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| | number = ML14155A209 | | | number = ML14155A209 |
| | issue date = 06/04/2014 | | | issue date = 06/04/2014 |
| | title = Brunswick Steam Electric Plant, Units 1 and 2 - E-mail Re. Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 805 (TAC Nos. ME9623 and ME9624) | | | title = E-mail Re. Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 805 |
| | author name = Hon A | | | author name = Hon A |
| | author affiliation = NRC/NRR/DORL/LPLII-2 | | | author affiliation = NRC/NRR/DORL/LPLII-2 |
| | addressee name = Hamrick G T | | | addressee name = Hamrick G |
| | addressee affiliation = Duke Energy Progress, Inc | | | addressee affiliation = Duke Energy Progress, Inc |
| | docket = 05000324, 05000325 | | | docket = 05000324, 05000325 |
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| =Text= | | =Text= |
| {{#Wiki_filter:Hon, Andrew From: Sent: To: Cc: | | {{#Wiki_filter:Hon, Andrew From: Hon, Andrew Sent: Wednesday, June 04, 2014 12:19 PM To: Murray, William R. (Bill) (Biii.Murray@duke-energy.com) (Biii.Murray@duke-energy.com) |
| | Cc: Fields, Leslie; Wall, Scott; Miller, Barry |
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| ==Subject:== | | ==Subject:== |
| Hon, Andrew Wednesday, June 04, 2014 12:19 PM Murray, William R. (Bill) (Biii.Murray@duke-energy.com) (Biii.Murray@duke-energy.com)
| | BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 AND 2- REQUEST FOR ADDITIONAL INFORMATION REGARDING VOLUNTARY RISK INITIATIVE NATIONAL FIRE PROTECTION ASSOCIATION STANDARD 805 (TAC NOS. ME9623 AND ME9624) |
| Fields, Leslie; Wall, Scott; Miller, Barry BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 AND 2-REQUEST FOR ADDITIONAL INFORMATION REGARDING VOLUNTARY RISK INITIATIVE NATIONAL FIRE PROTECTION ASSOCIATION STANDARD 805 (TAC NOS. ME9623 AND ME9624) Mr. George T. Hamrick, Vice President Brunswick Steam Electric Plant Duke Energy Progress, Inc. Post Office Box 1 0429 Southport, North Carolina 28461
| | Mr. George T. Hamrick, Vice President Brunswick Steam Electric Plant Duke Energy Progress, Inc. |
| | Post Office Box 10429 Southport, North Carolina 28461 |
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| ==Dear Mr. Hamrick:== | | ==Dear Mr. Hamrick:== |
| By letter dated September 25, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 12285A428), Duke Energy Progress, Inc. (the licensee) proposed to amend the operating license for the Brunswick Steam Electric Plant, Units 1 and 2, by adopting a new risk-informed based fire protection licensing basis in accordance with National Fire Protection Association Standard 805. The NRC staff has reviewed the licensee's application and responses to the NRC staff request for additional information (RAI) dated March 14, 2014, ADAMS Accession No. ML 14079A233. | | |
| We determined that further information is needed to complete our evaluation of the proposed change. On May 7, 2014, the NRC staff and representatives of the licensee held a conference call to provide the licensee with an opportunity to clarify the proposed RAI related to probabilistic risk assessment and to discuss your response schedule. | | By letter dated September 25, 2012 (Agencywide Documents Access and Management System (ADAMS) |
| The NRC staff's finalized this set of RAis is shown below. This request was discussed with Mr. Bill Murray of your staff on June 4, 2014, to confirm that these RAis do not contain sensitive information that should be withheld from the public and you would respond by June 27, 2014. The NRC staff considers that timely responses to RAis help ensure sufficient time is available for staff review and contribute toward the NRC's goal of efficient and effective use of staff resources. | | Accession No. ML12285A428), Duke Energy Progress, Inc. (the licensee) proposed to amend the operating license for the Brunswick Steam Electric Plant, Units 1 and 2, by adopting a new risk-informed performance-based fire protection licensing basis in accordance with National Fire Protection Association Standard 805. |
| Please note that review efforts on this task are continuing and additional RAis may be forthcoming. | | The NRC staff has reviewed the licensee's application and responses to the NRC staff request for additional information (RAI) dated March 14, 2014, ADAMS Accession No. ML14079A233. We determined that further information is needed to complete our evaluation of the proposed change. |
| 1 If you have any questions regarding this letter, please contact me. Andy Hon, PE Project Manager (Brunswick Nuclear Plant 1 & 2, Sequoyah Nuclear Plant 1 & 2) Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation 301-415-8480 OWFN08E5 Mail Stop 08G-9a andrew. hon@nrc. gov cc: Distribution via ListServ ADAMS Accession No.: ML 14155A209 REQUEST FOR ADDITIONAL INFORMATON VOLUNTARY FIRE PROTECTION RISK INITIATIVE DUKE ENERGY PROGRESS BRUNSWICK STEAM ELECTRIC PLANT. UNITS 1 AND 2 DOCKET NOS. 50-325 AND 50-324 Probabilistic Risk Assessment (PRA) RAI 01.d.02 In a letter dated March 14, 2014, ADAMS Accession No. ML 14079A233, the licensee responded to PRA RAI 1.d.01. The response to this RAI explains that, in addition to an in-depth review of a sampling of plant records for performance of the "Transient Fire Load Evaluation" procedure, the licensee assessed the last three years of transient combustible violations provided in the Fire Protection Program System Health Reports. A number of violations appear to be dismissed based on the following rationale: "Based on their fire procedure, this would likely not be a violation because Attachment 3 exempts this type of material from transient combustible controls for both 'No Storage' locations and 'Non-Intervening Combustible Zones'." These violations appear to represent circumstances in which quantities of combustible sources existed in the plant that could have contributed to a fire. a. Explain and justify how these violations were considered in the determination of reduced Heat Release Rates (HRRs) for transient fires. Include in this discussion explanation of whether these violations could have resulted in a transient fire exceeding the reduced HRR rates credited in the Fire PRA. RAI 01.f.ii.02 In the same letter, the licensee responded to PRA RAI 1.f.ii.01. | | On May 7, 2014, the NRC staff and representatives of the licensee held a conference call to provide the licensee with an opportunity to clarify the proposed RAI related to probabilistic risk assessment and to discuss your response schedule. The NRC staff's finalized this set of RAis is shown below. This request was discussed with Mr. Bill Murray of your staff on June 4, 2014, to confirm that these RAis do not contain sensitive information that should be withheld from the public and you would respond by June 27, 2014. |
