05000324/LER-2025-001, Automatic Actuation of Containment Isolation Valves During Testing
| ML25126A035 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 05/01/2025 |
| From: | Krakuszeski J Duke Energy Progress |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| RA-25-0115 LER 2025-001-00 | |
| Download: ML25126A035 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| 3242025001R00 - NRC Website | |
text
May 1, 2025
U.S. Nuclear Regulatory Commission Page 2 of 2 cc (with enclosure):
Mr. Julio Lara, Acting Regional Administrator, Region II Mr. Blake Purnell, NRC Project Manager Mr. Gale Smith, NRC Senior Resident Inspector
Abstract
At approximately 14:09 Eastern Daylight Time (EDT) on March 28, 2025, with Unit 2 in Mode 2 at approximately 1% rated thermal power during reactor startup, an actuation of Group 1 Primary Containment Isolation Valves (PCIVs) occurred during performance of the Unit 2 Turbine Control/Stop Valves Tightness Test procedure. The Group 1 PCIV actuation resulted when the Turbine Stop Valves were opened (with Control Valves remaining closed) while main condenser vacuum was below 10 inches Hg. The PCIVs automatically closed as designed when the Group 1 actuation signal was received.
This event resulted from legacy procedural inadequacies. Corrective actions include procedural revisions to ensure the Turbine Control/Stop Valves Tightness Test procedure is not executed with main condenser vacuum below 10 inches Hg.
There was no impact on the health and safety of the public or plant personnel. This event is being reported in accordance with 10 CFR 50.73(a)(2)(iv)(A) due to valid actuation of the Primary Containment Isolation System.
(See Page 2 for required number of digits/characters for each block)
(See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
Safety Assessment
There was no adverse impact on the health and safety of the public or plant personnel. The safety significance of this event is minimal. The automatic system actuations occurred as designed and all Main Steam Isolation Valves were reopened within approximately 20 minutes.
Corrective Actions
The Unit 1 and Unit 2 Turbine Control/Stop Valves Tightness Test procedures were revised to include a new prerequisite to ensure condenser vacuum is greater than 10 inches Hg prior to performing the test.
Previous Similar Events
No previous similar events have occurred within the past 5 years in which inadequate procedural guidance resulted in automatic PCIS actuation.
Commitments
No regulatory commitments are contained in this report.