200 E xe1u11 Wiy Exelon Generation ,.i.co!Tl · By letter dated May 12, 2015, (Reference 1) Exelon Generation Company, LLC (Exelon) requested to change the Nine Mile Point Unit 1

200 E xe1u11 Wiy

Exelon Generation Kennet, "quar2 PA 19348 www.exe1011co1,.i.co!Tl

10 CFR 5090

NMP1L3054

October 22, 2015

U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

Subject:

Nine Mile Point Nuclear Station, Unit 1 Renewed Facility Operating License No. DPR-63 NRC Docket No. 50-220

Response to Request for Additional Information #1 - "Application for Technical Specification Change Regarding Risk-Informed Justification tor the Relocation of Specific Surveillance Frequency Requirements to a Licensee Controlled Program (Adoption of TSTF-425, Revision 3)"

References: 1. Letter from J. Barstow (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission, "Application for Technical Specification Change Regarding Risk-Informed Justification tor the Relocation of Specific Surveillance Frequency Requirements to a Licensee Controlled Program (Adoption of TSTF-425, Revision 3)," dated May 12, 2015

2. Email from Brenda Mozafari (Senior Project Manager, U.S. Nuclear Regulatory Commission) to Ronnie Reynolds and Enrique Villar (Exelon) Request tor Additional Information Related to an Amendment to Adopt Technical Specification Task Force Traveller (TSTF) -425 to Relocate Specific Surveillance Frequency Requirements to a Licensee Controlled Program Nine Mile Point Nuclear Station Unit 1 Docket No. 50-220, dated September 22, 2015.

By letter dated May 12, 2015, (Reference 1) Exelon Generation Company, LLC (Exelon) requested to change the Nine Mile Point Unit 1 (NMP1) Technical Specifications (TS). The proposed amendment request would modify NMP1 TS by relocating specific surveillance frequencies to a licensee-controlled program with the implementation of Nuclear Energy Institute (NEI) 04-10, "Risk-Informed Technical Specifications Initiative 5b, Risk-Informed Method tor Control of Surveillance Frequencies."

Response to Request tor Additional Information #1 Adoption of TSTF-425, Revision 3 Page 2

On September 22, 2015, (Reference 2) the U.S. Nuclear Regulatory Commission (NRC) identified areas where additional information was necessary to complete the review. On October 1, 2015, a clarification teleconference was held between NRC and Exelon personnel.

Attachment 1 to this letter contains the NRC's request for additional information immediately followed by Exelon's response.

Exelon has reviewed the information supporting a finding of no significant hazards consideration and the environmental consideration provided to the NRC in Reference 1. The additional information provided in this response does not affect the bases for concluding that the proposed license amendment does not involve a significant hazards consideration. Furthermore, the additional information provided in this response does not affect the bases for concluding that neither an environmental impact statement nor an environmental assessment needs to be prepared in connection with the proposed amendment.

There are no commitments contained in this response.

If you should have any questions regarding this submittal, please contact Enrique Villar at 610-765-5736.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 22nd day of October 2015.

d~~ James Barstow Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC

Attachment1: Response to Request for Additional Information #1

cc: USNRC Regional Administrator, Region I USN RC Senior Resident Inspector - NMP USNRC Project Manager, NRR - NMP A. L. Peterson, NYSERDA

w/attachments

ATTACHMENT 1

Response to Request for Additional Information #1 to Support Review of Nine Mile Point Nuclear Station, Unit 1

Adoption of Technical Specification Task Force-425 Relocation of Specific Surveillance Frequency Requirements

to a Licensee Controlled Program (TAC No. MF6061)

Response to Request for Additional Information #1 Adoption of TSTF-425, Revision 3

Attachment 1 Page 1

PRA RAI 1 The license amendment request (LAR) notes that a peer review was performed in 2008 for the internal events PRA. Confirm that this was a full scope peer review. Also, confirm that Regulatory Guide (RG) 1.200, Revision 1 was used, and note which ASME/ANS standard version endorsed by RG 1.200, Revision 1 was used.

