ML20261H423

NRR E-mail Capture - Request for Additional Information: Diablo Canyon Unit 2 Fall 2019 Steam Generator Tube Inspection Report

ML20261H423
Person / Time
Site:	Diablo Canyon
Issue date:	09/17/2020
From:	Samson Lee NRC/NRR/DORL/LPL4
To:	Richardson M Pacific Gas & Electric Co
References
L-2020-LRO-0026
Download: ML20261H423 (2)

Text

From: Lee, Samson Sent: Thursday, September 17, 2020 8:28 AM To: Richardson, Michael

Subject:

Request for additional information: Diablo Canyon Unit 2 Fall 2019 Steam Generator Tube Inspection Report (EPID: L-2020-LRO-0026)

By letter dated May 13, 2020 (Agencywide Documents Access and Management System (ADAMS)

Accession No. ML20134J139), Pacific Gas and Electric Company (PG&E, the licensee), submitted information summarizing the results of their fall 2019 steam generator (SG) tube inservice inspections performed during the end of the cycle 21 refueling outage (2R21) at Diablo Canyon Power Plant (Diablo Canyon), Unit 2. Technical Specification (TS) Section 5.6.10, Steam Generator (SG) Tube Inspection Report, requires that a report be submitted within 180 days after the initial entry into hot shutdown (MODE 4) following completion of an inspection of the replacement SGs performed in accordance with TS Section 5.5.9, Steam Generator (SG) Program, which requires that a SG Program be established and implemented to ensure SG tube integrity is maintained.

The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the inspection report and determined that additional information is required to complete the review. The NRC staffs request for additional information (RAI) is listed below. The staff may have additional RAIs. The staff sent the draft RAI to the PG&E staff who decided a clarification call was not necessary. The PG&E staff requested, and NRC agreed, to a RAI response by October 19, 2020.

The NRC staff considers that timely responses to RAIs help ensure sufficient time is available for staff review and contribute toward the NRCs goal of efficient and effective use of staff resources. Please note that if you do not respond to this request by the agreed-upon date or provide an acceptable alternate date, we may conclude that PG&E has not provided the information required by TS Section 5.6.10. If circumstances result in the need to revise the agreed upon response date, please contact me at (301) 415-3168 or via e-mail Samson.Lee@nrc.gov.

Request for additional information:

1. Section 1.2 of the report states that the 2R21 (fall 2019) SG tube inspection is the last one planned for the Diablo Canyon Unit 2 SGs, but that a license amendment would be necessary to operate four cycles to retirement in 2025 without inspection. TS Section 5.5.9 currently allows no more than three operating cycles without an SG tube inspection. Referring to Section 4.3 of the report, the feedwater heater appears to be an active source of foreign objects with the ongoing potential to cause wear and affect tube integrity, including an object that remained lodged between two tubes at the end of 2R21. These and other foreign objects and loose parts will be a potential source of tube degradation throughout the life of the SGs. Therefore, please provide the following information about meeting the tube integrity performance criteria in TS 5.5.9:

a. A description of how the operational assessment addresses foreign objects in the SGs.

b. A description of any secondary-side inspection and foreign object search and retrieval plans for the remaining refueling outages, even if no primary-side eddy current examinations are performed.

Hearing Identifier: NRR_DRMA Email Number: 785 Mail Envelope Properties (DM8PR09MB61834B2AF5E99A5EA36F89FF9A3E0)

Subject:

Request for additional information: Diablo Canyon Unit 2 Fall 2019 Steam Generator Tube Inspection Report (EPID: L-2020-LRO-0026)

Sent Date: 9/17/2020 8:28:25 AM Received Date: 9/17/2020 8:28:25 AM From: Lee, Samson Created By: Samson.Lee@nrc.gov Recipients:

"Richardson, Michael" <MJRm@pge.com>

Tracking Status: None Post Office: DM8PR09MB6183.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 3087 9/17/2020 8:28:25 AM Options Priority: Normal Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: