ML20064K470
| ML20064K470 | |
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| Site: | 05000142 |
| Issue date: | 11/17/1982 |
| From: | Warf J COMMITTEE TO BRIDGE THE GAP, SOUTHERN CALIFORNIA, UNIV. OF, LOS ANGELES, CA |
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| NUDOCS 8301180415 | |
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N
&n 1
g UNITED STATES & AMERICA 4
NUCLEAR REGUIAIORY COMMISSION
'i 3EF&E THE ATOMIC SAFTfY AND LRXmm BCARD In the Matter of
)
Docket No. 50-142 THE REGENTS & THE UNIVERSITY s'
(Proposed Renewal of I
(UCIA Research Reactor)
DECIARATION & DR. JAMES C. WARF I, James C. Warf, declare as follows:
1.
I aa Professor of Chemistry at the University of Southern California (USC), where I have been a member of the faculty for the last thirty-four years. Prior to that time, I spent five years with the Manhattan Project, mostly at Ames Iowa, and,. to a Ieeser degree at the University of Chicago and at Oak Ridge, Tennessee. I specialized in the chemistry of nuclear satorials and was Croup Leader of the Analytical Section and, part of the time, the Inorganic Section, at times with seventy people working under me.
Directly after World War II, I played a role in the formation of the Federation of Atonio Scientists (later Federation of American Scientists).
Nearly thirty years ago I helped foual the Los Angeles Chapter of the Federation of American Scientists, which later became the Los Angeles Federation of Scientists and, most recently, the Southern California Federation of Scientists.
I remain active with the organization to tids day.
A more detailed statement of professional qualifications is attached hereto.
2.
I have reviewed certain documents related to the UCIA Argonaut reactor.
These documents have included: (1) " Analysis of Credible Accidents for Argonaut Reactors" by S. C. Hawley, el al, particularly those sections dealing with explosive chemical reactions and graphite fire, (2) a draft analysis by David DuPont of the Wigner energy section of the Hawley report, suwa, (3) " Fuel Temperatures in a'n Argonaut Reactor Core Following a Hypothetical Design Basis Accident (DBA)" by C.E. Cort, and (4) the fire response section of the March 1982 Emergency Response Flan for the UCLA Reactor, specifically the Los Angelos Fire Department fire response plan attached thereto as
" Attachment A."
Certain other relevant documents, identified below, have also been reviewed.
8301100415 830112 PDR ADOCK 05000 G
. 3.
It is my understaniing that, having operated for roughly twenty years, the UCIA Argonsut reactor is currently the subject of a safety review by the U.S. Nuclear Regulatory Commission as part of a license renewal proceeding.
i Such a review seems to me to be a sensible precaution, as occasionally some significant fact or facts, overlooked in an original analysis decades before, may be uncovered. And if nothing significant is found, a greater level of assurance of safety has been established. Thus, in my opinion, it would be prudent for such a safety review to take into accouat the following facts:
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The original Hazards Analysis for the UCIA reactor dismissed the probability of damage from fire resulting in the release of fission products as "very samll' in part because "nora cf the materf als of construction of the reactor are inflansable." (1960 UCIA Reactor Hazards.uialysis, p. 62,
" Fire"). While other facters may affect the probability of fission product release from fire, the statement that none of the msterials of conetruction j
of the reactor are inflammable is simply incorrect. A number of those materials--particularly the graphite, uranium, magnesium, ani even the aluminum, among others--cre, under the right coniitions, most definitely combustible.
5 The first and most obvious of the combustible materials used in the Argonaut reactor is the graphit&used as moderator, reflector, and thermal column. Graphite will, under the right circumstances, most definitely burn, as the Hawley report correctly iniicates.
(Charcoal is, after all, a graphitic substance, ani it will, of course, reartily burn.)
6.
Cr. page 82 of the Proceedings of the 1958 Atomic Energy Commission and l
Contractor Safety and Fire Protection Conference, held at AEC Headquarters l
in Germantown, kryl.ind, June 24-25, 1958, held in part to anslyze the l
implications for reactor saf ety of the Winiscale accident in which the graphite moderate,r and tha uranium fuel both caught fire, Dr. C. Rogers l
McCullough of the USAEC is quoted as saying:
By the way, this is an amusing Point. The belief had grown up on the part of many people in this country that graphite will not burn.