| The response to this RAI explains that main control room (MCR) abandonment is only credited for loss of habitability (i.e., not loss of control/function), and that MCR fire scenarios were separately evaluated for loss of control/function that leads to core damage without crediting alternate shutdown. | | The NRC staff considers that timely responses to RAis help ensure sufficient time is available for staff review and contribute toward the NRC's goal of efficient and effective use of staff resources. Please note that review efforts on this task are continuing and additional RAis may be forthcoming. |
| This approach is asserted to be conservative. | | 1 |
| Given that MCR abandonment appears to be evaluated as a single scenario using a single conditional core damage probability/conditional large early release probability (CCDP/CLERP) (though an event tree was used to calculate the single CCDP/CLERP values), it is still not clear how the abandonment scenario addresses the 2 possibility of different fire induced impacts like spurious failures that can accompany a fire that leads to abandonment. | | |
| : a. Explain how the single abandonment scenario addresses the various possible fire-induced failures. | | If you have any questions regarding this letter, please contact me. |
| Specifically include discussion of how the following scenarios are addressed: | | Andy Hon, PE Project Manager (Brunswick Nuclear Plant 1 & 2, Sequoyah Nuclear Plant 1 & 2) |
| : i. Scenarios where fire fails only a few functions aside from forcing MCR abandonment and successful alternate shutdown is straightforward ii. Scenarios where fire could cause some recoverable functional failures or spurious operations that complicate the shutdown but successful alternate shutdown is likely iii. Scenarios where the fire-induced failures cause great difficulty for shutdown by failing multiple functions and/or complex spurious operations that make successful shutdown unlikely. | | Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation 301-415-8480 OWFN08E5 Mail Stop 08G-9a andrew. hon@nrc. gov cc: Distribution via ListServ ADAMS Accession No.: ML14155A209 REQUEST FOR ADDITIONAL INFORMATON VOLUNTARY FIRE PROTECTION RISK INITIATIVE DUKE ENERGY PROGRESS BRUNSWICK STEAM ELECTRIC PLANT. UNITS 1 AND 2 DOCKET NOS. 50-325 AND 50-324 Probabilistic Risk Assessment (PRA) RAI 01.d.02 In a letter dated March 14, 2014, ADAMS Accession No. ML14079A233, the licensee responded to PRA RAI 1.d.01. The response to this RAI explains that, in addition to an in-depth review of a sampling of plant records for performance of the "Transient Fire Load Evaluation" procedure, the licensee assessed the last three years of transient combustible violations provided in the Fire Protection Program System Health Reports. A number of violations appear to be dismissed based on the following rationale: "Based on their fire procedure, this would likely not be a violation because Attachment 3 exempts this type of material from transient combustible controls for both 'No Storage' locations and 'Non-Intervening Combustible Zones'." These violations appear to represent circumstances in which quantities of combustible sources existed in the plant that could have contributed to a fire. |
| : b. If fire-induced failures of MCR functions are not considered in abandonment scenarios, provide justification for their exclusion. | | : a. Explain and justify how these violations were considered in the determination of reduced Heat Release Rates (HRRs) for transient fires. Include in this discussion explanation of whether these violations could have resulted in a transient fire exceeding the reduced HRR rates credited in the Fire PRA. |
| : i. Describe whether credited abandonment actions from the abandonment procedure is correct for loss of function or spurious actions that may occur as a result of a fire leading to abandonment. | | RAI 01.f.ii.02 In the same letter, the licensee responded to PRA RAI 1.f.ii.01. The response to this RAI explains that main control room (MCR) abandonment is only credited for loss of habitability (i.e., not loss of control/function), and that MCR fire scenarios were separately evaluated for loss of control/function that leads to core damage without crediting alternate shutdown. This approach is asserted to be conservative. Given that MCR abandonment appears to be evaluated as a single scenario using a single conditional core damage probability/conditional large early release probability (CCDP/CLERP) (though an event tree was used to calculate the single CCDP/CLERP values), it is still not clear how the abandonment scenario addresses the 2 |
| ii. If abandonment actions do not account for these effects then describe how fire-induced failures are considered in modeling of abandonment scenarios and include those failures as part of the integrated analysis performed in response to PRA RAI 23. PRA RAI 01.f.iii.02 In the same letter, the licensee responded to PRA RAI 1.f.iii.01. | | |
| The disposition to this RAI states that the large early release frequency (LERF) contribution from MCR abandonment due to habitability was estimated to be 10% of the core damage frequency (CDF) for MCR abandonment, based on the Internal Events PRA where LERF is 8% of CDF. Containment bypass scenarios, such as interfacing system loss-of-coolant-accident (ISLOCAs), are often major contributors to LERF. a. Justify that the relative likelihood/frequency of containment bypass scenarios for the Fire PRA, as compared to that for core damage scenarios, is not higher than for the Internal Events PRA. PRA RAI 06.02 The disposition to PRA RAI 06.01 presents results of a sensitivity in which Main Control Board (MCB) scenarios are multiplied by the whole MCB ignition frequency rather than a fraction of the frequency. | | possibility of different fire induced impacts like spurious failures that can accompany a fire that leads to abandonment. |
