05000272/LER-2024-001, Pressure Boundary Leakage Through a Reactor Coolant Pump Thermal Barrier Heat Exchanger

Pressure Boundary Leakage Through a Reactor Coolant Pump Thermal Barrier Heat Exchanger

ML24130A090
Person / Time
Site:	Salem
Issue date:	05/09/2024
From:	Desanctis R Public Service Enterprise Group
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
LR-N24-0038 LER 2024-001-00
Download: ML24130A090 (1)

LER-2024-001, Pressure Boundary Leakage Through a Reactor Coolant Pump Thermal Barrier Heat Exchanger

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
2722024001R00 - NRC Website

text

Richard J. Desanctis, Jr.

Plant Manager, Salem Generating Station, PSEG Nuclear LLC o PSEG I NUCLEAR PO Box 236

• Hancocks Bridge, New Jersey 08038-0221 10 CFR 50.73 LR-N24-0038 May 9, 2024 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Salem Generating Station, Unit 1 Renewed Facility Operating License No. DPR-70 Docket No. 50-272 Subject: Licensee Event Report 2024-001-00, Pressure Boundary Leakage through a Reactor Coolant Pump Thermal Barrier Heat Exchanger PSEG Nuclear LLC submits the attached licensee event report (LER) per 10 CFR

50. 73(a)(2)(i)(B).

There are no regulatory commitments contained in this letter.

• Please contact Mr. Harry Balian at (856) 339 - 2173 if you have questions.

Sincerely, Richard J. Desanctis, Jr.

Plant Manager, Salem Generating Station Attachment: Licensee Event Report cc:

USNRC Regional Administrator - Region 1 USNRC NRR Project Manager-Salem USN RC Senior Resident Inspector - Salem NJ Department of Environmental Protection, Bureau of Nuclear Engineering

Abstract

PSEG Nuclear LLC (PSEG) confirmed that Salem Generating Station, Unit 1 operated with reactor coolant PRESSURE BOUNDARY LEAKAGE through a reactor coolant pump (RCP) thermal barrier heat exchanger (TBHX) into the component cooling water (CCW) system. PSEG previously identified a TBHX as a possible leakage source and replaced the associated RCP during the fall 2023 refueling outage.

Limiting condition for operation (LCO) 3.4.6.2 prohibits operation with PRESSURE BOUNDARY LEAKAGE. It was determined that the plant operated with in-leakage to the CCW system from December 2022 to October 2023.

Vendor testing confirmed the leakage from the TBHX into CCW. Engineering subsequently determined this was PRESSURE BOUNDARY LEAKAGE. 10 CFR 50.73(a)(2)(i)(B) requires this report.

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' (04-02-202A)

U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 04/30/2027 LICENSEE EVENT REPORT (LER)

CONTINUATION SHEET (See NUREG-1 022, R.3 for instruction and guidance for completing thfs form http* llwww nrc_govlreading-un/doc--collectionslnuregs/staff/sr1022/r3Q

1. FACILITY NAME

,---------------, ~

Salem Generating Station. Unit 1

~ARRATIVE

PLANT AND SYSTEM IDENTIFICATION

050 052 Westinghouse - Pressurized Water Reactor (PWR/4)

Reactor Coolant System - EIIS' Identifier {AB}

Pump - EIIS Identifier {P}

IDENTIFICATION OF OCCURRENCE Discovery Date: April 18, 2024

2. DOCKET NUMBER

3. LER NUMBER I

05000272 NUMBER NO.

I YEAR SEQUENTIAL REV 1

001 1-0 Following receipt of a vendor testing report, Salem Generating Station, Unit 1 (Salem) confirmed there was leakage from the reactor coolant system (RCS), through the reactor coolant pump (RCP) thermal barrier heat exchanger (TBHX) into the component cooling water (CCW) system. Engineering determined this was PRESSURE BOUNDARY LEAKAGE.

CONDITIONS PRIOR TO OCCURRENCE MODE 1, POWER OPERATION.

No other structures, systems, or components (SSC) that could contribute to the event were inoperable during the event.