This is nonsense. Czaphite is carbon, and anyone knows that carbon will burn if you get it hot enough.
But this glib remaric, that graphite will not catch on fire, had become prevalent.
While not having personal knowledge of any widespread belief in this ccuntry that graphite could not burn, I concur with Dr. McCullough's statement that it, of course, can burn in air, as the Windscale fire unfortunately so clearly demonstrated. A belief to the contrary would be neither correct nor prudent.
t 7.
As to the matter of the ignition temperature of graphite, it is dependent upon a number of factors such as the purity and density of the graphite, the amount of air present and the velocity of the air, the particle size and surface-to-volume ratio of the graphite, and structural configuration influencing heat loss. Furthermore, there appear to be other uncer ninties, as evidenced by Cr. McCullough's comments at the sane page of the above-cited l
~
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proceeding:
Research work is going on; we are not satisfied that we know the ignition point of graphite.... Aj any rate, research is going on to learn more about the ignition temperature. It is a tough problem to solve, and we are exploring Possibilities.
Thus, there are some uncertainties as to ignition temperature of graphite, and it might be wise from the point of view of a conservative safety analysis to place or establish the magnitude of error on whatever estimate of ignition tagerature is used. However, I am not prepared at this time to su6 gest what error limits might be aymyzaate for any specific estimate of ignition temperature.
8 8.
The Hawley report uses a figure of 650 C as the point at which graphite will burn readily if sufficient caygen is supplied. That figure seems to me to be reasonable for reacter-grade graphite, although as I indicated in 7 above there are some uncertainties and some error limits might be appropriate. Any temperature estimate is valid only for a fixed set of parsuuters (density, purity, particle size, air supply, etc. )
9.
Once ignited, self-sustained combustion of the graphite must be assumed if the air supply $s adequate. Although this depenis upon configuration, airflow, and the like, it appears to me that somewhere arouni 650 C is the critical temperature for induction of a self-sustained fire in the Argonaut reactor's graphite. This temperature is above a glowin6 red heat but below a white heat. The reaction is exothermic, so if some of the graphite were ignited, it could release enough -heat to bring other graphite to the ignition temperature.
10.
In addition to graphite, I understand the Argonaut reactor at UCIA employs metallic uranium in a uranium-aluminum eutectic, clad with aluminum.
Metallic nanium readily burns in air if ignited, and underssomewhat more restrictive conditions, so can aluminum. Aluminum gives off more heat, pound for pound, th-n uranium metal when burned, but it is somewhat more resistant to burning. The fact that the uranium ami the alum.num are in a eutectic will not affect the ability of either to burn, although burning of the eutectic will give off slightly less heat than if the materials were not in a eutectic.
- However, the difference is insignificant.
In addition, _the fact that the cutectic melts at a relatively low temperature (640CC-Hawley, p.18),
will not affect the ability of the saterials to burn. The metals can burn as well in a liquid form as a solid. In fact, molten metal can cause fresh aluminum, withcut the normal protective oxide layer, to be exposed to air, = Iring hains far more likely.
11.
As to ignition temperature for uranium metal, 2681" there are some uncertainties.
Charles Russell (Resetor Safeguards, Pergamon Press, Oxford,1962, p.115-116, citing W.C. Reynolds, Heport NACA TN D-182,
" Investigation of Ignition Temperatures of Metals") gives the ignitien temperature of solid uranium metal in oxygen at 1 atmosphere as 6080 F (32 T C). Yemel'yanov and Yevstyukhin (The Metallurgy g Nuclear Fuel, l
1
..,a
, 0 Perg= man Press, Oxford,1969) state, "At a temperature above 700 0 solid compact uranium krns in air and in oxygen emitting a M*nding white light.
