FAQ
John McCarthy
Coffman's recent posts and an improved version of mine on why power
reactors aren't bombs.
--
John McCarthy, Computer Science Department, Stanford, CA 94305
*
He who refuses to do arithmetic is doomed to talk nonsense.
victor yodaiken
>These groups need an FAQ on nuclear energy. It could start from Gary
>Coffman's recent posts and an improved version of mine on why power
>reactors aren't bombs.
Except that yours begins with a fallacy ( I haven't read further, so I
won't comment on how many other fallacies it contains).
--
Michael Moroney
I thought it was a good description. What's the "fallacy"?
-Mike
victor yodaiken
That no current or contemplated design for a reactor could "go off
like a bomb". Fast breeder reactors can, I'm told, go prompt
critical. They are certainly contemplated and some advocates of
nuclear fission have argued that they are necessary for the nuclear
power system to be cost efficient.
--
John McCarthy
explosions of some possible designs still don't (I'm told) correspond
to bombs. As for nuclear power, I only posted, because it seemed
necessary, and it would be better if someone professionally concerned
with it drafted the FAQ answer.
John De Armond
>A qualification may be required for fast breeders, although the possible
>explosions of some possible designs still don't (I'm told) correspond
>to bombs. As for nuclear power, I only posted, because it seemed
>necessary, and it would be better if someone professionally concerned
>with it drafted the FAQ answer.
Yackadamn's vivid imagination notwithstanding, there is no concern that
a fast breeder could explode. The design-basis accident for a breeder
is called a "hypothetical core disassembly accident" or HCDA. In this
scenario, a prompt criticality transient occurs. Enough energy is
released to melt the core and (if present) boil the coolant. There
would not be a nuclear explosion for the same reasons real nuclear
explosions are so difficult to initiate. Many factors such as neutron
leakage, thermal doppler shift and the physical disruption of the core
geometry mitigate against a sustained reaction. Post-transient, there
are two major concerns. One, that the melted fuel could puddle and
achieve criticality again. This is prevented by designing the reactor
vessel so that the molten fuel flows into several non-critical sumps.
The second concern is the escape of plutonium vapor. For safety
analysis purposes It is assume that a significant portion of the Pu in
the fuel is vaporized and is available first as a gas and then as an
aerosol of either solid Pu or Pu oxide particles. The typical LWR
containment leak rate of 0.05 percent volume per day would be inadequate
to contain this mist to a degree necessary for public protection.
Most designs therefore propose multiple containments.
A good general reference is "Nuclear Reactor Engineering" by Glasstone and
Sesonkse. The bibliography points toward more specific references.
John
--
John De Armond, WD4OQC |Interested in high performance mobility?
Performance Engineering Magazine(TM) | Interested in high tech and computers?
Marietta, Ga | Send ur snail-mail address to
j...@dixie.com | per...@dixie.com for a free sample mag
Lee Harvey Oswald: Where are ya when we need ya?
victor yodaiken
>j...@SAIL.Stanford.EDU (John McCarthy) writes:
>
>>A qualification may be required for fast breeders, although the possible
>>explosions of some possible designs still don't (I'm told) correspond
>>to bombs. As for nuclear power, I only posted, because it seemed
>>necessary, and it would be better if someone professionally concerned
>>with it drafted the FAQ answer.
>
>Yackadamn's vivid imagination notwithstanding, there is no concern that
>a fast breeder could explode. The design-basis accident for a breeder
John de Armond: master of idiotic insult and pseudo-facts mixed with
even more idiotic bluster. As usual, your information is of negative
value. There is a theoretical possibility of a "bomb type" explosion
at a fast breeder, and the probabilities of such an event are in dispute
among people who really know science -- in contrast to those who think
that a weak grasp of logarithms gives them the expertise needed to settle
all open questions. I'll be happy to provide a reference if anyone wants
one.
>is called a "hypothetical core disassembly accident" or HCDA. In this
I like "core disassembly accident" : that's government for "explosion".
--
John De Armond
>>Yackadamn's vivid imagination notwithstanding, there is no concern that
>>a fast breeder could explode. The design-basis accident for a breeder
>John de Armond: master of idiotic insult and pseudo-facts mixed with
>even more idiotic bluster.
You're so much fun, yack. One little poke and you explode (but was it
a NUCLEAR explosion?) right on cue.
