ means no pumps and
no flow aids, just the convection currents generated by the temperature differential
across the reactor and steam generator.

This much information is available in the open literature and is the kind of common
knowledge you should possess if you have any interest in nuclear power outside the
narrow confines of you day job.

Are you also aware that post-TMI, every PWR in the nation had to qualify its primary
system for natural circulation cooling?  That is, the system has to dispose of decay
heat in the face of total reactor coolant pump failure.  Considering that the decay
heat in a moderately burned up core is >10% of full power for the first few minutes
after shutdown, this is a significant amount of energy, many times more than my
micro-nuke will produce.

I don't know a lot about the natural circ qualification testing because that's not my
specialty but my office-mate at TMI was the principle engineer in charge of TMI-1's
natural circ testing so a little information rubbed off.

>Trouble with some wanna-be's is they are so detached from reality they don't
>think about what is practical.  Just like your 'micronuke'.  It will never
>be practical to build such a small scale system until all other forms of
>energy are gone.

So are you going to be the one to accept my longbet.com prediction.  I'll only cost
you $200.  Given your confidence level, it should be a no-brainer for you.  I'm not
holding my breath, of course.  I'd love to bet on "until all other forms of energy
are gone" but I restrain myself to 20 years.

OK, we have several open issues that must be resolved.

First, your job, if any, in the nuclear industry.  You questioned my participation so
reciprocity is only fair.  I'm not convinced that you have any occupational role in
the industry but just in case you do, please describe it.  I don't care WHERE you
work - I can understand your not wanting your bosses to see your behavior here - but
do tell me what you do.  I have you pegged as an auxiliary operator, a "valve
buster", or maybe an instrument tech.

Next item, your claim of there being fission products that are volatile at the
proposed operating temperature of a micro-nuke.  I'd like to see your list.  When
compiling that list, please do take into consideration the chemical reactions that
mitigate release.  For instance, cesium and iodine are both fairly volatile elements
but they don't come out of the core even at high temperatures because they chemically
combine to form cesium iodide, a non-volatile compound.

If I might suggest some reading material, go to that LASL report archive that I
posted the URL to and look at the following reports:

LA-3325-MS 	Kiwi transient nuclear test
LA-3445-MS 	Fuel element and support element fragment study - Kiwi transient
nuclear test
LA-3446 	Gamma dose rate measurements : Kiwi transient nuclear test
LA-3519-MS 	Kiwi transient nuclear test dose rate survey
LAMS-2726 	Examination of gross particles from Kiwi-A3 nuclear rocket propulsion
reactor at Nevada test site
LA-3350-MS 	Description of the Kiwi-TNT Excursion and Related Experiments
LA-3351 	Kiwi-TNT "explosion"
LA-3395-MS 	Radiation Measurements of the Effluent from the Kiwi TNT Experiment

These reports all concern the final Kiwi nuclear rocket motor test that involved
rapid disassembly (OK, they caused the thing to blow up) caused by an intentional
super-critical transient.  They report on the fission product release detected both
in the close vicinity of the reactor and downwind.  Since the reactor normally
operated at about 2700 deg K (white hot), any volatile fission products would
certainly have presented themselves.

Finally, if you continue to drag LWR stuff into this discussion about micro-nukes,
then I must bow out.  It's nonsensical and I don't have the time nor the interest to
refute every wild tangent you sling into the mix.

Before we discuss anything else, however, I must insist that you address those two
specifics that you raised.  That is, your position in the industry and the volatile
isotope strawman.

John


From: John De Armond
Newsgroups: alt.energy.homepower
Subject: Re: Micro Nukes - a prediction comes true
Date: Sat, 29 Dec 2007 10:56:34 -0500
Message-ID: <6tgcn3p844vlseaua8ai19vgehqafgamg6@4ax.com>

On Fri, 28 Dec 2007 23:37:09 -0500, "daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com>
wrote:

>Since BWR containment is closed and sealed off from personnel access during
>power operation, there is no rad survey performed while at power at my
>plant.  There are a few times when at low power that access may be granted
>for emergent repairs in a BWR, but the 'survey' is done by the RP tech that
>is required to accompany the workers and its a hi-rad area.
>

The biological shield survey is done ONCE, during Startup & Test.

