Yucca Explosion
Dave Monti
yet...especially from anti-nukes.
Does anyone have *specific* and *reliable* information about the details
behind this study? I'm speaking of the controversy at LANL about the
possibility of the HLW repository undergoing an accidental nuclear
explosion.
All I've read so far at the AP press stories. My immediate thoughts are....
1) You've got to be kidding! Those of use who know what it takes for a
nuclear exposion to occur should know how unlikely--rather how impossible
that this is! The only possible way is if weapons grade Pu from
disassembled warheads (IF that was going to be stored in the Mtn.) was to
break out of a cask and somehow be combined and compressed by the
surrounding rock....or something like that (yeah, RIGHT!, that's the
ticket!).
2) I also believe that no matter how silly these people are made to look
when (if?) they are proven wrong, the public will still remember their
thesis. This will be a major blow to the nuclear industry--as far as
public perception is concerned.
3) I don't care if a couple of PhD's at Los Alamos came up with the
idea. There's a person who posts on this group from LANL who apparently
is quite uninformed about how "nuclear things work."
I fully realise that I could be missing an important concept behind this
claim, but I doubt it. Given the conditons for a nuclear exposion, the
composition of spent fuel, and the way the waste is stored, I see no way
whatsoever that such an explosion could EVER occur.
Thoughts on this?
--
Dave Monti
dav...@uxa.cso.uiuc.edu
"It's what you learn *after* you know it all that counts."
--Anonymous
Dave Monti
<iso...@igc.apc.org> wrote:
>
> davidm at uxa.cso.uiuc.edu writes in PANIC:
That's your opinion.
> Have you figured a vulcano into the equation? They make a real mess
> of things.
No, I haven't figured a volcano into the equation, because it is not a
concern in this report. The report is concerned about an accidental
supercriticality that will lead to a nuclear explosion.
The lab's response should be out in a week or two, according to a LANL
source who emailed me. Keep your eye out for it--on the other hand, you
may have to dig, since a report saying "you're wrong" isn't nearly as
newsworthy as "Oh my God! A nuclear explosion!"
> Dave Pettingill
> iso...@igc.org
Dave Pettingill
>behind this study? I'm speaking of the controversy at LANL about the
>possibility of the HLW repository undergoing an accidental nuclear
>explosion.
>I fully realise that I could be missing an important concept behind this
>claim, but I doubt it. Given the conditons for a nuclear exposion, the
>composition of spent fuel, and the way the waste is stored, I see no way
>whatsoever that such an explosion could EVER occur.
of things.
>"It's what you learn *after* you know it all that counts."
iso...@igc.org
B. Alan Guthrie
>Dave Monti (dav...@uxa.cso.uiuc.edu) wrote:
>: I'm very surprised that there hasn't been a flood of posts on this group
>accelerator trasmutation people who see themselves as an alternative to
>straightforward burial of spent fuel.
>
>Also from my copy of the report (a draft copy but it probably won't be all
>that different from the final) I noticed the following:
>
>1) The author's claim that this can happen to any type of HLW (ie: Pu
>from weapons, HEU, LEU, whatever) yet they only show calculations for
>PURE Pu 239 (yep that is right no 240 with those pesky spontaneous
>fissions)
>
>2) As part of the calculations the author's did MCNP calculations of
>homogenously mixed Pu in SiO2 (rock) with various H2O concentrations.
>There concern seems to lie mostly with H2O concentrations involving over
>10% by volume of water. Alot of water.
>
>3) The yield calculations were done assuming room temperature, thermal
>fission. An explosion were it to occur would involve temperatures
>of thousands of degrees which would greatly effect the neutron behavior.
>
>4) The author's premise is based on 10's of kg's of Pu diffusing into
>a volume of rock 10's of cm's in diameter (don't have the report in front
>of me right now). No mechanism is given which would do this in a period
>of time short enough that eith the Pu would decay or that it would reach
>a near critical or just critical stage and fission at mW power levels
>due to multiplication from neutrons in the enviroment.
>
>
Thanks for the information. Sounds to me like some of them gummint
scientists in search of funding.
My guess is that if a critical configuration were attained, then the
heat produced would dry out the lattice, shutting down the chain
reaction due to loss of moderation and cooling the material, then
water would seep back in, a new critical configuration would be
set up, it would dry out, .... Sounds like Oklo, doesn't it?
It would seem to me that the obvious and simple solution to the problem
is to pack the actinide-containing canisters in some sort of resin
which would hold up the fissile material so that it can't migrate
very far. Put some boron in the resin, and it will be very hard to
get a chain reaction going.
Of course, if the assembly needs 10% water volume, then it would seem
that problem really doesn't exist in the first place.
The more one thinks about it, the more apparent it becomes that the
whole study is just a bid for funding. Even in a critical configuration,
it won't explode like a bomb. But, if we don't make the problem
dramatic, then we can't get more funding....
The views expressed above do not necessarily reflect the views of
my employer.
--
B. Alan Guthrie, III | When the going gets tough,
| the tough hide under the table.
alan.g...@cnfd.pgh.wec.com |
| E. Blackadder
Jason Edward Floyd
: I'm very surprised that there hasn't been a flood of posts on this group
: yet...especially from anti-nukes.
: Thoughts on this?
IMHO the study is bull. First note that the study is being released by the
accelerator trasmutation people who see themselves as an alternative to
straightforward burial of spent fuel.
Also from my copy of the report (a draft copy but it probably won't be all
that different from the final) I noticed the following:
1) The author's claim that this can happen to any type of HLW (ie: Pu
from weapons, HEU, LEU, whatever) yet they only show calculations for
PURE Pu 239 (yep that is right no 240 with those pesky spontaneous
fissions)
2) As part of the calculations the author's did MCNP calculations of
homogenously mixed Pu in SiO2 (rock) with various H2O concentrations.
There concern seems to lie mostly with H2O concentrations involving over
10% by volume of water. Alot of water.
3) The yield calculations were done assuming room temperature, thermal
fission. An explosion were it to occur would involve temperatures
of thousands of degrees which would greatly effect the neutron behavior.
4) The author's premise is based on 10's of kg's of Pu diffusing into
a volume of rock 10's of cm's in diameter (don't have the report in front
of me right now). No mechanism is given which would do this in a period
of time short enough that eith the Pu would decay or that it would reach
a near critical or just critical stage and fission at mW power levels
due to multiplication from neutrons in the enviroment.
--
Jason E. Floyd jfl...@wam.umd.edu pnkf...@eng.umd.edu
Department of Materials and Nuclear Engineering
University of Maryland at College Park
College Park, MD 20742
"Life is a grapefruit." - Douglas Adams
NOW ANNOUNCING A NEW WEB HOME PAGE http://www.wam.umd.edu/~jfloyd
Bark
This is an attempt to revise a mildly jumbled attempt made last night.
