From: zcbag@cnfd.pgh.wec.com (B. Alan Guthrie)
Newsgroups: sci.environment
Subject: Re: PBS Frontline, April 22
Date: 18 Apr 1997 20:41:30 GMT

In article <x4h67xmqt74.fsf@steam.stanford.edu>,
John McCarthy  <jmc@steam.stanford.edu> wrote:
>Dennis Nelson <innrcrcl@erols.com> writes:
>
> >
> >
> > Mnestheus wrote:
> > >
> > > Message-ID: <3352A6DA.4913@deltanet.com>
> > >
> > > Somebody wrote:
> > >
> > > >I haven't seen any scientific studies showing radiation to be healthy
> > > Presumably the author of this quotel feel better after his carbon -14 has
> > > decayed away and spared him the ravages of low-level radiation.
> >
> >
> > I don't know how he feels about his C-14 levels but at least burning fossil
> > fuels doesn't contribute any C-14 to the atmosphere we breathe, unlike its
> > often touted compeditor nuclear power which makes C-14 from neutron activation
> > of atmospheric nitrogen.  There were even gas cooled reactors which used N2 as
> > a coolant.  You can imagine how much, 5,000 year half life, C-14 they produced.
>
>Dennis Nelson can imagine, and I can imagine.  Very likely we would
>imagine differently.  How about calculating?  Burning wood does put
>C-14 into the atmosphere unless the wood is very, very old, i.e. many
>C-14 half lives of 5715 years.  Ordinary nuclear power doesn't put
>C-14 into the atmosphere.  I'm dubious about how much C-14 went into
>the atmosphere from the N2 cooled reactors.
>
>The important question is how the amount compared to what is alread
>there.  If it is less than one part in a million, the impact is trivial.


   I guess that I really do need to read Dennis Nelson offerrings a
   little closer.  This gem slipped right by me.

   Let's look at the nuclear physics.  Nitrogen is about 99.64% N-14
   and the remain 0.36% is N-15.  If N-14 absorbs a neutron, it
   becomes N-15 which is stable.  If N-15 absorbs a neutron, it
   becomes N-16, which beta-decays to O-16 with a 7.11 sec
   half-life.  In other words, the neutron irradiation of nitrogen
   in a reactor does not produce C-14.

   There is (n,p) reaction in N-14 which produces C-14.  The minimum
   resonance is 11.30 MeV, which is substantially above the neutron
   energy from fission.



--
B. Alan Guthrie, III            |  When the going gets tough,
                                |  the tough hide under the table.
alan.guthrie@cnfd.pgh.wec.com   |
                                |                    E. Blackadder

From: jgd@rsiatl.UUCP (John G. De Armond)
Newsgroups: sci.energy
Subject: Re: Nuke CO2 Emissions
Keywords: Nuclear CO2 emissions over total fuel cycle
Message-ID: <2003@rsiatl.UUCP>
Date: 27 Apr 90 20:36:33 GMT

art@cs.bu.edu (Al Thompson) writes:

>|>    This report lists CO2 emissions from nuclear reactors as "negligible",
>|>    but added that a typical commercial nuclear plant emits
>|>    "8-9.5 curies of radioactive carbon-14 annually", environmentally
>|>    on par with natural gas fuel although the risks are "dramatically
>|>    different."

Umm. I don't think so.  I've not seen any soot piles forming outside
any plant stacks lately.

>I'm puzzled.  How does the C-14 from a nuclear plant differ from the
>"naturally occurring" C-14 found in fossil fuel?  How are the risks
>"dramatically different"?  Is somebody trying to say they are different?

C-14 is considered in most health-physics circles to be harmless.  The
low energy beta is so weak as to be unable to escape large molecules.
The only practical detection means are pass-through ionization chambers
and light fraction scintillation chambers.  There is a tiny quantity
produced in reactors through the same neutron capture reaction with
nitrogen that forms it in nature.  I've done a moderate biblio. search
of my H-P literature and only found one article and it refered to measurement
techniques.

I suspect from the tone of the original report that the reporter has
confused Sr-90 with C-14.  Sr-90 is a biohazard with a high
concentration factor in the body and is produced in large quantities
as a fission product.  Very little escapes, though a couple of curies
a year would be reasonable.

>Then there is the K-40 emitted from fossil fuels.  It has a very long half
>life.

Yep, We used  to design whole body counters and while working with them,
I made an interesting observation.  I can look at the K-40 concentration
in a person's body and fairly accurately predict lifestyle.  The
highest levels of K-40 generally correlate well to the veggie-type health
nuts.  Us meat'n'potatos eaters generally show the lowest level.  This
is a fact that really confounds the professional worriers :-)

John