05000333/LER-2022-001, Exhaust Drain Pot Line Filled with Water Up to HPCI Turbine Due to Relay Failure

Exhaust Drain Pot Line Filled with Water Up to HPCI Turbine Due to Relay Failure

ML22179A366
Person / Time
Site:	FitzPatrick
Issue date:	06/28/2022
From:	Timothy Peter Constellation Energy Generation
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
JAFP-22-0034 LER 2022-001-00
Download: ML22179A366 (1)

LER-2022-001, Exhaust Drain Pot Line Filled with Water Up to HPCI Turbine Due to Relay Failure

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(v), Loss of Safety Function
3332022001R00 - NRC Website

text

James A. FitzPatrick NPP Constellation PO Box 110 Lycoming. NY 13093

Timothy C. Peter Site Vice President-JAF

JAFP-22-0034 June 28, 2022

United States Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555-0001

James A. FitzPatrick Nuclear Power Plant Renewed Facility Operating License No. DPR-059 NRC Docket No. 50-333

Subject: LER: 2022-001, Exhaust Drain Pot Line Filled with Water up to HPCI Turbine due to Relay Failure

Dear Sir or Madam:

This report is being submitted pursuant to 10 CFR 50. 73(a)(2)(v)(D).

There are no new regulatory commitments contained in this report.

Questions concerning this report may be addressed to Mr. Richard Sullivan, Regulatory Assurance Manager, at (315) 349-6562.

TCP/RS

Enclosure : LER: 2022-001, Exhaust Drain Pot Line Filled with Water up to HPCI Turbine due to Relay Failure

cc : USNRC, Region I Administrator USNRC, Project Manager USNRC, Resident Inspector INPO Records Center (IRIS)

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 08/31/2023 (08-2020)

James A. FitzPatrick Nuclear Power Plant 05000333 1 OF 3

4. Title LER: 2022-001, Exhaust Drain Pot Line Filled with Water up to H PCI Turbine due to Relay Failure

5. Event Date 6. LER Number 7. Report Date 8. Other Facilities Involved Revision Facility Name Docket Number Month Day Year Year Sequential Number No. Month Day Year N/A N/A

Facility Name Docket Number 04 29 2022 2022 - 001 - 00   N/A N/A

9. Operating Mode 10. Power Level 1 100 No Yes (If yes, complete 15. Expected Submission date)

Abstract (Limit to 1560 spaces, i.e., approximately 15 single-spaced typewritten lines)

At 1251 EDT on April 29, 2022, while troubleshooting the failur e of the High Pressure Coolant Injection (HPCI)

Exhaust Drain Pot High Level Alarm to clear, it was discovered that the High Pressure Coolant Injection exhaust line condensate drain system was not functioning as des igned to support removal of condensate from the turbine exhaust. Troubleshooting determined that a logic re lay failed to start the HPCI Gland Seal Condensate pump. This resulted in some water accumulation in th e turbine casing.

Subsequently, the High Pressure Coolant Injection System was de clared inoperable. The turbine casing was manually drained and the failed relay was replaced. The system was restored to Operable.

As a result, this condition is being reported under 10 CFR 50.7 2(b)(3)(v)(D) as a condition that could have prevented fulfillment of the safety function at the time of dis covery.

NRC FORM 366 (08-2020)

Background

The High Pressure Coolant Injection (HPCI) System [EIIS Identif ier: BJ] at James A. FitzPatrick Nuclear Power Plant (JAF) is a part of the Emergency Core Cooling System (ECC S); HPCI provides and maintains an adequate coolant inventory inside the Reactor Pressure Vessel [ RPV] to prevent damage to the reactor core under postulated accident scenarios. The system is comprised of various components which include pumps, valves, piping, and instrumentation. The HPCI system is powered by a steam turbine using steam from the reactor. Steam is pressurized up to the admission valve 23MOV-1 4 which will open to admit steam to the HPCI turbine on a system initiation signal.

