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c ses Docket Nos.: 50-275 50-323 MEMORANDUM FOR: Raymond F. Fraley, Executive Director Advisory Committee on Reactor Safeguards FROM:
Thomas M. Novak, Assistant Director for Licensing Division of Licensing
SUBJECT:
STAFF EVALUATION OF DIABLO CANYON SEISMIC PROGRAM Enclosed for information of the Comittee is the staff evaluation of the PG&E proposed plan for the Long Term Seismic Program (LTSP). The plan was developed in response to License Condition 2.C.(7) in the Unit 1 full-power Operating License DPR-80. We intend to approve this plan after consideration of comments by the Comittee resulting from meetings with the Diablo Canyon Subcommittee on July 10 and the Comittee on July 11, 1985.
jA) Thomas M. Novak, Assistant Director for Licensing Division of Licensing
Enclosure:
As stated cc: w/ enclosure J. Knight A. Thadani R. Bosnak S. Israel G. Knighton J. Y,ane G. Lear G. Bagchi L. Reiter F. Cherny S. Brocoum L. Ong L. Heller R. Savio R. Rothman E. Igne H. Scnierling R. McMullen CONTACT:
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ENCLOSURE NRC STAFF EVALUATION OF THE PG&E LONG TERM SEISMIC PROGRAM PLAN Based on an August,1978 ACRS letter (Ref.1), in which the Connittee recommended that the seismic design basis of Diablo Canyon be reevaluated in 10 years, and the NRC staff's recognition that considerable new geologic and seismologic data had become available since the ASLB hearings in 1978-79, a license condition was established on April 18, 1984 in Amendment 9 to the Unit 1 low-power Operating License DPR-76 for a seismic design bases reevaluation program. The condition was subsequently included in the Unit 1 i
full-power Operating License DPR-80 which was issued on November 2,1984. The i
condition consists of four elements and reads as follows:
. Seismic Design Bases Reevalution Program (SSER 27 Section IV.5)
PG&E shall develop and implement a program to reevaluate the seismic design bases used for the Diablo Canyon Nuclear Power Plant.
The program shall include the following elements:
(1)
PG&E shall identify, examine, and evaluate all relevant geologic and seismic data, information and interpretations that have become avai-lable since the 1979 ASLB hearing in order to update the geology, seismology, and tectonics in the region of the Diablo Canyon Nuclear Power Plant.
If needed to define the earthquake potential of the region as it affects the Diablo Canyon Plant, PG&E will also re-evaluate the earlier information and acquire additional new data.
(2)
PG8E shall reevaluate the magnitude of the earthquake used to determine the seismic basis of the Diablo Canyon Nuclear Plant using the information from Element 1.
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r I (3) PG&E shall reevaluate the ground motion at the site based on the results obtained from Element 2 with full consideration of site and other relevant effects.
(4) PG&E shall assess the significance of conclusions drawn from the seismic reevaluation studies in Elements 1, 2 and 3, utilizing a probabilistic risk analysis and deterministic studies, as necessary, to assu're adequacy of seismic margins.
PG&E shall submit for NRC Staff review and approval a proposed program plan and proposed schedule for implementation by January 30, 1985. The program shall be completed and a final report submitted to the NRC three years following the approval of the program by the NRC staff.
PG&E shall keep the Staff informed on the progress of the reevaluation program as necessary, but as a minimum will submit quarterly progress reports and arrange for semiannual meetings with the staff.
PG&E will also keep the ACRS informed on the progress of the reevaluation program as necessary, but not less frequently than once a year.
During the period October through December, 1984, meetings were held among PG8E and its consultants and the NRC staff and its advisors and consultants to discuss each of the four elements (Table 1). At these meetings PG&E presented plans for each element and the staff provided comments on the plans. The staff prepared meeting suninaries including the comments (Ref. 2, 3 and 4). A summary meeting was held on January 10, 1985, (Ref. 5) at which PG&E presented the proposed program plan which incorporated the comments of the NRC and its advisors and consultants (Table 1). The Program Plan was formally submitted on January 30, 1985 (Ref. 6).
In March, 1985 PG&E presented its program to the ACRS Subcommittees on Diablo Canyon and on Extreme External Phenomena and received comments (Ref. 7). The staff provided written comments on the program plan to PG&E on May 9, 1985, (Ref. 8) which are attached (Attachment 1). A meeting was held on May 22, 1985
4 during which PG&E responded to the NRC comments (Ref. 9).