Exelon Response to PRA RAI 1

The 2008 NMP1 PRA Peer Review was a full-scope review of all the Technical Elements of the internal events, at-power PRA [2). The peer review was based on RG 1.200, Revision 1 [3] and the latest version of the PRA Standard at that time, ASME RA-Sc-2007 [4].

PRA RAI 2 The LAR does not mention that a gap assessment was performed for the internal events PAA between AG 1.200, Revision 1 and AG 1.200, Revision 2. If this has not been done, perform a gap assessment. Provide the gap assessment findings and observations with their dispositions for the application.


A gap assessment was performed for the internal events PRA between AG 1.200, Revision 1 and AG 1.200, Revision 2 [5]. This gap assessment did not lead to the identification of any new "Not Mets" or changes to the original capability category ranking from the 2008 peer review. This is not unexpected since the peer review was based on ASME RA-Sc-2007 which was the starting point for the combined PAA standard, ASME/ANS RA-Sa-2009 [6] endorsed in RG 1.200, Revision 2 [7]. Therefore, the only remaining internal events gaps were those identified in Table 2-1 of the TSTF-425 LAA submittal for Nine Mile Point Unit 1 where the impact for this application was already noted [8].

PRA RAI 3 The LAR states that in performing assessments for other hazards groups, a qualitative or bounding approach will be utilized in most cases. Clarify which hazard groups are included in the "other hazards groups." Also, confirm that surveillance test interval evaluations, which are based on Individual Plant Examination for External Event studies, will take into consideration the current plant configuration and operation. In addition, if a detailed quantification is being proposed in the LAR for these hazard groups versus a qualitative or bounding analysis, then Regulatory Guide 1.200, Revision 2 should apply to these PAA models. If this is the case, describe your plans to address RG 1.200, Revision 2 for these PAA models other than the Fire PAA model, which was reviewed against this AG.



Attachment 1 Page 2

Aside from quantifying the PAA models for internal events, internal floods, and internal fires, the primary area of other external event evaluation at Nine Mile Point Unit 1 (NMP1} will be for seismic initiating events. In addition to internal fires and seismic events, the NMP1 Individual Plant Examination for External Events (IPEEE} [9] analysis of High winds, Floods, and Other (HFO} external hazards was accomplished by reviewing the plant environs against regulatory requirements regarding these hazards. HFO events were screened out by compliance with the 1975 SAP criteria. As such, these hazards were determined in the NMP1 IPEEE to be negligible contributors to overall plant risk. There are no pending plans to develop RG 1.200 PAA models for seismic events or other external hazards for NMP1 at this time.

By following Steps 1 Oa and 1 Ob of the NEI 04-1 O [1 O] guidance, the evaluation of other external events risk supporting this application will reflect and consider the current plant configuration and operating experience. For the surveillance test interval {STI} change evaluations, the intent is not to directly use any numerical results from the IPEEE, but to qualitatively assess any available information to determine the impact on the proposed surveillance interval changes consistent with Step 10a of the NEI 04-10 methodology. This qualitative assessment of other external event risk will include a review of applicability to the current plant configuration and operating experience. Additionally, for some STI change evaluations, per Step 10b of the NEI 04-10 methodology, qualitative reasoning and very low L\CDF and .!\LEAF results from the internal events analysis may be sufficient to support the STI change evaluation where Step 1 Ob reads in part:

"Alternative evaluations for the impact from external events and shutdown events are also deemed acceptable at this point. For example, if the fl GDF and llLERF values have been demonstrated to be very small from an internal events perspective based on detailed analysis of the impact of the SSC being evaluated for the ST/ change, and if it is known that the GDF or LERF impact from external events (or shutdown events as applicable) is not specifically sensitive to the SSC being evaluated (by qualitative reasoning), then the detailed internal events evaluations and associated required sensitivity cases (as described in Step 14) can be used to bound the potential impact from external events and shutdown PRA model contributors."

