ML20128C193
| ML20128C193 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 11/20/1992 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20128C169 | List: |
| References | |
| REF-GTECI-A-46, REF-GTECI-SC, TASK-A-46, TASK-OR GL-87-02, GL-87-2, NUDOCS 9212040277 | |
| Download: ML20128C193 (4) | |
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION EVALUATION OF GEORGIA POWER COMPANY'S PLANT HATCH. UNITS 1 AND 2 120-DAY RESPONSE TO SUPPLEMENT NO. 1 TO GENERIC LETTER 87-02 plQ;fT NOS. 50-321. 50-366 TAC-NOS.
M69451 AND M69452 INTRODUCTION By letter dated September 16, 1992, Georgia Power Company (the' licensee),
submitted its response to Supplement No. I to Generic Letter (GL) 87-02,
" Verification of Seismic Adequacy of Mechanical and Electrical Equipment in Operating Reactors,-Unresolved Safety Issue (US1) A-46," dated May 22, 1992, for Plant Hatch, Units 1 and 2.
In this supplement, the staff requested that.
affected licensees submit the following information within 120 days of the issue date.of the supplement:
1.
A statement whether you commit to use both the Seismic Qualification Utility Group (SQUG) commitments and the implementation guidance provided in the Generic Implementation Procedure, Revision 2 (GIP-2) as supplemented by the staff's Supplemental Safet.y Evaluation Report No. 2 (SSER No. 2) for the resolution of USI A-46.
In this case, any devia-tion from GIP-2, as supplemented by the SSER No. 2,-most be identified, justified, and documented.
If you do not make such a commitment, you must provide your alternative for responding to GL 87-02.
2.
A plant-specific schedule for the ' implementation of the GIP and submission of a report to the staff that summarizes the results of the USI A-46 review, if you are committing to implement GIP-2.
This schedule shall be such that each affected plant will complete its implementation and submit the summary report within 3 years after the issuance of the SSER No. 2, unless otherwise justified.-
3.
The detailed information as to what procedures and criteria were used to generate the in-structure response spectra to be used for USI A-46 as requested in the SSER No. 2.
The-licensee's in-structure response spectra are considered acceptable for USI A-46 unless-the staff indicates otherwise during a 60-day review period.
9212040277 921120 FDR ADOCK 03000321 P
s l In addition, the staff requested in SSER No. 2 that the licensee inform the staff, in the 120-day response, if it intends to change lts licensing basis to reflect a commitment to the USI A-46 (GIP-2) methodology for verifying the -
seismic adequacy of mechanical and electrical equipment, prio,* to receipt of the staff's plant-specific safety evaluatioa resolving USI A-46.
EVALUATION With regard to Item 1, the licensee stated that it "... commits to the SQUG commitments set forth in the GIP in their entirety, including the clarifications, interpretations, and exceptions identified in SSER-2 as clarified by the August 21, 1992, SQUG letter responding to SSER-2." The licensee also stated that, "GPC generally will be guided by the remaining (non-commitment) sections of the GIP, i.e., GIP implementation guidance, which comprises suggested methods for implementing the applicable commitments."
The licensee's response is unclear as to whether or not the licensee intends to implement both the SQUG commitments and the. implementation guidance.
In accepting GIP-2 as a method-for resolving USI A-46, it was the staff's under-standing that the SQUG members who chose to implement GIP-2 would essentially use the entire procedure, including the SQUG commitments, which contain the general programmatic objectives and goals, and the implementation guidance, which contains the specific criteria and procedures to be used for the resolu-tion of USI A-46.
This understandir.g was the basis for the staff's position, which was stated in SSER No. 2, that if the licensee commits to use GIP-2 for the implementation of USI A-46, it must commit to both the SQUG commitments and the use of the entire implementation guidance provided in GIP-2, unless otherwise justified to the staff.
In order to allow some flexibility in implementing GIP-2, the staff acxnowledged in the supplement to GL 87-02 that SQUG members who commit to GIP-2 (both the SQUG commitments and the implementation guidance) may deviate from it-provided that such deviations are identified, documented and justified. However, it was also indicated in SSER No. 2 that if a licensee uses methods that dedate from the criteria.and pro-cedures described in the SQUG commitments and in the implementation guidance of GIP-2 without prior NRC approval, the staff may find the. use of such -
methods unacceptable with regard to satisfying the provisions of GL 87-02.
In light of the above, the staff interprets the licensee's response to Supplement No. I to GL 87-02 as a commitment to the entire GIP-2 including both the SQUG commitments and the implementation guidance, and therefore considers it acceptable.
If the staff's interpretation is incorrect, then in accordance with Supplement No.1 to GL 87-02, the licensee should provide for staff review, as soon as practicable prior to implementation, its alternative-criteria and procedures for responding to GL 87-02.