| Given that this sensitivity study appears to only impact sequence frequencies, it is not clear why there is asymmetry between CDF and LERF sensitivity results. Similarly, the results of the integrated analysis provided in response to PRA 23 shows that, whereas change in (6) CDF, 6 LERF, and CDF increased as a result of the integrated analysis, the LERF decreased in a number of cases. It is not clear why LERF would trend in an opposite direction from CDF. a. Please explain and justify these seeming anomalies. | | : a. Explain how the single abandonment scenario addresses the various possible fire-induced failures. Specifically include discussion of how the following scenarios are addressed: |
| PRA RAI 22.c.01 In the same letter dated March 14, 2014, the licensee responded to PRA RAI 22.c. Regarding the final five bullets of part (c) of this RAI, on improvements made to facilitate fire modeling, two of the explanations are not clear. 3 | | : i. Scenarios where fire fails only a few functions aside from forcing MCR abandonment and successful alternate shutdown is straightforward ii. Scenarios where fire could cause some recoverable functional failures or spurious operations that complicate the shutdown but successful alternate shutdown is likely iii. Scenarios where the fire-induced failures cause great difficulty for shutdown by failing multiple functions and/or complex spurious operations that make successful shutdown unlikely. |
| : a. Explain more fully what the constant of 6 minutes was used for and the modeling with which it was replaced. | | : b. If fire-induced failures of MCR functions are not considered in abandonment scenarios, provide justification for their exclusion. |
| | : i. Describe whether credited abandonment actions from the abandonment procedure is correct for loss of function or spurious actions that may occur as a result of a fire leading to abandonment. |
| | ii. If abandonment actions do not account for these effects then describe how fire-induced failures are considered in modeling of abandonment scenarios and include those failures as part of the integrated analysis performed in response to PRA RAI 23. |
| | PRA RAI 01.f.iii.02 In the same letter, the licensee responded to PRA RAI 1.f.iii.01. The disposition to this RAI states that the large early release frequency (LERF) contribution from MCR abandonment due to habitability was estimated to be 10% of the core damage frequency (CDF) for MCR abandonment, based on the Internal Events PRA where LERF is 8% of CDF. Containment bypass scenarios, such as interfacing system loss-of-coolant-accident (ISLOCAs), are often major contributors to LERF. |
| | : a. Justify that the relative likelihood/frequency of containment bypass scenarios for the Fire PRA, as compared to that for core damage scenarios, is not higher than for the Internal Events PRA. |
| | PRA RAI 06.02 The disposition to PRA RAI 06.01 presents results of a sensitivity in which Main Control Board (MCB) scenarios are multiplied by the whole MCB ignition frequency rather than a fraction of the frequency. Given that this sensitivity study appears to only impact sequence frequencies, it is not clear why there is asymmetry between CDF and LERF sensitivity results. Similarly, the results of the integrated analysis provided in response to PRA 23 shows that, whereas change in (6) CDF, 6 LERF, and CDF increased as a result of the integrated analysis, the LERF decreased in a number of cases. It is not clear why LERF would trend in an opposite direction from CDF. |
| | : a. Please explain and justify these seeming anomalies. |
| | PRA RAI 22.c.01 In the same letter dated March 14, 2014, the licensee responded to PRA RAI 22.c. Regarding the final five bullets of part (c) of this RAI, on improvements made to facilitate fire modeling, two of the explanations are not clear. |
| | 3 |
| | : a. Explain more fully what the constant of 6 minutes was used for and the modeling with which it was replaced. |
| : b. Also, describe more fully how the hot gas layer (HGL) modeling basis changed, including how the "total energy released" is modeled in the updated HGL analysis. | | : b. Also, describe more fully how the hot gas layer (HGL) modeling basis changed, including how the "total energy released" is modeled in the updated HGL analysis. |
| PRA RAJ 23.01 With respect to the response to RAI 01.d.02, if the transient combustible violations cited cannot be explained or justified to support use of reduced transient heat release rates (HRRs), then use another value for the HRR to a. Justify its use and incorporate that value in the integrated analysis provided in response to PRA RAI 23. In addition, based on the response to RAI 24.01 below, revise all estimates of the risk and risk metrics to exclude the credit for the "panel methods" approach. | | PRA RAJ 23.01 With respect to the response to RAI 01.d.02, if the transient combustible violations cited cannot be explained or justified to support use of reduced transient heat release rates (HRRs), then use another value for the HRR to |
| PRA RAJ 24.01 In the same letter dated March 14, 2014, the licensee responded to PRA RAI 24. The disposition to this RAI presents a new implementation item (i.e., #13) that commits to replacing unacceptable methods with acceptable methods prior to self-approval in cases where impact was shown to be minimal in the current submittal, with one exception. | | : a. Justify its use and incorporate that value in the integrated analysis provided in response to PRA RAI |
| That exception is stated to be replacing the "panel methods" approach (assumption that 10% of the electrical panels meet the definition of an open panel). a. Either provide justification for this, including a phenomenological basis beyond the historical fire events database, or b. Confirm how you will modify the new implementation item #13 to include removal of credit for use of the "panel factors" method. 4}} | | : 23. In addition, based on the response to RAI 24.01 below, revise all estimates of the risk and delta-risk metrics to exclude the credit for the "panel methods" approach. |
| | PRA RAJ 24.01 In the same letter dated March 14, 2014, the licensee responded to PRA RAI 24. The disposition to this RAI presents a new implementation item (i.e., #13) that commits to replacing unacceptable methods with acceptable methods prior to self-approval in cases where impact was shown to be minimal in the current submittal, with one exception. That exception is stated to be replacing the "panel methods" approach (assumption that 10% of the electrical panels meet the definition of an open panel). |
| | : a. Either provide justification for this, including a phenomenological basis beyond the historical fire events database, or |
| | : b. Confirm how you will modify the new implementation item #13 to include removal of credit for use of the "panel factors" method. |