Formal responses to each NRC comment were submitted by PG&E on June 11, 1985, (Ref. 10) which are attached (Attachment 2). These comments amend and are an integral part of the program plan.
The program plan, as amended by PG&E's responses to NRC comments, displays an understanding of the current research, data, working hypotheses and methodologies necessary to carry out the proposed program. The amended plan is responsive to the comments made by the NRC and its consultants and advisors.
The overall organization and administration of the program are appropriate.
The members of the Consulting Board and the Advisory Groups respond to the key elements of the program. The consultants should provide independent state-of-the-art guidance to the program.
The ' program plan has a reasonable scheaule to meet the program scope. However, it appears that several segments of the program plan may have to be modified to allow completion of the program within three years.
In view of this and the possibility of new developments, it is important for the program to remain flexible.
PG&E has used the four elements of the license condition as the basis for its long term seismic program plan (LTSPP).
The program is sufficiently flexible to allow revisions that may be necessary to accommodate new information obtaineo during the course of the program. The ouarterly progress reports and
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- frequent meetings will provide coordination and input from all parties involved. PG&E will keep in close contact with the staff so that there can be constructive interaction throughout the duration of the program. This will allow for staff review of future program revisions.
As stated in the program plan submittals (Ref. 6 and Ref. 10) PG&E is con-ducting a scoping analysis, the results of which are expected to be available in November, 1985.
It will address the program details which were the sub-stance of many of the staff's comments. The staff will evaluate the results of the scoping analysis and will consider any appropriate modification to the program.
In its evaluation of the program plan the staff received assistance in the subjects of geology and tectonics from the U.S. G'eological Survey and Dr. David B. Slemmons who will continue to provide such assistance throughout the program. The staff is arranging for assistance on the subjects of (1) theoretical numerical modelling, and (2) soil structure interaction through the Lawrence Livermore National Laboratory and Brookhaven National Laboratory, respectively.
The staff has not had the benefit of their technical assistance in the reviewof these two subject areas.
In addition, the staff also intends to obtain technical assistance for the evaluation of the probabilistic risk analysis effort under Element 4 of the license condition.
The staff has reviewed the long term seismic program plan (Ref. 6) and the PG&E responses (Ref.10) to earlier staff coments.
The staff concludes that the
t 5-amended program plan is responsive to the license condition for a reevaluation of the seismic design bases.
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o Table 1 NRC/PG&E Meeting Seismic License Condition 1.
October 4,1984 (Ref. 2)
Overall Program Plan, Schedule Organization and Staffing i
Element 1 - Geology and Tector.ics 2.
November 15-16, 1984 (Ref. 3)
Element 2 - Earthquake Magnitude Element 3 - Ground Motion, Soil / Structure Interaction 3.
December 11, 1984 (Ref. 4)
Element 2 - Probabilistic Risk Assessment 4.
January 10,1984 (Ref. 5)
Summary Meeting Proposed Program Plan, Including Responses to NRC Comments made at Previous Meeting 5.
May 22, 1985 (Ref. 9)
PG&E Response to NRC Comments I
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-t References 1.
U.S. Nuclear Regulatory Commission, " Report on Diablo Canyon Nuclear Power Stations Units 1 and 2,"
Letter from S. Lawroski, ACRS Chairman, to J. Hendrie, NRC Chairwen, dated July 14, 1978.
2.
U.S. Nuclear Regulatory Commission, " Summary of NRC Meeting with PG&E dated October 4,1984 - Seismic Reevaluation Program for Diablo Canyon,"
dated November 14, 1984.
3.
U.S. Nuclear Regulatory Commission, " Summary of NRC Meeting with PG&E on November 15 & 16, 1984 - Seismic Reevaluation Program for Diablo Canyon," dated December 7,1984.
4.
U.S. Nuclear Regulatory Commission, " Summary of NRC Meeting with PG8E on December 11, 1984 Seismic Reevaluation Program for Diablo Canyon,"
dated January 7, 1985.
5.
U.S. Nuclear Regulatory Commission, " Summary of NRC Meeting with PG&E on January 10, 1985 Regarding the OL License Seismic Condition for Diablo Canyon," dated March 6, 1985.
6.