>Main steam tunnel radiation monitors (remember, BWR steam is radioactive)
>typically read 1000 to 1500 mR/hr.  And that's *outside* containment.

Pick a number, any number.  Let's make it 15,000 mR/hr.  That's still several orders
of magnitude below the radiation intensity that space-borne electronics withstand.
Remember this l'il ole link?


http://www.aero.org/publications/crosslink/summer2003/07.html


>> Ya mean like Viking?  Any idea what kind of radiation field exists in
>> synchronous
>> orbit?
>
>Much less than inside the containment of a reactor at power.

So, still waiting on you to acknowledge your little mistake here.

>
>Did you know that 'containment radiation monitors' are often behind several
>inches of lead?

Really?  Other than the containment dome monitor and the RegGuide 1.97 high range
containment monitors (two units out of several dozen area radiation monitors in a
typical plant), what constitutes "often"?


>> Let's see if you'll admit your error.
>
>You think that your refueling floor radiation level is the entire
>containment??  What's the radiation level down by the reactor coolant pumps
>in a PWR??  Just a *tad* higher than your 10 mR/hr.

But we put neither radiation monitors nor instrumentation in those parts.

Still waiting on that admission of error.

>Below, in your 'arm-chair rambings' you mention using a porous fuel at one
>point.  So fission products just might make their way into the coolant?
>Things like the halogens that will be carried along in your lead coolant
>then and make for a significant radiation field don't you think?

Which "halogens" are you referring to other than iodine? (answer: none.  Just more,
as you call it, "arm-chair BS".  Very little iodine comes out because it combines
with cesium to form cesium iodide.

Even if it does come out, it is immaterial.  The entire fission product inventory,
what doesn't decay off, remains inside the sealed reactor can for the life of the
plant.

If you're trying to link this back to some alleged radiation damage to
instrumentation (Your thought processes are so splattered that I can't tell WHERE
you're trying to go with this) then since all instrumentation is located out of the
reactor room and behind shielding, your linkage failed.

What is your point?  Show me your point, any point, as relates to a micro-nuke.

>
>Funny, EQ for equipment in the containment always includes maximum dose
>rates.  Many safety-related instruments in the drywell of BWR's have to
>withstand dose rates in excess of 20,000 Rads and still perform their
>function during an accident.

There you go impersonating a nuke again.  If you're going to try impersonation, at
least study up on the terms.  Hint:  Dose is RADs.  Dose RATE is RADS/hr.  See that
reciprocal time factor in there?

Now to your 20,000 RAD number.  My BS detector went off but rather than trust my
memory, I looked it up.  Here's some NRC correspondence regarding Rosemont's pressure
transmitter:

http://www.nrc.gov/reading-rm/doc-collections/event-status/part21/1998/1998671.htm

I call your attention to paragraph 7.1 where the NRC requirement for dose is
mentioned.  Specifically, the transmitter must withstand a 55.5 megaRAD TID and not
just survive but OPERATE WITHIN SPEC.  It did so with flying colors.  Again, you
missed it by several orders of magnitude.

Third point, perhaps you could refresh my memory.  I don't recall much of anything in
the drywell other than the control rod drives, the In-Core Instrumentation (ICI) and
the Traveling In-Core Probe (TIP) system.  I admit that is has been awhile since I
supervised the ICI upgrade at BFNP-1 (and most of BFNP-2 before I got redeployed on
other projects) after the fire in '75.  This was where we removed ALL the neutron
detectors and replaced them with upgraded versions.  I spent several weeks in the
drywell on that project.  I suppose it's possible that I simply missed this array of
rad-hardened instrumentation you claim is in there.  Like I say, refresh my memory.

>This limits the materials that can be used in
>the instrument, it's seals, and the type of electrical insulation.  But hey,
>if *you* say the dose is only 10 mR/hr, then I guess all us engineers that
>have gone through the dose rate calcs have just been wasting our time.

"us engineers"? *chuckle*


>You haven't discussed moderator much.

That's because I described concepts and not design specifications.

>All the stuff I've seen on neutron scintillator's use Li to detect neutrons
>and have a lifetime much shorter than your forty year plan.

That's because you simply haven't seen much.  Even the poseur should know that Google
is your friend.