Here uranium mixed oxide is fo_med according to the reaction 3U + 4
)
U 0g + Q 3
where Q = 845 2 k mol. " Turnings of reactor-grade uranium have ignitai when being cut using a lathe, evidently from friction. Finely divided uranium ignitee in air at room temperature. Thus the ignition temperature is a variable, depending on circumstances, but in general uranium metal must be :nnsidered more combustible than graphite.
I have had no experience with uranium-aluminum eutectic, but the coLbustibility of the alloy certainly merits invest Qation, in both solid and liquid states.
12.
It is my unders+mnding that the control blades at the UCIA reactor are < =dmium-tipped and protected by magnasium shrouds.
Magnesium can also burn, and when it does so it gives off considerable energy. The ignition temperature of Mg metal is variable, depending on its particle size, etc.
If you specify an ignition temperature you want, from 25 up, I can prepare a specimen which will ignite at that temperature. One should tie aware that slow oxidation occurs below ignition temperature.
('admium metal is a lou-selting metal with a relatively high vapor pressure.
The Handbook of_ Chemistry and Physics reports its melting temperature as 3200C.
If the control blades are nude of the metal and not the oxide, it would thus seem prudent to analyze the rer.ctivity and other possible l
consequences of an incident which resulted in the melting of the control bladas. Furthermore, the volatility of < ndmium could potentially result
(
in < =Amium vapor being released in a fire or other incident involving elevated temperatures.
If so, the cadmium vapor or its oxide would likely rapidly condense in air as minute particles and could cause a potential hazard for fire-fighters or others due to the toxic nature of cadmium. This, too, should protably be considered, it would seem to me, in de=4 gning fire-fighting plans and analyzing potential accident sequences ani consequences.
13.
I also understand that UCIA is requesting a license for 2 curies of plutmium-239 in a plutonium-beryllium neutron source for the reactor facility.
'4ere this Pu-Be source to become involved in fire, the consequences could verge on the catnatrophic. Plutonium metal, of course, can burn, releasing minute particles into the air, dispersed by the energy of the fire. Fire-fighting would be extremely hazardous due to the presence of the plutonium oxide in the air, and the public health implications would be awful.
(2 curies of Pu-239 is by no means an insignificant amounts placed near the skin, it will cause radiation burns in a few minutest inhalation of even microgram amounts is exceedingly dangerous).
When Pu metal burns, it goes to PuC2 in limited air, to Pu3 8 in excess air, 0
just like uranium.
3e is comparable to Al in its combustion, but is higher melting. Again, the chemical form of the :nterial is important, i.e. whether in metal or oxide. Bec is volatile in steam at hiGh temperatures.
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. 14 The issue of how to fight a graphite-uranium fire leaving aside the possibility of cadmium and plutenium particles being released, has no easy answers ani would require considerabLs prior analysis of the problems inherent ani prepmtion in advance in the form of emergency phnnina.
There could be great danger, in particular, in employing either water or, to a lesser degree, carbon dioxide to put out the fire.
In either case, an explosion might occur ewing to the formtion e
of combustible gases.
15 Dr. Mccullough's report on the Windscale incident, in the AEC document referred to above, describes how those fighting the fire tried various methods over a couple of days to put the fire out, which involved both uranium and graphite, all to no avail, ani how they had to try, as a last resort, water:
Now they were faced with the decision either to use water or to let the fire burn up.
They decided there was nothing left for them to do but put water in.
There was some trepidation about this, as you can imagine, because they well knew that water on glowing uranium makes hydrogen. Water on glowing carbon makes bydrogen and CO you have then a nice sixture of hydrogen, CO, and air, and you might have an explosion.
But they had no other choice.
They, in the end, followed techniques learned during World War II in' extinguishing incendiary bombs, and fortunately the gamble paid off.
But they had no other choice, and righty worsoextremely worried about the potential for an explosion. The fact that one did not occur at Windscale, in my opinion, does not get one arouni the fact that such an explosion is clearly possible, could be quite dangerous, ani that water should, if at all possible', not be used, or if used, used with the potential danger clearly thought out. As McC.nllough concluded:
I think it took a great deal of courage on the part of these people to pit water on this reactor. They did it with fear and trepidation, and in talking with them they will not guarantee that they could do it a seconi time without an explosion.
