05000249/LER-2024-002, Nuclear Power Station, Unit 3, Low Pressure Coolant Injection Pump Suction Relief Valve Inoperable as a Primary Containment Isolated Valve Resulted in a Condition Prohibited by Technical Specifications
| ML25022A141 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 01/21/2025 |
| From: | Joseph C Constellation Energy Generation |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| 25-0006 LER 2024-002-00 | |
| Download: ML25022A141 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 2492024002R00 - NRC Website | |
text
Constellation.
January 21, 2025 SVPL TR: #25-0006 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Dresden Nuclear Power Station, Unit 3 Renewed Facility Operating License No. DPR-25 NRC Docket No. 50-249 Dresden Nuclear Power Station 6500 North Dresden Road Morris, IL 60450 10 CFR 50.73
Subject:
Licensee Event Report 2149/2024-002-00, "Low Pressure Coolant Injection Pump Suction Relief Valve Inoperable as a Primary Containment Isolation Valve Resulted in a Condition Prohibited by Technical Specifications" Enclosed is Licensee Event Report 249/2024-002-00, "Low Pressure Coolant Injection Pump Suction Relief Valve Inoperable as a Primary Containment Isolation Valve Resulted in a Condition Prohibited by Technical Specifications." This report describes an event being reported in accordance with 10 CFR 50.73(a)(2)(i)(B) for an Operation or Condition Prohibited by Technical Specifications and a Loss of Safety Function.
There are no regulatory commitments contained in this submittal.
Should you have any questions concerning this letter, please contact Mr. Daniel J. Murphy, Regulatory Assurance Manager, at (779) 231-7443.
Respectfully,
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? I et t1. + f\l\e1. "'-t\'-l c..,r Carolyne Joseph Site Vice President
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Dresden Nuclear Power Station
Enclosure:
Licensee Event Report 249/2024-002-00 CC:
Regional Administrator - NRC Region Ill NRC Senior Resident Inspector - Dresden Nuclear Power Station
Abstract
On 11/20/2024 at 1407 CST, the Main Control Room was notified that the operating handle for the 3A Low Pressure Coolant Injection (LPCI) Suction Relief Valve was found positioned higher than the operating handles for the other relief valves in the system, making the valve inoperable as a Primary Containment Isolation Valve (PCIV). Technical Specification (TS) 3.6.1.3 Condition C was entered. At 1650 CST, the operating handle for the 3A LPCI Suction Relief Valve was moved to the down position in accordance with station procedure and TS 3.6.1.3 Condition C was exited. The valve had been replaced during refueling outage activities on 11/8/2024. At 0202 on 11/15/2024, Dresden Unit 3 entered Mode 2 and the 4-hour required completion time for Condition C and subsequent actions of Condition E became applicable. Therefore, the station concluded the TS was not met from 0602 CST on 11/15/2024 to 1650 CST on 11/20/2024. This event is being reported in accordance with 10 CFR 50.73(a)(2)(i)(B) for an Operation or Condition Prohibited by Technical Specifications.
Prior to the replacement of the valve, there is no record of valve failure or mispositioning. An evaluation of the event is currently in progress. A supplemental report will be submitted with the conclusions of this evaluation.
PLANT AND SYSTEM IDENTIFICATION
- 2. DOCKET NUMBER YEAR 00249 2024
- 3. LER NUMBER SEQUENTIAL NUMBER 002 REV NO.
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: 3 Event Date:
November 20, 2024 Event Time:
1407 Reactor Mode: 1 Mode Name: Power Operation Power Level: 100%
No structures, systems, or components were inoperable at the time of the event that contributed to the event.
B. DESCRPTION OF EVENT On 11/20/2024 at 1407 CST, with Dresden Unit 3 at 100 percent power, the Main Control Room was notified that the operating handle for the 3A Low Pressure Coolant Injection (LPCI) [BO] Suction Relief Valve [RV] was found positioned higher than the operating handles of the other relief valves in the system. The relief valve [RV] is normally seated closed and relieves back to the suppression pool [NH] to provide over-pressure protection of the LPCI [BO]
piping when the pump [P] is isolated. The relief valve [RV] also functions as a Primary Containment Isolation Valve (PCIV) [ISV]. As a PCIV [ISV], its safety-related function is to isolate containment from the LPCI [BO] system.
Technical Specification (TS) 3.6.1.3 Condition C requires lines with only one PCIV [ISV] to be isolated within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> and to be verified isolated every 31 days when in Operating Modes 1, 2, and 3. If this action is not met, Condition E of TS 3.6.1.3 requires the operating unit to be placed in Mode 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and Mode 4 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. At 0202 on 11/15/2024, Dresden Unit 3 entered the applicable Mode 2. The station concluded the condition existed from this time to 1650 CST on 11/20/2024 when the operating handle for the 3A LPCI [BO] Suction Relief Valve [RV] was moved to the down position in accordance with station procedure and TS 3.6.1.3 Condition C was exited.
This event is being reported in accordance with 10 CFR 50.73(a)(2)(i)(B) for a condition prohibited by Technical Specifications.
C. CAUSE OF EVENT
The relief valve [RV] had been replaced on 11/08/2024 during a refueling outage. Prior to the replacement of the relief valve [RV], there is no record of valve failure or mispositioning. 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 safety significance of the event is very low. The open relief valve [RV] piping ties back to the same suction piping upstream of the 3A LPCI [BO] pump P] suction. The open relief valve [RV] did not create any additional flow paths that would divert LPCI [BO] pump [P] discharge flow away from the reactor vessel or Suppression Pool [NH] and did not negatively affect the available pump [P] suction head. As discussed
- 2. DOCKET NUMBER
- 3. LER NUMBER YEAR SEQUENTIAL REV NUMBER NO.
00249 2024 -
002 00 in the Dresden Updated Final Safety Analysis Report (UFSAR), for closed system piping which communicates with the suppression pool [NH] and is expected to remain submerged during a Loss of Cooling Accident (LOCA), the intact piping or the water seal acts as the penetration isolation barrier and ensures that the primary containment boundary is maintained intact until another barrier can be established to isolate the penetration. The LPCI [BO] suction line is closed system piping which communicates with the suppression pool [NH] and is expected to remain submerged during a LOCA. Therefore, the water seal can be credited as an isolation barrier maintaining the safety function of the primary containment system.
E. CORRECTIVE ACTIONS
At 1650 CST on 11/20/2024, the operating handle for the 3A LPCI Suction Relief Valve was moved to the correct (down) position in accordance with station procedure.
Additional corrective actions will be determined by the evaluation currently in progress.
F. PREVIOUS OCCURENCES
A 5-year internal corrective action program and LER database review was performed for Dresden Nuclear Power Station (DNPS). One occurrence of a relief valve operating handle being found in the lifted position at DNPS from 2019 was identified. The cause was determined to be that the work package instructions did not include direction for control of the relief valve lifting device during or upon completion of installation.
The relief valve for this event was part of a different system and of a different type than the relief valve that is the subject of this report. This occurrence is being reviewed for potential relevance to the issue documented in this report as part of the evaluation that is currently in process. The relevance of this occurrence, as well as any others identified during the evaluation, will be discussed in the supplemental report.
G. COMPONENT FAILURE DATA
No equipment failures are applicable. Page_3_ of _3_