I believe this go-around is more clear, more accurate, and less
"opinioned."
All comments welcome.
For Discussion: Underground Autocatalytic Criticality from
Plutonium and Other Fissile Material
As I see it, the gentlemen performing the study started with the
assumption of an explosion, and worked backwards to develop a
scenario, and forward to determine yields. I do not think that it is
sufficient at this point to merely discuss whether or not their
suppositions are valid. If something must be said about this report,
we might consider examining what, exactly, this report is telling us.
What is the Proposed Process?
In the scope of the report, Pu "shapes", "pits" (or whatever you
choose to call them) are the source of the material. Although such
material is highly enriched, it starts it's repository life in one
coherent, subcritical mass.
As such items are initially subcritical, they typically require
appropriate shock compression / initiation to detonate as-designed.
I am not aware of any contention that this detonation mechanism
is infeasible following deposition.
However, Bowman & Venneri (B&V) point out several "other"
mechanisms for reaching prompt supercriticality, typically those
resulting from a positive reactivity feedback.
The paper claims that one transport mechanism for Pu isotopes
would involve formation of Pu salts. These salts would migrate
with water and travel through the rock matrix. Over time, the rock
matrix would simultaneously becomes water-saturated, Pu-saturated,
and SiO2 saturated (acting as a reflector).
In such a configuration, the material is still subcritical, and now
occupies a much larger volume than before. The degree of
subcriticality in this configuration is affected by the presence of
thermal moderation, specifically water. In this state, the material
is "primed" for a positive reactivity excursion resulting from a
decrease in the molar fraction of water.
Following the logic of the paper, as the water begins to migrate
away from the diffused pit material, it leaves the Pu, the SiO2, and
has a k-inf that increases as additional water is removed. Since the
approach to criticality results from the loss of moderator, and is
due to the positive reactivity coefficient. The result is a feedback
system involving accelerated water loss, thermal excursion, and
positive reactivity feedback. The author calls this process
"autocatalytic."
The authors provide several similar examples of migrating Pu, and
both positive and negative reactivity effects resulting in excursion.
It is suggested that the excursion is sufficiently rapid to produce a
detonation prior to melting or thermal dispersion. The result, claim
the authors, is a detonation that exceeds unconstrained results
above ground.What is potentially wrong with this theory?
The question that has to be asked, is: "How likely are these
scenarios?"
The authors assume deposition of untreated, highly-enriched, "bomb
grade material." The authors assume that containment is breached
such that it is neglected from further consideration. Many of the
assumptions are sufficiently vague to make the treatment entirely
hypothetical.
The argument for commercial fuel following a similar path first
assumes that the material has been enriched through a process of
selective diffusion. There is very little discussion of how poisons
would be removed, or concentrations increased. A vague mention
of preferential solubility and decay products is not sufficient to
credibly support this assumption. It is assumed that once this is
achieved, the material then follows the same path as described
earlier. This two-step treatment bounds the treatment of
commercial fuel substantially less- likely than for weapons-grade
material.
The feasibility that the rock matrix would perform selective
separative work is potentially questionable, even assuming
thousands of years of selective-random migration.
The authors assume particular purities of materials and isotopes
originating from a substantial mix of isotopes. It is difficult to
describe the likelihood that diffusion would occur in precisely the
manner spelled out by the requirements for prompt criticality with
a positive reactivity. Since the process can be described, the
probability that it could occur is greater than zero. It is clear that
the probability of non-preferential random diffusion into a specific
range of geometrical and material configurations is very nearly
zero.
The authors project specific conditions for the next 6,500 to 10,000
years. As such, these processes should lead to potential excursions
(if the theory is correct) sometime between the years 8495 and
11995. Such foresight for a series of interactions as specific and
complex as this is exceptionally speculative.
The authors utilize a graph of molar fractions and criticality quite
incautiously. Specific conclusions are made in reference to the
position of molar fractions expressed by this chart. It is anticipated
that the curves shown on this chart are not stable with respect to
molar mix, and need to be adjusted. The fact that horizontal lines
are pulled from this graph as an attempt to identify regions of
positive and negative feedback is, therefore, skeptical. B&V rely
on such techniques extensively, therefore the accuracy should be
investigated.
What, then, can be said about this process?
To the authors' credit, this is an interesting phenomena to consider.
The likelihood of the phenomena, as described, is fanciful at best.
William C. Sailor, a member of the original review team described
the situation best with:
"Supercriticality is probably 1*10-4 as likely as criticality.
An 'explosion' is probably 1*10-4 as likely as supercriticality... [and
the likelihood of any criticality whatsoever is already extremely
low]. The overall likelihood of this situation is smaller than the
chance that a large meteor will strike on Yucca Mtn. A large
explosion is simply against the laws of physics..."
If I wanted to serve my own interests, I could embrace this report,
and state that it demonstrates our only acceptable spent fuel option
is reprocessing. Although the authors propose that their
autocatalytic theory is sufficient-cause to support transmutation of
the waste... I believe they have shown that transmutation is not
sufficient. If they are correct, and if this process can occur with
spent commercial fuel, it is not certain that transmutation would be
sufficiently to assure the possibility of an autocatalytic reaction has
been eliminated. This assumption is based upon, as B&V have
elected by default, the assumption that any non-zero probability is
worth considering. All natural uranium deposits may have to be
mined for the same reason.
Following this logic, if deposition and transmutation are
unacceptable, our only option is to reprocess and reuse the fuel as
much as we can. This expanded fuel cycle would include
utilization of the plutonium cycle, and suggest the installation of
several appropriate commercial reactors to handle the demand for
material consumption.
Admittedly, it would be irresponsible to make such a claim based
only on the information in this report. The proposed theory is far
too weak to draw such (or any) conclusions. The probabilities are
exceptionally, specifically, remarkably low.
THIS FACT IS SIGNIFICANT!
This paper describes a theoretical phenomena, and is primarily an
exercise in reverse- engineering the requirements for a criticality
excursion. This report successfully identifies those chains of events
that are required to develop favorable conditions for criticality.
BECAUSE these probabilities can be demonstrated to be
EXCEPTIONALLY low, it is clear that the mechanisms described
by this analysis are sufficiently unlikely to be ignored. Although
the phenomena is interesting, further consideration does not appear
to be justified.
If an argument needs to be made in favor of geologic disposal, this
is it. Few scenarios are demonstrably less likely. From the point
of criticality, then, geologic disposition must be a safe option.