In addition, Enclosure 2 provides the staff's response, dated October 2, 1992, to the August 21, 1992, SQUG 1etter. The staff does not concur with all of the' 3QUG's clarifications and positions stated in that letter, and thus, the licensee should not use the August 21, 1992, letter as guidance in responding to Supplement No. I to GL 87-02.
The licensee should refer to Enclosure 2 for the staff's position on the SQUG 1etter.
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., With regard to Item 2, the licensee stated that it will submit a summary report to the NRC summartzing the results of the USI A-46 program at Plant Hatch, Units 1 and 2, by June 1, 1995.
This submittal date is within the 3-year response period requested by the staff and is therefore acceptable.
For the USI A-46 issue resolution of Unit 1, GPC proposes to use one-half (1/2) the seismic margin earthquake (SME) in-structure response spectra (IRS),
which was developed from the Hatch Unit I seismic margin assessment (SMA) program.
The GPC's proposal to use the 1/2 SME IRS for the USI A-46 issue resolution of Unit 1 is acceptable based on the facts that: (1) the 5% damped Unit I design basis earthquake (DBE), which is a Housner ground spectra tied to a peak ground acceleration of 0.15g, is enveloped with significant margin by the 1/2 X 5% damped SME spectra, (2) the Unit 1 IRS of the SMA program were developed by performing a detailed soil-structure interaction (SSI) analysis, and (3) NRC's concerns such as soil properties, use of deconvolution process, etc., in the SSI analysis were previously resolved and accepted by the staff.
GPC also proposes to use the developed 1/2 SME IRS of the SMA program for the USl A-46 issue resolution of Unit 2.
The proposal is based on the arguments that (1) the 5% damped Unit 2 design basis earthquake (DBE), which is a modified Newmark ground spectra tied to a peak ground acceleration of 0.15g, is about equal to the 1/2 X 5% damped SME spectra and (2) Unit 2 is a sister unit to Unit 1 (e.g., both units share same control building, diesel generator building and intake structure except the reactor buildings; however, these reactor buildings designed by the same architect / engineering organizations are nearly identical, and contain nearly identical equipment in the buildings).
Therefore, GPC's proposal to use the 1/2 SME IRS for the USI A-46 issue resolution of Unit 2 is acceptable.
As GPC indicated in its submittal, the GPC's SME IRS are to be treated as
' median-centered' response spectra for the purpose of Units 1 & 2 USI A-46 issues resolution.
ihe above conclusions are based on an assumption that the statements made in the submittal, including the procedures used in generation of the floor response spectra, correctly reflect the FSAR and other licensing basis. The staff may audit the process by which the in-structure response spectra were generated.
Regarding the timing of NRC staff responses to requests for additional information from the licensee, you should refer to Item I.2 in Enclosure 2 for the staff's position on this issue.
t' The licensee indicated that it intends to change its licensing basis methodology, via-10 CFR 50.59, for verifying the seismic adequacy of new, replacement, and existing electrical and mechanical equipment consistent with guidelines in GL 87-02, Supplement 1, upon receipt of a final plant-specific SER resolving USI A-46.
The staff recognizes that, upon receipt of a plant-specific SER resolving USI A-46 at Plant Hatch, Units 1 and 2, the licensee may revise its licensing basis in accordance with 10 CFR 50.59 to reflect the acceptability of the USI A-46 (GIP) methodology for verifying the seismic adequacy of electrical and mechanical equipment covered by the GIP.
CONCLUSIONS The staff interprets the licensee's response to Supplement No. I to GL 87-02 as a commitment to the entire GIP-2 including both the SQUG commitments ar.d the implementation guidance, and therefore considers it acceptable.
If the licensee does not commit to implement the entire GIP-2, then in accordance with Supplement No. I to GL 87-02, the licensee should provide for_ staff-review, as soon as practica.le prior to implementation, its alternative criteria and procedures for responding to GL 87-02.
Additionally,-the licensee should not merely follow the August 21, 1992, SQUG letter for implementing GIP-2, but should refer to Enclosure 2 for the staff's response to the SQUG letter.
The implementation schedule proposed by the licensee is within the 3-year response period requested by the staff in Supplement No. I to GL 87-02 and is therefore acceptable.
The licensee's response regarding in-structure response spectra is adequate and acceptable.
Regarding the timing of NRC staff responses to requests for additional information from the licensee, you should refer to Item I.2 in Enclosure 2 for the staff's position on this issue.
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The staff recognizes that, upon receipt of a plant-specific SER resolving USI l
A-46 at Plant Hatch, Units 1 and 2, the licensee may revise its licensing basis in accordance with 10 CFR 50.59 to reflect the acceptability of the USI A-46 (GIP) methodology for verifying the seismic adequacy of electrical and nechanical equipment covered by the GIP.
