ML16015A003

NRR E-mail Capture - Request for Additional Information - Relief Request 1B3-3 for Comanche Peak Nuclear Power Plant, Unit 1

ML16015A003
Person / Time
Site:	Comanche Peak
Issue date:	01/14/2016
From:	Balwant Singal Plant Licensing Branch IV
To:	Hope T Luminant Generation Co
References
MF6125
Download: ML16015A003 (4)

Text

NRR-PMDAPEm Resource From: Singal, Balwant Sent: Thursday, January 14, 2016 1:26 PM To: Hope, Timothy Cc: Jack.Hicks@luminant.com; Alley, David; Collins, Jay

Subject:

Request for Additional Information - Relief Request 1B3-3 for Comanche Peak Nuclear Power Plant, Unit 1 (CAC No. MF6125)

Attachments: MF6125-RAI.docx By letter dated April 20, 2015, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15119A216), as supplemented by letter dated October 15, 2015 (ADAMS Accession No.

ML15300A013), Luminant Generation Company, LLC (the licensee), proposed an alternative to Title 10 of the Code of Federal Regulations (10 CFR), Paragraph 50.55a(g)(6)(ii)(F) for Comanche Peak Nuclear Power Plant, Unit 1. This regulation, in part, defines the inspection frequency requirement for the reactor vessel inlet butt welds in accordance with American Society of Mechanical Engineers Boiler and Pressure Vessel Code Case N-770-1, Alternative Examination Requirements and Acceptance Standards for Class 1 PWR

[Pressurized Water Reactor] Piping and Vessel Nozzle Butt Welds Fabricated With UNS N06082 or UNS W86182 Weld Filler Material With or Without Application of Listed Mitigation Activities,Section XI, Division 1 with U. S. Nuclear Regulatory Commission (NRC) conditions. The licensee is requesting an extension of the required inspection frequency from once every 7 calendar years to once every 9 calendar years.

The NRC staff has reviewed and evaluated the information provided by the licensee and has determined that the information described in the attachment to this e-mail is needed in order to complete its review of the relief request.

The Draft request for additional information (RAI) was transmitted on January 12, 2016. Rob Slough of your organization informed us on January 14, 2016 that a clarification call is not needed. You are requested to respond to this request within 30 days of this e-mail. However, considering the fact that relief is needed in support of the upcoming Unit 1 refueling outage, please expedite your response.

Please treat this e-mail as formal transmittal of RAIs.

Thanks.

Balwant K. Singal Senior Project Manager (Comanche Peak and Columbia)

Nuclear Regulatory Commission Division of Operating Reactor Licensing Balwant.Singal@nrc.gov Tel: (301) 415-3016 Fax: (301) 415-1222 1

Hearing Identifier: NRR_PMDA Email Number: 2596 Mail Envelope Properties (b196d572e3a549578e173b8f944e86e0)

Subject:

Request for Additional Information - Relief Request 1B3-3 for Comanche Peak Nuclear Power Plant, Unit 1 (CAC No. MF6125)

Sent Date: 1/14/2016 1:26:00 PM Received Date: 1/14/2016 1:26:00 PM From: Singal, Balwant Created By: Balwant.Singal@nrc.gov Recipients:

"Jack.Hicks@luminant.com" <Jack.Hicks@luminant.com>

Tracking Status: None "Alley, David" <David.Alley@nrc.gov>

Tracking Status: None "Collins, Jay" <Jay.Collins@nrc.gov>

Tracking Status: None "Hope, Timothy" <Timothy.Hope@luminant.com>

Tracking Status: None Post Office: HQPWMSMRS02.nrc.gov Files Size Date & Time MESSAGE 2064 1/14/2016 1:26:00 PM MF6125-RAI.docx 26457 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received: ZZZ