Phrased another way, B&V have conducted a "null-hypothesis."
As presented, their analysis makes considerable efforts to exploit
any opportunity to reach criticality. Since the document has
effectively illustrated the low probability, a clear argument can be
made that this criticality mechanism may be eliminated from
consideration. This effort should be used to reduce concerns over
the geologic disposition of defense items such as pits and navy
fuel.
Although it may require time and debate, I expect this conclusion
is inevitable.
Bark
The principle concern with respect to volcanic activity is that
the deposited material would become molten, and be ejected to
the surface, potentially requiring that the solidified material be
mined... repackaged... and disposed.
..which is why nobody intends to put anything in there that
has the slightest chance of coming back up. Too expensive! Best
safety feature of all, no?
As for volcanic activity and "criticality"... I get the feeling
that the original poster is thinking of nuclear material as
some sort of contact explosive that is ready to blow at the
slightest provocation. This is a poor analogy for even the
most highly enriched materials.
The "activity" or energy of a volcano is not likely to generate
the *focused* compressive forces required to detonate bomb-
grade material. Not likely = beyond likelihood of a single
occurance over 10,000 catastrophic events. (Descriptive definition,
not a quantitative one!) Scientists specializing in shock
compression work many long hard hours trying to get the stuff
to go bang. You're not going to have the concentrated
energies required, and *even if you did* you aren't going to
have the proper timing to get an appreciable yeild... ie, it
would fizzle.
Keep in mind that if we are assuming a situation where criticality
is even a remote possiblity... the detonation would actually
be *preferable* to having the material spread around by the
volcanic activity. ie: you would really *want* it to go off,
but unfortunately that would not occur.
Does this make the situation clearer?
1) Criticality is not remotely likely.
2) Criticality is not a significant health concern, regardless.
3) If you are assuming nuclear material is going to be
ejected, you should prefer that it would detonate... but
it won't.
4) You would never expect reactor fuel to "detonate" under any
circumstances.
A small part of the site characterization effort is directed
at identifying *historical* volcanic activity.
The main value of this information
is for characterization of the geologic strata and "whatnot."
As I understand it, the possibility of active volcanic activity
has long since been eliminated. Kinda like making sure you
aren't building your house on a swamp... it gets checked before
anything else.
:-)
Take care,
--b.
Dave Pettingill
>concern in this report. The report is concerned about an accidental
>supercriticality that will lead to a nuclear explosion.
>Given the coditons for a nuclear exposion, the
>composition of spent fuel, and the way the waste is stored, I see no way
I suggest a volcano as a cause of supercriticality.
Volcanoes have happened there in the past.
>The lab's response should be out in a week or two, according to a LANL
>source who emailed me. Keep your eye out for it--on the other hand, you
>may have to dig, since a report saying "you're wrong" isn't nearly as
>newsworthy as "Oh my God! A nuclear explosion!"
I will read it because I live in Nevada. I may agree. I may say nothing.
It is possible I won't understand the scenario. I might even ask a
a question or two. You see, in Nevada the issue is more than a
academic matter.
Dave Pettingill
iso...@igc.org
.
B. Alan Guthrie
>In article <APC&1'0'5765f90a'9...@igc.apc.org>, Dave Pettingill
><iso...@igc.apc.org> wrote:
>
>>
>> davidm at uxa.cso.uiuc.edu writes in PANIC:
>
>That's your opinion.
>
>> Have you figured a vulcano into the equation? They make a real mess
>> of things.
>
>No, I haven't figured a volcano into the equation, because it is not a
>concern in this report. The report is concerned about an accidental
>supercriticality that will lead to a nuclear explosion.
>
>The lab's response should be out in a week or two, according to a LANL
>source who emailed me. Keep your eye out for it--on the other hand, you
>may have to dig, since a report saying "you're wrong" isn't nearly as
>newsworthy as "Oh my God! A nuclear explosion!"
>
>
A former colleague who was once a nuclear engineer and is now involved
in the natural gas industry sent me the following synopsis of a report
which was on National Public Radio on March 8, 1995 (specifically on
Morning Edition, I believe). He heard the report in the morning and
e-mailed his recollection of it late in the afternoon, so his quotes
should not be considered to be exact, although he does say that they
accurately portray the gist of the report.
NPR did a story this morning.
The lab formed 3 teams to evaluate:
Red - Tries to rip appart the theory
Blue - Tries to defend the theory
Gray - Senior scientists act as technical judge.
Results:
Red did a good job. Blue tried as hard as they
could, but couldn't defend. Gray sided with red.
A quote from the Blue team leader: "This was
very hard to defend. There were significant
errors in Geology, Nuclear Engineering, Physics,
Base Mathematics. I found it impossible to defend.
"The author got defensive far beyond the scientific
debate taking the work personnaly. I and others
are not restricting this work. We suggested that
it be published in the scientific press, where it
will get ripped to shreds. Sofar the author is only
releasing it to press and political groups."
The author is claiming that there is a coverup by the
lab, and several anti waste site politicians are
using this as ammunition.
My colleague (who tends toward the liberal end of the political
spectrum) observes that if NPR finds fault with a report critical
of the nuclear industry then the report must really be garbage.
I have received several e-mails speculating that the author of
the report has the hidden agenda of attempting to show the folly
of the burial of plutonium, rather than its recycling. If such
is indeed his goal, then I say that his study is a completely
sober and thorough analysis of the situation and his conclusions
are entirely warranted. :-)
Mike Baker
>
>I suggest a volcano as a cause of supercriticality.
>Volcanoes have happened there in the past.
>
I would suggest the volcano would be more likely to prevent the formation of
a geometry required for supercriticality or break it up if such a geometry
existed. A volcano could contribute to radioactive material spread but not
to the condition being discussed.
--
========================================================================================
Michael Baker ... ba...@nucst11.neep.wisc.edu
========================================================================================
Larry L. Taylor
dav...@uxa.cso.uiuc.edu (Dave Monti) wrote:
> I'm very surprised that there hasn't been a flood of posts on this group
> yet...especially from anti-nukes.
>
> Does anyone have *specific* and *reliable* information about the details
> behind this study? I'm speaking of the controversy at LANL about the
> possibility of the HLW repository undergoing an accidental nuclear
> explosion.
>
> All I've read so far at the AP press stories. My immediate thoughts are....
>
> 1) You've got to be kidding! Those of use who know what it takes for a
> nuclear exposion to occur should know how unlikely--rather how impossible
> that this is! The only possible way is if weapons grade Pu from
> disassembled warheads (IF that was going to be stored in the Mtn.) was to
> break out of a cask and somehow be combined and compressed by the
> surrounding rock....or something like that (yeah, RIGHT!, that's the
> ticket!).
