ML15293A602

Diablo Canyon 1 and 2 - Requests for Additional Information for License Amendment Request 15-03 to Adopt the Alternative Source Term Per 10 CFR 50.67 (TAC Nos. MF6399 and MF6400)

ML15293A602
Person / Time
Site:	Diablo Canyon
Issue date:	10/20/2015
From:	Lingam S P Plant Licensing Branch IV
To:	Soenen P R Pacific Gas & Electric Co
References
MF6399, MF6400
Download: ML15293A602 (3)

Text

1 NRR-PMDAPEm Resource From:Lingam, Siva Sent: Tuesday, October 20, 2015 9:50 AM To: Soenen, Philippe R (PNS3@pge.com)

Cc:Markley, Michael; Jackson, Christopher; Hardgrove, Matthew; MacFee, William;

Schrader, Kenneth (KJSe@pge.com); 'mjrm@pge.com'

Subject:

Diablo Canyon 1 and 2 - Requests for Addi tional Information for License Amendment Request 15-03 to Adopt the Alternative So urce Term per 10 CFR 50.67 (TAC Nos.

MF6399 and MF6400)By a letter dated June 17, 2015 2015 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15176A539), as supplemented by letter dated August 31, 2015 (ADAMS Accession No. ML15243A363), Pacific Gas and Electric (PG&E, the licensee), submitted a license amendment request (LAR) to revise the licensing bases to adopt the alternative source term (AST) as allowed by Title 10 of the Code of Federal Regulations (10 CFR), Part 50, Section 50.67, "Accident source term," for Diablo Canyon Power Plant (DCPP), Units 1 and 2 Please note the following official requests for additional information (RAIs) from our Reactor Systems Branch (SRXB) for the AST LAR regarding the Appendix B of Attachment 4 of the application for the Updated Final Safety Analysis Report (UFSAR) Chapter 15 analysis. Please provide your responses within 60 days from the date of this e-mail. We transmitted the draft RAIs to you on September 28, 2015, and we had a clarification call on October 7, 2015. As a result, the U.S. Nuclear Regulatory Commission (NRC) staff revised the SRXB RAI-2, and had another clarification call on October 13, 2015. Your timely responses will allow the NRC staff to complete its review on schedule.

SRXB - RAI 1 Table 1 in supplement letter dated August 31, 2015, contains the current licensing basis (CLB) summary for the AST thermal hydraulic safety analyses for DCPP. The UFSAR accidents listed are loss-of-coolant accident (LOCA) peak cladding temperature [PCT], LOCA containment response, locked rotor accident [LRA], control rod ejection accident [CREA], main steam line break (MSLB) steam releases, steam generator tube rupture (SGTR), and loss of load (LOL) steam releases. For each UFSAR accident, the following items are listed per Table 1: source document, implemented by license amendment or 10 CFR 50.59, analysis date, and code methodology. The CLB for MSLB steam releases, SGTR, and LOL steam releases were done under the 10 CFR 50.59 process. The source documentation references two topical reports, WCAP-16638-P, "Diablo Canyon Units 1 and 2 Replacement Steam Generator Program NSSS [Nuclear Steam Supply System] Licensing Report," Revision 1, dated January 2008, and WCAP-16985-P, "Diablo Canyon Units 1 and 2 Tavg and T feed Ranges Program NSSS Engineering Report," Revision 2, dated April 2009. The NRC staff did not review these topical reports with the implementation being done under the 10 CFR 50.59 process. The NRC staff requests that the licensee provide WCAP-16638-P, Revision 1, and WCAP-16985-P, Revision 2, for information for review of the applicable UFSAR Chapter 15 analyses thermal hydraulic parameter changes in support of the adoption of the proposed AST. Additionally , the NRC staff requests that the licensee provide calculation documents in support of these UFSAR Chapter 15 analyses in support of the adoption of the proposed AST. This information can be made available for NRC staff inspection via an audit.

SRXB - RAI 2 Section 4.3, "Gap Fractions for Non-LOCA Events," of of the LAR contains the information for the application regarding the gas gap fractions for the proposed AST for DCPP. The licensee states that the referenced gap fractions are contingent upon meeting Note 11 of Regulatory Guide [RG] 1.183, "Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors." Note 11 states the following:

2The release fractions listed here have been determined to be acceptable for use with currently approved LWR [light-water reactor] fuel with a peak burnup of 62,000 MWD [megawatt days]/MTU

[metric ton of uranium] provided that the maximum linear heat generation rate does not exceed 6.3 kw [kilowatts]/ft [foot] peak rod average power for burnups exceeding 54 GWD [gigawatt days]/MTU. As an alternative, fission gas release calculations performed using NRC-approved methodologies may be considered on a case-by-case basis. To be acceptable, these calculations must use a projected power history that will bound the limiting projected plant-specific power history for the specific fuel load. For the BWR [boiling-water reactor] rod drop accident and the PWR [pressurized-water reactor] rod ejection accident, the gap fractions are assumed to be 10% for iodines and noble gases.

