05000334/LER-2025-001, Condition Prohibited by Technical Specifications and Event or Condition That Could Have Prevented Fulfillment of a Safety Function
| ML25357A047 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 12/23/2025 |
| From: | Blair B Vistra Operations Company |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| L-25-226 LER 2025-001-00 | |
| Download: ML25357A047 (0) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(v), Loss of Safety Function |
| 3342025001R00 - NRC Website | |
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L-25-226 December 23, 2025 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
SUBJECT:
Beaver Valley Power Station, Unit Nos. 1 Docket No. 50-334, License No. DPR-66 LER 2025-001-00 Beaver Valley Power Station Barry N. Blair Site Vice President P.O. Box4 Shippingport, PA 15077 10 CFR 50.73 Enclosed is Licensee Event Report (LER) 2025-001-00, "Condition Prohibited by Technical Specifications" and "Event or Condition that Could Have Prevented Fulfillment of a Safety Function." This event is being reported in accordance with 10 CPR 50.73(a)(2)(i)(B) and 10 CPR 50.73(a)(2)(v)(D).
There are no regulatory commitments contained in this submittal. If there are any questions or if additional information is required, please contact Ms. Hope Gilliam, Manager, Regulatory Compliance, at 724-682-4224.
Barry N. Blair
Beaver Valley Power Station Unit No. 1 L-25-226 Page2 Enclosure: Beaver Valley Power Station, Unit No. 1 LER 2025-001-00 cc:
NRC Region I Administrator NRC Senior Resident Inspector NRC Project Manager INPO Records Center (via INPO Industry Reporting and Information System)
BRP/DEP
Beaver Valley Power Station Unit No. 1 L-25-226 Page 3 Enclosure L-25-226 Beaver Valley Power Station, Unit No. 1 LER 2025-001-00
Abstract
At 0014 on October 29, 2025, during the Beaver Valley Power Station, Unit No. 1 (BVPS-1) thirtieth refueling outage (1 R30), a pin hole leak was discovered on the 'A' recirculation spray (RS) heat exchanger channel head. Ultrasonic testing (UT) found that areas of the 'A' and 'C' RS heat exchangers did not meet minimum wall thickness requirements. Since both train 'A' RS heat exchangers did not meet minimum wall thickness requirements, one train of the RS system was inoperable greater than the allowable outage time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> allowed per Technical Specification 3.6.7. A review determined that the 'A' and 'C' RS heat exchangers were in this condition greater than three years from the time of discovery and this could have prevented the fulfillment of the safety function since both trains would have been inoperable at the same time during this period. The cause of the event is under investigation. The supplement LER will provide detailed information from the causal product. The equipment was repaired and returned to operable status on November 18, 2025 and November 19, 2025.
This event is being reported as a condition prohibited by Technical Specifications, 10 CFR 50.73(a)(2)(i)(B), and an event or condition that could have prevented fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident, 10 CFR 50.73(a)(2)(v)(D).
n additional areas and surveillance Energy Industry Identification System (El IS) codes are identified in the text as [XX]. All times listed in this report are in Eastern Daylight Time.
BACKGROUND The BVPS-1 RS system [BE] consists of four fifty-percent capacity subsystems (two per train). Each subsystem is composed of a spray pump, associated heat exchanger [HX] and flow path. The 'A' and 'C' RS heat exchangers are 'A' train components and the 'B' and 'D' are 'B' train components. The RS heat exchangers [BEHX] are located inside containment [NH] and are cooled by safety-related reactor plant river water system [Bl]. The RS system provides a spray of subcooled water into the upper regions of containment to reduce the containment pressure and temperature during a design basis accident (DBA). The RS system is a containment engineered safety feature system and designed to ensure that heat removal capability required during post accident period can be attained.
TS 3.6.7 defines the allowable outage time for one RS subsystem is 7 days and the allowed outage time for two RS subsystems in one train is 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. Two RS subsystems make up one train.
DESCRIPTION OF EVENT
On October 29, 2025 at time 0014, during the BVPS-1, thirtieth refueling outage with the plant in mode 6, following the successful completion of type B leak testing on a nearby mechanical expansion joint (MEJ), which pressurized the equipment to above the postulated containment pressure would be during a loss of coolant accident (LOCA). At this time, a pin hole leak was discovered on the 'A' recirculation spray (RS) heat exchanger channel head. During UT to characterize the pinhole leak associated with the 'A' RS heat exchanger, a area of the inlet and outlet channel heads was found to be below minimum wall thickness requirements. An extent of condition investigation was completed identifying the 'C' RS heat exchanger was also found to have of the inlet and outlet channel heads that was below minimum wall thickness requirements. Since the 'A' and 'C' RS heat exchangers were below minimum wall thickness requirements per American Society of Mechanical Engineers (ASME) code, this rendered both heat exchangers inoperable. UT determined the 'B' and 'D' RS heat exchangers have acceptable wall thickness.