Actually, there all kinds of proposals out there to try and deal with
nuclear waste disposal, both commercial and defense related. Commercial
spent fuels are relatively benign with respect to criticality issues in
geologic storage. Not necessarily so for HEU and weapons Pu. DOE threw
this issue into a cocked hat when they decided to shutdown defense
reprocessing. N-reactor fuels were never intended for long terms storage
in water - and now we have a serious problem with them.
HEU SNF poses a different set of problems in geologic disposal. Double
contingency protection against criticality utilizes either spacing, mass
limits, poisoning, or moderator exclusion to protect against a critical
event in current storage and processing systems. While at least two
contingencies can (and will) be in effect at time of disposal, there are no
guarantees they will always be in place through the 10,000 year life of the
repository. The 10,000 year life is predicated on the decay of Sr-90 and
Cs-137, but what of the Pu-239 decay (22,000+ years half-life [which
incidentally decays to . . U-235!]), U-235
(7.0E08 years half-life)
>
> 2) I also believe that no matter how silly these people are made to look
> when (if?) they are proven wrong, the public will still remember their
> thesis. This will be a major blow to the nuclear industry--as far as
> public perception is concerned.
The apparent goal of Dr. Bowman is to keep the US government from doing
something stupid in terms of throwing valuable material away. The current
set of NRDC bureaucrats in office within DOE seem to think
out-of-sight-out-of-mind throw away policies (under the guise of nuclear
non-proliferation) are cheaper than reprocessing the material and 'burning
it up' in nuclear reactors. The costs of the burial approach have not even
begun to be tallied. When it does will make engineered, monitored
retrievable storage and the dreaded "r" word [whisper: reprocessing] look
all that more sensible.
>
> 3) I don't care if a couple of PhD's at Los Alamos came up with the
> idea. There's a person who posts on this group from LANL who apparently
> is quite uninformed about how "nuclear things work."
Could be. Bowman's contention is laced with a great number of "then a
mircle occurs here" suppositions that gets the Pu chemistries changed, and
transport by water, and differential separation from waste packages, and .
. . It is generally acknowledged in his draft paper _and_ the peer critique
that there will more than likely be one or more critical events (see
reference to 'slow cooker' below) preceeding the 'big bang'.
One should not lose sight of the goal of the anti-nukes, which seems to be
to constipate the nuclear fuel cycle. If we were ever allowed to
demonstrate safe closure of the fuel cycle, then nuclear power production
becomes a viable option for bulk power generation.
>
> I fully realise that I could be missing an important concept behind this
> claim, but I doubt it. Given the conditons for a nuclear exposion, the
> composition of spent fuel, and the way the waste is stored, I see no way
> whatsoever that such an explosion could EVER occur.
>
> Thoughts on this?
>
There is work in progress that addresses the very issue of nuclear
criticalities in a repository, both from commercial fuels in Yucca Mtn and
defense HEU SNF (wherever it might end up). [Work on disposal of weapons
Pu is in much earlier stages of even trying to address disposal issues].
Of all the scenarios and mechanisms postulated leading to a criticality
after burial, a moderated 'slow cooker' was the most likely event, and it
would likley undergo cyclic operation at about 1.0 kW (much as the Okla
phenomena was thought to experience). The total fissions at that level,
even for 10,000 years would not come even close to equaling the total
fissions already in place inm the waste packages in terms of heat
generation or the number of new fission products generated.
> --
> Dave Monti
> dav...@uxa.cso.uiuc.edu
>
> "It's what you learn *after* you know it all that counts."
>
> --Anonymous
--
"nuclear waste at rest tends to stay at rest"
Larry L. Taylor email: lar...@pmafire.inel.gov
Bark
to clarify some of what has been going on. As best I can,
I will not present an opinion... Deal?
Okay.
As I see it, the gentlemen performing the study *started*
with the assumption of an explosion, and worked backwards
from there, and forward to determine yeilds.
In the scope of the report, Pu "shapes", "pits" or whatever
you choose to call them are the source of the material.
These items start subcritical.
The paper claims that a transport mechanism could be the
dissolution of Pu salts in water which travels through
the rock matrix. The rock matrix becomes water-saturated,
Pu-saturated, and SiO2 saturated (acting as a reflector).
In such a configuration, the material is still subcritical,
but is set up for a positive reactivity effect from loss
of moderator (water).
In the paper, then, the water begins to migrate elsewhere,
leaving the Pu, leaving the SiO2, and with a kinf that
increases as the water is removed.
Criticality and approach to powered-critical will generate
more heat, and drive off more water... increasing
criticality more and more. The author calls this process
"autocatalytic."
Commercial reactors are designed to have a negative
reactivity effect upon loss of moderator. This is why
they shut down, rather than revving up more and more.
Because the condition in the paper is highly enriched, and
because it has a positive feedback, the author supposes
that a power excusion and detonation is possible.
The question you have to ask yourself, is: "How likely
is this scenario?"
The author assumes deposition of untreated highly enriched
"bomb parts." There is currently no such agreed waste
form, therefore this is hypothetical.
The argument that commercial fuel could do the same thing
is based upon the collection of specific isotope mixtures
in a tight area from random migration. ie: mother nature
decides to perform selective seperative work on the fuel.
The author assumes particular purities of materials and
isotopes resulting from a migration of a witches brew of
nearly unseperable materials and isotopes. As I've said
before, if you can describe something, you can give it
a probability. If I try to pass my hand through a wall
an infinite number of times, one could assume that one
of those attempts would result in my hand passing through
the wall with no resistance.
The author projects specific conditions for the next
8 to 10,000 years. These excusions would (if the theory is
correct) occur on/near the year 11995. Think about it.
The author uses drastic simplifications of molar fractions,
then draws specific conclusions from outside the initial
range (see: accuracy of extrapolation).
To the author's credit, this is an interesting phenomena
to consider. If I were self-serving, I would suggest that
this report demonstrates that our only acceptable spent
fuel option is reprocessing. Although the author proposes
that this theory is sufficient reason to transmute the
waste... I believe he has shown that transmutation is not
sufficient.
If his theory were true:
Our only option is to reprocess and reuse the fuel as
much as we can.
It would be irresponsible for me to make
that claim, because the proposed theory is too weak to
draw such a conclusion (or any conclusions.) It is merely
an exercise in working-backwards through the process which
demonstrates (clearly) how improbable this situation is.
If anyone ever needed an argument *for* geologic disposal,
this is it. Few things could be less likely than this,
therefore, it must be a safe option. If you will, this is
the "null-hypothesis" which proves this criticality
mechanism may be eliminated.