>As usual, your information is of negative
>value. There is a theoretical possibility of a "bomb type" explosion
>at a fast breeder, and the probabilities of such an event are in dispute
>among people who really know science -- in contrast to those who think
>that a weak grasp of logarithms gives them the expertise needed to settle
>all open questions. I'll be happy to provide a reference if anyone wants
>one.
It's fun watching Layman Yack struggle to sound scientific. Let's hear
your "references". Should be worth at least a chuckle.
I'll grant you one little point, Yack. It IS theoretically possible to
make a reactor core undergo a nuclear explosion. Just as there is
a theoretical probability that the random motions of the air molecules in
your room will synchronize and all will move to the other side of
the room and you will suffocate (where there's hope....) The physics
version of this I will call nuclear homeopathy (imagining something where
nothing exists) or simply the Yackadamn Effect. If the Yackadamn
Effect were somehow to be exerted such that the breeder core were
to be held together in a supercritical mass through about, oh, 50 or so
neutron generations, through a temperature rise of a few million degrees,
and despite the thermodynamic effects working to counter the Yackadamn
Effect, then maybe an explosion of some sort might occur. I'm sure Yack
could exert this force with his bare hands.
Most rational people not trying to belabor a nit would agree that the
probability of either event is so small that there is no material difference
between that probability and "Impossible".
>>is called a "hypothetical core disassembly accident" or HCDA. In this
>I like "core disassembly accident" : that's government for "explosion".
By your (il)logic then, when I knock my coffee cup to the floor and it
undergoes a "ceramic disassembly accident", it has really exploded.
Fascinating redefinition of the term "explosion." What is it they
call that technique, "post-constructionism" or something like that?
Orwell called it "newspeak".
Another reference for you, Yacky. "The Effects of Nuclear Weapons", USGPO,
in the first 20 pages defines the nuclear explosion in excrutiating
detail. Now I admit that this text involves some elemental math including
an exponent and a derivative. I'd more than understand if it were too
complicated for you as a layman.
Jeremy Whitlock
>
>I like "core disassembly accident" : that's government for "explosion".
>
No it's not. TMI was a core disassembly accident. It didn't explode.
--
Jeremy Whitlock "My thoughts are mine, not Mac's"
Dept. Engineering Physics
McMaster University
Hamilton, Ontario, Canada
E. Michael Smith
>In article <1quufe...@ymir.cs.umass.edu> yoda...@chelm.cs.umass.edu (victor yodaiken) writes:
>>
>>I like "core disassembly accident" : that's government for "explosion".
>
>No it's not. TMI was a core disassembly accident. It didn't explode.
Um, I *think* that "core disassembly accident" is nuke engineer for 'toy broke'
;-) ;-) ;-) ;-)
--
E. Michael Smith e...@apple.COM
'Whatever you can do, or dream you can, begin it. Boldness has
genius, power and magic in it.' - Goethe
I am not responsible nor is anyone else. Everything is disclaimed.
victor yodaiken
>yoda...@chelm.cs.umass.edu (victor yodaiken) writes:
>It's fun watching Layman Yack struggle to sound scientific. Let's hear
>your "references". Should be worth at least a chuckle.
It's interesting that after several years of frothing at me on the
net you still seem to believe that I'm posting from a liberal arts
department. BTW, there's more to science than "sounding scientific" , a
goal which I suspect motivates your endless parading of acronyms.
>I'll grant you one little point, Yack. It IS theoretically possible to
>make a reactor core undergo a nuclear explosion. Just as there is
>a theoretical probability that the random motions of the air molecules in
>your room will synchronize and all will move to the other side of
This is a Typical Nuclear Industry Factoid (TNIF) where one conflates
a physical measurement (the probabilities of brownian motion) with
an engineering conjecture (the "risks" involved in the operation of
a fast breeder). Without a solid grounding in basic science, it is
easy to make the error of assuming that different measures that are
given in like units can be swapped back and forth at will.
--
Bruce Gold
|> [Fallacy] That no current or contemplated design for a reactor could "go off
|> like a bomb". Fast breeder reactors can, I'm told, go prompt
|> critical. They are certainly contemplated and some advocates of
|> nuclear fission have argued that they are necessary for the nuclear
|> power system to be cost efficient.
I just phoned one of the design engineers of the FFTF sodium-cooled breeder
reactor. This isn't the biggest reactor around, only a few hundred megawatts,
but I figured he would know something about this subject. He said that the
worst-case situation would produce excess pressure within the containment
building of 2 psi. The building can contain that easily.