Date:
November 20, 1992 l
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ENCLUSURE 2
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OCT 0 2 W Mr. Neil Smith, Chairman Scismic Qualification Utility Group c/o EPRI 1019 19th Street, N.W.
Washington, DC 20036
SUBJECT:
NRC RESPONSE TO SEISMIC QUALIFICATION UTILITY GROUP (SQUG)
Re:
Letter, N. Smith, EPRI, To J. Partlow, NRR, dated August 21, 1992, concerning USI A-46 Issues.
Dear Mr. Smith:
This is to acknowledge the receipt of the SQUG response to Supplement No. I to Generic Letter (GL) 87-02, and Supplemental Safety Evaluation (SSER) No. 2, on the SQUG Generic Imp'ementation Procedure for Seismic Verification of Nuclear Plant Equipment, Revi.iion 2, as corrected February 14, 1992 (GIP-2).
The NRC staff believes that successful implementation of the entire GIP-2, supple-mented by the staff's SSER No. 2, by each SQUG licensee will result in cost-effective plant safety enhancement for their USI A-46 plants.
The staff also believes that the positions delineated in Supplement No. I to GL 87-02 and SSER No. 2 are clear and correct, and should not be misinterpret-ed.
The staff's comments on SQUG's August 21, 1992, letter and attachment are provided in the enclosure to this letter.
If you need further clarification concerning our response, please contact Mr. James Norberg at 504-3288.
Sincerely, r
Skdt James G. Partlow Associate Director for Projects Office of Nuclear Reactor Regulation
Enclosure:
As stated l
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t ENCLOSURE I.
NRC's Coments on the SOUG Letter of Auau:t 21.192:
1.
In regard to the is:ue of seismic qualification, the staff reiterates the position stated in the SSER No. 2, in that ttle GIP-2 methodology is not considered to be a seismic qualification method, rather, it is an acceptable evaluation method, for USI A-46 plants only, to verify the seismic adequacy of the safe-shutdown equipment and to ensure that the pertinent equipment seismic requirements of General Design Criterion 2 and the purpose of the NRC regulations relevant to equipment seismic adequacy including 10 CFR Part 100 are satisfied.
2.
The second paragraph on page 2 of your letter addressed the issue of timing of staff response to additional information requested from a licensee. Although you are correct in your statement regarding the sixty-day period for response to initial submittal of in-structure response spectra (ISRS) information, we do not agree that the same concept applies to a licensee's submittal of-additional information received following a rejection or a question from the staff.
To eliminate any potential misunder-standing in this regard, the staff has determined that it will respond to any submittal of additional information received from a licensee within 60 days.
However, in this response, the staff will either state its approval (or rejection) of the information provided, or indicate the time duration needed for the review of such information, prior to transmitting a follow-up response of acceptance (or rejection) to the licensee.
This time duration will vary depending on the complexity of the submittal.
3.
Regarding the EBAC and ANCHOR computer. codes, the staff's evaluations and concerns stated in the SSER No. 2 are correct and valid.
The ANCHOR code does not consider the effects of base plate flexibility on the anchorage capacity.
l 4.
With respect to transfer of knowledge regarding major problems identified, and lessons learned, in the USI A-46 plant walkdowns and third-party reviews, we request that you include the NRC in-the distribution of written communications to all member utilities in this regard, and inform the NRC staff of any planned workshops on A-46 implementation for possible staff participation.
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II.
NRC's Comments on the procedure for Reviewino'the GIP 1
1.
The staff supports SQUG's establishment of a Peer Review Panel composed of seismic experts since it should serve to enhance the review process of substantive changes to the technical requirements in the GIP, prior to its submittal to NRC for approval.
However, since the NRC no longer intends to help finance a Peer Review Panel, the staff does not believe it s
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. is appropriate to participate in the selection of the Peer Review members, who will be financed by SQUG/EPRI.
We would like to emphasize that staff's review of a proposed GIP change will receive thnrough independent NRC evaluation and will be assessed on its merits.
2, With respect to the NRC review and approval of the changes to the GIP (Item 5, page 3 of the procedure), the staff's position on the issue of its response timing is identical to that delineated in the response to a licensee submittal of additional information (refer to item 2 of NRC's Comments on the SQUG letter in this enclosure).
This comment also applies to the section " LICENSING CONSIDERATIONS" on page 5 of the Attachment to the SQUG letter.
3.
With respect to item 4, " Additional Restrictions," the text should be expanded to reflect that new information which indicates that existing GIP criteria and guidelines may be unconservative should be evaluated for potential 10 CFR Part 21 implications.
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