I suppose it will take some time and an unfortunate amount
of hype before this realization is made by the community
at-large.
I hope this wasn't too biased. I hope everyone keeps an
open mind, and goes through the process/equations for
themselves. It does no good for anyone to blindly accept
something they have not understood for themselves.
Take care,
--Rob.
Dave Monti
<iso...@igc.apc.org> wrote:
> I suggest a volcano as a cause of supercriticality.
> Volcanoes have happened there in the past.
Apparently you're not clear on the definition of supercriticality. While
it is true that volcanoes have existed there millions of years ago,
volcanic activity will have little to do with the possibility of
criticality, much less a supercriticality that ends in a nuclear bomb-like
explosion.
I don't know what the official "pronuke" answer to past volcanic activity
is, but anyone who knows is welcome to contribute. I *assume* that they
have somehow determined with reasonable confidence that volcanic activity
will not occur over the 10,000 year design spec.
>
> >The lab's response should be out in a week or two, according to a LANL
> >source who emailed me. Keep your eye out for it--on the other hand, you
> >may have to dig, since a report saying "you're wrong" isn't nearly as
> >newsworthy as "Oh my God! A nuclear explosion!"
>
> I find your hysterics distracting. Heck, I have'nt made my mind up yet.
> I will read it because I live in Nevada. I may agree. I may say nothing.
> It is possible I won't understand the scenario. I might even ask a
> a question or two. You see, in Nevada the issue is more than a
> academic matter.
I'm not being hysteric--I'm immitating the media and the typical
antinuclear person. I'm glad that you're apparently witholding your
judgement until you hear more about this. I like the fact that you're
asking questions of someone who is 1) admittedly biased, but nevertheless
2) honest, and 3) somewhat educated about the issues. I know that I may
not convince you, but I hope I'm putting up good points for "my side."
I see your point about being a Nevada resident and your concern, but I
would like to say that just because I am still a student (a masters
candidate), the issue is not just academic to me. I truly care about what
happens to *our* waste and the locations at which we store it.
>
> Dave Pettingill
> iso...@igc.org
Dave Monti
lar...@pmafire.inel.gov (Larry L. Taylor) wrote:
> The apparent goal of Dr. Bowman is to keep the US government from doing
> something stupid in terms of throwing valuable material away. The current
> set of NRDC bureaucrats in office within DOE seem to think
> out-of-sight-out-of-mind throw away policies (under the guise of nuclear
> non-proliferation) are cheaper than reprocessing the material and 'burning
> it up' in nuclear reactors. The costs of the burial approach have not even
> begun to be tallied. When it does will make engineered, monitored
> retrievable storage and the dreaded "r" word [whisper: reprocessing] look
> all that more sensible.
I like the idea of reprocessing. I've done an independent study paper on
weapons grade Pu disposal, and I came to the conclusion that MOX burning
is the way to go. Similarly, I also support LWR fuel recycle.
A clarification for anyone who cares....(not related to the above response)
> > 3) I don't care if a couple of PhD's at Los Alamos came up with the
> > idea. There's a person who posts on this group from LANL who apparently
> > is quite uninformed about how "nuclear things work."
I don't mean to put down the authors of the original report. I only
wanted to point out that just because someone sports a PhD doesn't mean
that they are "a good PhD." There is research other than "bombs" going on
at LANL, so just because someone's email address says they're from LANL,
it doesn't mean that they are a weapons physics expert.
Ieromnimon F
[ elaboration on the paper deleted to save space ]
>To the authors' credit, this is an interesting phenomena to consider.
>The likelihood of the phenomena, as described, is fanciful at best.
>William C. Sailor, a member of the original review team described
>the situation best with:
>
> "Supercriticality is probably 1*10-4 as likely as criticality.
>An 'explosion' is probably 1*10-4 as likely as supercriticality... [and
>the likelihood of any criticality whatsoever is already extremely
>low]. The overall likelihood of this situation is smaller than the
>chance that a large meteor will strike on Yucca Mtn. A large
>explosion is simply against the laws of physics..."
>
[ more deletions ]
I would agree that the notion of sedimentary fission "devices" is rather far-
fetched. However, what about another wild-flight-of fancy scenario?
What if a relatively large amount of Pu (or weapons-grade U235), of the order
of tens of kilograms, just happened to roll "together" in a super-critical
geometry, as say in the bottom of a drain or any other appropriately shaped
vessel (like a very badly designed breeder-reactor vessel)? Would the inertia of
the large mass of metal/oxide be sufficient to keep the lot together long enough
for prompt criticality and subsequent detonation? Reactor-grade Pu (large
percentage of Pu241) would be worse in this respect, as there would be more
spontaneous fission neutrons to trigger an "excursion". I seem to remember this
scenario as a reason why a meltdown in a large breeder reactor would be a Very
Bad Thing. Comments anyone?
Frank Ieromnimon,
ie...@essex.ac.uk
Carl J Lydick
=quation, because it is not a
=>concern in this report. The report is concerned about an accidental
=>supercriticality that will lead to a nuclear explosion.
=
=excuse me , you said
=>Given the coditons for a nuclear exposion, the
=>composition of spent fuel, and the way the waste is stored, I see no way
=>whatsoever that such an explosion could EVER occur. (your emphasis)
=
=I suggest a volcano as a cause of supercriticality.
Care to tell us how you suppose a volcano would cause supercriticality?
--------------------------------------------------------------------------------
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.
Jason Edward Floyd
: I'm very surprised that there hasn't been a flood of posts on this group
: yet...especially from anti-nukes.
: Thoughts on this?
Here is the Los Alamos internal review committee report on Bowman and
Venneri's findings:
COMMENTS ON "NUCLEAR EXCURSIONS" AND "CRITICALITY ISSUES"
LAUR-95-0851
Gregory H. Canavan, Stirling A. Colgate, O'Dean P. Judd
Albert G. Petschek, Thomas F. Stratton
Los Alamos National Laboratory
Technical reviews of papers on criticality and energy release from
underground
storage of fissile material concluded the probability of each of the steps
required is
vanishingly small and the probability of occurrence of all of them is
essentially zero.
Even if they could occur, any release would be too small and slow to
produce significant
consequences in the repository or on the surface
The Laboratory provided technical reviews of papers by Drs. Bowman and
Venneri. The first, entitled "Nuclear Excursions and Eruptions from
Plutonium and Other
Fissile Material Stored Underground"[1] ("Nuclear Excursions") was reviewed in
December, 1994, and a written response was submitted to the authors through
Laboratory
management. The second, entitled "Criticality Issues for Thermally Fissile
Material in
Geologic Storage"[2] ("Criticality Issues"), which was a response to the
issues raised in
the December review, was reviewed in February, 1995. This review summarizes the
assessment of both. Very recently, the authors released a third paper, entitled
"Underground Autocatalytic Criticality from Plutonium and Other Fissile
Material."[3]
("Underground Autocatalytic Criticality"). However, it is largely a
compilation, without
correction, of materials from the first two; thus, our comments apply to it
as well.
