ML20127N494
| ML20127N494 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 11/17/1992 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20127N443 | List: |
| References | |
| REF-GTECI-A-46, REF-GTECI-SC, TASK-A-46, TASK-OR GL-87-02, GL-87-2, NUDOCS 9212010287 | |
| Download: ML20127N494 (4) | |
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x . . . . . ,j SAFETY EVALVATJON BY THE OfflCE Of NUCLEAR REACTOR REGULATION EVALVATION Of THE PHILADELPHIA ELECTRIC COMPANY'S PEACH BOTTOM ATOMIC POWER STATION < UNITS 2 AW_l 129-DAY RESPONSE TO SUPPLEMENT NO. 1 TO GENERIC LETTER 87-02 DOCKET NOS. 50-277 AND 50-278 1.0 JNTRODUCTION By letter dated September 18, 1992, the Philadelphia Electric 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 (USI) A-46," dated May 22, 1992, for the Peach Bottom Atomic Power Station (PBAPS), Units 2 and
- 3. In Supplement No. 1, 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 Safety Evaluation Report No. 2 (SSER No. 2) for the resolution of USI A-46, in this case, any deviation from GIP-2, as supplemented by the SSER No. 2, must be identified, justified, and documented, if you do not make such a commitment, you must provide your alternative for responding to GL 87-02.
l 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.
l 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, in addition, the staff requested in Section 1.2.3.1 of SSER No. 2 that the licensee inform the staff, in the 120-day response, if it intends to change its licensing basis to reflect a commitment to the USI A-46 (GIP-2) 9212010207 921117
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l methodology for verifyin the seismic adequacy of mechanical and electrical equipment, prior to rece pt of the staff's plant-specific safety evaluation '
resolving USI A-46. This safety evaluation report provides the NRC staff's evaluation of the licensee's response.
2.0 M LUATION Wi*h regard to item 1, the licensee stated that, 'Specifically, PECo hereby 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 1etter responding to SSER-2."
The licensee also stated that, "PECo 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 comitments ind 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 comitments, which contain the general programmatic objectives and goals, and the implementation guidance, which contains the s)ecific criteria and procedures to be used for the resolu-tion of USI A-46. T11s understanding 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 USl A-46, it must commit to both the SQVG 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 acknowledged in the supplement to GI 37-02 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 deviate 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 unaccePable with regard to satisfyin. 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. I 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 re>ponse, dated October 2,1992, to the August 21, 1992, SQUG letter. The staff does not concur with all of the SQVG'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 letter.
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With regard to item 2, the licensee stated that it will submit a summary '
report to the NRC summarizing the results of the USI A-46 program at PBAPS, !
Units 2 and 3, by November 20, 1995. This submittal date is within the 3-year response period requested by the staff and is therefore acceptable.
With regard to Item 3 the following comments address the details of the procedures used by PEco to generate the licensing basis (LB) floor response spectra (FRS):
- 1. PECo performed a fixed-base, dynamic analysis using the time history technique to generate the LB FRS. The mathematic models consist of stick models with lumped masses and stiffness coefficients.-
- 2. The plant SSE is 0.12g, and the OBE is 0.05g. For defining the site ground design spectra, PEco used the Housner spectra normalized to 0.05g for OBE and 0.129 for the SSE. For developing the FRS for the plant, PECo used the July 12,1952 Taf t S69E ear % quake spectrum normalized to 0.05g for 2% damping. A synthetic time history was generated, whose spectrum envelnped the design ground spectrum.
- 3. A structural damping value of 2% was used in generating the FRS for OBE.
The SSE FRS was obtained by multiplying the OBE spectral values by the ratio of SSE to OBE, i.e., 2.4, ignoring the beneficial effects of higher damping e SSE.
- 4. No vertical dynamic analysis was done; however, two-thirca of the horizontal responses were taken to be the vertical res3onses, and the effr's of the vertical component were combined with tiose of the horizontal component using the absolute sum method.
- 5. Although no mention is made of any peak broadening of FRS, the spectral curves provided by PBAPS show some minimal amount of peak broadening.