| | 4}} |
Letter Sequence RAI |
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MONTHYEARBSEP 12-0106, License Amendment Request to Adopt NFPA 805 Performance-Based Standard for Fire Protection for Light Water Reactor Electric Generating Plants (2001 Edition)2012-09-25025 September 2012
License Amendment Request to Adopt NFPA 805 Performance-Based Standard for Fire Protection for Light Water Reactor Electric Generating Plants (2001 Edition)
Project stage: Request
ML13004A3382013-01-0808 January 2013
Acceptance for Review of License Amendment Request for NFPA Standard 805 (TAC Nos. ME9623 and Me9624)
Project stage: Acceptance Review
ML13123A2312013-05-15015 May 2013
Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 805
Project stage: RAI
ML13141A6222013-05-23023 May 2013
RAI Re. Overall Integrated Plan in Response to the Commission Order Modifying Licenses with Regard to Requirements for Reliable Spent Fuel Pool Instrumentation (EA-12-051)
Project stage: RAI
BSEP 13-0066, Response to Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 8052013-06-28028 June 2013
Response to Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 805
Project stage: Response to RAI
BSEP 13-0070, Response to Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 8052013-07-15015 July 2013
Response to Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 805
Project stage: Response to RAI
ML14079A2372013-07-16016 July 2013
Fourth Quarter 2011 Fire Protection Program Health Report, Enclosure 5
Project stage: Other
ML14079A2382013-07-16016 July 2013
Fourth Quarter 2012 Fire Protection Program Health Report, Enclosure 6
Project stage: Other
BSEP 13-0083, Response to Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 8052013-07-31031 July 2013
Response to Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 805
Project stage: Response to RAI
ML13246A2772013-08-28028 August 2013
Enclosure 3 - Revised Brunswick NFPA 805 Transition Report, Transition to 10 CFR 50.48(c) - NFPA 805 Performance-Based Standard for Fire Protection for Light Water Reactor Electric Generating Plants, 2001 Edition, Transition Report, August
Project stage: Other
BSEP 13-0097, Response to Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard (NFPA) 8052013-08-29029 August 2013
Response to Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard (NFPA) 805
Project stage: Response to RAI
ML13277A0412013-09-19019 September 2013
Transition to 10 CFR 50.48(c) - NFPA 805 Performance-Based Standard for Fire Protection for Light Water Reactor Electric Generating Plants, 2001 Edition
Project stage: Other
BSEP 13-0107, Response to Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard (NFPA) 805 (NRC TAC Nos. ME9623 and ME9624)2013-09-30030 September 2013
Response to Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard (NFPA) 805 (NRC TAC Nos. ME9623 and ME9624)
Project stage: Response to RAI
ML14079A2352014-01-0909 January 2014
FIR-NGGC-0009, NFPA 805 Transient Combustibles and Ignition Source Controls Program, Enclosure 3
Project stage: Other
ML13365A3202014-01-14014 January 2014
Second Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 805
Project stage: RAI
ML14079A2362014-01-24024 January 2014
Fourth Quarter 2013 Fire Protection Program Health Report, Enclosure 4
Project stage: Other
ML14028A1782014-02-12012 February 2014
Second Set of Probabilistic Risk Assessment Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 805
Project stage: RAI
BSEP 14-0023, Response to Second Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 805 (NRC TAC Nos. ME9623 and ME9624)2014-02-28028 February 2014
Response to Second Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 805 (NRC TAC Nos. ME9623 and ME9624)
Project stage: Request
BSEP 14-0029, Response to Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 8052014-03-14014 March 2014
Response to Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 805
Project stage: Response to RAI
BSEP 14-0035, Response to Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 8052014-04-10010 April 2014
Response to Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 805
Project stage: Response to RAI
ML14079A2342014-04-30030 April 2014
BNP-PSA-086, Bnp Fire PRA - Fire Scenario Data, Enclosure 2, Attachment 25
Project stage: Other
ML14155A2092014-06-0404 June 2014
E-mail Re. Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 805
Project stage: RAI
BSEP 14-0076, Response to Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 805 (NRC TAC Nos. ME9623 and ME9624)2014-06-26026 June 2014
Response to Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 805 (NRC TAC Nos. ME9623 and ME9624)
Project stage: Response to RAI
ML14205A5922014-07-24024 July 2014
Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 805 (TAC Nos. ME9623 and ME9624)
Project stage: RAI
ML14220A2132014-08-0808 August 2014
E-mail Re. Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 805
Project stage: RAI
BSEP 14-0092, Response to Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 805 (NRC TAC ME9623 and ME9624)2014-08-15015 August 2014
Response to Request for Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 805 (NRC TAC ME9623 and ME9624)
Project stage: Response to RAI
BSEP 14-0100, Response to Request Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 8052014-08-29029 August 2014
Response to Request Additional Information Regarding Voluntary Risk Initiative National Fire Protection Association Standard 805
Project stage: Other
ML14297A2662014-10-24024 October 2014
Record of Review, Brunswick Steam Electric Plant, Units 1 and 2, LAR Attachment U- Table U-1 Internal Events PRA Peer Review- Facts and Observations (F&Os), 10/24/14
Project stage: Other
BSEP 14-0122, Additional Information Regarding License Amendment Request to Adopt Voluntary Risk Initiative National Fire Protection Association Standard 8052014-11-20020 November 2014
Additional Information Regarding License Amendment Request to Adopt Voluntary Risk Initiative National Fire Protection Association Standard 805
Project stage: Request
BSEP 14-0134, Additional Information Regarding License Amendment Request to Adopt Voluntary Risk Initiative National Fire Protection Association Standard 805 (NRC TAC Nos. ME9623 and ME9624)2014-12-18018 December 2014
Additional Information Regarding License Amendment Request to Adopt Voluntary Risk Initiative National Fire Protection Association Standard 805 (NRC TAC Nos. ME9623 and ME9624)
Project stage: Request
ML14310A8082015-01-28028 January 2015
