ML20040F360
| ML20040F360 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 02/05/1982 |
| From: | Bloch P, Paris O, Shon F Atomic Safety and Licensing Board Panel |
| To: | CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| NUDOCS 8202090115 | |
| Download: ML20040F360 (5) | |
Text
{{#Wiki_filter:' .o ,\\ CI,z UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSI0hgg F 9 wu:r egg kBg O Q ATOMIC SAFETY AND LICENSING BOARD '82 FEB -5 P2 4 "$"wg, /9g Before Administrative Judges. 4,g Peter B. Bloch, Chairina~n:!- ff Tp-N Dr. Oscar H. Paris' ~ Na 'b Mr. Frederick J. Shon $yg,u PLh In the Matter of Docket No. 50-155 (Spent Fuel Pool Amendment) CONSUMERS POWER COMPANY (Big Rock Point Plant) February 5, 1982 MEMORANDUM AND ORDER (Denying Summary Disposition of Criticality Contention) Af ter reviewing the motion for summary disposition of a contention dealing with the calculation of criticality in the spent fuel pool, we have concluded that there is a genuine issue of fact and that the motion for summary disposition must therefore be denied. Although our decision on-other aspects of the motions for summary disposition has not yet been completed, we decided to issue this separate opinion because of the seriousness of the issues raised by intervenors. The criticality contention is only one of several contentions which have been addressed in motions for summary disposition. Consumers Power Company (applicant) and the staff of the Nuclear Regulatory Commission (staff) both filed motions for summary disposition on October 5,1981. These motions were opposed by Christa-Maria, Jim Mills cnd Joanne Bier (Christa-Maria) and by John O'Neill in filings of December 11 and 14,1981 and in an additional, undated filing by Mr. O'Neill. Christa-Maria also filed a " Supplemental Memorandum" on January 28, 1982. 50} D s 4 8202090115 820205 PDR ADOCK 05000155 0 PDR
e d Summary Disposition (Criticality): 2 I THE CONTENTION O'Neill contention II E-3 states: The application has not adequately analyzed the possibility of criticality occurring in the fuel pool because of the increased density of storage without a gross distortion of the racks. If this contention is true, its implications are serious. The importance of criticality analyses has been recognized by the Commission, which requires substantial margins of safety in the calculation of criticality. The attainment of criticality would initiate a self-sustaining nuclear reaction. The analyses submitted in this case were performed and reviewed by experts. Dr. Yong S. Kim, a nuclear engineer employed by NUS Corporation, has an M.S. in Nuclear Engineering from the Massachusetts Institute of Technology and a Ph.D. from the Catholic University D America; he has over 20 years of relevant professional experience. He performed the calculations for applicant. Mr. Edward Lantz, a Senior Reactor Engineer who reviewed the criticality analysis for the Comission, has a B.S. in Engineering Physics from the Case Institute of Technology and a Masters of Science degree in Physics from Union College; he has 20 years professional experience in the nuclear field. The analysis of criticality apparently was found acceptable by the staff. Lantz at 3-4. Commission practices require that these calculations incorporate conservative assumptions that allow substantial room for error. For example, the calculations assume that there is fresh fuel in the spent fuel pool rather than the spent, less active fuel placed there. Kim at 9,
- 11. The pool water is assumed to be boiling, which increases calculated reactivity. Kim at 9.
