05000254/LER-2025-006, High Pressure Coolant Injection Inoperable Due to Turbine Inlet Valve Failure to Open
| ML25308A004 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 11/04/2025 |
| From: | Hild D Constellation Energy Generation |
| To: | Office of Nuclear Material Safety and Safeguards, Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| SVP-25-061 LER 2025-006-00 | |
| Download: ML25308A004 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v), Loss of Safety Function |
| 2542025006R00 - NRC Website | |
text
Constellation, SVP-25-061 November 4, 2025 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Quad Cities Nuclear Power Station, Unit 1 Renewed Facility Operating License No. DPR-29 NRC Docket No. 50-254 10 CFR 50.73
Subject:
Licensee Event Report 254/2025-006-00 "High Pressure Coolant Injection Inoperable Due to Turbine Inlet Valve Failure to Open" Enclosed is Licensee Event Report 254/2025-006-00 "High Pressure Coolant Injection Inoperable Due to Turbine Inlet Valve Failure to Open".
This report is being submitted in accordance with 10 CFR 50.73(a)(2)(v)(D) for an event or condition that could have prevented the fulfillment of a safety system needed to mitigate the consequences of an accident.
There are no regulatory commitments contained in this letter.
Should you have any questions concerning this report, please contact Conner Bealer at 779-231-6207.
Doug Hild Site Vice President Quad Cities Nuclear Power Station cc:
Regional Administrator - NRC Region Ill NRC Senior Resident Inspector-Quad Cities Nuclear Power Station
Abstract
On September 4, 2025 at 1845 during the performance of a Unit 1 High Pressure Coolant Injection (HPCI) Operability Test, it was identified that the system's steam inlet motor operated valve (MOV) failed to open. The inability to open this valve prevented the steam driven system from fulfilling its function of providing emergency core cooling. The cause of this condition, discovered on September 5, 2025, was a degraded breaker which was found to contain a degraded open coil and a binding contact roller. This prevented electrical power from being provided to the valve. The degraded coil was replaced and the roller attachment was cleaned, lubricated, and reinstalled.
The breaker failed due to an inadequate maintenance strategy.
This report is being submitted in accordance with 10 CFR 50. 73(a)(2)(v)(D) for an event or condition that could have prevented the fulfillment of a safety function needed to mitigate the consequences of an accident.
PLANT AND SYSTEM IDENTIFICATION
General Electric - Boiling Water Reactor, 2957 Megawatts Thermal Rated Core Power Energy Industry Identification System (EIIS) codes are identified in the text as [XX].
EVENT IDENTIFICATION High Pressure Coolant Injection Inoperable Due to Turbine Inlet Valve Failure to Open
A. CONDITION PRIOR TO EVENT
Unit: 1 Reactor Mode: 1 Event Date: September 5, 2025 Mode Name: Power Operation Event Time: 1845 hours0.0214 days <br />0.513 hours <br />0.00305 weeks <br />7.020225e-4 months <br /> CST Power Level: 100%
No systems, structures, or components that were inoperable at the start of the event contributed to the event.
B. DESCRIPTION OF EVENT
On September 4, 2025 at 1845 during the performance of a High Pressure Coolant Injection (HPCI) [BJ]
Operability Test, operators discovered that the Turbine Inlet Motor Operated Valve (MOV) [V] 1-2301-3 would not open. Multiple attempts were made to open the MOV from the control switch and the associated breaker contacts could not be heard cycling.
Troubleshooting on September 5, 2025 at 0130, determined that the electrical breaker [BKR] feeding the MOV had an opening coil [CL] that had failed, and rollers associated with the coil assembly were binding.
Discovery of the opening coil degradation confirmed that the MOV would fail to open in either manual or automatic HPCI demands, as opposed to failure to operate only from the valve control switch. The coil was replaced, and the roller assembly was cleaned and relubricated. Post maintenance testing of the MOV was completed on September 5, 2025 at 2228. The MOV breaker prevented proper HPCI operation for 27 hours3.125e-4 days <br />0.0075 hours <br />4.464286e-5 weeks <br />1.02735e-5 months <br /> and 43 minutes.
The HPCI Operability Test was subsequently completed with satisfactory results.
Event Notification System (ENS) report number 57905 was submitted to the NRC on September 5, 2025.
This report is being submitted in accordance with 10 CFR 50. 73(a)(2)(v)(D) for an event or condition that could have prevented the fulfillment of a safety function needed to mitigate the consequences of an accident.
C. CAUSE OF EVENT
YEAR 2025
- 3. LER NUMBER SEQUENTIAL NUMBER 006 REV NO.
00 The self-reveling cause of the event was an inadequate maintenance strategy applied to the associated breaker which allowed contactor lubrication to degrade such that it prevented contacts from closing. A preventative maintenance task was retired which inspected the associated breaker while also cleaning and lubricating the contactors.
D. SAFETY ANALYSIS
System Design
The HPCI system is designed to ensure that adequate core cooling takes place for all break sizes less than those for which Low Pressure Coolant Injection (LPCI) or Core Spray systems can adequately protect the core without assistance from other engineered safety features.
The purpose of the breaker in question is to permit power to the Unit 1 HPCI Turbine Inlet MOV during both automatic and manual system initiation. Without the ability to power and open this valve, steam is unable to reach the HPCI turbine. Without this turbine driving the HPCI pumps, the system is not capable of injection.
Safety Impact The safety significance of this event is minimal. At the time of the event, Unit 1 was at full power in a normal electric plant lineup with all other means of Reactor Coolant Injection available.
The Unit 1 Reactor Core Isolation Cooling (RCIC) system and the Unit 1 Automatic Depressurization System (ADS) remained Operable throughout the event. There was no impact on the health and safety of the public or plant personnel.
This event was within the analysis of UFSAR Chapter 15. There was no radioactive release associated with this event.
This event is considered a Safety System Functional Failure per NEI 99-02, Revision 8.
E. CORRECTIVE ACTIONS
Immediate:
- 1. The breaker coil was replaced. The roller assembly was cleaned and relubricated.
Follow up:
- 1. Revise the breaker's maintenance strategy.
- 2. Conduct Strategic Engineering teaching and learning related to this event.
F. PREVIOUS OCCURENCES
- 2. DOCKET NUMBER
- 3. LER NUMBER YEAR SEQUENTIAL REV NUMBER NO.
00254 2025 -
006 00 The station events database, LERs and INPO Industry Reporting Information System (IRIS) were reviewed for similar events at Quad Cities Nuclear Power Station. This event was caused by equipment failures causing operations to isolate the HPCI system. No previous occurrences in the previous three years were identified on this breaker.
G. COMPONENT FAILURE DATA
Thermal Overload Relay Manufacturer: Eaton I QualTech NP Nomenclature: Coil, Overload Model/Part Number: H1029 This event has been reported to IRIS. Page_4_ of _4_