REQUEST FOR ADDITIONAL INFORMATION REQUEST FOR RELIEF FROM 10 CFR 50.55a(g)(6)(ii)(F) REQUIREMENTS FOR COLD LEG WELD INSPECTION FREQUENCY LUMINANT GENERATION COMPANY, LLC, COMANCHE PEAK NUCLEAR POWER PLANT, UNIT 1 DOCKET NO. 50-445 By letter dated April 20, 2015, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15119A216), as supplemented by letter dated October 15, 2015 (ADAMS Accession No. ML15300A013), Luminant Generation Company, LLC (the licensee),

proposed an alternative to Title 10 of the Code of Federal Regulations (10 CFR), Paragraph 50.55a(g)(6)(ii)(F) for Comanche Peak Nuclear Power Plant, Unit 1. This regulation, in part, defines the inspection frequency requirement for the reactor vessel inlet butt welds in accordance with American Society of Mechanical Engineers Boiler and Pressure Vessel Code Case N-770-1, Alternative Examination Requirements and Acceptance Standards for Class 1 PWR [Pressurized Water Reactor] Piping and Vessel Nozzle Butt Welds Fabricated With UNS N06082 or UNS W86182 Weld Filler Material With or Without Application of Listed Mitigation Activities,Section XI, Division 1 with U. S. Nuclear Regulatory Commission (NRC) conditions. The licensee is requesting an extension of the required inspection frequency from once every 7 calendar years to once every 9 calendar years.

The NRC staff has reviewed and evaluated the information provided by the licensee and has determined that the following information is needed in order to complete its review of the relief request.

Discussion on Flow Tolerance (Page 3 of 7 of the Letter Dated October 15, 2015)

A discussion of flaw tolerance is provided as part of the technical basis to support the relief request. The licensee states, in part, Based on the circumferential crack growth results, even for the most conservative case (high temperature with a 25% weld repair), a flaw with a depth of 15% of the wall thickness would not grow to the maximum allowable ASME flaw size in less than 10 years of continued operation.

Additionally, Figure 4 of Attachment 9.1 of letter dated April 20, 2015, shows that a Long SE

[Safe End] 25% Repair AR [Aspect Ratio] =10, High Temp flaw would grow from 10% through-wall to the ASME Code allowable flaw depth of 75% through-wall in approximately 20 years.

NRC staff performed a series of independent calculations and determined these values are not conservative. Additionally, the NRC staff did not identify a sufficient technical basis to address the potential of axial flaw growth. Therefore, the NRC staff requests the following;

1. The axial and hoop weld residual stresses (WRS) at operating temperature of the subject welds. If a generic WRS is used, include a basis for the WRS being conservative. (e.g. 50% weld repair, WRS validation used, safe end length, etc.)

2. Piping loads for the subject welds to include pressure, deadweight, 100% power normal operating thermal expansion, seismic events, and Loss of Coolant Accident (LOCA).

3. Weld dimensions for the subject welds include outside diameter and weld thickness.

NRR-PMDAPEm Resource From: Singal, Balwant Sent: Thursday, January 14, 2016 1:26 PM To: Hope, Timothy Cc: Jack.Hicks@luminant.com; Alley, David; Collins, Jay

Subject:

Request for Additional Information - Relief Request 1B3-3 for Comanche Peak Nuclear Power Plant, Unit 1 (CAC No. MF6125)

Attachments: MF6125-RAI.docx By letter dated April 20, 2015, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15119A216), as supplemented by letter dated October 15, 2015 (ADAMS Accession No.

ML15300A013), Luminant Generation Company, LLC (the licensee), proposed an alternative to Title 10 of the Code of Federal Regulations (10 CFR), Paragraph 50.55a(g)(6)(ii)(F) for Comanche Peak Nuclear Power Plant, Unit 1. This regulation, in part, defines the inspection frequency requirement for the reactor vessel inlet butt welds in accordance with American Society of Mechanical Engineers Boiler and Pressure Vessel Code Case N-770-1, Alternative Examination Requirements and Acceptance Standards for Class 1 PWR

[Pressurized Water Reactor] Piping and Vessel Nozzle Butt Welds Fabricated With UNS N06082 or UNS W86182 Weld Filler Material With or Without Application of Listed Mitigation Activities,Section XI, Division 1 with U. S. Nuclear Regulatory Commission (NRC) conditions. The licensee is requesting an extension of the required inspection frequency from once every 7 calendar years to once every 9 calendar years.

The NRC staff has reviewed and evaluated the information provided by the licensee and has determined that the information described in the attachment to this e-mail is needed in order to complete its review of the relief request.

The Draft request for additional information (RAI) was transmitted on January 12, 2016. Rob Slough of your organization informed us on January 14, 2016 that a clarification call is not needed. You are requested to respond to this request within 30 days of this e-mail. However, considering the fact that relief is needed in support of the upcoming Unit 1 refueling outage, please expedite your response.