I note also that the steam that ensued carried with it very significant quantities of fission products into the environment.
16.
The potential for metal-water or metal-steam reactions should be examined in putting together fire-fighting plans. Aluminum, uranium, magnesium, ani graphite all can react in a steam environment, producing large amounts of energy, liberating hydrogen which can cause explosion Russell indicates the Al-H O reaction liberates mere than dangers.
2 twice the energy of nitroglycerin, in calories per gram, and five times the energy of black powdert the magnesium-water reaction just slightly less than aluminum; and the U-H O reaction just somewhat less than black powder.
2 (Al + NH NC was used as a cheap explosive in Vietnam, "raisy Cutter.")
g 3
. 17.
I do not believe it likely that a group of firefighters ardving on the scene would have the competence to judge whether to use water, and if so, how, etc. Furthermore, it would seem most prudent for an emergency plan to have been considered in advance of the appropriate fire-fighting response, and for the requisite materials to be randily available for such fire-fighting. Utere are non-moderating materials that couLi be used to smother the fire that would not react explosively with h,-ning core compononts:
i careful ccasideration should be given to the choice of these.
Pty randing j
of the one-page fire-fighting plan included in the March 1982 emergency plan seems to me inadequate in these regards.
18.
'Ihe use of CO2 on such a fire could also be dangerous. Graphite is oxidized by CO2, yielding carbon monoxide, which is also explosive in the presence of air.
19 Simple carbon tetrachloride extinguishers that formerly were used for lab fires have a host of problems assaociated with their use, notably the toxic phosgene they give off when used on fires. And even some chemical fosas :316 t have a favorable moderating effect that needs to be taken into h
account (this can be gotten around Perhaps, by the addition of baron-t containing compounds to ruch foams).
20.
Firefighters would also have to be prepared to deal with potentially toxic substances such as cadmium fumes.in the air, and work in an environment pcssibly cantaminated with fission products and perhaps plutonium. They would need good information as to what materials had been released in to i
the air and roughly in what concentrations, good detectors for those materials, and ability to read and interpret that information. They I
would need ayywyulate equipment to protect themselves from inhalation of the materials and from direct exposure.
21.
As stated above, the one page plan by the LA Fire Department, in my opinion, does not adequately address the above potential problems. While one hopes that such an energency never occurs, and trusts that adequate precautions will te taken to minimize any potential for such an emergency, an emergency plan must realistically deal with the conditions that could occur if such an emergency were to happen. The existing plans to control a reactor fire are, it seems to me, inadequate. A revised emergency response could profitably include the followings rapid determination of any radiation h?zard, rapid evacuation of personnel, stockpiling of fire-fighting substances safe for reactor materials, and knowledge of access ports to the reactor.
The fire-fighters Jhould not have to locate and confer with any particular reactor personnel, who might not be available at once.
22 I understand that therte is some question about positive temperature coefficients of reactivity for graphite. Sitch a positive effect has been known for a long ti= waainly we in the Manhattan Project knew about it forty years ago.
23.
As to the Wigner effect, the small size of the UCIA reactor does not necessarily mean that the amount of Wigner energr absorbed per gram of graphite is likewise small.
In fact, vers a large-sized reactor and UCIA's far smaller reactor to both produce 1 W-day of energy, all other things being equal, the amount of Wigner energy absorbed in each gram of adjacent y
1 f graphite would be considerably greater in the UCIA reactor than in the larger reactor, for the simple reason that the larger reactor has far more graphite to absorb the same amount of energy, thus the energy absorption per gram of graphite is " diluted." All other things being equal, a large reactor with the same neutron flux as the UCLA reactor, run for the same length of time, would produce the same amount of energy absorbed per gram of graphite as the UCLA reactor. And it is the energy absorbed per gram cf graphite that is the key to whether enough energy has been stored to bring any. d of the graphite to ignition if enough air is presents and, given the paper configuration, one unit of graphite ignited could release enough heat to bring nany additional units of graphite to the ignition potut.
analysis of the Wigner energy matter,
'24 I have read the Hawley, et, als as well as Mr. DuPont's critique thereof. It appears to me that there is considerable disagreement as to how much Vigner energy can actually be absorbed, given operating limits, in the UCIA reactor. As I understand it, Mr. DuPont uses the same analytical method as Mr. Hawley, yet takes issue with some of the numerical values Mr. Hawley used in his ~1-1=tions, particularly the neutron flux ard number of MWD
- of operation at UCIA and the appropriate cal /g absorption idgure that should be used for exposures at low doses.