Issuance of Amendment Regarding Transition to a Risk-Informed, Performance-Based Fire Protection Program in Accordance with 10 CFR 50.48(C)
Project stage: Approval
2014-01-09
[Table View] |
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Category:E-Mail
MONTHYEARML24249A1362024-09-0404 September 2024
EN 57304 - Westinghouse Electric Company, LLC, Final Report - No Embedded Files. Notification of the Potential Existence of Defects Pursuant to 10 CFR Part 21
ML24179A1292024-06-24024 June 2024
Acceptance Review for LAR to Revise TS to Adopt TSTF-234-A, Revision 1
ML24066A0132024-03-0505 March 2024
Bru 2024-002 Radiation Safety Baseline Inspection Information Request
ML23248A2612023-09-0505 September 2023
NRR E-mail Capture - Brunswick Steam Electric Plant, Units 1 and 2 - Acceptance of License Amendment Request to Revise the 10 CFR 50.69 Categorization Process
ML23202A0652023-07-19019 July 2023
NRR E-mail Capture - Request for Additional Information - Brunswick Steam Electric Plant, Units 1 and 2, Torus Liner Inspection Alternative Request (L-2022-LLR-0089)
ML23142A2732023-05-22022 May 2023
Duke Fleet - Request for Additional Information Proposed Alternative for Steam Generator Welds in Accordance with 10 CFR 50.55a(z)(1)
ML23073A2282023-03-13013 March 2023
Duke Fleet- Adoption of TSTF-554, Revision 1, Revise Reactor Coolant Leakage Requirements - Acceptance Review
ML23032A2472023-01-26026 January 2023
Document Request Letter for Brunswick Upcoming RP Inspection 2023002
ML23018A1892023-01-17017 January 2023
Document Request for RP Inspection at Brunswick Inspection Report 2023-01
ML23006A0642023-01-0606 January 2023
NRR E-mail Capture - Acceptance Review Results for Brunswick, Unit Nos. 1 and 2 - Proposed Alternative Request RA-22-0308
ML23006A1892023-01-0606 January 2023
NRR E-mail Capture - Corrected - Acceptance Review Results for Brunswick, Unit Nos. 1 and 2 - Proposed Alternative Request RA-22-0308
NRC-2100-2022, EN 55999 Valcor Coil Shell Assemblies Final Notification (004)2022-09-12012 September 2022
EN 55999 Valcor Coil Shell Assemblies Final Notification (004)
NRC 2110-2022, EN 55999 - Valcor Engineering Corporation (009)2022-07-18018 July 2022
EN 55999 - Valcor Engineering Corporation (009)
ML22115A1412022-04-25025 April 2022
NRR E-mail Capture - Duke Common EOF Relocation - Request for Addition Information
ML22038A1572022-02-0707 February 2022
NRR E-mail Capture - Duke Energy Fleet - Acceptance of License Amendment Request Regarding Adoption of TSTF-541, Revision 2
ML22018A0272022-01-18018 January 2022
2022 All RFI Responses - Exercise and Program Inspections - Revl
ML21357A0472021-12-23023 December 2021
NRR E-mail Capture - Brunswick Steam Electric Plant, Units 1 and 2 - Acceptance of License Amendment Request Regarding Adoption of TSTF-580
ML21361A0122021-12-23023 December 2021
NRR E-mail Capture - Accepted for Review - Duke Energy Fleet License Amendment Request to Relocate Emergency Operations Facility
ML21354A8612021-12-15015 December 2021
NRR E-mail Capture - Request for Additional Information - Duke Fleet Request RA-19-0352 - Alternative for RPV Closure Stud Exams (L-2020-LLR-0156)
ML21277A0952021-10-0101 October 2021
NRR E-mail Capture - Request for Additional Information - Brunswick Exemption Request from 10CFR 55.47 License Operator Exam Two-year Waiver Limit
ML21200A1582021-07-16016 July 2021
NRR E-mail Capture - Accepted for Review - Brunswick License Amendment Request to Adopt TSTF-439, Eliminate Second Completion Times Limiting Time from Discovery
ML21168A0042021-06-17017 June 2021
Notification of Inspection and Request for Information
ML21137A1622021-04-26026 April 2021
NRR E-mail Capture - Accepted for Review - Brunswick License Amendment Request to Adopt TSTF-505 Risk-Informed Completion Time (L-2021-LLA-0060)
ML21082A0162021-03-22022 March 2021
Accepted for Review - Brunswick License Amendment Request to Change Tech Spec Limit for Standby Liquid Control System Boron Solution Storage Tank Volume L-2021-LLA-0022
ML21075A0032021-03-12012 March 2021
Emergency Preparedness Exercise Inspection Request for Information for - Brunswick, Catawba, North Anna, Oconee, Vogtle 1 & 2
ML21049A2632021-02-0404 February 2021
NRR E-mail Capture - Request for Additional Information - Duke Energy Fleet License Amendment Request to Revise Emergency Plan
ML21019A3772021-01-13013 January 2021
002 Radiation Safety Baseline Inspection Information Request
ML21007A3722021-01-0707 January 2021
NRR E-mail Capture - Acceptance Review - Duke Fleet - RA-19-0352 - Proposed Alternative for Reactor Vessel Close Stud Examinations (L-2020-LLR-0156)
ML20323A4072020-11-18018 November 2020
NRR E-mail Capture - Request for Additional Information - Brunswick License Exemption Request from 10CFR73 Annual Force on Force Exercise Requirements (EPIC L-2020-LLE-0180)
ML20309A5212020-10-29029 October 2020
Request for Additional Information - Brunswick License Amendment Request to Modify Its Approved 10 CFR 50.69, Risk-Informed Categorization and Treatment of SSC Categorization Process
ML20294A0642020-10-20020 October 2020
NRR E-mail Capture - Accepted for Review - Duke Energy Fleet License Amendment Request to Adopt TSTF-582 RPV Water Inventory Control Enhancements(L-2020-LLA-0218)
ML20297A3102020-10-13013 October 2020
NRR E-mail Capture - Acceptance Review - Duke Fleet - RA-20-0191 - Request to Use a Provision of a Later Edition of the ASME B&PV Code, Section XI - IWA-5120, IWA-5213, IWA-5241, IWA-5242, and IWA-5250 (L-2020-LLR-0126)
ML20297A3082020-10-0707 October 2020
NRR E-mail Capture - Acceptance Review - Duke Fleet - RA-20-0263 - Request to Use a Provision of a Later Edition of the ASME B&PV Code, Section XI for Repair/Replacement (L-2020-LLR-0124)
ML20297A3092020-10-0606 October 2020
NRR E-mail Capture - Acceptance Review - Duke Fleet - RA-20-0262 - Request to Use a Provision of a Later Edition of the ASME B&PV Code, Section XI - IWA-4540(b) (L-2020-LLR-0125)
ML20275A2972020-10-0101 October 2020
NRR E-mail Capture - Request for Additional Information - Brunswick Request for Alternate Examination of Reactor Vessel Nozzles
ML21033A8562020-08-0505 August 2020
NRR E-mail Capture - Accepted for Review - Brunswick Relief Request for RPV Nozzle-to-Vessel Weld and Inner Radii Examination Requirements EPID-L-2020-LLR-0091
ML20121A1262020-04-29029 April 2020
Radiation Safety Baseline Inspection Information Request
ML20111A1212020-04-20020 April 2020
NRR E-mail Capture - Accepted for Review - Brunswick Request for Alternative to Examination Category B-N-1 (VT-3) Visual Examination of Accessible Areas of the Reactor Vessel Interior - EPID: L-2020-LLR-0048