HPCI has a Gland Exhaust System to collect steam leakage from t he turbine shaft seals, turbine control & stop valve stems, and turbine exhaust casing drains. The system work s with the HPCI exhaust Drain Pot to collect condensation from the bonnets of several valves and the HPCI tu rbine casing. The condensation is collected in the Gland Seal Condenser, and then pumped to Radwaste while in a standby lineup.

23LS-98 senses level in the Exhaust Drain Pot, causes Annunciat or ARP-09-3-3-18 (HPCI Exhaust Drain Pot Level High) and opens a valve to allow the Drain Pot to drain t o the Gland Seal Condenser.

23LS-100 senses level in the Gland Seal Condenser, energizes 23 A-K31, and auto starts the 23P-141 (HPCI Gland Seal Condensate Pump) to pump the Gland Seal Condenser to Radwaste.

Event Description

On April 28, 2022, at 2245, control room annunciator ARP-09-3-3 -18, HPCI drain pot water level alarm was received. Troubleshooting determined that HPCI logic relay 23A K31 failed to activate the HPCI Gland Seal Condensate pump to remove condensate from the turbine exhaust. As a result, water from 23MOV-14 steam leakby had accumulated in the HPCI turbine casing.

The crew placed the HPCI auxiliary oil pump in Pull to Lock to mitigate any potential impact to personnel while draining the HPCI exhaust. The Pull to Lock switch position pre vents the HPCI turbine from starting. The HPCI Exhaust Drain Pot was manually drained by Operations. Fol lowing draining, the HPCI system was declared operable.

The condition was reported as a condition which could have prev ented fulfillment of a safety function to mitigate the consequences of an accident per 10 CFR 50.72(b)(3) (v)(D), as submitted by ENS 55871.

Event Analysis

Level switch 23LS-100 senses water level in the HPCI gland seal condenser. On a high level, the level switch actuates relay 23A-K31 which alarms in the control room and sta rts the HPCI gland seal condenser pump (23P-141). The pump removes the condensate by pumping the water to the radwaste system. Troubleshooting determined that 23A-K31 had failed, preventing the auto start o f 23P-141. This caused the HPCI exhaust drain pot to fill with condensate and subsequently a volume of condensate also accumulated in the HPCI turbine casing.

The potential effects of water in the HPCI turbine casing is th at a slug of water could cause a HPCI exhaust rupture disk diaphragm to be damaged upon HPCI initiation. Anot her potential effect of water in the turbine NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 08/31/2023 (08-2020)

James A. FitzPatrick Nuclear Power Plant 05000 - 333 NUMBER N0.

2022 - 001 - 00 exhaust line is that it could cause abnormal turbine operation due to high exhaust pressure. The backup of water into the HPCI turbine is a condition that could have prev ented the operation of HPCI and is reportable per 10 CFR 50.73(a)(2)(v)(D).

Cause

The direct cause of this event was a failure of 23A-K31 from ac tuating 23P-141 to pump down the condensate water before it filled the HPCI exhaust drain pot.

Similar Events

Condition Report: AR 04381156,Suspected leakage past 23MOV-14, dated October 31, 2020

FAILED COMPONENT IDENTIFICATION:

Manufacturer: General Electric Manufacturer Model Number: CR2820B SERIES A Manufacturer Code: G080 Component Code: RLY FitzPatrick Component ID: 23A-K31

Corrective Actions

Completed Actions Operators manually drained the HPCI Drain Pot The HPCI Logic Relay 23A-K31 was replaced Planned Actions Evaluate PM strategy for affected relay and condensate drain sy stem.

Perform further analysis on impacts of water in HPCI turbine ca sing.

Operations refresher training on Abnormal Condition Monitoring Plans.

Safety Significance

Nuclear safety - There were no actual consequences caused by this condition. The potential consequence during a postulated accident scenario is when HPCI actuates, th e water present in the turbine could damage or prevent the system operation. While HPCI is operating, the a bility to drain water through the drain pot is not required for continued system operation since excess water accu mulation is pushed out with steam exhaust.

The risk for this event is restricted to the period when the re lay failed to automatically actuate the pump to remove water which was determined to be less than 14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br />.

References Issue Report - IR 04496616, HPCI Exhaust Drain Pot Level Hi Tro ubleshooting, dated April 29, 2022