The Chernobyl mess involved a reactor sans containment building. Had there been
a containment building, even the carbon fire would have been promptly snuffed out
by its own products of combustion.
The worst-case situation for one of the pressurized water reactors he mentioned,
would produce excess pressure withing its containment building of 65 psi and its
containment building can contain that. Worst-case explosions would pretty well
fit Mr. McCarthy's descriptions, in which core makes a mess of itself before it
can turn into a Hiroshima-style explosion and specifically, before it can breech
the containment building. He limited his comments on containment building
integrity to the breeder reactor there and to the specific PWR he and I
discussed. He expressed confidence in the integrity of the containment buildings
of North American reactors and lack of knowledge about Eastern European reactors.
Perhaps you suspect this fellow of being self-serving in his statements and
evaluations. I'm sure he is. Remember, he lives within a few miles of it and
he works inside and next door to the reactor. He loves live as much as anybody
I know. How self-serving can you get?
--
Bruce Gold
Utah
Michael R James
>>I'll grant you one little point, Yack. It IS theoretically possible to
>>make a reactor core undergo a nuclear explosion. Just as there is
>>a theoretical probability that the random motions of the air molecules in
>>your room will synchronize and all will move to the other side of
>This is a Typical Nuclear Industry Factoid (TNIF) where one conflates
>a physical measurement (the probabilities of brownian motion) with
>an engineering conjecture (the "risks" involved in the operation of
>a fast breeder). Without a solid grounding in basic science, it is
>easy to make the error of assuming that different measures that are
>given in like units can be swapped back and forth at will.
Yea,yea,yea. You promised a reference earlier.
I have become sufficiently interested to check this out.
Please provide.
--
Michael James mrjg...@uxa.cso.uiuc.edu
"Ludwig Boltzmann, who spent much of his life studying statistical
mechanics, died in 1906, by his own hand. Paul Ehrenfest, carrying
on the work, died similarly in 1933. Now it is our turn to study
statistical mechanics."
-David L. Goodstein "States of Matter"
Jere Jenkins
In article <1qsmei...@ymir.cs.umass.edu>, yoda...@chelm.cs.umass.edu (victor yodaiken) writes:
|
|> >
|> >I thought it was a good description. What's the "fallacy"?
|>
|> That no current or contemplated design for a reactor could "go off
|> like a bomb". Fast breeder reactors can, I'm told, go prompt
|> critical. They are certainly contemplated and some advocates of
|> nuclear fission have argued that they are necessary for the nuclear
|> power system to be cost efficient.
|>
Aw Vic. You will have to do better than that. Do you really understand
what is necessary to bring a fuel to that point? Maybe you should try
the calculations yourself. Saying that someone told you it would happen.
We actually have reactors that are prompt critical (supercritical) by design
and they haven't caused any enormous disasters (see the Godiva experiments).
As for the FAQ, Tino has been trying to write one, and since
we are both here at PU, I guess the two of us could get one together
and maintain it. Please send any questions/comments to either:
jen...@cs.purdue.edu or je...@ecn.purdue.edu
cons...@ecn.purdue.edu
--jenkins
--
Here I am in a house full of doors with no exits.- N.O.
--------------------------------------------------------------------------
Jere Jenkins (The Modern Day Sisyphus) || Computer Science Hardware Staff
je...@little-boy.cs.purdue.edu || CS 279, (317) 494-0835
victor yodaiken
|yoda...@chelm.cs.umass.edu (victor yodaiken) writes:
|
|>>I'll grant you one little point, Yack. It IS theoretically possible to
|>>make a reactor core undergo a nuclear explosion. Just as there is
|>>a theoretical probability that the random motions of the air molecules in
|>>your room will synchronize and all will move to the other side of
|
|>This is a Typical Nuclear Industry Factoid (TNIF) where one conflates
|>a physical measurement (the probabilities of brownian motion) with
|>an engineering conjecture (the "risks" involved in the operation of
|>a fast breeder). Without a solid grounding in basic science, it is
|>easy to make the error of assuming that different measures that are
|>given in like units can be swapped back and forth at will.
|
|Yea,yea,yea. You promised a reference earlier.
|I have become sufficiently interested to check this out.
But not sufficiently motivated to look it up. Well wait a week or so,
and I'll venture into the library, a place that seems to be foreign to
many participants on this net. If you do brave the stacks, look for
some discussion of supercriticality in fast breeders.