Pacific Gas and Electric Company, January 30. 1985, from D. Brand (PG8E) to H. R. Denton (NRC), Subject Submittal Of Long Term Seismic Program - Program Pan.
7.
U.S. Nuclear Regulatory Commission, ACRS Subcommittees on Extreme External Phenomena and on Diablo Canyon, March 21, 1985, Transcript pages 268 through 449.
8.
G. W. Knighton (NRC) to J. D. Shiffer (PG&E),
SUBJECT:
NRC Staff Comments On PG8E's Long Term Seismic Program Plan,1985 For Diablo
.. Canyon.
9.
U. S. Nuclear Regulatory Commission, " Summary of NRC Meeting with PG&E on May 22, 1985, Seismic Reevaluation Program for Diablo Canyon,"
June 11, 1985.
- 10. Pacific Gas and Electric Company, June 11, 1985, from J. D. Shiffer (PG8E) to H. R. Denton (NRC),
Subject:
Diablo Canyon Units 1 and 2 -
Long Term Seismic Program Plan.
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J ATTACHMENT 1 U.S. Nuclear Regulatory (Comission, May 9,1985, from G. W. Knighton (NRC) to J. D. Shiffer PG8E),
Subject:
NRC Staff Coments On PG8E's Long Term Seismic Program Plan, 1985 For Diablo Canyon.
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UNITED STATES ET g
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MAY 9 1985 Dncket Nos.: 50-275 and 50-323 Mr. J. D. Shiffer,.Vice President Nuclear Power Generation c/o Nuclear Power Generation, Licensing Pacific Gas and Electric Company 77 BeaTe Street, Room 1451 San Francisco, California 94106
Dear Mr. Sniffer:
Subject:
-NRC Staff Coments on PG&E's Lono Term Seismic Program Plar.,1985 for Diablo Canyon The staf# has comoleted its review of your crocosed Long Term Seismic Procram Plan. Althougn we find that the program is comprehensive and thorough, there were a number of ouestions and comments generated among our staff and consultants wnich need to be discussed. We propose these cuestions be used as the agenda for the meeting in Bethesda arranged for May 22 and 23, 1985. A notice cf the meeting and the questions and comments are enclosed.
Sincerely, jf I
N eerge W nighton,,2'!ier Licensing 3 ranch No. 3 Division of Licensing
Enclosure:
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ATTACHMENT 2 Pacific Gas and Electric Company, June 11, 1985, from J. D. Shiffer PG&E to H. R. Denton (NRC),
Subject:
Diablo Canyon Units 1 And 2 Long Term Sesmic Program Plan.
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PACIFIC GAS AND E LE C T RIC C O M PANY Z ~.: 7 n erAtt sTaccr. SAN r=ANCISCO. CALIFCRNIA 941C6. (415) 781 4 :1 Tv.x );C.37;.6567 June 11,1985
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peuCL Aa 80wtG GenetaT+C8e PGandE Letter No.: DCL-85-210 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Wa shin gton, D. C.
20555 Re: Docket No. 50-275, OL-DPR-80 Docket No. 50-323, OL-DPR-81 Diablo Canyon Units 1 and 2 Long Term Seismic Program Plan
Dear Mr. Denton:
The enclosure to this letter contains PGandE's responses to NRC Staff coments on the Diablo Canyon Long Term Seismic Program Plan. This Program Plan was submitted to the NRC Staff for review and approval on January 30, 1985.
The Staff's comments were forwarded to PGandE by MtC letter dated May 9,1985. On May 22,1985, PGandE met with the Staff and verbally responded to the comments. At that meeting, the Staff requested that PGandE provide a documented response.
These responses consist of supplemental clarifying information for items that are currently described in the Program Plan. There are no new studies or investigations proposed in these responses. As the program progresses, additional pertinent information will be identified.
PGandE intends to provide the Staff with that information in progress reports and at meetings held during the course of the program.
Kindly acknowledge receipt of this material on the enclosed copy of this letter and return it in the enclosed addressed envelope.
Sincerely, J.
i f fer' Enclosure cc:
S. T. Al germissen D. Perkins (3)
D. Bernreuter (2)
A. J. Philippacopoulos R. D. Brown M. Reich C. J. Costantino ACRS (5)
R. P. Savio, ling (5)
H. E. Schier J. Davis R. T. Do ddst D. B. Sl emmons J. B. Martin y,_/
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