>I'm sure it's full of pretty pictures.  Now, I'd refer you to a few texts on
>reactor design, like Glasstone.

You know about Glasstone?  I didn't realize he'd published the coloring book version.

>Superphoenix started operation in '85 (construction started in 71).
>Shutdown in '96 for a grand total of 11 years of production.

Do ya suppose they had some considerable body of experience with liquid metals when
they designed the thing prior to '71?

>And none of
>those used lead (maybe those engineers know more about reactor design than
>you???)

Oh, I'm sure that they knew a LOT more about large metal cooled reactor design than I
do.  But we're not talking about large reactors, remember?  Man, you have a short
attention span.  Repeat after me.  "Micro-Nukes.  Micro-Nukes.  Micro-Nukes."  Now
can you remember what we're talking about?

>> Really?  Can you point out to me in that simplistic and unrefined
>> design that I just outlined exactly when and where access to the hot
>> side will be needed? There is no actively powered equipment in the hot
>> side.
>
>Okay, so here's a thought, how do you melt the lead prior to reactor
>startup?

Well, there are several methods that spring to mind.  Probably the simplest is to let
the reactor provide the heat.  Since we don't have any lead-filled piping and only
have a simple pool of metal to deal with, we can simply run the reactor at a suitably
low power until the lead is melted.  Simple, no?

>Liquid sodium plants use electric heaters on piping and components
>to melt/keep the sodium liquified (melts at 208 F).  You found a way to heat
>all the primary up to the melting point of lead (620F) without 'actively
>powered equipment'?

Of course.  See above.  I could, of course, include an electric heater.  It would be
turned off during operation so there would still be no actively powered equipment.

>
>Since you don't want to generate any high-pressure steam, how you going to
>drop the temperature between your liquid lead coolant and the low pressure
>steam generator?  Maybe add another tertiary loop with some other fluid
>circulating between the +620 primary and the much lower temperature steam
>generator?  Details, details...

I have no idea what you're talking about (and neither do you.)  There is NO "primary
loop" in a pot (or "pool" if you prefer) type design.  The primary coolant never
leaves the pot.

The heat is transported out by an intermediate loop containing the material of your
choice.  The intermediate loop hx is shielded by the lead coolant from the core's
most intense radiation, therefore the fluid choices are multiple.  It could be water
at moderate pressure.  It could be silicone or some other oil.  It might be something
like Fluorinert - no idea if it is radiation-resistant enough or not - something for
the material scientists to work out.  Regardless of the fluid, large delta-Ts aren't
necessary - kinda obvious, wouldn't you say?

><snip>
>>
>> See, in engineering we formulate an engineering goal and then do the
>> work necessary to achieve that goal.  My first-cut goal would be a
>> temperature rise of no more than 100 deg.
>>
>> Let's call it 500 deg just to make a good round number.
>
>Funny, lead doesn't even melt until 620 deg F.  You sure you've given this
>any real thought, 'engineer'?

I was thinking about a low melting point alloy for the temperature range of interest
but what the heck?  Use 620 degrees.  Now answer the question.

>
>> Now I want YOU to consult YOUR nuclide chart and tell me what isotopes
>> are volatile at that temperature.  If you figure out any, now tell me
>> how many are volatile enough not to condense out on the cooler metal
>> surrounding the core and on the gas containment structures.
>
>Let's see, I ask you a question, and you simply turn around and ask me to
>answer it?  Nice tactic.

Well, let's see.  Here's your statement that I was responding to:

>
>BTW, if you want the coolant to be about 350 degF, the centerline
>temperature of the fuel will obviously be higher than that.  Ceramic fuels
>would have a centerline that is at least a few hundred degrees higher than
>clad surface (assuming a really low power density).  If you check your
>nuclide chart, you'll find there are several more fission products that are
>volital enough to come off the fuel at those temperatures.  Xe and Kr come
>off when cold, but you'll be getting quite a few more from 'hot' fuel.

I don't see a question.  Just an empty assertion.  I'd like to see your evidence to
back that assertion. So I repeat, consult your nuclide table and show me the list of
nuclides that are volatile at 620 degrees F.  Stay focused now.  I know it's hard
when you're playing with your Glasstone coloring book but make an attempt.  That list
of nuclides, remember?

