ML21189A046

NRR E-mail Capture - Draft Request for Additional Information - Diablo Canyon Emergency Amendment Request to Revise Technical Specification 3.7.8, Auxiliary Saltwater (Asw) System

ML21189A046
Person / Time
Site:	Diablo Canyon
Issue date:	07/07/2021
From:	Samson Lee NRC/NRR/DORL/LPL4
To:	Richardson M Pacific Gas & Electric Co
References
L-2021-LLA-0123
Download: ML21189A046 (3)

Text

From: Lee, Samson Sent: Wednesday, July 7, 2021 12:20 PM To: Richardson, Michael

Subject:

DRAFT request for additional information - Diablo Canyon emergency amendment request to revise Technical Specification 3.7.8, Auxiliary Saltwater (ASW) System (EPID L-2021-LLA-0123)

Michael, Below is DRAFT request for additional information (RAI) for the Diablo Canyon emergency license amendment request for the Auxiliary Saltwater (ASW) System. Please let me know if you need a clarification call. We expect an RAI response soon today.

Thanks, Sam

Background:

On July 7, 2021, Pacific Gas and Electric Company (PG&E or the licensee) provided an advance draft copy of an emergency license amendment request (LAR) to revise the Technical Specification (TS) for the Diablo Canyon Nuclear Power Plant, Units 1 (Diablo Canyon or DCPP) (ADAMS Accession Nos. ML21188A038, ML21188A036, ML21188A037, ML21188A035, and ML21188A034). The proposed amendments would provide a new TS 3.7.8 Condition A note to allow a one-time Completion Time (CT) of 144 hours0.00167 days <br />0.04 hours <br />2.380952e-4 weeks <br />5.4792e-5 months <br /> to replace the ASW pump 1-1 motor during Cycle 23.

Risk Insights:

RAI APLA-1 For DCPP ASW pump 1-1:

1. In the LAR, the licensee indicated that they will tailboard [pre-job brief] operators on providing backup cooling from firewater to charging pumps.

a. Are there any job performance measures for this activity?

b. Describe the nature of the reactor coolant pump (RCP) seals and any enhancement (i.e., Gen III SHIELD shutdown seal or Abeyance).

2. Will there be any restrictions on performing on-line maintenance for other systems, structures, and components (SSCs) during the extended allowable outage time (AOT)?

3. When doing the risk analysis, what assumptions were made on common cause failure (CCF) and why?

4. Was an all-hazards model used to estimate core damage frequency (CDF)/large early release frequency (LERF)?

Electrical Engineering:

RAI EEEB-1 In the LAR, the licensee stated that the proposed changes would revise the operating license to provide a new TS 3.7.8 Condition A note to allow a one-time CT of 144 hours0.00167 days <br />0.04 hours <br />2.380952e-4 weeks <br />5.4792e-5 months <br /> to replace the

ASW pump 1-1 motor during Cycle 23. Please clarify the type of the replacement motor and the specifications of both existing and replacement motors. Also, please confirm no load changes as the result of the motor replacement.

Reactor Systems:

RAI SNSB-1 The LAR states, The TS 3.7.9 Ultimate Heat Sink (UHS) requirements are currently being met with the UHS (Pacific Ocean) temperature below 64°F. Given that the safety analysis assumes a maximum ASW temperature of 64°F, provide information on the expected UHS temperature for the duration of the proposed 144-hour CT in order to assure that the single operable train of ASW will continue to meet the design basis.

Mechanical Engineering:

RAI EMIB-1 In Section 2.0, Detailed Description, under Reason for the Proposed Change, it is stated, It is expected an additional 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> beyond the 72-hour completion time could be required to address contingency actions that may occur during the return of ASW Pump 1-1 to OPERABLE status. Provide a description of the contingency actions.

Hearing Identifier: NRR_DRMA Email Number: 1260 Mail Envelope Properties (SA1PR09MB8653469B8339D5828854C1D59A1A9)

Subject:

DRAFT request for additional information - Diablo Canyon emergency amendment request to revise Technical Specification 3.7.8, Auxiliary Saltwater (ASW) System (EPID L-2021-LLA-0123)

Sent Date: 7/7/2021 12:20:16 PM Received Date: 7/7/2021 12:20:00 PM From: Lee, Samson Created By: Samson.Lee@nrc.gov Recipients:

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

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