GNRO-2012/00153, Supplement to Request to Revise the Standby Service Water Passive Failure Methodology
| ML12353A602 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 12/17/2012 |
| From: | Mike Perito Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GNRO-2012/00153, TAC 69404 | |
| Download: ML12353A602 (6) | |
Text
~~Entergy GNRO-2012/00153 December 17,2012 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 Entergy Operations, Inc.
P. O. Box 756 Port Gibson. MS 39150 Michael Penta Vice President, Operations Grand Gulf Nudear Station Tel. (601) 437-6409
SUBJECT:
REFERENCES:
Dear Sir or Madam:
Supplement to Request to Revise the Standby Service Water Passive Failure Methodology Grand Gulf Nuclear Station, Unit 1 Docket No. 50-416 License No. NPF-29 1.
NRC Letter from Joseph D. Neighbors to John C. Brons Re: Approval of Indian Point 3 Nuclear Power Plant Methodology Change for Postulating Service Water System Breaks (TAC No. 69404) 2.
SECY-77-439, NRC Information Paper on Single failure Criterion dated August 1,1977 (ML060260236) 3.
NUREG-0138, Staff Discussion of Fifteen Technical Issues Listed in Attachment to November 3, 1976 Memorandum from Director, NRR to NRR Staff, Issue No.7, Passive failures Following a Loss-of Coolant Accident, November 1976 4.
Request to Revise the Standby Service Water Passive Failure Methodology Dated September 14,2012 (GNRO-2012/00102)
Entergy Operations, Inc. (Entergy) submitted a request to revise the Standby Service Water Passive Failure Methodology (reference 4) on September 14,2012. This letter supplements reference 4 by adding the no significant hazards consideration statements that were inadvertently omitted from the request.
There are no new commitments in this letter. If you have any questions or require additional information, please contact Jeffery A. Seiter at 601-437-2344.
I declare under penalty of perjury that the foregoing is true and correct. Executed on December 17,2012.
~
MP/jas Attachment and cc: (see next page)
GNRO-2012/00153 Page 2 of2
Attachment:
No Significant Hazards Consideration for the GGNS Request to Revise the Standby Service Water Passive Failure Methodology cc:
U.S. Nuclear Regulatory Commission ATIN: Mr. Elmo E. Collins, Jr. (w/2)
Region Administrator, Region IV 1600 East Lamar Boulevard Arlington, TX 76011-4511 U. S. Nuclear Regulatory Commission ATIN: Mr. Alan Wang, NRR/DORL (w/2)
Mail Stop OWFN 8 B1 Washington, DC 20555-0001 Dr. Mary Currier, M.D., M.P.H State Health Officer Mississippi Department of Health P. O. Box 1700 Jackson, MS 39215-1700 NRC Senior Resident Inspector Grand Gulf Nuclear Station Port Gibson, MS 39150
Attachment GNRO-2012/00153 No Significant Hazards Consideration for the GGNS Request to Revise the Standby Service Water Passive Failure Methodology
GNRO-2012/00153 Page 1 of 3 1.0 No Significant Hazards Consideration 10 CFR 50.91(a)(1) requires that licensee requests for operating license amendments be accompanied by an evaluation of no significant hazard posed by issuance of the amendment. Entergy has evaluated this proposed amendment with respect to the criteria given in 10 CFR 50.92(c). The following is the evaluation required by 10 CFR 50.91(a)(1).
Entergy is requesting an amendment to the Grand Gulf Nuclear Station, Unit 1 (GGNS)
Facility Operating License No. NPF-29. The proposed change would revise the Updated Final Safety Analysis Report (UFSAR) to describe the use of revised methodology for postulating single phase failures of the Standby Service Water (SSW) to be consistent with NRC guidance published in References 2 and 3 which state that credible passive SSW failures that can result in a loss of fluid post-accident are limited to pump or valve seal leakage, not ruptures of SSW system piping.
Entergy has evaluated whether or not a significant hazards consideration is involved with the proposed amendment by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below:
1.
Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?
Response: No.
Grand Gulf Nuclear Station (GGNS) proposes the utilization of limited size breaks (through-wall leakage cracks) in the analysis of passive failures of Standby Service Water (SSW) piping during the post-LOCA phase of an accident. Postulating passive pipe ruptures and heat exchanger tube ruptures, and pipe fitting (tee, elbow, reducer, etc) ruptures in the SSW piping is overly conservative. SECY 77-439 underscores the fact that the probability of failure of the service water piping during the critical 24-hour period after a loss of coolant accident (LOCA) is so low that it does not constitute a credible event.
Additionally, crack locations and sizes postulated under the guidance of Standard Review Plan (SRP) (NUREG 0800) Sections 3.6.1 and 3.6.2 are applicable and bounding in terms of the consideration of passive failures as addressed in SECY 77-439, and are thus applicable to the Grand Gulf Nuclear Station pipe failure analysis. Therefore, the proposed change does not involve a significant increase in the probability of an accident previously evaluated.
The consequences of a previously evaluated accident are not significantly increased. The proposed change does not affect the performance of any equipment credited to mitigate the radiological consequences of an accident.
Evaluation of the proposed UFSAR changes demonstrated that the availability of credited equipment is not significantly affected because of the adoption of revised methodology for postulating single phase failures of the Standby Service Water (SSW) to be consistent with NRC guidance published in References 2 and 3.
Therefore, the proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
GNRO-2012/00153 Page 2 of 3 2.
Does the proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?
Response: No.
The proposed UFSAR change allows GGNS to be consistent with NRC guidance published in References 2 and 3 which state that credible passive SSW failures that can result in a loss of fluid post-accident are limited to pump or valve seal leakage, not ruptures of SSW system piping. The proposed UFSAR change does not introduce any failure mechanisms of a different type than those previously evaluated, since there are no physical changes being made to the facility.
No new or different equipment is being installed. No installed equipment is being operated in a different manner. As a result, no new failure modes are being introduced. The way surveillance tests are performed remains unchanged.
Therefore, the proposed change does not create the possibility of a new or different kind of accident from any previously evaluated.
3.
Do the proposed changes involve a significant reduction in a margin of safety?
Response: No.
The proposed revision of the Updated Final Safety Analysis Report (UFSAR) to describe the use of revised methodology for postulating single phase failures of the Standby Service Water (SSW) to be consistent with NRC guidance published in References 2 and 3 which state that credible passive SSW failures that can result in a loss of fluid post-accident are limited to pump or valve seal leakage, not ruptures of SSW system piping. The impact of the change on system availability is not significant, based on the frequency of the testing being unchanged, the existence of redundant systems and equipment, and overall system reliability. The proposed change does not significantly impact the condition or performance of structures, systems, and components relied upon for accident mitigation. The proposed change does not result in any hardware changes or in any changes to the analytical limits assumed in accident analyses. Existing operating margin between plant conditions and actual plant setpoints is not significantly reduced due to these changes. The proposed change does not impact any safety analysis assumptions or results.
Therefore, the proposed change does not involve a significant reduction in a margin of safety.
Based on the responses to the above questions, GGNS concludes that the proposed amendment with respect to the UFSAR change presents no significant hazards consideration under the standards set forth in 10 CFR 50.92(c) and, accordingly, a finding of "no significant hazards consideration" is justified.
GNRO-2012/00153 Page 3 of 3 4.
Conclusion In conclusion, based on the considerations discussed above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
2.0 ENVIRONMENTAL CONSIDERATION
The proposed change would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, and would change an inspection or surveillance requirement. However, the proposed change does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluent that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure.
Accordingly, the proposed change meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed change.