ML25196A165
| ML25196A165 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 01/17/1977 |
| From: | Bender M Advisory Committee on Reactor Safeguards |
| To: | Rowden M NRC/Chairman |
| References | |
| Download: ML25196A165 (1) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION ADVISORY COMMITTEE ON REACTOR SAFEGUARDS WASHINGTON, D. C. 20555 Honorable Marcus A. Rowden Chairman January 17, 1977 u.s. Nuclear Regulatory Conmission Washington, OC 20555
SUBJECT:
REPORl' ON NORI'H ANNA PCMER Sl'ATION, UNITS 1 AND 2
Dear Mr. Rowden:
At its 201st meeting, January 6-8, 1977, the Advisory Conmittee on Reac-tor Safeguards conpleted its review of the application of the Virginia Electric and Power Ccmpany for a license to operate North Anna Power Station, Units 1 & 2. This project was also considered during a Subcom-mittee meeting held in Washington, o.c., on January 5, 1977. The Com-mittee previously conpleted a partial review of this project at its 198th meeting, October 14-16, 1976, as discussed in its report to you, dated October 26, 1976. During its review, the Conmittee had the benefit of discussions with representatives and -consultants of the Virginia Electric and Power Conpany, the Westinghouse Electric Corporation, the Stone and Webster Engineering Corporation, and the Nuclear Regulatory Conmission"""
(NRC) Staff. The Comnittee also had the benefit of the documents listed.
In its report of October 26, 1976, on North Anna, Units 1 & 2, the ACRS had not conpleted its review of the adequacy of seismic design bases and seismic design; loss-of-coolant accidents and emergency core cooling; quality assurance and control of on-site fabrication and installation; asynmetric loads on pressure vessel structures arising from certain pos-tulated pipe breaks; and plans for upgrading protection against fires.
The NRC Staff has now ccmpleted its review of the Stafford fault zone and concluded that the available geological and seismological information supports the conclusion that the Stafford fault zone is not capable with-in the meaning of Appendix A to 10 CFR Part 100, and that the available information does not warrant any change in the previously approved seismic design bases for North Anna 1 and 2. Represe,itatives of the U.S.
Geological Survey concurred that there exists no definitive information showing significant movement during the last million years and that the fault is not capable. Consultants to the ACRS concur with this interpre-tation. While they generally find the current design bases acceptable for 1116
Honorable Marcus January 17, 1977 the already constructed North Anna plants, they have recommended that, in view of the uncertainties of knowledge concerning the sources of earthquakes in the Eastern United States, a minimum safe shutdown earth-quake (SSE) of 0.2g acceleration should be utilized for new plants for which construction permit applications are submitted in the future.
The Applicant presented partial information concerning the calculated safety factors during safe shutdown earthquake conditions for some of the engineered safety features. The Comnittee recormnends that the NRC Staff review this aspect of the design in detail and assure itself that significant margins exist in all systems required to accomplish safe shutdown of the reactors and continued shutdown heat removal, given an SSE. The Conmittee believes that such an evaluation need not delay the start of operation of North Anna 1 and 2. The Conmittee wishes to be kept informed.
The NRC Staff has now conpleted its review of emergency core cooling system performance and found it to be acceptable. The Comnittee con-curs.
The NRC Staff has conducted and is continuing extensive investigation of construction activities of North Anna Units 1 and 2. These investi-gations have been separated into four phases:
- 1. investigation of specific allegations made by three individuals of faulty construction practices;
- 2. a detailed inspection of certain saf.ety-related piping not directly implicated in the original allegations but which was potentially subject to similar problems;
- 3. detailed 100nitoring of the nondestructive preservice baseline examination of selected welds in safety-related piping by the Licensee and his contractors; and
- 4. inspections of the performance of selected conponents in specific piping systems during the preoperational testing program.
The NRC Staff has concluded that various items of non-corrpliance with NRC requirements have occurred and has defined a program to remedy the matter.
The Corrmittee has had the benefit of a review and evaluation of this matter by its own consultant, who supports the adequacy of the NRC 1117
Honorable Marcus January 17, 1977 investigations and has made several recommendations, including one related to a program to ascertain that significant deficiencies do not exist in safety related piping systems. The ACRS concurs. The Committee wishes to be kept informed regarding resolution of these recomnendations.
The NRC Staff has reported that the matter of asynmetric loads on pres-sure vessel structures is essentially resolved. The ACRS has had the benefit of meetings of an Ad Hoc working Group on this general subject, in Toronto on August 5, 1976, and in Los Angeles on Deceni:>er 1, 1976.
The COlllDittee agrees that, subject to final evaluation by the NRC Staff, this matter is in an acceptable status for North Anna 1 and 2.
