05000387/LER-2021-003, Automatic Reactor Scram Due to Main Turbine Trip

Automatic Reactor Scram Due to Main Turbine Trip

ML21259A059
Person / Time
Site:	Susquehanna
Issue date:	09/16/2021
From:	Cimorelli K Susquehanna
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
PLA-7967 LER 2021-003-00
Download: ML21259A059 (3)

LER-2021-003, Automatic Reactor Scram Due to Main Turbine Trip

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(iv)(B), System Actuation
3872021003R00 - NRC Website

text

Kevin Cimorelli Susquehanna Nuclear, LLC Site Vice President 769 Salem Boulevard Berwick, PA 18603 TALEN~.

Tel. 570.542.3795 Fax 570.542.1504 Kevin.Cimorelli@TalenEnergy.com ENERGY September 16, 2021

Attn: Document Control Desk 10 CFR 50.73 U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

SUSQUEHANNA STEAM ELECTRIC STATION LICENSEE EVENT REPORT 50-387/2021-003-00 UNIT 1 LICENSE NO. NPF-14 PLA-7967 Docket No. 50-387

Attached is Licensee Event Report (LER) 50-387/2021-003-00. The LERreports an event involving an automatic scram due to a main turbine trip. The condition is being reported in accordance with 10 CFR 50.73(a)(2)(iv)(A) as an event that resulted in an automatic actuation of the Reactor Protection System (including a reactor scram).

There were no actual consequences to the health and safety of the public as a result of this event.

This letter contains no new or revised regulatory commitments.

Attachment: LER 50-387/2021-003-00

Copy: NRC Region I Ms. A. Klett, NRC Project Manager Mr. C. Highley, NRC Senior Resident Inspector Mr. M. Shields, PA DEP/BRP

Abstract

On July 21, 2021, at approximately 18:26, Susquehanna Steam Electric Station Unit 1 reactor automatically scrammed due to a main turbine trip. Both divisions of the Reactor Protection System (RPS) actuated and all control rods inserted. This event was reported by Event Notification 55370 in accordance with 1 O CFR 50.72(b)(2)(iv)(B) and (b)(3)(iv)(A). This event is also reportable in accordance with 10 CFR 50.73(a)(2)(iv)(A) as an event that resulted in automatic actuation of a system listed in 1 O CFR 50.73(a)(2)(iv)(B).

The cause of the event is under investigation and will be provided under a supplement to this LER along with associated corrective actions.

There were no actual consequences to the health and safety of the public as a result of this event.

NRC FORM 366 (08-2020)

U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 08/31/2023 of Information unless the document

Susquehanna Steam Electric Station Unit 1 05000-387 NUMBER NO.

2021 - 003 - 00

NARRATIVE

CONDITIONS PRIOR TO EVENT

Unit 1 - Mode 1, approximately 100 percent Rated Thermal Power Unit 2 - Mode 1, approximately 100 percent Rated Thermal Power There were no structures, systems, or components that were inoperable at the start of the event that contributed to the event.

EVENT DESCRIPTION

On July 21, 2021, at approximately 18:26, Susquehanna Steam Electric Station Unit 1 reactor automatically scrammed due to a main turbine [EIIS System/Component Code: TA/TRB] trip. The Unit 1 Control Room received indication of a main turbine trip with both divisions of the Reactor Protection System (RPS) [EIIS System Code: JC] actuated and all control rods inserted. The Reactor Recirculation Pumps [EIIS System/Component Code: AD/P] tripped on End of Cycle Recirculation Pump Trip.

Operations subsequently maintained reactor water level at the normal operating band using the Reactor Feed Water system [EIIS System Code: SJ].

This event was reported by Event Notification 55370 in accordance with 10 CFR 50.72(b)(2)(iv)(B) and (b)(3)(iv)(A). This event is also reportable in accordance with 10 CFR 50.73(a)(2)(iv)(A) as an event that resulted in automatic actuation of a system listed in 10 CFR 50. 73(a)(2)(iv)(B).

CAUSE OF EVENT

The cause of the event is under review and will be provided in a supplement to this LER.

ANALYSIS/SAFETY SIGNIFICANCE

Safety significance information will be provided in the supplement to this LER.

CORRECTIVE ACTIONS

Corrective actions will be provided in a supplement to this LER.

COMPONENT FAILURE INFORMATION

Component failure information, as applicable, will be provided in a supplement to this LER.

PREVIOUS OCCURRENCES

Previous occurrences, as applicable, will be provided in the supplement to this LER.