In its review of the gas gap fractions for the UFSAR Chapter 15 analyses, the NRC staff notes that the licensee is not calculating fission gas releases based on a bounding power history. Instead, the licensee is proposing new gas gap fractions selected from NUREG/CR 5009 and Safety Guide 25 without any analyses confirming that the values are bounding. The NRC staff requests that the licensee demonstrate that the new gas gap fractions are bounding based on fission gas rele ase calculations performed using NRC-approved methodologies and using a bounding power history. Please include all information used to determine the new gas gap fractions for the DCPP AST. This information may include, but is not limited to, the following: analyses performed, methods used, operational power histories, input parameters, and assumptions or calculation

bases applied.

Siva P. Lingam U.S. Nuclear Regulatory Commission Project Manager (NRR/DORL/LPL4-1)

Cooper Nuclear Station Diablo Canyon Nuclear Power Plant Location: O8-D5; Mail Stop: O8-B3 Telephone: 301-415-1564; Fax: 301-415-1222 E-mail address: siva.lingam@nrc.gov

Hearing Identifier: NRR_PMDA Email Number: 2465 Mail Envelope Properties (Siva.Lingam@nrc.gov20151020094900)

Subject:

Diablo Canyon 1 and 2 - Requests for Additional Information for License Amendment Request 15-03 to Adopt the Alternative Source Term per 10 CFR 50.67 (TAC Nos. MF6399 and MF6400)

Sent Date: 10/20/2015 9:49:39 AM Received Date: 10/20/2015 9:49:00 AM From: Lingam, Siva Created By: Siva.Lingam@nrc.gov

Recipients: "Markley, Michael" <Michael.Markley@nrc.gov> Tracking Status: None "Jackson, Christopher" <Christopher.Jackson@nrc.gov> Tracking Status: None "Hardgrove, Matthew" <Matthew.Hardgrove@nrc.gov> Tracking Status: None "MacFee, William" <William.MacFee@nrc.gov> Tracking Status: None "Schrader, Kenneth (KJSe@pge.com)" <KJSe@pge.com> Tracking Status: None

"'mjrm@pge.com'" <mjrm@pge.com> Tracking Status: None "Soenen, Philippe R (PNS3@pge.com)" <PNS3@pge.com>

Tracking Status: None Post Office: Files Size Date & Time MESSAGE 5544 10/20/2015 9:49:00 AM

Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: Recipients Received:

1 NRR-PMDAPEm Resource From:Lingam, Siva Sent: Tuesday, October 20, 2015 9:50 AM To: Soenen, Philippe R (PNS3@pge.com)

Cc:Markley, Michael; Jackson, Christopher; Hardgrove, Matthew; MacFee, William;

Schrader, Kenneth (KJSe@pge.com); 'mjrm@pge.com'

Subject:

Diablo Canyon 1 and 2 - Requests for Addi tional Information for License Amendment Request 15-03 to Adopt the Alternative So urce Term per 10 CFR 50.67 (TAC Nos.

MF6399 and MF6400)By a letter dated June 17, 2015 2015 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15176A539), as supplemented by letter dated August 31, 2015 (ADAMS Accession No. ML15243A363), Pacific Gas and Electric (PG&E, the licensee), submitted a license amendment request (LAR) to revise the licensing bases to adopt the alternative source term (AST) as allowed by Title 10 of the Code of Federal Regulations (10 CFR), Part 50, Section 50.67, "Accident source term," for Diablo Canyon Power Plant (DCPP), Units 1 and 2 Please note the following official requests for additional information (RAIs) from our Reactor Systems Branch (SRXB) for the AST LAR regarding the Appendix B of Attachment 4 of the application for the Updated Final Safety Analysis Report (UFSAR) Chapter 15 analysis. Please provide your responses within 60 days from the date of this e-mail. We transmitted the draft RAIs to you on September 28, 2015, and we had a clarification call on October 7, 2015. As a result, the U.S. Nuclear Regulatory Commission (NRC) staff revised the SRXB RAI-2, and had another clarification call on October 13, 2015. Your timely responses will allow the NRC staff to complete its review on schedule.

