ML20054C665
| ML20054C665 | |
| Person / Time | |
|---|---|
| Site: | 05000142 |
| Issue date: | 04/05/1982 |
| From: | Robkin M NRC COMMISSION (OCM), WASHINGTON, UNIV. OF, SEATTLE, WA |
| To: | |
| Shared Package | |
| ML20054C649 | List: |
| References | |
| NUDOCS 8204210477 | |
| Download: ML20054C665 (5) | |
Text
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l UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of
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THE REGENTS OF THE
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Docket No. 50-142 UNIVERSITY OF CALIFORNIA
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(Proposed Renewal fo Facility License)
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(UCLA Research Reactor)
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AFFIDAVIT OF MAURICE A.
ROBKIN I,i M a u r i c e A.
Robkin,do depose and state:
C1)
I am a Professor of Nuclear Engineering and a Professor of Environmental Health on the faculty of the University of Washington (U.W.),
Seattle, Washington.
A statement of my professional quali-fications is attached to this affidavit.
C2)
I am now an employee of the U.W.
which holds a license to oper-ate an Argonaut research reactor.
I have been on the faculty since 1967 in the Department of Nuclear Engineering.
The Argonaut reac-tor is operated by the Department of Nuclear Engineering.
I have not been part of the operating staff of the reactor.
C3)
I am currently on the faculty of the U.W.
and am payed by the University.
C4)
I have acquaintance with the staff of the U.W.
reactor.
I have known all of the staff since we are in the same Department and since I have taught classes which utilized the reactor.
These staff mem-bers include Mr.
W.P.
Miller, Associate Director for Reactor Opera-tions; Mr. DeLoss L.
Fry, Assistanct Director for Facilities Engin-eering; Mr. Astor G. Rask, Chief Electronics Engineer; and Professor W.S. Chalk, Director of the Nuclear Reactor Laboratory. In each case, the relationship has been a professional one.
C5)
My knowledge of the Argonaut reactor includes its configuration, j
fuel, operation, flux levels, kinds of experiments performed and its use as a research and teaching tool.
C6)
I have never been directly employed at an Argonaut reactor.
My employment at an Argonaut licensee is as described in Cl through C4.
C7)
I have never operated an Argonaut reactor.
C8)
I served as a consultant to Battelle and submitted a report for the " Graphite Fire" section.
My report was edited somewhat, but, 8204210477 820419 PDR ADOCK 05000142 O
PDR except for residual typographical errors, I endorse that section for the combination of the report and the typographical error errata sheet.
There are residual typographical errors on page 39, line 9 (for " prevent" read "present") and page 43, line 3 (for " opening" read "tae open").
While I did not personally perform or verify the calculations used for other sections of this report, I have reviewed the document and find nothing implausible or unreasonable.
C9)
As discussed in C8, I did not find anything implausible or un-reasonable in any part of the report.
C10) The abstract and summary are reasonable representation of the content of the report.
Cll) In my opinion, the abstract and summary are reasonable repre-sentations of the content of the report.
C12) Those accidents described in the report which lead to a graph-ite fire are credible in the sense that they do not require any un-usual physical phenomena to occur.
They depend on equipment malfunc-tion or human error, both of which are credible.
Similarly, with respect to other accidents, they are physically possible but, barring overt sabotage, I consider them to be unlikely.
C13) I did not evaluate the dose which might accrue to any person or persons as the result of a graphite fire, My assignment specifi-cally excluded dosimetry.
C14) I analyzed as many credible scenarios leading to a graphite fire as I could think of, given the limitations of time and effort.
There is always the possibility that someone else could think of an-other credible scenario.
I believe that I have discussed a complete set of credible scenarios for which any specific scenario omitted would be merely a particular alternate case which would not materi-ally alter any conclusions reached.
For accidents other than those leading to a graphite fire, I was not able to postulate a credible potentially destructive accident mode which was not considered by the other authors.
C15) A probabilistic analysis of the scenarios was outside the scope of the work.
Thus, ranking the scenarios leading to a graphite fire as to their relative credibility was not done.
In order to evaluate the relative credibility would require additional effort.
Non of the scenarios which I analyzed, in my opinion, can plausibly lead to a graphite fire of such magnitude and duration as to result in fuel melting and dispersion of significant amounts of radioactivity.
- Thus, it does not appear to be necessary to give them any attention beyond that which has already been given.
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75)
An Argonaut reactor is contained in a massive, thick concrete shield.
This shield is penetrated by beam tubes, most of which are sealed at their inner end.
Two of the tubes are open at their inner end.
In addition, a pneumatic rabbit system may be installed.
The rabbit system is composed of an aluminum flight tube which penetrates the shield and graphite moderator.
When these experimental facilities are not in use, their outer ends are closed by plugs or a closed rabbit catcher.
The outer sur-face of the thermal column is closed by a set of plugs.
The space around these closures between the penetrations and the concrete is highly limited because of the close fitting nature of the tubes and plugs.
There is a small drainage hole in the bottom concrete support pad beneath the reactor.
.When the ventilating fan is running, air.can. flow through the concrete shield at rates up to 250 cfm.
However, when the fan is not running, the air flow into the space between the shield and the graphite would be very.small.
The exact exchange-rate of-air from a t h e.To on t o inside the shield when the fan is off is not known, but it is difficult to see how it could be other than small.
Because of the close stacking of the graphite stringers, air cannot readily: flow between them.
Thus, when the fan is not running and all experimental facilities are not in use and closed, the reactor would be resistant to air inflow.
