ML21110A684

NRR E-mail Capture - RAI - Hatch Unit 2 - One-Time Emergency RHR LAR (L-2020-LRO-0068)

ML21110A684
Person / Time
Site:	Hatch
Issue date:	04/20/2021
From:	John Lamb NRC/NRR/DORL/LPL2-1
To:	Enfinger T Southern Nuclear Operating Co
References
L-2020-LRO-0068
Download: ML21110A684 (3)

Text

From: Lamb, John Sent: Tuesday, April 20, 2021 3:39 PM To: Enfinger, Timothy Lee

Subject:

RAI - Hatch Unit 2 - One-Time Emergency RHR LAR (L-2020-LRO-0068)

Importance: High

Tim, By letter dated April 19, 2021 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML21010A388), Southern Nuclear Operating Company (SNC, the licensee) submitted a one-time emergency residual heat removal (RHR) license amendment request (LAR) for Edwin I. Hatch Nuclear Plant, Unit 2. The proposed amendment would make a one-time revision to Condition A of Technical Specification 3.5.1, ECCS [Emergency Core Cooling System] - Operating, to extend the Completion Time (CT) from 7 days to 15 days.

To complete its review of the inspection, the U.S. Nuclear Regulatory Commission (NRC) staff requests the below additional information.

On April 20, 2021, the NRC staff provided draft request for additional information (RAI) questions to SNC to make sure that the RAIs are understandable, the regulatory basis is clear, to ensure there is no proprietary information, and to determine if the information was previously docketed. The NRC staff is requesting that SNC would provide the RAI response commensurate with the emergency situation.

If you have any questions, you can contact me at 301-415-3100.

Sincerely, John REQUEST FOR ADDITIONAL INFORMATION By letter dated April 19, 2021 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML21010A388), Southern Nuclear Operating Company (SNC, the licensee) submitted a one-time emergency residual heat removal (RHR) license amendment request (LAR) for Edwin I. Hatch Nuclear Plant, Unit 2. The proposed amendment would make a one-time revision to Condition A of Technical Specification 3.5.1, ECCS [Emergency Core Cooling System] - Operating, to extend the Completion Time (CT) from 7 days to 15 days.

To complete its review of the inspection, the U.S. Nuclear Regulatory Commission (NRC) staff requests the following additional information:

• Provide a detailed analyses of the performance of the 2A, 2B, and 2C RHR pumps, and

• Review of industry operating experience pertaining to Ingersoll-Rand pumps.

Regulatory Requirement Regulatory Guide 1.177, Revision 1 Discussion

RG 1.177 Element 2: Perform Engineering Analysis reads in part:

The licensee should examine the proposed TS change to verify that it meets existing applicable rules and regulations. In addition, the licensee should determine how the change impacts defense-in-depth aspects of the plants design and operation and should determine the adequacy of safety margins following the proposed change. The licensee should consider how plant and industry operating experience relates to the proposed change, and whether potential compensatory measures could be taken to offset any negative impact from the proposed change.

LAR Emergency Circumstances Section 2.1 Why this Situation Could Not be Avoided provides considerable detail to explain that were no precursors (e.g., pump flow, discharge pressure, differential pressure, vibration analysis, oil analysis, thermography etc.) that could have predicted the failure of the 2D RHR pump.

In contrast, the LAR does not provide a similar performance review and analyses (2A, 2B, and 2C RHR pumps) of the RHR redundant trains pumps or residual same train RHR pump.

In addition, Enclosure to NL-21-0411 of the LAR does not contain a review of industry or pump vendor (Ingersoll-Rand) operating experience that would support a preface that common mode failure is highly unlikely.

To complete its review of the inspection, the U.S. Nuclear Regulatory Commission (NRC) staff requests the following additional information:

1. A new foreign object (FO) indication in tube Row 1, Column 2 (R1C2) was identified during RFO 1R22 (spring 2020). The spring 2020 SG tube inspection report (SGTIR) stated that lookback showed a precursor signal for the FO indication in tube R1C2.

a. The report does not indicate in which outage, or in how many outages, the precursor signal was present. Please provide this information.

b. Tube R1C2 was not plugged during 1R22. The spring 2020 SGTIR stated that no secondary side activities were performed during 1R22. Please discuss SNCs decision not to perform FO search and retrieval to confirm the presence of the FO and to attempt to remove it.

2. Table 8 in the RFO spring 2020 SGTIR includes the two broached tube support plate (TSP) wear indications identified during 1R22. Both broached TSP wear indications were first identified during RFO 1R21 (fall 2018). The broached TSP wear indication in tube R44C21 was reported to be in SG-4 in the RFO spring 2020 SGTIR, but it was reported to be in SG-1 in the RFO fall 2018 SGTIR (ADAMS Accession No. ML19080A329).

Please confirm the SG in which the broached TSP wear indication in tube R44C21 is located.

Hearing Identifier: NRR_DRMA Email Number: 1137 Mail Envelope Properties (MN2PR09MB508427573F8D2D34C46A1570FA489)

Subject:

RAI - Hatch Unit 2 - One-Time Emergency RHR LAR (L-2020-LRO-0068)

Sent Date: 4/20/2021 3:38:53 PM Received Date: 4/20/2021 3:38:53 PM From: Lamb, John Created By: John.Lamb@nrc.gov Recipients:

"Enfinger, Timothy Lee" <TLENFING@SOUTHERNCO.COM>

Tracking Status: None Post Office: MN2PR09MB5084.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 4728 4/20/2021 3:38:53 PM Options Priority: High Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: