05000237/LER-2025-002, Valid Reactor Protection System Actuation While Shutdown
| ML25360A001 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 12/26/2025 |
| From: | Patel D Constellation Energy Generation |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| SVPLTR 25-0071 LER 2025-002-00 | |
| Download: ML25360A001 (0) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| 2372025002R00 - NRC Website | |
text
Constellation _
December 26, 2025 SVPL TR 25-0071 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Dresden Nuclear Power Station, Units 2 and 3 Dresden Nuclear Power Station 6500 North Dresden Road Morris, IL 60450 10 CFR 50.73 Renewed Facility Operating License Nos. DPR-19 and DPR-25 NRC Docket Nos. 50-237 and 50-249
Subject:
Licensee Event Report 237/2025-002-00, Valid Reactor Protection System Actuation While Shutdown Enclosed is Licensee Event Report 237/2025-002-00, Valid Reactor Protection System Actuation While Shutdown. This report describes an event being reported in accordance with 10 CFR 50.73(a)(2)(iv)(A) for a valid Reactor Protection System actuation.
There are no regulatory commitments contained in this submittal.
Should you have any questions concerning this letter, please contact Ms. Tara Noah, acting Regulatory Assurance Manager, at (779) 231-7447.
Respectfully, rf1- (lJ,.__,
Hardik Patel Site Vice President Dresden Nuclear Power Station
Enclosure:
Licensee Event Report 237/2025-002-00
\
Abstract
At 0117 CDT on 10/27/2025, with Unit 2 in Mode 3 at 0 percent power, an actuation of the Reactor Protection System (RPS) occurred during restoration of the Scram Discharge Volume (SDV) high level bypass switch to normal. The cause of the RPS system actuation was a valid high level in the SDV. All control rods had been previously inserted and the RPS system automatically initiated a scram signal as designed when the SDV high level signal was received. The scram was reset in accordance with station procedures at 0121 CDT. An evaluation of this event is currently in progress to determine any contributing causes to the event as well as additional corrective actions.
This event is reportable under 10 CFR 50.73(a)(2)(iv)(A) for a valid RPS system actuation.
PLANT AND SYSTEM IDENTIFICATION - UNIT 2
- 2. DOCKET NUMBER
- 3. LER NUMBER YEAR SEQUENTIAL REV NUMBER NO.
00237 2025 -
002 00 General Electric - Boiling Water Reactor, 2957 megawatts thermal rated core power Energy Industry Identification System (EIIS) codes are identified in the text as [XX].
A. CONDITIONS PRIOR TO EVENT
Unit: 2 Reactor Mode: 3 Event Date: October 27, 2025 Mode Name: Hot Shutdown Event Time: 0117 CDT Power Level: 0%
No systems, structures, or components that were inoperable at the start of the event contributed to the event.
8. DESCRIPTION OF EVENT
At 0117 CDT on 10/27/2025, with Unit 2 in Mode 3 at O percent power, an actuation of the Reactor Protection System (RPS) [JC] occurred during restoration of the Scram Discharge Volume (SDV) high level bypass switch to bypass switch to normal. The cause of the RPS [JC] system actuation was a valid high level in the SDV. All control rods had been previously inserted and the RPS [JC] system automatically initiated a scram signal as designed when the SDV high level signal was received. The scram was reset 0121 CDT in accordance with station procedures. ENS#58008 was transmitted to the NRC at 0750 CDT on 10/27/2025. An evaluation of this event is currently in progress.
This event is being reported in accordance with 10 CFR 50. 73(a)(2)(iv)(A).
C. CAUSE OF EVENT
The cause of the event was a valid high level in the SDV. An evaluation of the event is currently in progress. A supplemental report will be submitted with the conclusions of this evaluation.
D. SAFETY ANALYSIS
The RPS [JC] monitors reactor [RCT] core parameters. If these parameters exceed predetermined limits, the RPS [JC] logic will initiate a scram. The SDV is used to limit the loss of, and contain, the reactor vessel [RPV]
water from all Control Rod Drives (CRDs) [AA] during a scram. During normal operation, the SDV is empty with open drain [ORN] and vent valves [VTV]. On a scram signal, the RPS [JC] is deenergized and the SDV pilot valves [V] vent the discharge volume valve [VJ operators, causing them to close. All systems and components responded as expected to the valid high SDV level signal. Additionally, all CRDs [AA] had been previously inserted. There was no impact to the health and safety of the public from this event.
E. CORRECTIVE ACTIONS
- 2. DOCKET NUMBER YEAR 00237 2025 -
- 3. LER NUMBER SEQUENTIAL NUMBER 002 REV NO.
00 At 0121 CDT on 10/27/2025, the scram was reset in accordance with station procedures. Additional corrective actions will be determined by the evaluation currently in progress.
F. PREVIOUS OCCURENCES
A 5-year internal corrective action program and Licensee Event Report (LER) database review was performed for Dresden Nuclear Power Station (DNPS). No previous occurrences of valid RPS [JC] actuation were found.
Other events identified during the evaluation in progress will be discussed in the supplemental report.
G. COMPONENT FAILURE DATA
Not applicable Page_3_ of _3_