ML20017A1602020-01-17017 January 2020
E-mail Notification of Inspection and Request for Additional Information
ML19283D0852019-10-0909 October 2019
Request for Additional Information - Brunswick Atrium 11 LAR
ML19252A4572019-09-0808 September 2019
(FEMA Email 09-08-19) Tentative Notification of Brunswick Preliminary Capability Assessment Results
ML19252A4092019-09-0606 September 2019
(E-mail to FEMA 09-06-19) FEMA Notification for Planned Restart of Brunswick Units 1 and 2
ML19219A2132019-08-0707 August 2019
NRR E-mail Capture - Duke Energy Fleet - Acceptance of Requested Licensing Action Amendment Requests to Relocate the TSs Staff Qualification Requirements to the Duke Energy Corporation QAPD
ML19179A1312019-06-27027 June 2019
NRR E-mail Capture - Brunswick RAIs - LAR to Revise TS 5.5.12, Primary Containment Leakage Rate Testing Program for Permanent Extension of Maximum Appendix J Test Intervals (L 2019-LLA-0031)
ML19177A0122019-06-25025 June 2019
NRR E-mail Capture - Draft Brunswick RAIs - LAR to Revise TS 5.5.12, Primary Containment Leakage Rate Testing Program for Permanent Extension of Maximum Appendix J Test Intervals (L 2019-LLA-0031)
ML19162A3912019-06-11011 June 2019
NRR E-mail Capture - Duke Energy Fleet - Acceptance of Requested Licensing Action Relief Request (19-GO-001) Proposed Alternative to Use Encoded Phased Array Ultrasonic Examination in Lieu of Radiography
ML19162A3902019-06-11011 June 2019
NRR E-mail Capture - Brunswick Steam Electric Plant, Units 1 and 2 - Acceptance of Requested Licensing Action Fourth 10-Year Inservice Inspection Interval ISI-12
ML19092A1152019-04-0101 April 2019
NRR E-mail Capture - Brunswick Steam Electric Plant, Unit Nos. 1 and 2 - Acceptance of Requested Licensing Action Amendment Request to Modify Surveillance Requirements for Safety Relief Valves (L-2019-LLA-0043)
ML19092A1142019-04-0101 April 2019
NRR E-mail Capture - Brunswick Plant, Unit 1 and 2 - Acceptance of Requested Licensing Action Amendment Request to Modify TS 5.5.12 for Permanent Extension of Type a and Type C Leak Rate Test Frequencies (L-2019-LLA-0031)
ML19067A2712019-03-0707 March 2019
NRR E-mail Capture - Brunswick 3rd Round RAI - LAR to Allow Implementation of the Provisions 10 CFR 50.69
2024-09-04
[Table view]
Category:Request for Additional Information (RAI)
MONTHYEARML23202A0652023-07-19019 July 2023
NRR E-mail Capture - Request for Additional Information - Brunswick Steam Electric Plant, Units 1 and 2, Torus Liner Inspection Alternative Request (L-2022-LLR-0089)
ML23142A2732023-05-22022 May 2023
Duke Fleet - Request for Additional Information Proposed Alternative for Steam Generator Welds in Accordance with 10 CFR 50.55a(z)(1)
ML23032A2472023-01-26026 January 2023
Document Request Letter for Brunswick Upcoming RP Inspection 2023002
ML23018A1892023-01-17017 January 2023
Document Request for RP Inspection at Brunswick Inspection Report 2023-01
ML22192A0862022-07-12012 July 2022
RQ Inspection Notification Letter
ML22115A1412022-04-25025 April 2022
NRR E-mail Capture - Duke Common EOF Relocation - Request for Addition Information
ML21354A8612021-12-15015 December 2021
NRR E-mail Capture - Request for Additional Information - Duke Fleet Request RA-19-0352 - Alternative for RPV Closure Stud Exams (L-2020-LLR-0156)
ML21277A0952021-10-0101 October 2021
NRR E-mail Capture - Request for Additional Information - Brunswick Exemption Request from 10CFR 55.47 License Operator Exam Two-year Waiver Limit
ML21239A0652021-09-0808 September 2021
Request for Additional Information Regarding Proposed Alternative to ASME Section XI Requirements for Repair - Replacement of Buried Service Water Piping (EPID L-021-LLR-0014) - Public
ML21075A0032021-03-12012 March 2021
Emergency Preparedness Exercise Inspection Request for Information for - Brunswick, Catawba, North Anna, Oconee, Vogtle 1 & 2
ML21049A2632021-02-0404 February 2021
NRR E-mail Capture - Request for Additional Information - Duke Energy Fleet License Amendment Request to Revise Emergency Plan
ML21019A3772021-01-13013 January 2021
002 Radiation Safety Baseline Inspection Information Request
ML20323A4072020-11-18018 November 2020
NRR E-mail Capture - Request for Additional Information - Brunswick License Exemption Request from 10CFR73 Annual Force on Force Exercise Requirements (EPIC L-2020-LLE-0180)
ML20309A5212020-10-29029 October 2020
Request for Additional Information - Brunswick License Amendment Request to Modify Its Approved 10 CFR 50.69, Risk-Informed Categorization and Treatment of SSC Categorization Process
ML20275A2972020-10-0101 October 2020
NRR E-mail Capture - Request for Additional Information - Brunswick Request for Alternate Examination of Reactor Vessel Nozzles
ML20017A1602020-01-17017 January 2020
E-mail Notification of Inspection and Request for Additional Information
ML19283C5532019-10-18018 October 2019
Redacted - Brunswick Steam Electric Plant, Units 1 and 2 - Request for Additional Information
ML19283D0852019-10-0909 October 2019
Request for Additional Information - Brunswick Atrium 11 LAR
ML19179A1312019-06-27027 June 2019
NRR E-mail Capture - Brunswick RAIs - LAR to Revise TS 5.5.12, Primary Containment Leakage Rate Testing Program for Permanent Extension of Maximum Appendix J Test Intervals (L 2019-LLA-0031)
ML19177A0122019-06-25025 June 2019
NRR E-mail Capture - Draft Brunswick RAIs - LAR to Revise TS 5.5.12, Primary Containment Leakage Rate Testing Program for Permanent Extension of Maximum Appendix J Test Intervals (L 2019-LLA-0031)
ML19081A0722019-03-21021 March 2019
Notification of Inspection and Request for Information for NRC Problem Identification and Resolution Inspection
ML19067A2712019-03-0707 March 2019
NRR E-mail Capture - Brunswick 3rd Round RAI - LAR to Allow Implementation of the Provisions 10 CFR 50.69
ML19065A0962019-03-0606 March 2019
NRR E-mail Capture - Brunswick RAIs - LAR to Revise Allowable Value for TS 3.3.8.1 Time Delay on Loss of Voltage
ML19058A0742019-02-26026 February 2019
NRR E-mail Capture - Draft Brunswick RAIs - LAR to Revise Allowable Value for TS 3.3.8.1 Time Delay on Loss of Voltage
ML19056A2212019-02-25025 February 2019
NRR E-mail Capture - Brunswick Draft 3rd Round RAI - LAR to Allow Implementation of the Provisions 10 CFR 50.69
ML19015A0302019-01-14014 January 2019
NRR E-mail Capture - Brunswick 2nd Round RAIs - LAR to Allow Implementation of the Provisions 10 CFR 50.69
ML19010A3872019-01-10010 January 2019
