ML13309A752
| ML13309A752 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 10/30/2013 |
| From: | Mark D. Sartain Dominion Nuclear Connecticut |
| To: | Document Control Desk, NRC/FSME, Office of Nuclear Reactor Regulation |
| References | |
| 13-590, TAC ME9733 | |
| Download: ML13309A752 (6) | |
Text
Dominion Nuclear Connecticut, Inc. F D .. 0 5000 Dominion Boulevard, Glen Allen, VA 23060 '" Doinion Web Address: wwwv.dom.com October 30, 2013 U. S. Nuclear Regulatory Commission Serial No.13-590 Attention: Document Control Desk NSSL/WDC RO Washington, DC 20555 Docket No. 50-423 License No. NPF-49 DOMINION NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 3 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING RELOCATION OF SPECIFIC SURVEILLANCE FREQUENCY REQUIREMENTS TO A LICENSEE CONTROLLED PROGRAM (TAC NO. ME9733)
By letter dated October 4, 2012, Dominion Nuclear Connecticut, Inc. (DNC) submitted a license amendment request (LAR) for Millstone Power Station Unit 3 (MPS3). The proposed amendment would relocate certain technical specification (TS) surveillance frequencies to a licensee controlled program by adopting Technical Specification Task Force (TSTF)-425, Revision 3, "Relocate Surveillance Frequencies to Licensee Control
- RITSTF [Risk-Informed Technical Specification Task Force Initiative] 5b." The proposed change would also add a new program, the Surveillance Frequency Control Program, in accordance with TSTF-425. In a letter dated December 18, 2012, the NRC transmitted a request for additional information (RAI) to DNC related to the LAR. DNC responded to the RAI in a letter dated January 4, 2013. In a letter dated March 8, 2013, the NRC transmitted a second RAI to DNC related to the LAR. DNC responded to the RAI in a letter dated April 17, 2013. Subsequently, in a letter dated October 9, 2013, the NRC transmitted a third RAI to DNC. DNC agreed to respond to the RAI by November 1, 2013. Attachment 1 provides DNC's response to the NRC's RAI.
If you have any questions regarding this submittal, please contact Wanda Craft at (804) 273-4687.
Sincerely, VICKI L. HULL Mark D. Sartain Notary Public Vice President - Nuclear Engineering and Development Commonwealth of Virginia g g ~140542 My Commission Expires May 31. 2014 COMMONWEALTH OF VIRGINIA - . . . . . . . . . . .
COUNTY OF HENRICO The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by Mark D. Sartain, who is Vice President - Nuclear Engineering and Development of Dominion Nuclear Connecticut, Inc.
He has affirmed before me that he is duly authorized to execute and file the foregoing document in behalf of that company, and that the statements in the document are true to the best of his knowledge and belief.
Acknowledged before me this , y of A* .t-z, 2013.
My Commission Expires: 5-D1I Notary Public
Serial No.13-590 Docket No. 50-423 Page 2 of 2
Attachment:
- 1. Response to Request for Additional Information Regarding Relocation of Specific Surveillance Frequency Requirements to a Licensee Controlled Program Commitments made in this letter: None cc: U.S. Nuclear Regulatory Commission Region I 2100 Renaissance Blvd Suite 100 King of Prussia, PA 19406-2713 J. S. Kim Project Manager - Millstone Power Station U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 08-C2A Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station
Serial No.13-590 Docket No. 50-423 ATTACHMENT 1 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING RELOCATION OF SPECIFIC SURVEILLANCE FREQUENCY REQUIREMENTS TO A LICENSEE CONTROLLED PROGRAM DOMINION NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 3
Serial No.13-590 Docket No. 50-423 Attachment 1, Page 1 of 3 By letter dated October 4, 2012, Dominion Nuclear Connecticut, Inc. (DNC) submitted a license amendment request (LAR) for Millstone Power Station Unit 3 (MPS3). The proposed amendment would relocate certain technical specification (TS) surveillance frequencies to a licensee controlled program by adopting Technical Specification Task Force (TSTF)-425, Revision 3, "Relocate Surveillance Frequencies to Licensee Control
- RITSTF [Risk-Informed Technical Specification Task Force Initiative] 5b." The proposed change would also add a new program, the Surveillance Frequency Control Program (SFCP), in accordance with TSTF-425. In a letter dated December 18, 2012, the NRC transmitted a request for additional information (RAI) to DNC related to the LAR. DNC responded to the RAI in a letter dated January 4, 2013. In a letter dated March 8, 2013, the NRC transmitted a second RAI to DNC related to the LAR. DNC responded to the RAI in a letter dated April 17, 2013. Subsequently, in a letter dated October 9, 2013, the NRC transmitted a third RAI to DNC. This attachment provides DNC's response to the NRC's RAI.