>I see how you've snipped my point that conventional steam plants re-tube and
>re-work their boilers much more often than LWR nucs do.

I snipped because a) it is irrelevant to this discussion and b) boiler tubes
generally fail from OUTSIDE corrosion.  You know, where the flue gases contact the
metal.

> Must be you can't
>bring yourself to admit that water chemistry in LWR has *improved* component
>life, dispite your assertion that it's caused corrosion problems that
>wouldn't be there if they had stuck to 'conventional steam plant chemistry'.

I hear you talk but I don't see any evidence.  This is the Internet.  Google is your
friend.  Show us da evidence.

>
><snip>
>>
>> What a silly argument.  You do realize, don't you, that the latest navy
>> sub reactors can make almost full power using natural circulation only?
>> That's "well over 50MWt" (the actual classified value is significantly
>> larger than that) - 100X what I predict - from a pot not much larger
>> than a 55 gallon drum.  Natural circ means no pumps and no flow aids,
>> just the convection currents generated by the temperature differential
>> across the reactor and steam generator.
>
>Considering I was on the team that brought Trident class submarines (S8G) to
>production

Yeoman swabbing the bilge, no doubt.

>(not the first Naval plant to use natural circ either BTW, look
>at S5G), I think I know a bit more about 'natural nucs' than you.  Tell me,
>have you considered what the difference in thermal expansion coefficient
>between water and lead will do to your circulation?  It doesn't look like
>it, or maybe you don't understand that coolant parameter's impact on natural
>circulation calculations?  Water's coefficient of expansion is quite a bit
>higher than lead.  That means you get a lot more driving head for a given
>temperature difference and height.  And by the way, lead is more viscous
>than hot water, another ding against natural convection.

Hmm, the literature seems to disagree with you.  Suggest you gain access to
"Thermophysical properties of lead and lead)bismuth eutectic", V. Sobolev, SCK┬ĚCEN,
Belgian Nuclear Research Centre, Boeretang 200, B-2400, Mol, Belgium, "Journal of
Nuclear Materials", Volume 362, Issues 2-3, 31 May 2007, Pages 235-247.

Abstract:

"Among different heavy liquid metals, lead (Pb) and lead)bismuth eutectic (Pb)Bi) are
considered at present as the potential candidates for the liquid spallation targets
of neutron sources and accelerated driven systems and for the coolant of new
generation fast reactors due to their very good neutron and thermal features.

Up to now, the published data on the properties of the lead alloys of interest are
still limited and significant discrepancies exist between the values given by
different sources. This work is a critical review of old and new data reported in the
open literature on the main thermo-physical properties of the molten Pb and Pb)Bi:
characteristic temperatures, latent heats of melting and evaporation, surface
tension, density, heat capacity, viscosity, electric and thermal conductivity.

In general, the reliability of data is satisfactory, however, a large uncertainty
still exists in the saturation vapour pressure, sound velocity, heat capacity and
thermal conductivity. The critical parameters of Pb and Pb)Bi are not well defined
yet, and this hinder the development of the equations of state for these coolants.
The correlations developed on the basis of the fundamental physical models and the
`best fit' approach are proposed for engineering estimations and design
calculations."

Hmmm, looks some other folks besides l'il ole' me are thinking about lead and lead
alloys as reactor coolants.  Great minds think alike......

>> So are you going to be the one to accept my longbet.com prediction.
>> I'll only cost you $200.  Given your confidence level, it should be a
>> no-brainer for you. I'm not holding my breath, of course.  I'd love to
>> bet on "until all other forms of energy are gone" but I restrain myself
>> to 20 years.
>
>Hmmm.... 'No brainer'.  Tie up $200 with you for 20 years at 0% interest
>just because your panties are in a wad?  Or not....  decisions, decisions...

Neither of us get the money from longbet.com.  It goes to the charity of the winner's
choice.  Your argument is specious.

Since you're so confident that micro-nukes will never happen, there's really little
decision to be made.  Remove $200 from your United Way contribution for next year and
put it where your mouth is.  Your charity will still get ultimately get the money and
the transaction is dollar-neutral to you.

So, show me da money or show me your yellow streak.