SRXB - RAI 1 Table 1 in supplement letter dated August 31, 2015, contains the current licensing basis (CLB) summary for the AST thermal hydraulic safety analyses for DCPP. The UFSAR accidents listed are loss-of-coolant accident (LOCA) peak cladding temperature [PCT], LOCA containment response, locked rotor accident [LRA], control rod ejection accident [CREA], main steam line break (MSLB) steam releases, steam generator tube rupture (SGTR), and loss of load (LOL) steam releases. For each UFSAR accident, the following items are listed per Table 1: source document, implemented by license amendment or 10 CFR 50.59, analysis date, and code methodology. The CLB for MSLB steam releases, SGTR, and LOL steam releases were done under the 10 CFR 50.59 process. The source documentation references two topical reports, WCAP-16638-P, "Diablo Canyon Units 1 and 2 Replacement Steam Generator Program NSSS [Nuclear Steam Supply System] Licensing Report," Revision 1, dated January 2008, and WCAP-16985-P, "Diablo Canyon Units 1 and 2 Tavg and T feed Ranges Program NSSS Engineering Report," Revision 2, dated April 2009. The NRC staff did not review these topical reports with the implementation being done under the 10 CFR 50.59 process. The NRC staff requests that the licensee provide WCAP-16638-P, Revision 1, and WCAP-16985-P, Revision 2, for information for review of the applicable UFSAR Chapter 15 analyses thermal hydraulic parameter changes in support of the adoption of the proposed AST. Additionally , the NRC staff requests that the licensee provide calculation documents in support of these UFSAR Chapter 15 analyses in support of the adoption of the proposed AST. This information can be made available for NRC staff inspection via an audit.

SRXB - RAI 2 Section 4.3, "Gap Fractions for Non-LOCA Events," of of the LAR contains the information for the application regarding the gas gap fractions for the proposed AST for DCPP. The licensee states that the referenced gap fractions are contingent upon meeting Note 11 of Regulatory Guide [RG] 1.183, "Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors." Note 11 states the following:

2The release fractions listed here have been determined to be acceptable for use with currently approved LWR [light-water reactor] fuel with a peak burnup of 62,000 MWD [megawatt days]/MTU

[metric ton of uranium] provided that the maximum linear heat generation rate does not exceed 6.3 kw [kilowatts]/ft [foot] peak rod average power for burnups exceeding 54 GWD [gigawatt days]/MTU. As an alternative, fission gas release calculations performed using NRC-approved methodologies may be considered on a case-by-case basis. To be acceptable, these calculations must use a projected power history that will bound the limiting projected plant-specific power history for the specific fuel load. For the BWR [boiling-water reactor] rod drop accident and the PWR [pressurized-water reactor] rod ejection accident, the gap fractions are assumed to be 10% for iodines and noble gases.

In its review of the gas gap fractions for the UFSAR Chapter 15 analyses, the NRC staff notes that the licensee is not calculating fission gas releases based on a bounding power history. Instead, the licensee is proposing new gas gap fractions selected from NUREG/CR 5009 and Safety Guide 25 without any analyses confirming that the values are bounding. The NRC staff requests that the licensee demonstrate that the new gas gap fractions are bounding based on fission gas rele ase calculations performed using NRC-approved methodologies and using a bounding power history. Please include all information used to determine the new gas gap fractions for the DCPP AST. This information may include, but is not limited to, the following: analyses performed, methods used, operational power histories, input parameters, and assumptions or calculation

bases applied.

Siva P. Lingam U.S. Nuclear Regulatory Commission Project Manager (NRR/DORL/LPL4-1)

Cooper Nuclear Station Diablo Canyon Nuclear Power Plant Location: O8-D5; Mail Stop: O8-B3 Telephone: 301-415-1564; Fax: 301-415-1222 E-mail address: siva.lingam@nrc.gov

Hearing Identifier: NRR_PMDA Email Number: 2465 Mail Envelope Properties (Siva.Lingam@nrc.gov20151020094900)

Subject:

Diablo Canyon 1 and 2 - Requests for Additional Information for License Amendment Request 15-03 to Adopt the Alternative Source Term per 10 CFR 50.67 (TAC Nos. MF6399 and MF6400)

Sent Date: 10/20/2015 9:49:39 AM Received Date: 10/20/2015 9:49:00 AM From: Lingam, Siva Created By: Siva.Lingam@nrc.gov

Recipients: "Markley, Michael" <Michael.Markley@nrc.gov> Tracking Status: None "Jackson, Christopher" <Christopher.Jackson@nrc.gov> Tracking Status: None "Hardgrove, Matthew" <Matthew.Hardgrove@nrc.gov> Tracking Status: None "MacFee, William" <William.MacFee@nrc.gov> Tracking Status: None "Schrader, Kenneth (KJSe@pge.com)" <KJSe@pge.com> Tracking Status: None

"'mjrm@pge.com'" <mjrm@pge.com> Tracking Status: None "Soenen, Philippe R (PNS3@pge.com)" <PNS3@pge.com>

Tracking Status: None Post Office: Files Size Date & Time MESSAGE 5544 10/20/2015 9:49:00 AM

Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: Recipients Received: