05000458/LER-2023-001-01, Ultimate Heat Sink Inoperable Due to Boundary Valve Leakage

Ultimate Heat Sink Inoperable Due to Boundary Valve Leakage

ML23229A121
Person / Time
Site:	River Bend
Issue date:	08/17/2023
From:	Hansett P Entergy Operations
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
RBG-48244 LER 2023-001-01
Download: ML23229A121 (1)

LER-2023-001, Ultimate Heat Sink Inoperable Due to Boundary Valve Leakage

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat
4582023001R01 - NRC Website

text

) entergy RBG-48244 Philip Hansett Site Vice President 225-381-437 4 10 CFR 50.73 Augu st17,2023 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Subject: Licensee Event Report 50-458 / 2023-001-01, Ultimate Heat Sink Inoperable due to Boundary Valve Leakage River Bend Station -Unit 1 NRC Docket Nos. 50-458 Renewed Facility Operating License No. NPF-47 On May 23, 2023, Licensee Event Report 50-458 / 2023-001-00, Ultimate Heat Sink Inoperable due to Boundary Valve Leakage (ML23143A276} was submitted by Entergy Nuclear Operating Inc. This letter is a supplement to the report to provide the updated results of the causal evaluation. The updated information is denoted by revision bars located in the right-hand margin. The report is submitted in accord ance with 1 O CFR 50.73.

This document contains no commitments.

Should you have any questions, please contact Mr. Randy Crawford, Regulatory Assurance Manager, at 225-381-4177.

Respectfully, ft/

Phil Hansett PH/twf Enclosure:

cc: Licensee Event Report 50-458 / 2023-001-01, Ultimate Heat Sink Inoperable due to Boundary Valve Leakage NRC Region IV Regional Administrator -Region IV NRC Senior Resident Inspector -River Bend Station Entergy Operations, Inc., 5485 U.S. Highway 61 N. St. Francisville, LA 70775 Enclosure RBG-48244 Licensee Event Report 50-458 / 2023-001-01, Ultimate Heat Sink Inoperable due to Boundary Valve Leakage Entergy Operations, Inc., 5485 U.S. Highway 61 N. St. Francisville, LA 70775 NAC FOAM 366 U.S. NUCLEAR REGULATORY COMMISSION (03-14-2023)

!¥.\\ \\ l,,.., /..... LICENSEE EVENT REPORT (LER)

(See Page 2 for required number of digits/characters for each block)

(See NUREG-1O22, R.3 for instruction and guidance for completing this form hllQ:/ www nr.gQv/reagmg-rmdog-coll!l!ion nureg/taff sr10,121r3/)

1. Facility Name River Bend Station, Unit 1 4.Title Ultimate Heat Sink Inoperable due to Boundary Valve Leakage APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 08/31/2023 Es!lmaIed 050 2. Docket Number 3. Page D 052 458 1 OF 3

5. Event Date 6. LER Number 7. Report Date B. Other Facilities Involved Month Day Year Number No. N/A 050 N/A 03 24 2023 2023 -001 - 01 08 17 2023 Facility Name Docket Number N/A 052 NIA

9. Operating Mode 110. Power Level 4 0%

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Abstract

On March 24, 2023, River Bend Station was in Mode 4 during Refuel Outage 22 when testing revealed leakage rates from Division 1 of the Standby Service Water system that could have previously rendered the Ultimate Heat Sink inoperable. On May 6, 2023, testing on Division 2 of the Standby Service Water system also resulted in leakage rates that could have previously rendered the Ultimate Heat Sink inoperable. These discoveries were made when River Bend Station was not in a required Mode of Applicability for the Ultimate Heat Sink. Corrective actions to restore compliance with the allowed design basis leakage were completed for both of the conditions described above prior to the completion of the refuel outage.

These events are being reported in accordance with 10 CFR 50.73(a)(2)(v)(B) as an event that could have prevented fulfillment of the safety function provided by the Ultimate Heat Sink and 10 CFR 50. 73(a)(2)(i)(B) as an operation or condition prohibited by Technical Specifications. The events are being reported in a single Licensee Event Report per guidance contained in NUREG-1022, Revision 3.

EVENT DESCR IPTION Esl1ma1ed

2. DOCKET NUMBER 3. LER NJP.eER NUMBER NO.

458 2023 -002 - 1. Re-categorize SWP-MOV57 A and SWP-MOV578 to Category A in the 1ST basis documents.

12. Establish surveillance test procedures for leak testing SWP-MOV57A and SWP-MOV578 per 1ST basis docum ents.

3. Establish preventative maintenance tasks for internal inspection of SWP-MO V57 A and SWP-MOV578.

4. Issue Engineering Analysis to ensure an engineering basis document exists that clearly defines the Standby Service Water System boundaries and valve classifica tions, as well as act ions required to maintain inventory.

PREVIOUS SIMILAR OCCURRENCES LER 201 004-00 was submitted by RBS on September 26, 2014, due to the UHS water inventory being less than the accident analysi s required amount. The condition was a result of a design basis deficiency that did not account for the adve rse effects of aggregate system leakage on compliance with the 30-da y inventory required by Regulatory Guide 1.27.

Energy Industry Identification System (EIIS) codes are identified in the text as [XX]. River Bend equipment codes are identified as (XX).