NRR E-mail Capture - Brunswick RAIs - LAR to Revise TSs to Adopt TSTF-439, Eliminate Second Completion Times Limiting Time from Discovery of Failure to Meet an LCO
ML18360A0352018-12-21021 December 2018
NRR E-mail Capture - Brunswick Draft 2nd Round RAIs - LAR to Allow Implementation of the Provisions 10 CFR 50.69
ML18360A0362018-12-21021 December 2018
NRR E-mail Capture - Draft Brunswick RAIs - LAR to Revise TSs to Adopt TSTF-439, Eliminate Second Completion Times Limiting Time from Discovery of Failure to Meet an LCO
ML18282A1492018-10-0909 October 2018
NRR E-mail Capture - Brunswick RAIs - LAR to Allow Implementation of the Provisions 10 CFR 50.69
ML18263A3042018-09-20020 September 2018
NRR E-mail Capture - Brunswick Draft RAIs - LAR to Allow Implementation of the Provisions 10 CFR 50.69
ML18250A3082018-08-31031 August 2018
NRR E-mail Capture - Brunswick RAIs - LAR to Revise TS to Relocate the Pressure-Temperature Limits to the Pressure and Temperature Limits Report
ML18225A0122018-08-10010 August 2018
NRR E-mail Capture - Draft Brunswick RAIs - LAR to Revise TS to Relocate the Pressure-Temperature Limits to the Pressure and Temperature Limits Report
RA-18-0011, Response to Request for Supplemental Information Regarding Duke Energy'S Response to GL 2016-01 Monitoring of Neutron-Absorbing Materials in Spent Fuel Pools2018-05-30030 May 2018
Response to Request for Supplemental Information Regarding Duke Energy'S Response to GL 2016-01 Monitoring of Neutron-Absorbing Materials in Spent Fuel Pools
ML18130A8262018-05-15015 May 2018
Supplemental Information Needed for Acceptance. Amendment Request to Revise the Technical Specifications to Relocate the Pressure Temperature Limit Curves to a Pressure and Temperature Limits Report
ML18088A0072018-03-27027 March 2018
NRR E-mail Capture - Brunswick Units 1 & 2 Request for Additional Information - Relief Request for RPV Shell Circumferential Weld Examination (L-2018-LLR-0001)
ML18071A3732018-03-12012 March 2018
NRR E-mail Capture - Correction: Brunswick Unit 1 and Unit 2 Request for Additional Information Related Human Factors in the Mellla+ LAR (CACs MF8864 and MF8865, EPID: L-2016-LLA-0009)
ML18067A1032018-03-0808 March 2018
NRR E-mail Capture - Brunswick Unit 1 and Unit 2 Request for Additional Information Related Human Factors in the Mellla+ LAR (CACs MF8864 and MF8865, EPID: L-2016-LLA-0009)
ML18010A0502018-01-0505 January 2018
E-mail Re. Brunswick Units 1 and Unit 2 - Request for Additional Information Related to the Mellla+ LAR (CACs MF8864 and MF8865)
ML18010A0512018-01-0505 January 2018
Unit 2 - Request for Additional Information Related to the Mellla+ LAR (CACs MF8864 and MF8865) (Nonproprietary)
ML17339A9132017-12-0505 December 2017
NRR E-mail Capture - Brunswick Unit 1 and Unit 2 Request for Additional Information Related the Exigent Amendment Request for One-Time Extension of EDG Completions Time - Human Factors (EPID: L- 2017- LLA- 0398)
ML17339A0702017-12-0404 December 2017
NRR E-mail Capture - Brunswick Unit 1 and Unit 2 Request for Additional Information Related the Exigent Amendment Request for One-Time Extension of EDG Completions Time - Electrical Engineering (EPID: L- 2017- LLA- 0398)
ML17317B0022017-12-0404 December 2017
Request for Additional Information Related to License Amendment Request to Revise Technical Specifications to Adopt TSTF-542, Revision 2 (CAC Nos. MF9905 and MF9906; EPID L-2017-LLA-0242)
ML17339A0732017-12-0404 December 2017
NRR E-mail Capture - Brunswick Unit 1 and Unit 2 Request for Additional Information Related the Exigent Amendment Request for One-Time Extension of EDG Completions Time - PRA (EPID: L- 2017- LLA- 0398)
ML17328A4872017-11-24024 November 2017
Unit 2 - Request for Additional Information Related the Emergency Amendment Request for One-Time Extension of EDG Completions Time
ML17275A2772017-10-0202 October 2017
E-mail, Request for Additional Information Related Containment Accident Pressure in the Mellla+ LAR (CAC Nos. MF8864 and MF8865) (Non-Proprietary)
ML17192A4842017-07-11011 July 2017
NRR E-mail Capture - Duke Energy Fleet RAIs Alternative for Reactor Pressure Vessel Flange Threads Examination (MF9513 to MF9521)
ML17082A3042017-03-0909 March 2017
NRR E-mail Capture - Brunswick Unit 1 and Unit 2 Request for Additional Information Related Containment Accident Pressure in the Mellla+ LAR (CACs MF8864 and MF8865)
ML17037A0022017-02-0303 February 2017
NRR E-mail Capture - Brunswick Unit 1 and Unit 2 Request for Additional Information Related to LAR to Modify the TS Requirements for End States Associated with the Implementation of the Approved TSTF Traveler TSTF-423-A (MF8466 and MF8467)
ML16020A2632016-01-20020 January 2016
Brunswick Steam Electric Plant - Notification Of Inspection And Request For Information
2023-07-19
[Table view] |
Text
Hon, Andrew From: Hon, Andrew Sent: Wednesday, June 04, 2014 12:19 PM To: Murray, William R. (Bill) (Biii.Murray@duke-energy.com) (Biii.Murray@duke-energy.com)
Cc: Fields, Leslie; Wall, Scott; Miller, Barry
Subject:
BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 AND 2- REQUEST FOR ADDITIONAL INFORMATION REGARDING VOLUNTARY RISK INITIATIVE NATIONAL FIRE PROTECTION ASSOCIATION STANDARD 805 (TAC NOS. ME9623 AND ME9624)
Mr. George T. Hamrick, Vice President Brunswick Steam Electric Plant Duke Energy Progress, Inc.
Post Office Box 10429 Southport, North Carolina 28461
Dear Mr. Hamrick:
By letter dated September 25, 2012 (Agencywide Documents Access and Management System (ADAMS)
Accession No. ML12285A428), Duke Energy Progress, Inc. (the licensee) proposed to amend the operating license for the Brunswick Steam Electric Plant, Units 1 and 2, by adopting a new risk-informed performance-based fire protection licensing basis in accordance with National Fire Protection Association Standard 805.
The NRC staff has reviewed the licensee's application and responses to the NRC staff request for additional information (RAI) dated March 14, 2014, ADAMS Accession No. ML14079A233. We determined that further information is needed to complete our evaluation of the proposed change.
On May 7, 2014, the NRC staff and representatives of the licensee held a conference call to provide the licensee with an opportunity to clarify the proposed RAI related to probabilistic risk assessment and to discuss your response schedule. The NRC staff's finalized this set of RAis is shown below. This request was discussed with Mr. Bill Murray of your staff on June 4, 2014, to confirm that these RAis do not contain sensitive information that should be withheld from the public and you would respond by June 27, 2014.