Question 1 The response to RAI 5 (April 17, 2013) indicates that Millstone Power Station Unit 3 (MPS3) plans to follow NEI 04-10 guidance from Step lOb. However, it further proposes a specific alternative bounding analysis methodology for fire initiatingevents which is not described in Nuclear Energy Institute (NEI) 04-10, Step lOb, and indicates that otherhazard bounding analysis will use a bounding analysis not explicitly described in NEI 04-10, Step lOb. This step provides examples of alternative bounding approaches if the structure, system, or component is not explicitly in the probabilistic risk assessment (PRA). However, as the methodology is described in the response for fire-initiatingevents, the staff cannot find it a bounding methodology due to an apparent lack of Fire PRA attributes. Given that MPS3 does not have a Fire PRA, according to the response to the RAI, an acceptable bounding analysis method should be consistent with alternative evaluation guidance describedin NEI 04-10, Step lOb. As noted in NEI 04-10, this step also applies to other hazards analyses. More generally, if an alternative bounding analysis approach is proposed other than the examples noted in this step, sufficient justification should be provided to ensure it is a bounding analysis. Therefore, please describe the bounding method to be used for internal fire or other external events, how it is consistent with NEI 04-10, Step lOb, and how the bounding analysis considersthe current plant configuration and operation.
DNC Response DNC is committed to evaluating changes to surveillance frequencies in accordance with the guidance provided in NEI 04-10, Rev. 1. NEI 04-10 methodology allows a qualitative screening or bounding analysis to provide justification for acceptability of proposed surveillance frequency changes. Since the MPS3 PRA internal events model
Serial No.13-590 Docket No. 50-423 Attachment 1, Page 2 of 3 does not currently include external events (e.g., internal fires, seismic, external floods),
the NEI 04-10 guidance will be used to evaluate the potential risk impact of external events associated with surveillance frequency changes. The Millstone Individual Plant Examination of External Events (IPEEE) report represents the MPS3 plant configuration and operation at the time of the IPEEE submittal. External event information from the IPEEE report, supplemented with relevant operating experience and additional risk insights garnered since the IPEEE, will be evaluated in accordance with NEI 04-10, Rev. 1, Step 10. That is, the information will be reviewed and qualitatively assessed in accordance with NEI 04-10, Rev. 1, Step 10a to determine the impact of the external events on surveillance frequency changes. If the qualitative information is deemed to be insufficient, then a bounding (i.e., quantitative) analysis will be performed. DNC will perform the bounding analysis in accordance with NEI 04-10, Rev. 1 Step 10b. The bounding analysis will be based on risk insights and analysis documented in the MPS3 IPEEE report with consideration of the IPEEE accident sequences, as well as relevant operating experience and additional risk insights garnered since the IPEEE, in the context of the current plant configuration and operation.
NEI 04-10, Rev. 1, Step 10b, provides three (3) examples for acceptable bounding approaches if a structure, system, or component (SSC) is not explicitly included in the probabilistic risk assessment (PRA).
The first example states:
"... bounding analysis is performed for those SSCs that are not explicitly modeled in the PRA model, but ratherare implicitly included..."
The second example states:
"...if the A CDF and LILERF values have been demonstratedto be very small from an internal events perspective ... and if it is known that the CDF 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.. .can be used to bound the potential impact from external events and shutdown PRA model contributors."
The third example states:
the ACDF and ALERF values have been demonstratedto be very small from
.if an internal events perspective ... and if it is known that the plant CDF and LERF results of the external event or shutdown PRA are much smaller than the corresponding values for the internalevent full power PRA, (that is, less than 10%),
then the results of the internal events analysis alone would suffice for the STI consideration. This example is likely to be applicable for a situation where the SSC associated with the STI change is modeled in the internal event full power PRA, but not in the external event or shutdown PRA."
Serial No.13-590 Docket No. 50-423 Attachment 1, Page 3 of 3 If it is deemed that the assessment of the risk performed in accordance with NEI 04-10, Rev. 1, Step 10 inadequately represents the current plant configuration and operation, then a more detailed PRA assessment will be performed in accordance with NEI 04-10, Rev. 1, Step 11. Step 11 is entered through NEI 04-10, Rev. 1, Step 10 page 10 item 4, which states:
"Dependingon the outcome from the bounding analysis in Steps lOb and 10c, there is also potential that more detailed modeling could be desirable to perform an appropriateevaluation of the STI change. In that case, the process would refer back to Step 11 to revise the PRA as needed to perform the detailed assessment."
Question 2 The LAR notes that a self-assessment of the MPS3 internalevents PRA was performed in 2007 using an ASME/ANS Standard. Please indicate which version of the ASME/ANS Standardwas used.
DNC Response The self-assessment/independent review of the MPS3 PRA was assessed to the American Society of Mechanical Engineers (ASME) PRA Standard, ASME RA-Sb-2005 addenda to ASME-S-2002, "Standard for Probabilistic Risk Assessment for Nuclear Power Plant Applications."