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Docket Nos.: 50-275 and 50-323 dUl 2 0 E4 MEMORANDUM FOR: James P. Knight, Assistant Director for Components and Structures Engineering Division of Engineering Lester S. Rubenstein, Assistant Director for Core and Plant Systems Division of Systems Integration FROM:
Thomas M. Novak, Assistant Director for Licensing Division of Licensing
SUBJECT:
DIABLO CANYON SER, SUPPLEMENT 27 Enclosed for your concurrence is Supplement 27 of.the Diablo Canyon SER which supports the issuance of the Diablo Canyon, Unit 1 full power license.
It is requested that the Division of Engineering specifically) review the discussion in SSER 27 on the following three license conditions (1 Seismic Design Bases RevalidationProgram(pages 1, 8, 9, & 10), (2) Jet Impingement (pages 2 & 12),
and (3) Piping and Piping Supports (pages 2 & 12), respectively.
It is requested that the Division of Systems Integration review the discussion on Overhead
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Heavy-Load Handling Systems (pages 1,10, & 11). -
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Please return a copy of this transmittal memorandum with your concurrence in the space provide below to reflect your approval of the supplement content for publication and return this memo to B. Buckley.
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Thomas M. Novak, Assistant Director for Licensing Division of Licensing DISTRIBUTION Docket File 50-275/323 '
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Docket Nos.: 50-275
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and 50-323 MEMORANDUM FOR: James P. Knight, Assistant Director for Components and Structures Engineering Division of Engineering lester S. Rubenstein, Assistant Director for Core and Plant Systems Division of Systems Integration FROM:
Thomas M. Novak, Assistant Director.
for Licensing Division of Licensing
SUBJECT:
DIABLO CANYON SER, SUPPLEMENT 27 Enclosed for your concurrence is Supplement 27 of the Diablo Canyon SER which supports the issuance of the Diablo Canyon, Unit i full power license.
It is requested that the Division of Engineering specifically) review the discussion in SSER 27 on the following three license conditions (1 Seismic Design Bases Revalidation Program (pages 1, 8, 9, & 10), (2) Jet Impingement (pages 2 & 12),
and (3) Piping and Piping Supports (pages 2 & 12), respectively.
It is requested that the Division of Systems Integration review the discussion on Overhead Heavy-Load Handling Systems (pages 1, 10, & 11).
Please return a copy of this transmittal memorandum with your concurrence in the space provide below to reflect your approval of the supplement content for publication and return this memo to B. Buckley.
L(w Thomas M. Novak, Assistant Director for Licensing Division of Licensing J. P. Knight (fA 6 A 1
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'JIII. 2 6 W Docket Nos.:
50-275 and 50-323 MEMORANDUM FOR:
James P. Knight, Assistant Director for Components and Structures Engineering Division of Engineering lester S. Rubenstein, Assistant Director for Core and Plant Systems Division of Systems Integration F. ROM:
Thomas M. Novak, Assistant Director for Licensing Division of Licensing
SUBJECT:
DIABLO CANYON SER, SUPPLEMENT 27 Enclosed for your concurrence is Supplement 27 of the Diablo Canyon SER which supports the issuance of the Diablo Canyon, Unit 1 full power license.
It is requested that the Division of Engineering specifically) review the discussion ihn SSER 27 on the following three license conditions (1 Seismic Design Bases RevalidationProgram(pages 1, 8, 9, & 10), (2) Jet Impingement (pages 2 & 12),
and (3) Piping and Piping Supports (pages 2 & 12), respectively.
It is requested that the Division of Systems Integration review the discussion on Overhead Heavy-Load Handling Systems (pages 1, 10, & 11).
Please return a copy of this transmittal memorandum with your concurrence in the space provide below to reflect your approval of the supplement centent for publication and return this memo to B. Buckley.
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Thomas M. Novak, Assistant Director for Licensing-
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Division of Licensing Y ~, bd... (
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-y.y J. P. Knight L. 5. Rubenstein 6
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In its June 20, 1984 letter, the ACRS recommended consideration of its consultants' advice concerning the proposed seismic reevaluation, which are summarized as follows:
1.
Analyses should include inelastic response of the plant structures under strong earthquake ground motion.
2.