"Otherwise normally sealed" refers to this condition.
77)
In figure 12.2, page 329 of " Nuclear Graphite",
R.E.
Nightingale, ed.,
the value of the energy storage rate at 50 C due to the Wigner effect is shown to be somewhat less than 300 cal /gm per 1000 mwd /At or 0.3 cal /gm per mwd /At.
81)
To estimate the potential for the glass components of an experi-ment in the reactor softening due to nuclear heating from the (n, alpha) reaction in Boron, consider the following nominal case:
Consider a long glass tube of radius 1 cm with a wall thickness of 2mm containing Boron in an amount to generate 200 cal /gm-hr under i
the conditions of 3he experiment.
Borosilicate glass has a density of about 2.2 gm/cm
(" Chemical Engineering Handbook,5th ed.",
R.H.
Perry and C.H. Chilton (3.C.), page 23-60).
The heat generation rate is then 0.12 cal /cm -sec.
Consider that the tube is in place in a beam tube taken to be l
coaxially surrounding it with inner radius of 6 cm.(5 cm airgap).
I Consider the beam tube to be lined with aluminum in close physical contact with the graphite moderator.
The thermal conductivity of aluminum is about 0.55 cal /sec-cm-C
(" Principles of Engineering Heat Transfer", W.H.Giedt, page 237) and of nuclear graphite in the crystal perpendicular direction 0.33 cal /sec-cm-C
(" Nuclear Graph-ite",
R.E.
Nightingale, ed.,
page 45)
I Take the thermal conductivity of aluminum to be equal to that of graphite (a conservative assumption).
Neglect the thermal resis-tance of the liner-graphite interface.
Graphite stringers are alter-nately stacked in opposite directions in close contact.
Thus, taking the perpendicular heat transfer coefficient to represent the entire graphite mass compensates for the small thermal resistance of the e
. stringer interfaces.
The emissivity of borosilicate glass is 0.94
(" Engineering Materials Handbook, 1st.
ed."
C.L.
Mantell, page 35-11). Consider the case when the reactor, moderator and experimental apparatus have come to thermal equilibrium.
At equilibrium, treat the graphite as having no heat source and as at its equilibrium bulk temperature of about 50 C (323 K).
Based on the Fourier heat conduction equation in cylindrical geometry with no heat source, the temperature distribution in the graphite in the direction perpendicular to the long glass tube is N
T(r)=T +
LG in [1 2nk r
where T is the temperature at the aluminum surface at radius r =6cm and whehe q is the linear heat generation rate of the glass tube.
g cal q,c= 0.12 c; x 2n x2 cm x 0.2 cm=0.1s cm-sec cm -sec cal and k is the thermal conductivity, 0.33 cm-sec-C 6
- Thus, T(r)=T +0.07 in 1
r C
Let r increase to the location of the bulk temperature, r b*
As an extreme, take r =10,000xr =60,000 cm.
For this value,T is less Take T =324 K. Neglect all cbnduc-1 than one degree largeh than T tive heat transfer (conservatkv.e).
The heat transfer due to radi-ation is given by the Stefan-Boltzmann equation as:
cal 4
4 qLR"
(
~ l m-see o o o
-12 where o is the Stefan-Boltzmann constant, 1.355x10 cal /sec-cm -K c
is the emissivity of the glass,0.94, T is the absolute temperature l
o? the glass tube of radius r =1cm. and w0ere q is the linear heat LR dissipation rate from the gla,ss tube.
For qLR"9LG' 4
- 8
- ~"*"~
T =324 +
-12 2Hxlcmx0.94x1.355x10 cal /sec-cm - K T =3.98x10 K
for which T =447 K or 174 C, well below the softening point for borosilicatE glass of 820 C (P.C.,page 23-60).
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. The safety factor is so large, and the assumptions made suffi-ciently conservative, that it is clear that the glass will never soften.
In order for the glass to soften, it would have to be ther-mally insulated from its surroundings, which is an unlikely situation.
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I hereby certify that the preceding information is true and correct to the best of my knowledge and belief.
~
/ M CA
/Maurice A.
Robkin l
s Subscribed.'and sworn before me on this day o f 'A p r i l,-1 9 8 2.
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Nota!y Public
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ny commiesion expires:
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4
MAURICE A.
ROBKIN Professional Qualifications My name is Maurice A.
Robkin.
I am Professor of Environmental j
Health, Professor of Nuclear Engineering, Member of the Radiologi-cal Sciences Group and Chairman of the Radiation Safety Committee at the University of Washington, Seattle, Washington.
I received a Bachelor of Science degree in Physics in 1953 from Caltech, a. certificate in-Reactor Technology in 1954 from the Oak Ridge School of Reactor Technology and a Ph.D. in Nuclear Engi-meering in 1961 from M.I.T.
4From 1954/to 1956, I worked at the Bettis Atomic Power Laboratory in the area of reactor shielding.
From 1961 to 1967, I worked at the Vallecitos Atomic Laboratory of the General Electric Company in the area of reactor physics.
Since 1967, I have been on the faculty of the University of Washington in the Department of Nuclear Engin-eering.
In 1981, I received a joint appointment to the Department of Environmental Health.
I am a member of the American Nuclear Society, the Health Physics Society, the Radiation Research Society, The American Association for the Advancement of Science, Sigma Xi, and the New York Academy of Sciences.
I am a consultant to industry in the area of nuclear technology and I am a Licensed Professional Engineer (Nuclear) in
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the State of Washington.
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