ML25196A284
| ML25196A284 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 10/12/1977 |
| From: | Bender M Advisory Committee on Reactor Safeguards |
| To: | Hendrie J NRC/Chairman |
| References | |
| Download: ML25196A284 (1) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION ADVISORY COMMITTEE ON REACTOR SAFEGUARDS WASHINGTON, D. C. 20555 Honorable Joseph M. Hendrie Chairman October 12, 1977 U. s. Nuclear Regulatory Comnission Washington, DC 20555 SUBJECl':
REPORI' ON PII.GRIM NUCLEAR GENERATING srATICN, UNIT NO. 2
Dear Dr. Hendrie:
During its 210th meeting, October 6-8, 1977, the Advisory Conmittee on Reactor Safeguards conpleted its review of the application of Boston Edison Corrpany and joint applicants (Applicants) for a permit to construct the Pilgrim Nuclear Generating Station, Unit No. 2. The application was pre-viously reviewed by the Comnittee in 1975 and the results of its review are covered in its Interim Report of November 14, 1975. Subsequently, the Applicants undertook an extensive investigation to provide additional data on foundation stability and on tectonic interpretations for establishing the seismic design basis for the site. These items, along with IOCA-ECCS, fire protection, and industrial security, were the principal matters of this review. A Subconmittee meeting with the Nuclear Regulatory Comnis-sion (NRC) Staff and Applicants was held in Boston, Massachusetts on September 22, 1977. The Comni ttee had the benefit of discussions with representatives and consultants of the Applicants, Conbustion Engineering, Inc., Bechtel Corporation, u. S. Geological Survey, and the NRC Staff.
The Conmittee also had the benefit of the documents listed.
As noted in the Conmittee's Interim Report of November 14, 1975, the Nuclear Steam Supply System (NSSS) for Pilgrim Nuclear Generating Station, Unit No. 2 will be furnished by Combustion Engineering, Inc. It will con-sist of a pressurized water reactor with a two-loop reactor coolant system and will be rated at a thermal power output of 3473 megawatts. The design of the NSSS is similar to that of San Onofre Units 2 and 3 on which the Conmittee reported in its letter of July 21, 1972.
The plant will be located in Plynouth County, Massachusetts, approximately 38 miles southeast of Boston. The NRC Staff has designated a group of con-tiguous communities consisting of Plynouth Center, West and North Plynouth, and Kingston Center as the nearest population center (1970 population of 20,000 and projected 1990 population of 25,000). The minimum exclusion distance is 441 meters and the low population zone radius is 2.3 miles, 1273
Honorable Joseph M. Hendrie 2 -
October 12, 1977 revised from 1.5 miles since the Committee's Interim Report. Major land uses in the vicinity of the plant site are for residential and recreational activities.
The Applicants have performed extensive investigations to assess site and regional geologic and seismic conditions in accordance with the guidelines of Appendix A to 10 CFR Part 100 and have determined that the controlling earthquake is one of intensity VII (MM) assumed to occur in the vicinity of the site. Using either the Neumann or the Trifunac-Brady relationship between intensity and acceleration, the trend of the means of the peak acceleration values corresponding to intensity VII (MM) is 0.13g. The NRC Staff also has concluded that the controlling earthquake should be intensity VII (MM) but that the appropriate design acceleration for the safe shutdown earthquake (SSE) should be increased fran 0.13g to 0.2g at the ground sur-face due to the possibility of soil ~lification at the Pilgrim site. The U.S. Geological Survey's conclusion is consistent with that of the NBC Staff. Based on the above, the Conmittee agrees that a SSE with 0.2g acceleration at the ground surface is appropriate.
The resistance of the foundation soils to liquefaction has been evaluated using both observational and analytical methods. The lowest determined safety factor was 1.8 allowing for ground acceleration levels as high as
- 0. 25g. Settlement of Category 1 structures is expected to be minimal.
Measurements of actual settlement will be evaluated at the operating license stage of review.
Recent calculations show conpliance with the criteria of 10 CFR Part 50.46 based on a peak linear heat generation rate of 13.0 kilowatts per foot.
The Comnittee believes that resolution of the seismic, foundation, and ECCS-LOCA matters noted above are adequate and that the other items mentioned in its November 14, 1975 Interim Report can be satisfactorily resolved during construction.
With regard to generic problems applicable to this plant, refer to "Status of Generic Items Relating to Light-Water Reactors: Report No. 5" dated February 24, 1977. Items considered relevant to the Pilgrim Nuclear Gener-ating Station, Unit No. 2 are: II-1, 2, 3, 4, 5 (loose parts monitoring resolved) 6, 7, 10; II-A 3, 4, 5, 6, 7; II-B 1, 2; II-C 1, 2, 3, 4, 5, 6; and II-D 2. These problems should be dealt with by the NRC Staff and Appli-cants as solutions are found.
1274
Honorable Joseph M. Hendrie 3 -
October 12, 1977 The Advisory Committee on Reactor Safeguards believes that, if due consideration is given to the foregoing, the Pilgrim Nuclear Generating Station, Unit No. 2, can be constructed with reasonable assurance that it can be operated without undue risk to the health and safety of the public.
REFERENCES:
M. Bender Chairman
- 1. Boston Edison Company and joint applicants, "Pilgrim Nuclear Generating Station, Unit No. 2 Preliminary Safety Analysis Report" (PSAR) Vols. I-IX
- 2. Amendments 1-36 to the PSAR
- 3. Safety Evaluation Report, NUREG--75/054, related to the con-struction of the Pilgrim Nuclear Generating Station, Unit No. 2, June 1975
- 4. Supplement Nos. 1-3 to NUREG-75/054 1275