05000410/LER-2022-002, Reactor Protection System Actuation While Shutdown
| ML22312A003 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 11/03/2022 |
| From: | Sterio A Constellation Energy Generation |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NMP2L2824 LER 2022-002-00 | |
| Download: ML22312A003 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| 4102022002R00 - NRC Website | |
text
Constellation.
NMP2L2824 November 3, 2022 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Nine Mile Point Nuclear Station, Unit 2 Renewed Facility Operating License No. NPF-69 Docket No. 50-410 10 CFR 50.73
Subject:
NMP2 Licensee Event Report 2022-002, Revision 0, Reactor Protection System Actuation While Shutdown In accordance with the reporting requirements contained in 10 CFR 50.73(a)(2)(v)(B), please find enclosed NMP2 Licensee Event Report (LER) 2022-002, Revision 0, Reactor Protection System Actuation While Shutdown There are no regulatory commitments contained in this letter.
Should you have any questions regarding the information in this submittal, please contact Brandon Shultz, Site Regulatory Assurance Manager, at (315) 349-7012.
Respectfully,
~ciAD..lt-Alexander D. Sterio Plant Manager, Nine Mile Point Nuclear Station ADS/JRA
Enclosure:
NMP2 Licensee Event Report 2022-002, Revision 0, Reactor Protection System Actuation While Shutdown cc:
NRC Regional Administrator, Region I NRC Resident Inspector NRC Project Manager
Enclosure NMP2 Licensee Event 2022-002, Revision 0 Reactor Protection System Actuation While Shutdown Nine Mile Point Nuclear Station, Unit 2 Renewed Facility Operating License No. NPF-69
Abstract
On Sunday, September 4, 2022, at approximately 1638 hours0.019 days <br />0.455 hours <br />0.00271 weeks <br />6.23259e-4 months <br /> with reactor power at 0%, Nine Mile Point Unit 2 (NMP2) experienced a Reactor Protection System (RPS) Actuation on RPV Low Water Level (Level 3) of 159.3 inches. At the time of the RPS Actuation, the reactor was already in a shutdown condition with all rods fully inserted. The Level 3 condition also initiated an isolation signal to Groups 4 and 5 Primary Containment Isolation valves which were already closed. Operators took action to restore RPV water level to the normal operating band.
This event is reportable per 1 0CFR 50.73(a)(2)(iv)(A).
The cause of this event is under investigation and a Supplemental Report is planned for submittal by December 20, 2022.
The event described in this LER is documented in the plant's Corrective Action Program (CAP) as IR 04520704.
THE ENERGY INDUSTRY IDENTIFICATION SYSTEM (EIIS) COMPONENT FUNCTION IDENTIFIER AND SYSTEM NAME OF EACH COMPONENT OR SYSTEM REFERRED TO IN THIS LER ARE ENCLOSED WITHIN [BRACKETS]
I.
DESCRIPTION OF EVENT
A. PRE-EVENT PLANT CONDITIONS:
Prior to the event, NMP2 was in Mode 3 (Hot Shutdown), performing a cooldown to support a planned maintenance outage.
- 8. EVENT:
On Sunday, $eptember 4, 2022, at approximately 1638 hours0.019 days <br />0.455 hours <br />0.00271 weeks <br />6.23259e-4 months <br />, NMP2. experienced an actuation of the Reactor Pr.ote~tion System [JC] due to reactor low water level while in Mode 3, Hot.Shutdown. At the time of the RPS Actuation, all control rods were already fully inserted and groups 4 and 5 containment isolation valves were already closed.The Containment Isolation [JM] signal impacted Residual Heat Removal (RHR) [BO], Shutdown Cooling, RHR letdown to radwaste, and RHR sampling valves. Following the RPS Actuation, Operators restored Reactor Water Level utilizing level control valve CNM-LV137.
Nine Mile Point Unit 1 (NMP1) was unaffected by the NMP2 RPS Actuation.
On September 4, 2022 at approximately 2131 hours0.0247 days <br />0.592 hours <br />0.00352 weeks <br />8.108455e-4 months <br />, this event was reported to the NRC via Event Notification#56089 pursuant to the requirements of 1 0CFR50. 72(b)(3)(iv)(A) Specified System Actuation of any of the systems listed in 1 0CFR50.72(b)(3)(iv)(B).
C. INOPERABLE STRUCTURES, COMPONENTS, OR SYSTEMS THAT CONTRIBUTED TO THE EVENT:
None. Any non-safety related equipment that contributed to the event will be provided in the supplement.
D. DATES AND APPROXIMATE TIMES OF MAJOR OCCURENCES AND OPERATOR ACTIONS:
September 4, 2022:
1506 - NMP2 entered Mode 3 on a planned Reactor SCRAM to enter a maintenance outage.
1638 - Reactor water level lowered to Level 3 (159.3"), which caused a Reactor Protection System Actuation.
1639 - Reactor water level was returned to normal by Operators.
Additional dates and times bf major occurrences and operator actions may be provided in the supplement when the investigation is complete.
E. METHOD OF DISCOVERY
This event was self-revealing via Main Control Room RPV level indications and RPS related annunciators.
F. SAFETY SYSTEM RESPONSES:
All safety systems responded per design.
II.
CAUSE OF THE EVENT
The cause of this event is being investigated and will be provided in the supplement.
Ill.
ANALYSIS OF THE EVENT
The RPS Actuation had no impact to health or safety of the public.
The analysis of the event will be provided in the supplement.
IV. CORRECTIVE ACTONS A. ACTION TAKEN TO RETURN AFFECTED SYSTEMS TO PRE-EVENT NORMAL STATUS:
Operators restored reactor level to normal.
B. ACTION TAKEN OR PLANNED TO PREVENT OCCURRENCE:
To be provided in the su*pplement when the cause is completed.
V. ADDITONAL INFORMATION A. FAILED COMPONENTS:
None B. PREVIOUS LERs ON SIMILAR EVENTS:
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