>
>I gave you some of my work experience in a previous post, don't you read?
>34 years, Naval Reactors, SRO at two different BWR's, engineering department
>including EQ quals (also done several integrated leak-rates on PWR and BWR
>containments), ops-training instructor, and safety-related SQA to name a
>few.

Hmmm, let's do some math.  You're not going into Naval Reactors until you have at
least a BS so let's say you started at age 22.  Add 34 years to that and we have 56.
Four years to do the RO training is 60.  Two more years for SRO, 62.  Requal again
for that second BWR SRO, two more years.  64.  After you get that second SRO license,
the utility's probably not going to let you waste that investment without your
"turnin' the knobs'n' pullin' the rods" for a couple of years.  That'd make you 66.
Let's allow two years each for bouncing around between jobs in "engineering, operator
training and SQA"  That'd make you what?  72 years old?  Really?

Hmm, is that the stench of prevarication I smell?

But hey, stranger things have happened.  After all, I did have the unfortunate
experience of sharing an office with Rickhover at TMI when he was older than that.
Maybe you are still working in your dotage.  But humor me, how 'bout some specifics?
Starting with your real name and the names of some actual facilities.

>
>>
>> Next item, your claim of there being fission products that are volatile
>> at the proposed operating temperature of a micro-nuke.  I'd like to see
>> your list.
>
>Well, you can't seem to decide what temperature you're going to operate at,
>and I asked you first and you just turned around and asked me to do your
>work for you.  So, are you going to operate at just a couple hundred degrees
>(say, 350F to get your 100 psi process steam production?), or round it up to
>500 degrees F for 'a nice round number'?  Or are you going to operate above
>the melting point of lead so your coolant won't be solidified (621 F) plus
>maybe a fifty degree margin and 100 degree temperature rise for 770 F?
>Funny thing is, 621F is hotter than LWR coolants. (  Good thing you don't
>want the same power density )

So pick a temperature that makes you happy.  We both know your list of volatile
nuclides is going to be empty.

>
>But hey, next time you have a minute, go look at the source term
>calculations for an accident in an LWR (yes, I know you don't want to hear
>about LWR, but the data is available and relevant to any U-235 reactor).
>Notice that dropped fuel during refueling accident has a much different
>'spread' of fission product release than a LOCA? (don't look at the
>magnitude of the release, look at the ratio of halogens, noble gasses,
>etc...)  Ever wonder why that is? (hint, it has a lot to do with the fuel
>temperature during the accident).  Accident source term calcs consider three
>different severity levels, simple fuel failure releasing noble gasses,
>overheated fuel releasing volatile fission products (and yes, they consider
>that many will react with cooler components and containment structure thanks
>to TMI analysis), and finally fuel melt.

You mean that fiction that passes for "maximum credible accident"?  Silly stuff like
"double-ended guillotine breaks" reactor coolant piping?  Stuff that couldn't happen
in a million years.  I thought that we as an industry were past that.  Oh wait, we
are.  It's you that isn't.

I'm not really interested in analysis of fictional scenarios, the kind  that got us
in the mess we had during TMI.  The so-called "worst case scenario" that had 'em
ready to evacuate the whole eastern end of PA for fear of a China Syndrome core melt
while in reality the core was just sitting there fat, dumb and happy, if a bit
crispy.  That kind of institutionalized hyperbole is the major ingredient in what
killed nuclear power for the last 30 years.  Nobody other than some imposter trying
to win an internet argument would sling such excrement these days.

Even if that kind of argument had any relevance to anyone other than the regulators,
it is irrelevant to the discussion of low temperature, low energy density
micro-nukes.  An intrinsically safe micro-nuke can't have a LOCA - by definition. The
fuel isn't going to get hot enough to vaporize any fission products of note and even
if it does, it's of no consequence since the pot is hermetically sealed.

Your prevarication and ducking and weaving and refusal to back specific claims with
evidence of any sort has revealed you for what you are, a mouthy fake.  I've wasted
way too much time on you already.  If someone else wants to discuss micro-nukes them
I'm game but I'm finished playing games with someone who would have to be the oldest
working nuke alive for your claims to be true.

Meanwhile I'm still waiting for someone to call my longbet.  Got a feeling I'll be
waiting awhile.

John


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