--
Michael R James
>|Yea,yea,yea. You promised a reference earlier.
>|I have become sufficiently interested to check this out.
>But not sufficiently motivated to look it up. Well wait a week or so,
>and I'll venture into the library, a place that seems to be foreign to
>many participants on this net. If you do brave the stacks, look for
>some discussion of supercriticality in fast breeders.
Spliced from an earlier article:
yoda...@chelm.cs.umass.edu (victor yodaiken) writes:
>As usual, your information is of negative
>value. There is a theoretical possibility of a "bomb type" explosion
>at a fast breeder, and the probabilities of such an event are in dispute
>among people who really know science -- in contrast to those who think
>that a weak grasp of logarithms gives them the expertise needed to settle
>all open questions. I'll be happy to provide a reference if anyone wants
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>one.
Maybe we have a misunderstanding here. I understood you to mean
that you _already_ had a specific reference in mind.
While my original request may have been curt, it was honest.
Can you say the same?
victor yodaiken
|yoda...@chelm.cs.umass.edu (victor yodaiken) writes:
|
|>|Yea,yea,yea. You promised a reference earlier.
|>|I have become sufficiently interested to check this out.
|
|>But not sufficiently motivated to look it up. Well wait a week or so,
|>and I'll venture into the library, a place that seems to be foreign to
|
| yoda...@chelm.cs.umass.edu (victor yodaiken) writes:
|
| >As usual, your information is of negative
| >value. There is a theoretical possibility of a "bomb type" explosion
| >at a fast breeder, and the probabilities of such an event are in dispute
| >among people who really know science -- in contrast to those who think
| >that a weak grasp of logarithms gives them the expertise needed to settle
| >all open questions. I'll be happy to provide a reference if anyone wants
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
| >one.
|
|Maybe we have a misunderstanding here. I understood you to mean
|that you _already_ had a specific reference in mind.
What a strange interpretation.
|While my original request may have been curt, it was honest.
|Can you say the same?
Certainly. If you can't wait, get thee to a library thou sluggard.
--
Michael R James
>| >all open questions. I'll be happy to provide a reference if anyone wants
>| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>| >one.
>|
>|Maybe we have a misunderstanding here. I understood you to mean
>|that you _already_ had a specific reference in mind.
>What a strange interpretation.
If you say so.
>|While my original request may have been curt, it was honest.
>|Can you say the same?
>Certainly. If you can't wait, get thee to a library thou sluggard.
Sluggard eh? Well I beat you to it (posting anyway).
The lowdown on "explosions" in fast breeders.
I culled this information from one reference [1] which I
gathered was representative of the literature in this area.
This reference is rather old, if anyone has anything newer that
changes what is presented here, I would certainly like to see it.
Can a fast breeder reactor core under certain conditions reach a
supercritical state and explode like a nuclear bomb?
Answer: Yes and No
The key is: What is meant by the phrase "like a nuclear bomb".
The difficulty in making a bomb is keeping the core together long
enough (we're talking fission bombs here) for the chain reaction
to liberate far more energy that it would normally want to. This is
most often done with explosives to bring two or more subcritical
masses together very quickly. The releases of energies can
be substantial with the units measured in ktons of TNT equivalent
where 1 ton of TNT is about 4E3 MJoules.
If the bomb is damaged or otherwise does not operate properly then
you can get only a partial explosion called a "fizzle " in the
parlance. This "fizzle" will generally be an explosion that
is of the same magnitude as conventional explosives.
As you might expect, the core of a fast breeder is not designed
to explode, but it is possible that certain accidents can bring
the core to an uncontrolled supercritical state. The worst
possible consequences of this have been investigated and I will
briefly summarize the results.
For a fairly large reactor core (500-100MWt) powered by PuO2/UO2
the largest sudden energy release that can be expected is approximately
2000 lb or 1 ton of TNT. These calculations were made assuming molten
core coming together in a homogenous sphere at the maximum rate
possible (ie gravity). The calculations show that actually the
most damaging circumstance would be the sudden vaporization of any
sodium coolant remaining. Even in this event, the
overpressures resulting would be only about 10% of the equivalent
explosion of TNT. As a point of reference, the original A-bombs
were in the 1-2 kiloton range.
I don't know what effects metal fuels would have on these calculations.
In summary: Can a fast breeder core theoretically "explode".
Yes, certainly.
Is it like an atom bomb?