The NRC staff considers that timely responses to RAis help ensure sufficient time is available for staff review and contribute toward the NRC's goal of efficient and effective use of staff resources. Please note that review efforts on this task are continuing and additional RAis may be forthcoming.
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If you have any questions regarding this letter, please contact me.
Andy Hon, PE Project Manager (Brunswick Nuclear Plant 1 & 2, Sequoyah Nuclear Plant 1 & 2)
Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation 301-415-8480 OWFN08E5 Mail Stop 08G-9a andrew. hon@nrc. gov cc: Distribution via ListServ ADAMS Accession No.: ML14155A209 REQUEST FOR ADDITIONAL INFORMATON VOLUNTARY FIRE PROTECTION RISK INITIATIVE DUKE ENERGY PROGRESS BRUNSWICK STEAM ELECTRIC PLANT. UNITS 1 AND 2 DOCKET NOS. 50-325 AND 50-324 Probabilistic Risk Assessment (PRA) RAI 01.d.02 In a letter dated March 14, 2014, ADAMS Accession No. ML14079A233, the licensee responded to PRA RAI 1.d.01. The response to this RAI explains that, in addition to an in-depth review of a sampling of plant records for performance of the "Transient Fire Load Evaluation" procedure, the licensee assessed the last three years of transient combustible violations provided in the Fire Protection Program System Health Reports. A number of violations appear to be dismissed based on the following rationale: "Based on their fire procedure, this would likely not be a violation because Attachment 3 exempts this type of material from transient combustible controls for both 'No Storage' locations and 'Non-Intervening Combustible Zones'." These violations appear to represent circumstances in which quantities of combustible sources existed in the plant that could have contributed to a fire.
- a. Explain and justify how these violations were considered in the determination of reduced Heat Release Rates (HRRs) for transient fires. Include in this discussion explanation of whether these violations could have resulted in a transient fire exceeding the reduced HRR rates credited in the Fire PRA.
RAI 01.f.ii.02 In the same letter, the licensee responded to PRA RAI 1.f.ii.01. The response to this RAI explains that main control room (MCR) abandonment is only credited for loss of habitability (i.e., not loss of control/function), and that MCR fire scenarios were separately evaluated for loss of control/function that leads to core damage without crediting alternate shutdown. This approach is asserted to be conservative. Given that MCR abandonment appears to be evaluated as a single scenario using a single conditional core damage probability/conditional large early release probability (CCDP/CLERP) (though an event tree was used to calculate the single CCDP/CLERP values), it is still not clear how the abandonment scenario addresses the 2
possibility of different fire induced impacts like spurious failures that can accompany a fire that leads to abandonment.
- a. Explain how the single abandonment scenario addresses the various possible fire-induced failures. Specifically include discussion of how the following scenarios are addressed:
- i. Scenarios where fire fails only a few functions aside from forcing MCR abandonment and successful alternate shutdown is straightforward ii. Scenarios where fire could cause some recoverable functional failures or spurious operations that complicate the shutdown but successful alternate shutdown is likely iii. Scenarios where the fire-induced failures cause great difficulty for shutdown by failing multiple functions and/or complex spurious operations that make successful shutdown unlikely.
- b. If fire-induced failures of MCR functions are not considered in abandonment scenarios, provide justification for their exclusion.
- i. Describe whether credited abandonment actions from the abandonment procedure is correct for loss of function or spurious actions that may occur as a result of a fire leading to abandonment.
ii. If abandonment actions do not account for these effects then describe how fire-induced failures are considered in modeling of abandonment scenarios and include those failures as part of the integrated analysis performed in response to PRA RAI 23.
PRA RAI 01.f.iii.02 In the same letter, the licensee responded to PRA RAI 1.f.iii.01. The disposition to this RAI states that the large early release frequency (LERF) contribution from MCR abandonment due to habitability was estimated to be 10% of the core damage frequency (CDF) for MCR abandonment, based on the Internal Events PRA where LERF is 8% of CDF. Containment bypass scenarios, such as interfacing system loss-of-coolant-accident (ISLOCAs), are often major contributors to LERF.
- a. Justify that the relative likelihood/frequency of containment bypass scenarios for the Fire PRA, as compared to that for core damage scenarios, is not higher than for the Internal Events PRA.
PRA RAI 06.02 The disposition to PRA RAI 06.01 presents results of a sensitivity in which Main Control Board (MCB) scenarios are multiplied by the whole MCB ignition frequency rather than a fraction of the frequency. Given that this sensitivity study appears to only impact sequence frequencies, it is not clear why there is asymmetry between CDF and LERF sensitivity results. Similarly, the results of the integrated analysis provided in response to PRA 23 shows that, whereas change in (6) CDF, 6 LERF, and CDF increased as a result of the integrated analysis, the LERF decreased in a number of cases. It is not clear why LERF would trend in an opposite direction from CDF.
- a. Please explain and justify these seeming anomalies.
PRA RAI 22.c.01 In the same letter dated March 14, 2014, the licensee responded to PRA RAI 22.c. Regarding the final five bullets of part (c) of this RAI, on improvements made to facilitate fire modeling, two of the explanations are not clear.
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- a. Explain more fully what the constant of 6 minutes was used for and the modeling with which it was replaced.
- b. Also, describe more fully how the hot gas layer (HGL) modeling basis changed, including how the "total energy released" is modeled in the updated HGL analysis.
PRA RAJ 23.01 With respect to the response to RAI 01.d.02, if the transient combustible violations cited cannot be explained or justified to support use of reduced transient heat release rates (HRRs), then use another value for the HRR to
- a. Justify its use and incorporate that value in the integrated analysis provided in response to PRA RAI
- 23. In addition, based on the response to RAI 24.01 below, revise all estimates of the risk and delta-risk metrics to exclude the credit for the "panel methods" approach.
PRA RAJ 24.01 In the same letter dated March 14, 2014, the licensee responded to PRA RAI 24. The disposition to this RAI presents a new implementation item (i.e., #13) that commits to replacing unacceptable methods with acceptable methods prior to self-approval in cases where impact was shown to be minimal in the current submittal, with one exception. That exception is stated to be replacing the "panel methods" approach (assumption that 10% of the electrical panels meet the definition of an open panel).
- a. Either provide justification for this, including a phenomenological basis beyond the historical fire events database, or
- b. Confirm how you will modify the new implementation item #13 to include removal of credit for use of the "panel factors" method.
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