The papers primarily discuss the underground emplacement of glassy logs
containing weapons plutonium, and purport to demonstrate that after on the
order of
10,000 years, geologic action will increase their reactivity to the point
where criticality,
auto-catalytic action, and explosive energy release are probable. The
significant
difference between the papers is that the first ascribes the increase in
reactivity to the
dilution of plutonium in a dry silicon dioxide medium, while the second two
ascribe the
increase of reactivity to the concentration of plutonium in a wet silicon
dioxide medium.
The review concluded that the discussion in the papers does not
describe a
credible sequence of geologic events leading to super criticality and
explosive energy
release. The probability of each of the necessary steps-increase in
reactivity to
criticality, auto-catalysis, and explosive energy release-is vanishingly
small, and the
probability of occurrence of all three is essentially zero. Moreover, even
if these steps
could occur, any energy release would be too small and slow to produce any
significant
consequences either in the repository or on the surface. Indeed, any
surface effects would
occur on times of tens of thousands of years, which are so long as to be
outside the time
scale of any credible scientific prediction.
Emplacement, dispersal, and criticality. The geological situations
discussed in
"Nuclear Excursions" were too unrealistic to provide a useful framework for
analysis or
to validate the proposed scenario. That was pointed out in the review, but
those situations
were still used in "Criticality Issues." "Nuclear Excursions" postulates
the emplacement
of fissile materials in geologic formations of pure silicon dioxide, which
is a weak
neutron absorber, is not a common geologic material, and has not been
proposed as a
repository material. Other elements present in all geologic formations
absorb neutrons
much more strongly than pure silicon dioxide, which reduces the reactivity
of the
mixture. Although the papers mention minor soil constituents with very
large absorption
cross sections, their calculations ignore them. The papers offer
unsupported estimates that
including them would increase the critical mass by 50%. When they are properly
included, it may not be possible to achieve criticality for the assumed
conditions even
with pure Pu-239. It is not possible to be more quantitative in our
response without
further analysis of weapons Pu and spent fuel in realistic media, which is
not performed
in these reports. That must be done in a more careful subsequent project.
The papers perform most of their calculations for pure Pu-239. The
weapons
plutonium of interest has a significant fraction of Pu-240, a strong
absorber that further
reduces reactivity. Even for the maximum loadings postulated in "Nuclear
Excursions,"
weapons plutonium could never disperse to a condition of criticality in
real, dry
repository materials. It is argued that the Pu-240 would decay, leaving the
more reactive
Pu-239, but that would happen over several times the 6,500 year half life
of Pu-240. Even
then the Pu-240 would be replaced by its daughter U-236, which is a weaker
but still
noticeable absorber, degrading the thermally fissile mixture.
The assumption of significant dispersion of plutonium into the
surrounding
geologic medium is without justification. Geologic processes would take
millions of
years, by which time plutonium would have decayed to uranium-235, which is less
reactive than Pu-239. We have not discovered a credible process that would
produce
more rapid dispersal. Anthropogenic measures are unlikely and are routinely
accounted
for in repository analyses. "Criticality Issues" argues that water flowing
down through the
repository would dissolve the glass log in 1,000 years and leave a fragile
powder, but its
calculation overestimates the amount of rainfall on-and water within-the
repository by
factors of 1,000, so the correct time scale for dispersal is about a
million years.[4]
Moreover, the temperature gradients driving the process are overestimated
by an order of
magnitude, and the leaching process could leave a residue as strong as the
original log.
Autocatalysis. The papers' assumptions about the behavior of the
fissile mixture
near criticality are not credible. Based on their improper interpretation
of published
equations of state, "Nuclear Excursions" and "Underground Autocatalytic
Criticality"
assumed the rock in which the fissile material is placed is rigid and would
prevent the
expansion of the material. Rock is compressible, and even at depths of
several kilometers,
lithostatic stresses are small and anisotropic, so that confining stresses
are small. Even if
the mixed material became critical, it would slowly heat and expand, which
would
decrease its reactivity below critical. Then its neutron flux would drop,
and it would
cool.[5] Thus, these dry mixtures have the negative temperature
coefficients characteristic
of most fissile assemblies, as discussed in detail in the open meetings of
the review, and
would not be autocatalytic for material motion over geologic time scales.
"Criticality Issues" again argued that fissile material could
diffuse to criticality,
although it shifted its argument to SiO2 with high amounts of water, which
have higher
reactivity.[6] However, the physics for such media is essentially the same
as that for dry
rock.[7] There are two parts to the argument, depending on whether the mixture
approaches criticality from the under moderated or over moderated side.
From the under
moderated side, as the mixture reached criticality, it would heat slightly.
That would
expel some water, which would reduce its reactivity, after which it would
cool.[8] This is
closely related to the stabilization of dry media by a negative temperature
coefficient.
From the over moderated side, as the mixture gradually passed
through criticality,
it would heat slightly-though not enough to expel significant water-which
would cause
it to expand. That would reduce its reactivity, after which it would
cool.[9] Thus, over
moderated, heavily hydrated mixtures generally also have negative temperature
coefficients.[10] Thus, there is nothing new in the papers on wet media,
which just repeat
the stability errors made in "Nuclear Excursions" in a different context.
A key feature not addressed in the papers reviewed is importance of
the evolution
in time of the criticality and temperature of the mixtures. For those of
interest, the time
scale for the increase of reactivity is very long-tens to hundreds of
thousands of years.
Thus, the excess levels of criticality and hence the time scales for the
release of energy
are correspondingly long-thousands to tens or hundreds of thousands of
seconds. And
the temperature increases are fractions of a degree. The slowness of those
processes
dominate the faster time-dependent processes postulated but not analyzed in
the reports.
There are some scientifically interesting interactions between the
negative
temperature coefficient of such mixtures from expansion and the potentially
small
positive coefficient from absorption and Pu-239 resonance broadening, but
those effects
are delicate and comparable even at very high levels of hydration.