Near field strong motion above a thrust fault, including the possi-bility of a strong velocity pulse, should be considered.
3.'
All components of near field strong ground motion should be included in the analysis simultaneously.
Torsional and rocking input ground motion should not be ignored.
4.
Three-dimensional soil structure interaction should be employed to provide estimates of structural response.
5.
Advantage should be taken of existing proprietary seismic profile and well data.
6.
A critical review and evaluation should be made of the regional tectonic structure as well as the onshore and near offshore faults at the site in light of the new evidence that they may connect with an underlying thrust fault.
g It is the staff's opinion that elements (1) and (2) of evised License Condition 2.C.(9) fully address ACRS consultants' rec mmendations 5 and 6. b b Element-(3) requires that soil structure interaction " W s be pe i a as discussed in recommendation 4.
Elements (2) and (3) which requir the assessment of ground motion generated by an underlying thrust fault w 11 take into account ACRS recommendations (2) and (3).
3as M k Element (4) provides for a seismic Probabilistic Risk Assessment (PRA) of the plant.
In a seismic PRA ground motion levels beyond the design are assumed and the consequences investigated.
The exact nature of the deter-ministic studies to be performed will be discussed with the licensee.
If it is deemed necessary to perform an inelastic analysis as prescribed in the ACRS recommendation then such an analysis will be performed.
The ACRS's final statement is " Based on the information developed in these meetings and considering the above comments, we find no reason to alter the conclusions stated in the Committee's report dated July 14, 1978 re-garding operation of this nuclear plant."
It is the staff's conclusion that while the requirements of the seismic conditions are being carried out by PG&E and the staff, there is no reason to modify previous conclusions on the seismic design basis.
License Cen-dition 2.C.(9) has been revised by the staff based on the results of the above cited meetings and discussions.
6.
Overhead Heavy-Load Handling Systems As a result of Generic Task A-36, " Control of Heavy Loads Near Spent Fuel," a set of guidelines was developed to assure safe handling of heavy Diablo Canyon SSER 27 10
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4 by January 30, 1985.
The program shall be completed and final report submitted to the NRC by July 1,1988."
On May 8, 1984 the staff and PG&E held a meeting regarding a program for revalidation of the Diablo Canyon seismic design basis.
The staff described in detail the specific elements that should be included in the program.
The following were among the elements described by the staff:
a.
Evaluate post 1979 ASLB hearing information b.
Reevaluate selected pre-1979 data that may be needed Reevaluate the magnitude of the controlling earthquake using c.
a multi-method approach d.
Reevaluate the ground motion at the site using analysis of empirical data, theoretical numerical modeling studies, and soil-structure interaction analyses.
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Assess the significanM the results of the preceding detee-e.
menoeW c analyses te t t r
.e khe seismic margins.
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f.
Submit quarterly progress reports, participate in semi-annual meetings with the staff and make annual presentations to the ACRS.
At the conclusion of the meeting a representative of PG&E indicated that overall, PG&E understands the reevaluation program, the elements laid out by the staff, and in general concurs in the concept of the approach for the program.
On May 24, 1984, the staff and its advisor the USGS, PG&E, and the combined ACRS Subcommittees on Diablo Canyon and Extreme External Phenomena and their geological and seismological consultants had a meeting.
The staff and PG&E presented their proposed seismic reevaluation programs.
On June 14, 1984 the staff and its advisors the USGS, PG&E, and the ACRS had a meeting.
The staff's proposed program was presented to the ACRS.
PG&E representatives indicated that they are in general agreement with the NRC staff proposal and will submit a program plan by January 30, 1985.
In its letter to the Commissioners (dated June 20, 1984) the ACRS stated "We believe that the elements outlined in the NRC Staff's proposal will provide a suitable basis for the seismic reevaluation. We believe also that the NRC Staff's proposal is responsive to the July 14, 1978 ACRS letter in which the ACRS suggested that the seismic design of Diablo Canyon be reevaluated in about ten years taking into account applicable new information." They also requested that the ACRS be given the oppor-tunity to review and comment on the PG&E program plan and schedule and that the NRC staff meet with them as appropriate to discuss the evalua-tion of the PG&E work.
Diablo Canyon SSER 27 9
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