Well, no not really. In the worst case, it would be only a small
pop, comparitively.
Sorry this is so long.
[1] E.P. Hicks and D.C. Menzies, Theoretical Studies on the Fast Reactor
Maximum Accident, Conference on the Safety, Fuel and Core Design
on Large Fast Power Reactors (1965) p 654
Louis Denger
> yoda...@chelm.cs.umass.edu (victor yodaiken) writes:
>
>
> The lowdown on "explosions" in fast breeders.
> I culled this information from one reference [1] which I
> gathered was representative of the literature in this area.
> This reference is rather old, if anyone has anything newer that
> changes what is presented here, I would certainly like to see it.
>
> Can a fast breeder reactor core under certain conditions reach a
> supercritical state and explode like a nuclear bomb?
> Answer: Yes and No
>
>
> the largest sudden energy release that can be expected is approximately
> 2000 lb or 1 ton of TNT. These calculations were made assuming molten
> core coming together in a homogenous sphere at the maximum rate
> possible (ie gravity). The calculations show that actually the
> most damaging circumstance would be the sudden vaporization of any
> sodium coolant remaining. Even in this event, the
> overpressures resulting would be only about 10% of the equivalent
> explosion of TNT. As a point of reference, the original A-bombs
> were in the 1-2 kiloton range.
>
> I don't know what effects metal fuels would have on these calculations.
>
> In summary: Can a fast breeder core theoretically "explode".
> Yes, certainly.
> Is it like an atom bomb?
> Well, no not really. In the worst case, it would be only a small
> pop, comparitively.
There is no need of nuclear explosion for the device to extremely
lethal.
If only 1/10000 of the stuff is vaporised into the atmospher,
this makes 50 kg or nearly 5 times the Hiroshima.
Enough to contaminate immense surfaces of land.
Regards
Louis
Gene Forrer
>From: lo...@medici.trl.OZ.AU (Louis Denger)
>Subject: Re: Breeders (was Re: FAQ) (ABC)
>Date: 30 Apr 93 09:42:11 GMT
spread of contamination. Before you say it didn't help at Chernobyl think
about the difference about American and Soviet safety concerns. The Soviets (
now Russians) are like a Pinto while the Americans would be more of a Jeep
Wagoneer (the big ones). FOr people to keep using Russian plants as a reason
to kill nuclear everywhere is ridiculous. The technologies involved are so
vastly different you might as well compare safety records of air and ocean
travel as areason to shut down the train industry.
Carl J Lydick
=There is no need of nuclear explosion for the device to extremely
=lethal.
=If only 1/10000 of the stuff is vaporised into the atmospher,
=this makes 50 kg or nearly 5 times the Hiroshima.
That's why nuclear plants in the United States have these big reinforced
concrete domes called "containment structures."
--------------------------------------------------------------------------------
Carl J Lydick | INTERnet: CA...@SOL1.GPS.CALTECH.EDU | NSI/HEPnet: SOL1::CARL
Disclaimer: Hey, I understand VAXen and VMS. That's what I get paid for. My
understanding of astronomy is purely at the amateur level (or below). So
unless what I'm saying is directly related to VAX/VMS, don't hold me or my
organization responsible for it. If it IS related to VAX/VMS, you can try to
hold me responsible for it, but my organization had nothing to do with it.
Michael R James
>From article by mrjg...@uxa.cso.uiuc.edu (Michael R James):
>>
>> In summary: Can a fast breeder core theoretically "explode".
>> Yes, certainly.
>> Is it like an atom bomb?
>> Well, no not really. In the worst case, it would be only a small
>> pop, comparitively.
>There is no need of nuclear explosion for the device to extremely
>lethal.
>If only 1/10000 of the stuff is vaporised into the atmospher,
>this makes 50 kg or nearly 5 times the Hiroshima.
>Enough to contaminate immense surfaces of land.
I won't disagree that dispersed radiactivity can be hazardous, but
your numbers don't make any sense.
The total fuel inventory for a reactor will vary with the
size of the power output with typical values a 3kg per MWe
for an LWR and 3-4 kg per MWe for an LMFBR (breeder) [1].
Your figures give a power output of 125000 MWe for a breeder.
That's about 100 times larger than anything that exists.
If you're going to use numbers, use the right ones.
[1] Lamarsh, John R, Introduction to Nuclear Engineering 2ed,
Addison-Wesley, Reading, Mass, 1983 p146