Unfortunately, they
cannot be evaluated from the calculations in "Criticality Issues," which
were apparently
all performed for cold soil, pure SiO2, and pure Pu-239. All three of those
restrictions
would have to be removed to provide an assessment beyond that in "The Myth
of Nuclear
Explosions at Waste Disposal Sites," which predicts overall stability.[11]
Energy release. Even if dispersion and criticality are assumed, the
conclusion that
an explosion would occur is incorrect. "Nuclear Excursions" postulates
"auto-catalytic"
behavior in which the release of energy leads to greater criticality, but
the discussion
above shows that in dry repository material, the release of energy instead
reduces
criticality and shuts the reaction off. "Criticality Issues" postulates
auto-catalytic behavior
in hydrated mixtures, but the discussion of the previous section shows that
to the extent
that the phenomenon has been quantified by earlier work, the release of
energy reduces
criticality there, too. Temperature increases appear to be limited to at
most fractions of a
degree for plausible dispersal times.
The postulated mechanisms for explosion are not credible. The
essential feature of
explosive process is the rate at which energy is released. The papers do
not calculate it;
they do not even estimate it. They simply assume it. For the largest
realistic rates the
most that appears possible is heating and evaporation of some water before
a smooth shut
down. There is no credible mechanism for releasing energy on a time scale
short enough
for even a steam explosion. A nuclear explosion must make the transition
from critical to
highly supercritical in a fraction of a second. A credible means to force
such a transition
in a repository has not been found.[12] Thus, the assertion that an
explosion would occur
is incorrect.
Even if dispersion, criticality, and energy release are assumed,
which appear
virtually impossible on the basis of the arguments above, there would be no
serious
consequences elsewhere in the repository or on the surface. Even if an
explosion could
occur, careful calculations indicate that the energy released would be on
the order of a
few percent of that from the natural decay of the Pu over the same time
scale. Detailed
hydrodynamic calculations indicate that the containment volumes from such
explosions
would be very small compared to the nominal spacing between storage
elements; thus,
there could not be any coupling between storage elements or any possibility
of greater
energy releases through synergisms.[13]
Relation with other work. That the critical mass may be reduced by
dilution by
moderating material, as discussed in the paper, is well understood by the
nuclear
community. Fermi used it to full advantage when he assembled the first pile
under the
grandstand at Stagg Stadium.[14] Fermi also used the advantages of
heterogeneity in
minimizing resonance losses in natural uranium, although that is irrelevant
to the
discussions of Pu reactivity here.
The National Academy of Science report does not suggest emplacement of
weapons plutonium in the manner discussed by "Nuclear Excursions," although
it did
comment on the advantages of higher fissile loadings. The Academy was alert
to the
potential for criticality and qualified its recommendations by stating that
further analysis
and discussion were needed before deciding on the best and safest geologic
disposition of
weapons and reactor spent fuel.
Summary. We should always be alert to unintended consequences and
open to
discussions that illuminate potential dangers in nuclear waste storage.
"Nuclear
Excursions" argued that there were serious dangers in proposed repository
concepts, but
review found the paper's major assumptions flawed and its major conclusions
incorrect
for fundamental, technical reasons, which were stated in detail and in
writing. "Criticality
Issues" did not respond to those criticisms; instead, it introduced a new
scenario, in which
it made the same technical errors in a new context. Those errors were
combined for
publication in "Underground Autocatalytic Criticality." We find no
technical merit in
these papers. However, they treat technical matters and apparently contain
no classified
material; thus, in accord with the Laboratory's policy of open and
unrestricted research
and discussion on unclassified matters, the authors should be free to
submit their paper
for publication in a peer reviewed journal.
We do not find any value in these two papers that would justify
their publication,
and do not see how to produce such a paper from them. They contain
fundamental errors
in concept and execution. They show no grasp of such elementary concepts as
the time
scale for the approach to criticality, the rate of energy release, and the
crucial role of the
negative temperature coefficient of the systems treated. Moreover, they show no
appreciation of these points even after they were pointed out clearly in
the review by
those who do did understand them. That is compounded by the shifting
scenarios on
which the papers are based and the alarmist estimates of potential effects,
which have
become less credible and more shrill throughout the review process.
The authors have shown little interest in technical suggestions or
inclination to
respond to them; thus, it would not appear to be useful to continue this
one-sided
discussion. However, it would be irresponsible for the Laboratory to
disseminate untested
opinions in this visible and controversial area. Thus, if this program is
continued, and
these individuals remain associated with it, the laboratory would be well
served by
establishing a permanent red team, funded by this program and composed of
members
from the cognizant technical divisions, with the responsibility of
independently checking
the calculations done by those in the program.
References
1. C. Bowman and F. Venneri, "Nuclear Excursions and Eruptions from
Plutonium and
Other Fissile Material Stored Underground," draft, 22 November 1994.
2. C. Bowman and F. Venneri, "Criticality Issues for Thermally Fissile
Material in
Geologic Storage," draft, February 1995.
3. C. Bowman and F. Venneri, "Underground Autocatalytic Criticality from
Plutonium
and Other Fissile Material," Los Alamos National Laboratory document
LA-UR-94-4022
(draft), March 1995.
4. T. Kunkle, "Bowman and Venneri, Part Deux," Los Alamos memo EES-5,
DDEES/CEP:95-006, 15 February 1995.
5. G. Canavan, "Time Dependence of Neutron Density and Material Temperature in
Thermally Fissile Mixtures," Los Alamos National Laboratory report , March 1995.
6. W. Stratton, "Neutron Transport Reactivity Calculations of Plutonium
Mixed with and
Reflected by Silicon Dioxide," Los Alamos memo, 14 December 1994, Fig. 7
and Table
V.
7. W. Stratton, "Pu/SiO2 Overmodulation and Autocatalysis," Los Alamos memo, 10
January 1994.
8. K. Despain, "keff vs. Assembly Radius from MCNP Calculations-Weapons
Grade Pu
in Tonopah Springs Rhyolite," Los Alamos memo for blue team, December 1994.
9. G. Canavan, "Time Dependence of Neutron Density and Material Temperature in
Thermally Fissile Mixtures," op. cit.
10. W. Stratton, "The Myth of Nuclear Explosions at Waste Disposal Sites,"
LA-9360,
October 1983.
11. W. Stratton, "The Myth of Nuclear Explosions at Waste Disposal Sites,"
op. cit.
12. J. Kammerdiener, ""Bowman-Venneri paper on 'Nuclear Excursions'," Los
Alamos
X-2 memo to Jas Mercer Smith, Blue Team Leader, 23 December 1994.
13. J. Mercer-Smith, "Super criticality Blue Team Preliminary Report," Los
Alamos
memo, December 1994.
14. E. Fermi, "Elementary Theory of the Chain-reacting Pile, Science, 10
January 1947.