Qualitative evaluation of other external events risk in support of step 1 Ob would also include consideration of applicability to the current plant configuration and operating experience. Therefore, by following Steps 1 Oa and 1 Ob of the NEI 04-1 O guidance, the evaluation of other external events will reflect and consider the current plant configuration and operating experience.

PRA RAI 4 The LAA does not discuss shutdown risk assessment, which is included in NEI 04-10 guidance. Describe the shutdown risk methodology to be used for NEI 04-10 evaluations.


Attachment 1 Page 3


While Nine Mile Point Unit 1 does not have a low power or shutdown PRA model, the Surveillance Frequency Control Program will assess shutdown events qualitatively per NEI 04-10 and Exelon procedural guidance.

PRA RAI 5 Do the failure probabilities of structures, systems, and components modeled in the NMP1 internal events PRA include a standby time-related contribution and a cyclic demand-related contribution? If not, please describe how standby timerelated contribution is addressed for extended intervals.


References

The standby time related failures will be assessed in accordance with NEI 04-10 (1 O] by direct change in the test interval for those SSCs that include a standby periodically tested failure mode in the Nine Mile Point Unit 1 PRA models along with the appropriate adjustments to common cause failure events. Where there is no standby periodically tested event in the PAA models and one is not added or the failure cannot be divided into time based and non-time based contributions, as allowed by RG 1.177 (11] all contributors to the failure rate will be assumed to be time based and the values adjusted accordingly.

If the SSCs do not appear explicitly in the PRA models, then either a bounding assessment using a surrogate event or a qualitative assessment will be performed in accordance with the NEI 04-1 O guidance.

(1] Letter from B.L. Mozafari, U.S. Nuclear Regulatory Commission, Request for Additional Information Related to an Amendment to Adopt Technical Specifications Task Force Traveler (TSTF)-425 to Relocate Specific Surveillance Frequencies to a Licensee Controlled Program, Nine Mile Point Nuclear Station Unit 1, Docket No. 50-220, September 22, 2015.

[2] BWROG, Nine Mile Point 1 Nuclear Plant 2008 PRA Peer Review Report, May 2008.

(3] U.S. Nuclear Regulatory Commission, An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk-Informed Activities, NRG Regulatory Guide 1.200, Revision 1, January 2007.

[4] American Society of Mechanical Engineers, Standard for Probabilistic Risk Assessment for Nuclear Power Plant Applications, ASME RA-Sc-2007, August, 2007.

(5] SAIC, Nine Mile Point 1 Probabilistic Risk Assessment GAP Assessment Work Plan, Revision O, August 2011.


Attachment 1 Page 4

[6] American Society of Mechanical Engineers I American Nuclear Society, Standard for Level 1/Large Early Release Frequency Probabilistic Risk Assessment for Nuclear Power Plant Applications, ASME/ANS RA-Sa-2009, March 2009.

[7] U.S. Nuclear Regulatory Commission, An Approach for Determining the Technical Adequacy of Probabilistic Risk Assessment Results for Risk Informed Activities, Regulatory Guide 1.200, Revision 2, March 2009.

[8] Exelon Generation Company, LLC, Application for Technical Specifications Change Regarding Risk-Informed Justification for the Relocation of Specific Surveillance Frequency Requirements to a Licensee Controlled Program (Adoption of TSTF-425, Revision 3), March 26, 2015. ADAMS Accession No. ML 15089A231.

[9] Nine Mile Point Nuclear Station - Unit 1 Individual Plant Examination for External Events (IPEEE), Main Report, August 1996.

[1 O] Risk-Informed Technical Specifications Initiative 5b, Risk-Informed Method for Control of Surveillance Frequencies, Industry Guidance Document, NEI 04-10, Revision 1 , April 2007.

[11] U.S. Nuclear Regulatory Commission, An Approach for Plant-Specific, RiskInformed Decisionmaking: Technical Specifications, Regulatory Guide 1.177, Revision 1, May 2011.

Documents

200 E xe1u11 Wiy Exelon Generation ,.i.co!Tl · By letter dated May 12, 2015, (Reference 1) Exelon Generation Company, LLC (Exelon) requested to change the Nine Mile Point Unit 1