Please treat this e-mail as formal transmittal of RAIs.

Thanks.

Balwant K. Singal Senior Project Manager (Comanche Peak and Columbia)

Nuclear Regulatory Commission Division of Operating Reactor Licensing Balwant.Singal@nrc.gov Tel: (301) 415-3016 Fax: (301) 415-1222 1

Hearing Identifier: NRR_PMDA Email Number: 2596 Mail Envelope Properties (b196d572e3a549578e173b8f944e86e0)

Subject:

Request for Additional Information - Relief Request 1B3-3 for Comanche Peak Nuclear Power Plant, Unit 1 (CAC No. MF6125)

Sent Date: 1/14/2016 1:26:00 PM Received Date: 1/14/2016 1:26:00 PM From: Singal, Balwant Created By: Balwant.Singal@nrc.gov Recipients:

"Jack.Hicks@luminant.com" <Jack.Hicks@luminant.com>

Tracking Status: None "Alley, David" <David.Alley@nrc.gov>

Tracking Status: None "Collins, Jay" <Jay.Collins@nrc.gov>

Tracking Status: None "Hope, Timothy" <Timothy.Hope@luminant.com>

Tracking Status: None Post Office: HQPWMSMRS02.nrc.gov Files Size Date & Time MESSAGE 2064 1/14/2016 1:26:00 PM MF6125-RAI.docx 26457 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received: ZZZ

REQUEST FOR ADDITIONAL INFORMATION REQUEST FOR RELIEF FROM 10 CFR 50.55a(g)(6)(ii)(F) REQUIREMENTS FOR COLD LEG WELD INSPECTION FREQUENCY LUMINANT GENERATION COMPANY, LLC, COMANCHE PEAK NUCLEAR POWER PLANT, UNIT 1 DOCKET NO. 50-445 By letter dated April 20, 2015, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML15119A216), as supplemented by letter dated October 15, 2015 (ADAMS Accession No. ML15300A013), Luminant Generation Company, LLC (the licensee),

proposed an alternative to Title 10 of the Code of Federal Regulations (10 CFR), Paragraph 50.55a(g)(6)(ii)(F) for Comanche Peak Nuclear Power Plant, Unit 1. This regulation, in part, defines the inspection frequency requirement for the reactor vessel inlet butt welds in accordance with American Society of Mechanical Engineers Boiler and Pressure Vessel Code Case N-770-1, Alternative Examination Requirements and Acceptance Standards for Class 1 PWR [Pressurized Water Reactor] Piping and Vessel Nozzle Butt Welds Fabricated With UNS N06082 or UNS W86182 Weld Filler Material With or Without Application of Listed Mitigation Activities,Section XI, Division 1 with U. S. Nuclear Regulatory Commission (NRC) conditions. The licensee is requesting an extension of the required inspection frequency from once every 7 calendar years to once every 9 calendar years.

The NRC staff has reviewed and evaluated the information provided by the licensee and has determined that the following information is needed in order to complete its review of the relief request.

Discussion on Flow Tolerance (Page 3 of 7 of the Letter Dated October 15, 2015)

A discussion of flaw tolerance is provided as part of the technical basis to support the relief request. The licensee states, in part, Based on the circumferential crack growth results, even for the most conservative case (high temperature with a 25% weld repair), a flaw with a depth of 15% of the wall thickness would not grow to the maximum allowable ASME flaw size in less than 10 years of continued operation.

Additionally, Figure 4 of Attachment 9.1 of letter dated April 20, 2015, shows that a Long SE

[Safe End] 25% Repair AR [Aspect Ratio] =10, High Temp flaw would grow from 10% through-wall to the ASME Code allowable flaw depth of 75% through-wall in approximately 20 years.

NRC staff performed a series of independent calculations and determined these values are not conservative. Additionally, the NRC staff did not identify a sufficient technical basis to address the potential of axial flaw growth. Therefore, the NRC staff requests the following;

1. The axial and hoop weld residual stresses (WRS) at operating temperature of the subject welds. If a generic WRS is used, include a basis for the WRS being conservative. (e.g. 50% weld repair, WRS validation used, safe end length, etc.)

2. Piping loads for the subject welds to include pressure, deadweight, 100% power normal operating thermal expansion, seismic events, and Loss of Coolant Accident (LOCA).

3. Weld dimensions for the subject welds include outside diameter and weld thickness.