The area of degradation is immediately adjacent to the weld from the stainless steel tubesheeUheat exchanger shell and the carbon steel channel heads. The most likely corrosion mechanism is galvanic corrosion caused by the use of dissimilar metals. Based on the UT reports and subsequent repairs, the area of wall loss was 360 degrees and relatively uniform and not localized. A past operability review determined that based on the measured wall thickness and the length of service time of the 'A' and 'C' heat exchangers, which are original plant equipment, the channel heads went below minimum wall thickness requirements in excess of three years from the date of discovery. Based on this review, the 'A' train RS heat exchangers were inoperable greater than the allowed outage time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> per Technical Specifications rendering this event a condition prohibited by Technical Specifications. During the time period of the 'A' train RS heat exchanger inoperability, the 'B' Train TS subcomponents were rendered inoperable on multiple occasions for maintenance activities, resulting in both trains being inoperable, a condition that could have prevented fulfillment of the safety function.
Following repairs to the affected areas of the 'A' and 'C' RS heat exchangers, testing was successfully completed and heat exchangers were returned to service. The 'A' RS heat exchanger was returned to an operable status on November 18, 2025 at 0250 and the 'C' RS heat exchanger returned to an operable status on November 19, 2025 at 0905.
CAUSE OFTHE EVENT The degraded conditions were most likely caused by galvanic corrosion caused by dissimilar metals
ANALYSIS OF EVENT
This event is being reported as a condition prohibited by Technical Specifications, 10 CFR 50.73(a)(2)(i)(B), and an event or condition that could have prevented fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident, 10 CFR 50. 73(a)(2)(v)(D).
The RS system, operating in conjunction with the quench spray system (QS) [BE], is designed to limit the post accident pressure and temperature in the containment following a OBA. Although the 'A' train RS heat exchangers were inoperable, at the time of the 'A' and 'C' RS heat exchanger discovery, there were no issues in the QS system that would indicate that it would not have been available.
No structures, systems, or components (SSCs) that were inoperable at the start of the event contributed to the event and the failure mode, mechanism, and the effect of each failed component is well understood.
The plant risk associated with the BVPS Unit 1 Recirculation Heat Exchangers 1 RS-E-1A and 1 RS-E-1 C not meeting minimum wall thickness requirements and not being capable of withstanding a seismic event is considered to be very low. This is based on the change in core damage frequency derived using the conditional core damage probability, and the change in large early release frequency derived using conditional large early release probability for the observed condition and exposure time. Additionally, the Large early release frequency is determined to remain unaffected from the pinhole leak itself at the bell end of 1 RS-E-1 A.
The event had no significant effect on public health and safety.
CORRECTIVE ACTIONS
The 'A' and 'C' RS heat exchangers repairs were completed on November 17, 2025 and tested. The 'A' RS heat exchanger was returned to operable status on November 18, 2025 at 0250 and the 'C' RS exchanger returned to operable status on November 19, 2025 at 0905.
The cause of the event is under investigation. The supplement LER will provide detailed information from the causal product.
PREVIOUS SIMILAR EVENTS
LER-2024-003-00, Unanalyzed Containment Bypass Condition Due to Degraded River Water Piping At 0800 on May 9, 2024, during the Beaver Valley Power Station, Unit No. 1 (BVPS-1) twenty-ninth refueling outage (1 R29), through wall flaws of reactor plant river water piping inside the containment building were identified during leak rate testing. The through wall flaws resulted in a containment bypass condition such that a gaseous release could have occurred at a location that is not analyzed during accident conditions.
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- 2. DOCKET NUMBER
- 3. LER NUMBER I
YEAR SEQUENTIAL REV I 2025 I NUMBER NO.
334
- - I 1-0 001 This condition was reported via Event Notification 57115 as an unanalyzed condition and a loss of safety function.
Containment was assumed inoperable with respect to LCO 3.6.1 from November 16, 2022 at 0427 to April 14, 2024 at 0140. The causes of the degraded piping were microbiologically induced corrosion and general corrosion due to the pipe being partially filled with water. There were no programmatic requirements in place to identify and prevent development of through-wall leaks in this piping. The degraded "A" train river water piping was repaired and the "D" train river water piping was replaced. Corrective actions did not prevent this event because the degradation mechanisms were different from this event, and therefore the heat exchanger channel heads were not scoped into the extent of condition. Page 4
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