The Applicant is in the process of studying fire protection measures at the plant in accordance with the guidelines of Appendix A to Auxiliary and Power Conversion Systems Branch Technical. Position 9.5-1. The NRC Staff has stated that, as a plant about to come into operation, North Anna 1 and 2 will be given priority in the evaluation of fire protection matters, and that most, if not all improvements will be implemented prior to the start of operation on the second fuel cycle. The Conmittee finds this approach to be acceptable.
The Conmittee notes that post-accident operation of the plant to maintain safe shutdown conditions may be dependent on instrl.Bllentation and electrical equipment within containment which is susceptible to ingress of steam or water if the hermetic seals are either initially defective or should be-come defective as a result of damage or aging. The Conmittee believes that appropriate test and maintenance procedures to assure continuous long-term seal capability should be developed.
The ACRS believes that, if due regard is given to the items mentioned above and in its report of October 26, 1976, and subject to satisfactory conpletion of construction and preoperational testing, there is reason-able assurance that the North Anna Power Station, Units 1 and 2, can be operated at power levels up to 2775 MWt without undue risk to the health and safety of the public.
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~ely,.~~o~~..,,.,,,----
M. Bender Chairman
Honorable Marcus
Attachment:
Report of W.R. Gall, ACRS Consultant, dated January 3, 1977,
Subject:
Review of Allegations and Inspectors Findings as Reported in NRC In-vestigation Report iS0-338/76-28, 50-339/76-16 North Anna, Units 1 and 2.
REFERENCES:
January 17, 1977
- 1. North Anna Power Station, Units 1 & 2 Final Safety Analysis Report, with Amendments 1 through 60.
- 2. Safety Evaluation Report (NOREG-0053) related to operation of North Anna Power Station, Units 1 and 2, with Supplements 1 through 5.
- 3. Virginia Electric and Power Conpany (VEPCO) letter Serial No. 338 to Mr. Benard C. Rusche, ONRR, NRC, dated November 24, 1976, on environmental testing*of safety related instrumentation.
- 4. VEPCO letter Serial No. 350 to Mr. Benard C. Rusche, ONRR, NRC, dated November 30, 1976, forwarding a document entitled, "Safety Related F.quipment Tenperature Transients During the Limiting Main Steam Line Break.*
- 5. VEPCO letter Serial No. 346 to Mr. Benard C. Rusche, ONRR, NRC, dated Novent>er 30, 1976, on measures considered for use at North Anna re overpressurization events.
- 6. VEPCO letter Serial No. 316A, dated December 3, 1976, re model testing of LBSI pmps.
- 7. VEPCO letter Serial No. 298/102276, dated December 16, 1976, contain-ing information on LOCA effects on reactor fuel. {Westinghouse PIO-PRIETARY).
- 8. NRC letter of Decenber 14, 1976, from D.B. Vassallo to Dr. Dade w.
Moeller, Chairman, ACRS, subject "Staff Report - Assessment of the Stafford Fault zone.*
- 9. NRC :meno dated Decenber 2, 1976, from Dudley Th011pson and Boyce H. Grier to Ernst Volgenau, I&E, subject, "Transmittal and Evaluation of In-vestigation Report, No. 50-338/76-28, 50-339/76 North Anna Units 1 and 2."
- 10. VEPCO letter Serial No. 371, dated December 9, 1976, forwarding a copy of VEPCO's reply to E. Volgenau re I&E Investigation Report Nmnber 50-338/76-28 and 50-339/76-16.
- 11. NRC letter dated December 6, 1976 from E. Volgenau, I&E, to VEPCO Attn: Mr. T. Justin Moore, President referring to the I&E investi-gation of construction activities at North Anna 1 and 2 forwarding a "Notice of Violation", and a "Notice of Proposed Irrposition of Civil Penalities."
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Honorable Marcus January 17, 1977 REFERENCES (con't)
Subject:
ninvestigation of alleged discrepancies in the construction and quality control program for piping installation at the North Anna Power Station.*
- 13. VEPCO letter serial 390 to Dr. Dade w. Moeller, Chairman, ACRS, for-warding a cor,y of Mr. T. Justin Moore's letter of December 23, 1976 to Dr. Ernst Volgenau re the North Anna investigation.
- 14. VEPCO letter Serial No. 391, dated January 4, 1977, providing infor-mation re concerns related to auxiliary power and containment systems.
- 15. North Anna Environmental Coalition (NAEC) letter dated January 5, 1977, to Dr. Dade w. Moeller and Dr. David Okrent, ACRS, requesting that certain items be made a part of the record of the January 6-8, 1977, ACRS meeting.
- 16. NAEC letter dated January 7, 1977, to Dr. Dade w. Moeller and Dr. David Okrent, ACRS, adding two additional items to the list submitted in the NAEC letter of January 5, 1977.
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