It appears that, if Mr. Hawley's calculational method is correct and if Mr. DuPont's num rical values are the ayywyulate '
ones, the~ amount of Wigner energy that er &i be absorbed in the UCIA reactor's graphite would be roughly twenty times i s amount Mr. Hawley indicates.
12 2
n/cm-sec.
Mr. DuPont uses 12,awley uses a neutron flux.of 10 25 Mr H
taken from the UCIA Application fr Relicensing at page 1 5 x 10 III/6-5 Mr. Hawley's report takes the valm 0 5 cal /g per *D7AT as the best value for the rat 9 of energy storage u. graphite irradiated at 3000.
Yet Nightingale (p. 34S) states, "More accurate values derived from measurements at very low exposures range from 0.6 to 1.C es1/ MWD /AT."
Mr. DuPont further takes issue with the Hawley study conversion to energy storage rate at 50 C graphing the Nightinrale data for the change in the rate of energy storage with temperature, Mr. DuPont finds 5/6ths the energy stored at 500C than at 3000, whereas the hawley report uses a smaller fraction. Finally, the 19mley study indicates;12 MWD to tate at UCLA Mr. DuPont says the correct figure is 17 WD, and if the reactor were to operate its licensed limit of 5% per year through the proposed license period (until the year 2000), an additional 37 MND could be produced. These modifications of the Hawley study calculations by Mr. DuPont seem reasonable, and raise a substantial question as to how much Vigner energy might be absorbed in the UCIA graphite.
26.
In addition, there are some uncertainties in makin.3 such calculationa, as they rely on employin6 empirically derived data from various irradiation locations in a few reactors and then extrapolating to another reactor of a different kind and configuration. Plus, I understard there is some uncertainty as to the part irradiation history of the UCIA reactor's graphite-whether, for example, it might have been previously used in another reactor prior to the construction of the UCLA reactor.
In light of the foregoing, I suggest removing some of the graphite from different
+ WD =eans megawatt-days.
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locations in the UCIA reactor core and experimentally determining how much Wigner energy has indeed been absorbed to date in the graphite.
This could be done by any of a variety of methods--calorimetric anna =T ing, X-ray diffraction patterns, heat of combustion measurements.
(I unierstand the UCIA reactor is occasionally used to color diamonds. If this effect is due to changes in the dimannd's crys +=114ne structure ani not to impurities in the diamond, this would be further evidence of this reactor's capability of causing radiatiat damage in graphite, as graphite and diamoni are the two crystalline forms of carbon and would react similarly to neutron bombardment. I also understani there is some questien as to whether the UCIA graphite has exhibited some swelling er dimensional changes if this is confirmed, it would also be evidence of Wigner energy storage ani would lend further reason to the possible usefulness of making actual measurements.)
27.
Both the Hawley ami che Cort studies examine certain accident scenarios that could, by themselves, cause substanthl temperature rises in the UCIA reactor.
In both cases-the Hawley analysis of power excursions and the Cort analysis of coolant restriction following earthquake-the temperature did not reach that of the molting of the fuel eutectic or aladding.
However, if substantial Vigner energy were stored in the graphite, such an incident could, conceivably, release that energy ani substantially raise the temperature that could be reached.
In addition, some experimental materials in the reactor core say have ignition temperatures below the melting point of the fuel, in which case fire could be initiated even -
though the initiating temperature did not approach the fuel's critical temperature.
