05000454/LER-2023-001, A Control Room Ventilation Inoperable Due to Jumpers Left on 0PR031J and 0PR032J

A Control Room Ventilation Inoperable Due to Jumpers Left on 0PR031J and 0PR032J

ML23135A079
Person / Time
Site:	Byron
Issue date:	05/15/2023
From:	Welt H Constellation Energy Generation
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
BYRON 2023-0025, 1D.101, 5A.108 LER 2023-001-00
Download: ML23135A079 (1)

LER-2023-001, A Control Room Ventilation Inoperable Due to Jumpers Left on 0PR031J and 0PR032J

Event date:
Report date:
4542023001R00 - NRC Website

text

Consteilat,on Energy Genera11or LLC {CEG!

Byron Station Constellation 4450 N German Church Road Byron. IL 61010-9794

www consre11a11onenergy com

May 15, 2023

L TR: BYRON 2023-0025 10CFR50.73

File: 1D.101 5A.108

United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

Byron Station, Units 1 and 2 Renewed Facility Operating License No. NPF-37 and NPF-66 NRG Docket No. STN 50-454

Subject: Licensee Event Report (LER) No. 454-2023-001-00 "QA Control Room Ventilation Inoperable due to Jumpers left on OPR031J and OPR32J"

Enclosed is Byron Station Licensee Event Report (LER) No. 454-2023-001-00 regarding failure of the QA Control Room Ventilation actuation during diesel generator sequence test due to jumpers were left on OPR31J and OPR32J. This condition is being submitted in accordance with 10 CFR 50.73, "Licensee Event Report System."

There are no regulatory commitments in this report.

Should you have any questions concerning this submittal, please contact Ms. Zoe Cox, Regulatory Assurance Manager, at (815) 406-2800.

Respectfully,

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is Welt Site Vice President Byron Generating Station

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Enclosure: LER 454-2023-001-00

cc: Regional Administrator - NRG Region Ill NRG Senior Resident Inspector - Byron Generating Station

Abstract

On March 16, 2023, at 14:40 CDT, the 0A Control Room Ventilation (VC) failed to actuate when performing the 1A Diesel Generator (DG) sequencer testing due to installed jumpers on 0PR031J and 0PR032J, Main Control Room Outside Air Intake A Monitors. Jumpers that were installed during the Bus 141 outage to defeat Main Control Room Radiation Monitor interlocks were not removed as expected at the conclusion of the bus outage. These jumpers prevented 0PR031J and 0PR032J, Main Control Room Outside Air Intake A Monitors from causing 0A Train VC actuations when required during 1A DG sequencer testing. 0PR031J and 0PR032J were declared inoperable. Once identified, the jumpers were removed from 0PR031J and 0PR032J and the monitors were restored to operable status.

This event is reportable in accordance with 10 CFR 50. 73(a)(2)(i)(B) for any operation or condition which was prohibited by the plant's Technical Specifications.

A. Plant Operating Conditions Before the Event

Event Date: March 16, 2023 Unit 1 - Mode 6 (Refueling) - Reactor Power: 0 Percent Unit 2 - Mode 1 - Reactor Power: 100 percent Reactor Coolant System (RCS) [AB]: Normal Operating Temperature and Pressure

No structures, systems or components were inoperable at the start of this event that contributed to the event.

B. Description of Event

On March 16, 2023, at 14:40 CDT, the 0A Control Room Ventilation (VC) failed to actuate when performing the 1A Diesel Generator (DG) sequencer testing due to installed jumpers on 0PR031J and 0PR032J, Main Control Room Outside Air Intake A Monitors which prevented the actuation of 0A VC train. Jumpers were installed to support Unit 1 Bus Outage and were not removed during the completion and restoration of the bus outage. This resulted in 0PR031J and 0PR032J being inoperable for approximately 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />. Once identified, the jumpers were removed from 0PR031J and 0PR032J and the monitors were restored to operable status.

C. Cause of Event

The cause of the event was an Instrument Maintenance First Line Supervisor (IM FLS) used the incorrect process to update the work instructions for installation of the jumpers. The IM FLS changed the installation instructions and did not change the restoration instructions of the work order. After completion of the bus outage, a second IM FLS did not review the jumper installation steps when an IM technician questioned the Equipment Plant Nomenclature (EPN) listed in the restoration instructions of the work order. EPNs listed in the work order (WO) were not correct due to a typographical error and did not match the plant radiation monitors where jumpers had previously been installed. The second IM FLS incorrectly assumed that jumpers were not installed and N/A'd the removal steps. This resulted in the jumpers remaining installed on 0PR31J and 0PR32J. Inadequate use of Technical Human Performance (THU) tools and Questioning Attitude by both IM FLS's resulted in these errors.

D. Safety Consequences

This condition had no safety consequences impacting plant or public safety. This event is not considered an event or condition that could have prevented fulfillment or a safety function.

The VC system has two full capacity, redundant equipment trains that perform the same function. The VC HVAC system is designed to ensure control or environmental conditions within specified maximum and minimum limits which are conducive to personnel habitability and prolonged service life of Safety Category 1 components under all normal and abnormal station operating conditions. The OB Train of VC remained operable during this event.

E. Corrective Actions

Corrective action taken and completed include:

• IM Training to perform a Needs Analysis to conduct training on Work Package Revision Guidelines and Work Execution and Closeout.

• IM Work Planning to revise work instructions for all AR/PR tasks related to Bus support activities for both units.

• Performance Management with the individuals involved with the event.

F. Previous Occurrences

No previous, similar Licensee Event Reports were identified at the Byron Station in the past three years.