05000424/LER-2022-001, Manual Reactor Trip Due to Loss of a Main Feed Pump

Manual Reactor Trip Due to Loss of a Main Feed Pump

ML22175A161
Person / Time
Site:	Vogtle
Issue date:	06/24/2022
From:	Ho Nieh Southern Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NL-22-0433 LER 2022-001-00
Download: ML22175A161 (4)

LER-2022-001, Manual Reactor Trip Due to Loss of a Main Feed Pump

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(iv)(A), System Actuation
4242022001R00 - NRC Website

text

HoNleh 7821 River RD Site V!ce President Waynesboro GA, 30830 Voglle Units 1*2 706-848-0001 tel 706-848-3321 fax June 24, 2022

Docket Nos.: 50-424 NL-22-0433

U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001

Vogtle Electric Generating Plant Unit 1 Licensee Event Report 2022-001-00 Manual Reactor Trip due to loss of a Main Feed Pumg

Ladies and Gentlemen:

In accordance with the requirements of 10 CFR 50.73(a)(2)(iv)(A), Southern Nuclear Operating Company is submitting the enclosed Licensee Event Report, 2022-001-00 for Vogtle Electric Generating Plant Unit 1.

This letter contains no NRC commitments. If you have any questions, please contact Jeff Deal at (706) 848-3792.

Respectfully submitted,

/ A'

(_~ -

HoNieh Site Vice President Vogtle 1&2

HN/KCW

Enclosure: Unit 1 Licensee Event Report 2022-001-00

cc: Regional Administrator NRR Project Manager - Vogtle 1 & 2 Senior Resident Inspector - Vogtle 1 & 2 RType: CVC7000 U. S. Nuclear Regulatory Commission NL-22-0433 Page 2

Vogtle Electric Generating Plant Unit 1 Licensee Event Report 2022-001-00 Manual Reactor Trip due to loss of a Main Feed Pump

Enclosure

Unit 1 Licensee Event Report 2022-001-00

Abstract

On May 3, 2022 at 15:41 EDT, with Unit 1 in Mode 1 and 100 percent power, the Control Room Operators observed lowering steam generator water levels and manually tripped the reactor. The lowering steam generator levels were caused by a malfunction of the 1 B Main Feed Pump control system. The trip was not complex, and all systems responded normally post trip.

The Operators stabilized the plant in Mode 3, and decay heat was removed by the stec:3m generators, through the steam dumps to the condenser. Unit 2 was not affected. The operating crew performed as expected. The Main Feed Pump control system was repaired and the unit was restarted.

Due to the manual Reactor Protection System (RPS) actuation and the automatic actuation of Auxiliary Feedwater (AFW)

System, this event is being reported under 10 CFR 50. 73(a)(2)(iv)(A).

NARRATIVE A. Event Descr iption On May 3, 2022 at 15:41 EDT, with Unit 1 in Mode 1 and 100 percent power, the Control Room Operators observed lowering steam generator water levels and manually tripped the reactor. The lowering steam generator levels were caused by a malfunction of the 1 B Main Feed Pump control system [JK]. The trip was not complex, and all systems responded normally post trip. The components that failed were General Electric IS420UCSBH1A control modules.

There were no Structures, Systems, or Components (SSCs) that were out of service at the beginning of the event that contributed to the event.

Due to the actuation of the Reactor Protection System (RPS)[JC] and the actuation of the Auxiliary Feedwater (AFW)[BA]

System, this event is being reported in accordance with 10 CFR 50.73(a)(2)(iv)(A).

B. Cause of Event

The cause of the event was a failure of the 1 B Main Feed Pump control system which caused the pump to slow down,

resulting in lowering main feedwater flow to the steam generators.

C. Safety Assessment The Main Feed Pumps [SJ] serve no safety-related function for the unit. When the Operators manually tripped the plant,

all the appropriate safety systems responded as designed. The AFW system actuated as designed and all control rods

[AA] fully inserted into the core. The operating crew performed as expected. The event was w ithin the analysis of the Updated Final Safety Analysis Report, Chapter 15, and there was no release of radioactivity. This event did not pose a threat to the health and safety of the public, therefore the safety significance of this issue is very low.

D. Corrective Actions

The control system for the Ma in Feed Pump was repaired.

E. Previous Similar Events

None.

NRC FO RM 366A (08-2020 ) Page 2 of 2