DESCRIPTION OF OCCURRENCE In January 2023, PSEG identified higher than normal tritium in the CCW system and found that counts on the respective radiation monitor had slowly begun rising in December 2022.

PSEG adapted chemistry methods used to monitor primary-to-secondary leakage to identify a TBHX as a possible source of radioactivity in the CCW system; however, this could not be confirmed while the plant was operating. Conservatively, PSE!3 replaced the associated RCP during the fall 2023 refuelin,g outage and radioactivity levels in the CCW system have returned to normal levels.

RCS leakage to CCW was immeasurable by routine methods. No changes to the RCS water inventory balance nor the CCW surge tank level were observed. RCS leakage into the CCW system was detected only because a slight increase that stabilized was identified on the CCW process radiation monitors as part of routine equipment performance monitoring. The leakage was not detectable via normal mass balance or online leak rate methods but has been estimated as 0.2 gallons per day or less. Page 2

of 4 (04-02-202A)

U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 04/30/2027 l



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.I LICENSEE EVENT REPORT (LER)

CONTINUATION SHEET (See NUREG-1022, R.3 for instruction and guidance for completing thfs form bttp* llwww nrc_gov/reading-lTTl/doc-collectionslnuregslstaff/sr1022/r3I)

1. FACILITY NAME

.--------------,

Salem Generating Station. Unit 1

?ARRATIVE 050 052

2. DOCKET NUMBER I

05000272

3. LER NUMBER NUMBER NO.

I YEAR SEQUENTIAL REV

- 1 001 1-G The removed RCP was sent to the vendor where pressure drop testing confirmed that leakage from the RCS side to the CCW side of the TBHX occurred.. Helium was used to pressurize the CCW side of the TBHX.

Once the CCW side of the TBHX was pressurized, a small pressure drop occurred, and helium was detected.

This confirmed that the TBHX had a small leak.

Subsequently, Engineering determined that leakage through the TBHX is PRESSURE BOUNDARY LEAKAGE.

CAUSE OF EVENT

Unknown. Leakage through the 12 RCP TBHX allowed radioactivity to enter the CCW.system, but the cause of the leak *is not known.

SAFETY CONSEQUENCES AND IMPLICATIONS

There were no safety consequences because of this event. The leakage was not detectable via normal mass balance or on-line leak rate methods but has been estimated as 0.2 gallons per day or less. A flaw in the TBHX can be isolated within the confines of CCW piping rated to 2,485 psig which is above normal operating pressure and prevents release of reactor coolant to the containment atmosphere. A relief valve protects this segment of CCW piping against over pressurization.

In the event of catastrophic TBHX failure, reactor coolant release outside of containment is prevented by check valves at the CCW inlet to the TBHX and a motor operated valve (MOV) at the combined CCW outlet from the TBHXs which automatically closes on high CCW flow-rate. Automatic closure of the CCW expansion tank vent valve prevents release of radioactivity from CCW to the Auxiliary Building when the CCW process radiation monitors detect excessive radioactivity.

With CCW to a TBHX isolated, the plant can continue operating and operators can complete an orderly shutdown if required. Operating procedures currently in effect guide operator response to CCW abnormalities, RCP abnormalities, and radiation abnormalities.

PREVIOUS EVENTS There were no similar events in the past three years. Page 3

of 4 (04-02-202A)

U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 04/30/2027

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3/4, LICENSEE EVENT REPORT (LER)

CONTINUATION SHEET (See NUREG-1022, R.3 for instruction and guidance for completing thfs form htto*UWWW nrc_govlreading-an/doc--collectionslnuregs/staff/sr1022/r3Q

1. FACILITY NAME Salem Generating Station. Unit 1

~ARRATIVE

CORRECTIVE ACTIONS

Salem replaced the affected RCP.

COMMITMENTS

There are no regulatory commitments in this LER.

l'IRC FORM 366A (04-02-2024) 050 052

2. DOCKET NUMBER

3. LER NUMBER I

05000272 NUMBER NO.

I YEAR SEQUENTIAL REV 1

001 1-0 Page 4

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