The calculation assumes, contrary to fact, that
Summary Disposition (Criticality): 3 no neutrons are lost from the system. Kim at 3-4. A variety of accident scenarios are considered, including earthquake. Kim at 10-11. See alsn Lantz at 1-5 (at 115, p. 4, concluding that neither fuel pool cooling nor the water i.tself is required to prevent criticality in the low enriched fuel); SER 3-1 to 3-2. II ANALYSIS OF INTERVENOR'S ARGUMENT On January 29, 1981, Christa-Maria submitted an argument opposing sumary disposition of 0',Neill Contention II E-3. The argument was not supported by any affidavits or documentary evidence. Nevertheless, we have concluded that the argument is basically correct and that it demonstrates the existence of a genuine issue of fact. The argument is: Criticality analysis performed by Dr. Kim is based on a water temperature of 212*F, assuming boiling of the spent fuel pool, with the containment at atmospheric pressure. Even assuming that the containment is at atmospheric pressure (not necessarily conservative after a LOCA [ loss of coolant accident]), the pressure at the bottom of the spent fuel pool, due to the hydrostatic load is 28.14 psia. The boiling terperature at that pressure is 247"F. Since the effective activity coefficient K is not permitted to exceed 0.95, and since Dr. Kim's alculations reached this maximum, assuming 212' F, it is questionable if the calculations can be considered conservative. This statement triggered a thorough review by the Board. We found that Dr. Kira adopted the " conservative" assumption that water in the pool would boil at 212"F. Kim at 9. Kim's most recent calculation, using that assumption, is that k is.9500, which is the maximum allowable eff figure under existing Commission guidance. Kim at 12; Standard Review Plan (NUREG 0-800) p. 9.1.2-3 at sII(5) and Proposed Revision 2 to Regulatory Guide 1.13, p. 1.13-9 to 15 at 1.2 (k not to exceed 0.95). See eff also Generic Environmental Impact Statement on Handling and Storage of Spent Light Water Reactor Fuel (March 1978, NUREG-0404) Vol. 2 at B-19 (212*F is the maximum possible spent fuel pool. temperature). Although this guidance
a o Summary Disposition (Criticality): 4 may not be strictly controlling in our proceeding, deviation from it would require careful explanation. Furthermore, we find that intervenor's assertion concerning a boiling temperature of 247" is consistent with our own calculations. It also is consistent with applicant's assertion elsewhere in our record that the water in the fuel pool at a depth of 21.4 feet, which is the location of the top of(the stored fuel, would reach 237"F. Affidavit of Daniel A. Prelewicz ~ concerning Christa-Maria contention 8, at 4. In addition, applicant also m i . has'ef timated that in a TMI II-type accident (the subject of Christa-Maria 8 s and)'NeillIIIE-2)therecouldbeanoverpressureof23psiginthe i. 'a containment. Affidavit of David P. Blanchard concerning Christa-Maria ^ by 1>' contention 8, at 3. This overpressure could further increase k eff I furtherincreasing.theboilingtemperatureofwaEeratthepoolbottom. i' We also have. reviewed the history of calculations of k in [' eff ,.s this proceeding and have found that the staff review may have been less than " adequate. ' Consumer Power Company's Safety Analysis of April 1979 stated, at ..,p,. i-{,- that the Maximum k is 0.9456. However, in his affidavit eff s. c concerning summary disposition, Dr. Kim stated that the maximum keff was 0.9500. K'm at 12. The apparent explanation for the discrepancy is that.0044, the' contribution to maximum k from the foration of eff bubbles due to boiling, was'not included 'in the Safety Analysis. Nevertheless, the staft 's Safety Evaluation Report accepted the k eff 0.946--apparently a rounding-off of the figure originally provided by applicant. SER at 3-1. 4 These~ problems give rise to additional doubts. For example, neither G applicant nor staff has explained how they have calculated the effect on of small bubbles, l.ance at 4 (114), Kim at 11. In addition, Dr. kgj ?y Kim has stated that fuel handling accidents, including a drop of a fuel assembly and the' inadvertent placement of a fuel assembly between a rack assembly and the pool wall, do not have a significant effect on keff' Kim at'9-10. s
O Summary Disposition (Criticality): 5 However, there apparently was no consideration of possible distortion of the racks from a drop of a fuel assembly, although such consideration would seem appropriate when k is at the highest permissible limit, eff 0.9500. Safety Analysis at 4-8 to 4-9. Furthermore, no consideration appears to have been given to possible distortion of racks during heating. We also cannot help but wonder whether staff's acceptance of applicant's analysis means that staff did not independently analyze k using its own assumptions and computer codes. Given the g importance of this analys'is, independent review by staff is necessary. ORDER For all the foregoing reasons and based on consideration of the entire record in this matter, it is this 5th day.gf February, 1982, ORDERED To the extent that the Motions,for Summary Disposition filed on October 5, 1981, by Consumers Power Company and the staff of the Nuclear Regulatory Corrinission addressed O'Neill contention II E-3, relating to'the adequacy of analyses of the criticality of the expanded fuel pool, those motions are denied. FOR THE ATOMIC SAFETY AND LICENSING 80ARD ~II Petei-B. oloch, Chairman ADMINISTRATIVE JUDGE [Y \\ Oscar H. Paris, ADMINISTRATIVE JUDGE Frederick J. Sh ' s JUDGE ADMIN! .n v / Bethesda, Maryland}}