05000237/LER-2023-001, HPCI Inoperable Due to Air Void Accumulation
| ML24019A030 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 01/19/2024 |
| From: | Joseph C Constellation Energy Generation |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| SVPLTR: #24-0001 LER 2023-001-00 | |
| Download: ML24019A030 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v), Loss of Safety Function |
| 2372023001R00 - NRC Website | |
text
Constellation January 19, 2024 SVPL TR: #24-0001 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Dresden Nuclear Power Station, Unit 2 Renewed Facility Operating License No. DPR-19 NRC Docket No. 50-237 Dresden Nuclear Power Station 6500 North Dresden Road Morris, IL 60450 10 CFR 55.31
Subject:
Licensee Event Report 237/2023-001-00, HCPI Inoperable Due to Air Void Accumulation Enclosed is Licensee Event Report 237 /2023-001 -00, HCPI Inoperable Due to Air Void Accumulation. This report describes an event being reported in accordance with 10 CFR
- 50. 73(a)(2)(v)(A) for a condition that could have prevented the fulfillment of a safety function of a system needed to mitigate the consequences of an accident.
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 (815) 416-2800.
Carolyne Jos Site Vice Pres ent Dresden Nuclear Power Station
Enclosure:
Licensee Event Report 237/2023-001 -00 CC:
Regional Administrator - NRC Region Ill NRC Senior Resident Inspector - Dresden Nuclear Poweir Station
Abstract
On 11/20/2023 at 0956 CST, a section of High-Pressure Coolant Injection (HPCI) discharge piping was found to have an air void during the monthly performance of a non-destructive ultrasonic testing examination for gas accumulation in the Emergenc:
Core Cooling Systems. Technical Specification 3.5.1 Condition G was entered and HPCI was declared inoperable. Venting was performed to restore the system to operable, which was confirmed via non-destructive ultrasonic testing at 1034 CST on 11/20/2023. This event is being reported in accordance with 10 CFR 50.73(a)(2)(v)(D) for a condition that could have prevente1 the fu lfilment of a safety function of a system needed to mitigate the consequences of an accident.
The cause of the event has not yet been determined. Investigation into the cause of the event is ongoing, and a supplemental report will be submitted after completion of the investigation. Additional corrective actions are being evaluated as part of the investigation and will be provided in the supplemental report.
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].
A. CONDITIONS PRIOR TO EVENT
SEQUENTIAL NUMBER 001 Unit: 2 Reactor Mode: 1 Event Date:
November 20, 2023 Mode Name: Power Operation Event Time: 0956 CST Power Level: 100%
8. DESCRIPTION OF EVENT
REV NO.
000 On November 20, 2023, at 0956 CST, a portion of the single-train High Pressure Coolant Injection system (HPCI) [BJ] discharge piping was discovered to have an air void during the monthly performance of a non-destructive ultrasonic examination (NOE UT) for gas accumulation in Emergency Core Cooling System (ECCS) piping. Upon notification of this discovery, the station entered Technical Specification 3.5.1 Condition G and declared HPCI inoperable. An 8-hour notification was made in accordance with 10 CFR
- 50. 72(b)(3)(v)(D) for a condition that, at the time of discovery, could have prevented the fulfillment of the safety function of a system needed to mitigate the consequences of an accident.
The NRC was notified via ENS 56866 at 1753 EST.
This event is being reported in accordance with 10 CFR 50.73(a)(2)(v)(D) for a condition that could have prevented the fulfillment of the safety function of a system needed to mitigate the consequences of an accident.
C. CAUSE OF EVENT
The cause of the event has not yet been determined. Investigation into the cause of the event is being performed under Issue Report (IR) 04718861. A supplemental report will be submitted after completion of this evaluation.
D. SAFETY ANALYSIS
The safety significance of the event is very low. TS 3.5.1 allows Unit 2 to remain at power for 14 days with HPCI inoperable, providing that the Isolation Condenser (IC) [BL] remains operable per the required actions for Condition G. Unit 2 maintained compliance with TS 3.5.1 given the IC was operable during the period in which HPCI was inoperable, and HPCI operability was restored in 38 minutes after the time of discovery.
E. CORRECTIVE ACTIONS
- 2. DOCKET NUMBER YEAR 00237 23
- 3. LER NUMBER SEQUENTIAL NUMBER 001 REV NO.
000 Venting was performed in accordance with station procedure to restore HPCI to operable. At 1034 CST on November 20, 2023, NOE UT confirmed the system piping was water solid and LCO 3.5.1 Condition G was exited.
Additional corrective actions are being reviewed as part of the investigation to determine the cause of the event. Any additional actions will be documented in a supplemental report.
F. PREVIOUS OCCURENCES
A review of DNPS LE Rs for the last three years did not identify any LERs associated with HPCI or other ECCS gas accumulation resulting in a loss of function. Additional occurrences of gas intrusion into ECCS piping will be reviewed as part of the investigation into the cause of this event and documented as applicable in the supplemental report.
G. COMPONENT FAILURE DATA
Not applicable Page _3_ of _3_