Bark
}what if a relatively large amount of Pu (or weapons-grade U235), of the order
}of tens of kilograms, just happened to roll "together" in a super-critical
}geometry, as say in the bottom of a drain or any other appropriately shaped
}vessel (like a very badly designed breeder-reactor vessel)? Would the inertia
}the large mass of metal/oxide be sufficient to keep the lot together long
}enoug for prompt criticality and subsequent detonation? Reactor-grade Pu (large
}percentage of Pu241) would be worse in this respect, as there would be more
}spontaneous fission neutrons to trigger an "excursion". I seem to remember this
}scenario as a reason why a meltdown in a large breeder reactor would be a Very
}Bad Thing. Comments anyone?
}Frank Ieromnimon, ie...@essex.ac.uk
Nothing, really. But let's step through it, anyway!
******First, some commentary******
(pardon any residual bias on my part...)
What would weapons-grade 235 be doing in a breeder-reactor vessel?
Breeding is not possible with U235, since no natural isotope will
generate 235.
Typical breeder reactions include:
Pu239-fissile and U238-fertile
or
U233-fissile and Th-232-fertile
Why do you suggest that "reactor grade" fuel would have a high
percentage of Pu241?
Then you ascribe the reactivity to the spontaneous fission of 241.
Spontaneous fission of Pu 241??
Pu-241 is not a player in the world of spontaneous fission.
Spontaneous fission (sf) half-lives for a range of plutonium isotopes is roughly:
238 5 * 10^10 YEARS
240 2 * 10^11 YEARS
241 negligible
242 7 * 10^10 YEARS
(Pardon minor errors, but my books just got moved to the other floor, and
I don't feel like fetching... feel free to make corrections.)
Furthermore...
It would be difficult to argue that Pu 241 (notation: 41) would produce a
significant neutron population from spontaneous fission. Suppose we were to
exaggerate (wildly) the contribution of all spontaneous fission neutrons from
all potential sources of spontaneous fission isotopes (Pu, U, Cm, Cf, etc...).
In that case, you would not come *close* to producing 1 * 10^4 neutrons per
square centimeter per second for ANY combination of isotopes, in ANY
configuration, under ANY physical conditions from spontaneous fission.
This is important, because you would expect that if you had a system which
was exactly critical, you would likely have a neutron density many orders of
magnitude greater than that. In other words, spontaneous fission would not
contribute any meaningful fraction of the neutrons affecting the criticality
of this system. For that reason, it is not possible to discuss spon.-f
contributions to excursions.
The reason a melting of the fuel in a breeder reactor (or any reactor) is a
"bad thing" is that you have invested a large quantity of resources, and have
lost that asset. There is also some health risk to the nuclear plant workers.
******End of Commentary******
(Much of what you are asking has terminology kinda jumbled, so it is
difficult to assess what you were really asking or wanted to know... so please
excuse me if I am not responding to your intended questions...)
As I see it, your only "real" question is: "What would happen if multiple
bomb pits were somehow forced together?"
I assume that this is the question you are asking.
Bomb pits would not be in a condition to "roll around." Although the exact
means of disposition has not been determined, they would most certainly
be canistered, and in no condition to "roll."
In fact, there is no mechanism by which packages, pits, fuel, or high-level
waste would be brought together... so the question is not applicable to
the repository, reactors, or cans of Spam. ;-)
Just for the sake of speculation, let's say that all the geologists are wrong,
and that Yucca mountain is about to become hyperactive, geologically-
speaking.
Let's suppose that the earth shifts so that multiple packages of weapons-
grade material is somehow pushed together into a single mass. I hope I
don't need to explain that the probability for any one of these events
is roughly equivalent to being invaded by an army of Elvis impersonators
from Mars, right?
Okay... LETS SAY IT HAPPENS!!! What then?
Any release of energy would be far too slow to result in any sort of
detonation. The thermal releases would be insignificant with respect to the
magnitude of the geologic activity around it.
I hope this has been of some use, and not too picky.
I hate when people nitpick instead of responding to the spirit of the
question.
Take care,
--b.
Atomic Rod
not make any sense.
First of all, even highly enriched materials generally have a negative
temperature coefficient of reactivity. Generally, a critical condition
causes the material to heat up and expand. The expansion allows more
neutrons to leak out of the boundaries of the material, thus reducing the
reactivity and preventing a large power excursion.
Forming an explosive device requires delicate timing to prevent the
expansion long enough for more fission reactions to occur. Generally
speaking, this requires an explosive detonation to compact a subcritical
configuration into a critical one. If it was easy to make a bomb, we
would not have needed three years of dedicated efforts by some of the
world's most distinguished scientists after the first chain reaction. I
find it impossible to believe that it can be done by accident.
Finally, am I the only one who remembers that the US government has been
detonating nuclear bombs under the dessert in Nevada for decades with
little effects on the environment above ground? Even though I believe a
nuclear explosion in a repository is impossible, I also cannot believe
that it would have too much impact. Surely the bombs that we have
produced on purpose have a higher yield than any postulated farfetched
accidental explosion.
All that said, I firmly believe that burying heavy metals is really,
really stupid. We are planning to waste an extremely valuable resource.
Future generations will not appreciate how difficult we made it for them.
Adams Atomic Engines is planning to develop cores that directly reuse both
spent nuclear fuel and former weapons stockpile material.
Rod Adams
Adams Atomic Engines, Inc
P. O. Box 1017
Tarpon Springs, Fl. 34689
Douglas A. Harrell
>
> The more one thinks about it, the more apparent it becomes that the
> whole study is just a bid for funding. Even in a critical configuration,
> it won't explode like a bomb. But, if we don't make the problem
> dramatic, then we can't get more funding....
Alan,
I think you've hit the nail on the head. Contrast your statement
with the following quote. I cannot remember the man's name, but it's
something close to 'Scheider' or 'Schneider'. He was a producer of
a CBS special entitled "The Fire Next Time" a couple of years ago,
which was an environmental scare piece, more or less. He was also
quoted as a source in Al Gore's book, _Earth in the Balance_. The
quote comes from a 1989 speech or enviro article (don't know which).
I can't put my hands on the exact cite right now, but I'm looking
for it. I know that the quote is word-for-word, though. Consider:
"To get some broad-based support, to capture
the public's imagination, we environmentalists
have to offer up scary scenarios, make simplified
dramatic statements, and make little mention of
any doubts we have; each of us have to decide
what the right balance is between being effective
and being honest."
Something to chew on.
Doug
--
Douglas A. Harrell | I'm in real trouble with Billary and the
Georgia Institute of Technology | PC Police: I'm a male, white, conservative,
Atlanta, Georgia | anti-gun-control, Christian, nuclear
gt0...@prism.gatech.edu | engineer with a '70 Chevy Camaro. Help!