05000296/LER-2024-001, Primary Containment Isolation Valve Inoperable Due to Incorrect Motor Operated Valve Setup
| ML24113A201 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 04/22/2024 |
| From: | Sivaraman M Tennessee Valley Authority |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| LER 2024-001-00 | |
| Download: ML24113A201 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 2962024001R00 - NRC Website | |
text
Post Office Box 2000, Decatur, Alabama 35609-2000 April 22, 2024 10 CFR 50.73 10 CFR 50.4(a)
ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Browns Ferry Nuclear Plant, Unit 3 Renewed Facility Operating License No. DPR-33 NRC Docket No. 50-296
Subject:
Licensee Event Report 50-296/2024-001 Primary Containment Isolation Valve Inoperable due to Incorrect Motor Operated Valve Setup The enclosed Licensee Event Report provides the details of an inoperable Primary Containment Isolation Valve on Browns Ferry Nuclear Plant, Unit 3. The Tennessee Valley Authority is submitting this report in accordance with Title 10 of the Code of Federal Regulations (10 CFR) 50.73(a)(2)(i)(B), as any operation or condition which was prohibited by the plants Technical Specifications.
There are no new regulatory commitments contained in this letter. Should you have any questions concerning this submittal, please contact David J. Renn, Site Licensing Manager, at (256) 729-2636.
Respectfully, Manu Sivaraman BFN Site Vice President Enclosure: Licensee Event Report 50-296/2024-001 Primary Containment Isolation Valve Inoperable due to Incorrect Motor Operated Valve Setup
U.S. Nuclear Regulatory Commission Page 2 April 22, 2024 cc (w/ Enclosure):
NRC Regional Administrator - Region II NRC Senior Resident Inspector - Browns Ferry Nuclear Plant NRC Project Manager - Browns Ferry Nuclear Plant
Abstract
On February 21, 2024, it was identified that primary containment isolation valve (PCIV)[FCV] 3-FCV-001-0055 Inboard Main Steam Drain Line Isolation Valve may not have been capable of fully closing and adequately sealing during a design basis accident with design basis differential pressure due to the setup of the closing control circuit of the motor operated valve (MOV). While the vulnerability has existed since the initial design of the MOV, per the Past Operability Evaluation (POE), this condition has existed since March 16, 2014. The safety function of containment isolation was maintained by the outboard isolation valve 3-FCV-001-0056, ensuring the function of primary containment was maintained at the affected penetration.
The cause of this condition is a legacy issue related to the close control wiring scheme for 3-FCV-001-0055. This valve has had this control wiring scheme since development of the NRC Generic Letter (GL) 89-10/96-05 MOV Program.
There were two Corrective Actions to Prevent Recurrence or to reduce the probability of similar events occurring in the future: 1)
Engineering Change Package (ECP) BFN-24-12 to remove the close torque switch and LS-16 from the control circuit and use LS-8 as the close limit switch for 3-MVOP-001-0055 has been implemented and 2) reviewed all MOV Program valves in the Tennessee Valley Authority (TVA) nuclear fleet for extent of condition and no additional valves with this issue were identified.
Page 7 of 7 B. Corrective Actions to Prevent Recurrence or to reduce the probability of similar events occurring in the future There were two Corrective Actions to Prevent Recurrence or to reduce the probability of similar events occurring in the future:
- 1) ECP BFN-24-12 to remove the close torque switch and LS-16 from the control circuit and use LS-8 as the close limit switch for 3-FCV-001-0055 has been implemented.
- 2) Reviewed all MOV Program valves in the TVA nuclear fleet for extent of condition and no additional valves with this issue were identified.
VII. Previous Similar Events at the Same Site
A search of LERs from BFN, Units 1, 2, and 3 over the last five years identified no similar events.
VIII. Additional Information
There is no additional information.
IX.
Commitments
There are no new commitments.