'Ihus, the significance of possible flammable characteristics of the reactor core contents ani the true amount of Wigner energy that could be absorbed during the license period nay well have significance in a safety review.
28.
Mucis work has been done on the attack of uranium ingots, clad in aluminum, through a pin hole. At elevated temperatures, air or water enters the pinhole, reacts, and the resulting oxide swells. 'Ihis breaks more Al skin, and the process continues faster; but so far as I know oxidation is retarded so much the ignition temperature is not reached.
Powdered uranium (from decomposition of UH ) can react with liquid water 3
and glow red, forming UO2 ani H2 Massive U metal must be heated to react.
i 29 Uranium and aluminum can be sepwated. chemically from their eutectic by any number of techniques.
One method is to dissolve the eutectic in hydrochloric acid, ani oxidize the uranium to uranyl ion using nitric acid.
Addition of excess sodium hydroxide precipitates the uranium as sodium diuranate, but converts the aluminum to the soluble aluminate ion.
Separation is effected by centrifuging. Alternatively, the uranyl nitrate can be extracted by other or butyl phosphate, leaving the aluminum in the-aqueous phase.
30.
I might also add that as I read the Hawley, g 3_,
analysis of 1
" credible accidents" for Argonaut reactors, I had the impression that certain extremely unlikely scenarios were examined ani then dismissed, with the cenclusien then asserted that there are no serious credible accident scenarios
)
. for Argonaut reactors, when scenarios more likely appeared not to have been analyzed whatsoever. Perhaps the above-desc.-ited facts can be of use in a fuller review of potential accidents ani consequences.
31.
The above-cited facts mi6ht also be of use in mitigatin6 consequences of or preventing accidents.
For example, it might be prudent to consider use of a uranium oxide fuel, which would be far less susceptible to burnin6 A boron-based control blade might get around the low-molting temperature problea for the cadmium (if it is in the metallic form). Boron-based fire-fighting foams or other atterials mi ht ameliorate problems cf using water 6
alone. Sani or a silicate, as 'a clay, perhaps could be used to smother the fire.
It might be best merely to close off the air supply mechanically, but the possibility that this might allcw the reactor to overheat should be eraainea.
I cannot overstress consideration of the danger of nains water on such a fire, should it ever occur. The use of water on such a fire cct:ld be disastrous.. Careful emergency planning before such an event occurs should hopefully result in fire-fi6hters not having to face the terrible choicot, faced by those responii46 to Wind-le.
I declare under penalty of perjury under the laws of the i
United States of America that the foregoing is true and correct to the best of my knowled e ani belief.
6 CN l
t2ms4.
James C. Warf l
Executed at M f4 8/M 44
, Palaysia l
Ms l7 th day of 4,e,d,er., 1982 l
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DR. JAMES C_. WARF Professor of Chemistry University of Southern California Professional qualifications 1939 3.S. degree in chemistry, University of Tulsa (Nc1=homa) 1940 41 Research chemist, Phillips Petroleum Co.
1941-42 Instructor in chemistry, University of Tulsa 1942-47 Manhattan Project. Group leader of analytical section and, during the last years, of the inorganic chemistry section, mostly at Iowa State University, Ames, but frequently at the University of Chicago and other sites. Hesearch on chemistry and analysis of nuclear materials, uranium, thorium, plutonium, fission products, etc.
1946 Ph.D. de6ree in inorganic chemistry, Iowa State University 1947-48 Guggenheim Fellow, inorganic chemistry, University of-3 erne, Switzerland 1948 to Assistant, Associate, Full Professor of Chemistry at the present University of Southern California, Los Angeles, Cplifornia.
Research: rare earth metals, uranium, solid state, crystallo6raphy, thermodynamics, liquid ammonia solutions.
1957-59, 1962-64, 1974-76, 1978-79, 1982-Visiting Professar of Chemistry at various universities in Indonesia or Malaysia 1969-70 Visiting Professor, Technical University of Vienna, Austria l
1964-70 Consultant, Jet Propulsion Laborad.ny, Pasadena, California l
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Author of approximately 65 scientific papers or encyclopedia articles, 8 books on chemistry.
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