Based on our review of the licensee's response and the staff positions delineated in the SSER No. 2, we conclude that the licensee's response is adequate and acceptable for the resolutien of USI A-46 only. Although certain aspects of the FRS generation have not been strictly satisfied per item II 4.2.3 of SSER 2, the staff is satisfied that the licensee has produced
" conservative, design" FRS for the Reactor Building and the Radwaste Building which are covered in its submittal of September 18, 1992. This conclusion is 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 bases. The staff may au: lit the process by which the floor response spectra were generated. Furthermore, the above staff approval of the FRS is subject to the assumption that the licensee will use the same procedures described above for the generation of FRS for other Category I structures in the future. If such is not the case, the licensee should inform the staff of any deviations from the approved procedures and obtain its approval.
3 Additionally, the staff disagrees with the licensee's coments regarding the timing of staff responses to additional information requested from a licensee.
The licensee essentially reiterated the SQUG position stated in the August 21, 1992, letter from SQUG to the NRC. 1he licensee should refer to item 1.2 in Enclosure 2 for the staff's position on this issue.
3.0 CONCLUS10N3 The staff interprets the licensce's response to Supplement No. I to GL 87-02 as a comitment to the entire GIP-2 including both the SQUG comitments and the implementation guidance, and therefore considers it acceptable. If the licensee does not comit 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 practicable prior to implementation, its alternativt 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 in-structure response spectra for the Reactor Building and the Radwaste Building are adequate and acce) table for the resolution of USI A-46 only. These spectra are considered to se " conservative, design" FRS.
The licensee stated in a telephone conversation on November 6, 1992, that they do not intend to modify the licensing basis to reflect their comitment to the GlP-2 methodology prior to receipt of the NRC's plant-specific SE.
The staff disagrees with the licensee's coments regarding the timing of staff responses to additional information requested from the licensee. The licensee should refer to item I.2 in Enclosure 2 for the staff's position on this issue.
Principal Contributors: P. Y. Chen M. McBrearty R. Pichumani J. Shea Date: November 17, 1992 I'
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ENCLOSURE 2
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OCT 0 2 3 Mr. Neil Smith, Chairman Seismic Qualification Utility Group c/o EPRI 1019 19th Street, N.W.
Washington, DC 20036
SUBJECT:
NRC RESPONSE TO SEISHIC QUAL!f! CATION UTILITY GROUP (SQUG)
Re: Letter, N. Smith, EPRI, To J. Partlow, NRR, dated August 21, 1992, concerning VS! 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 Implementation Procedure for Seismic Verification of Nuclear Plant Equipment, Revision 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 US! 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
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% dit James G. Partlow
, Associate Director for-Projects Officf of Nuclear Reactor Regulation l
Enclosure:
j As stated
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12JCIDSLE 2
- 1. !dC's (q; vents on 'he 50VG Le Rer of Auaust 21. 1992:
- 1. In regard to the issue of seismic qualification, the staff reiterates the position stated in the SSER No. 2, in that the GlP-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 regulatinns relevant to equipment seismic adequacy including 10 CFR Part 100 are satisfied.
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- 2. The second paragraph on page 2 of your letter iddressed the issue of timing of staff response to additional information requested from a licensee. Although you are correct in your statement regarding the st::ty-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 lictnsee's submittal of additional information received fcilowing a rejection or a question from the staff. To eliminate any potential misunder-standing in this regard, the sisff has determined that it will respond to any submittal of additional information received from a license 9 within 60 days. However, in this responso the staff will either state its aporoval (or rejection) of the information provided, or indicata the time duration needed for the review of such information, prior to transmitting a follow-up respone- of acceptance (or rejection) to the licensee. This time dur ri will vary depending on the complexity of the submittal.
- 3. Regarding the EBAC and M HOR 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.
- 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.
II, NRC's Comments on the Procedure for Reviewina the GIP
- 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 i
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-2 is appropriato to participate in the selection of the Feer Review members, who will be financed by SQUG/EPRI. We would like to emphasize that staff's review of a proporld GlP change will receive thorough indepenoent NRC evaluatica and will be assessed on its merits.
2.
With respect to the NRC review and epproval 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 "LICENSIPG CONS:DERATION5" 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 r.=w 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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