ENS 56553
ENS Event | |
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12:18 Jun 2, 2023 | |
Title | Unscheduled Shutdown |
Event Description | The following information was provided by the licensee via fax or email:
An unscheduled shutdown of the reactor occurred on 6/2/23 at 0818 EDT due to an abnormal response of the Safety Power Level channel during the approach to power of 1 MW at 150 kW. The Reactor Operator observed a discrepancy in power indications by the Linear Power Level and Safety Power Level channels and took immediate actions required by procedure NRP-OP-105, Response to SCRAMS, Alarms, and Abnormal Conditions. The reactor was shut down and secured immediately. The Designated Senior Reactor Operator was immediately notified. The Safety Power Level channel is required to be operable per Technical Specification 3.3.b Table 3.3-1 while the reactor is being operated. During the startup checklist, the channel performed satisfactorily. The Safety Power Level channel is part of the reactor safety system and has two automatic shutdowns (SCRAMs) associated with it. Reactor power was correctly monitored by all other operable power monitoring channels which have redundant SCRAM capabilities. No SCRAM occurred or was needed due to the power level of the reactor. Following the reactor shutdown, the reactor staff investigated and determined that the high voltage power supply in the Safety Power channel was faulty. The power supply was replaced and a channel calibration of the Safety Power channel will be performed using procedure PS 1-05-03A:S1 to verify the channel is operable. Maintenance Log #0888 has been opened. There was no safety issue with this event. Procedures were followed during reactor operation, shutdown, and the investigation. This unscheduled shutdown is a reportable event per TS 6.7.1 based on the circumstances and as defined in the facility Technical Specification (TS 1.2.24.d) for reportable events from operation in violation of Limiting Conditions for Operation (LCO) established in TS. TS 1.2.24.d, does not allow for an exception for taking prompt remedial action. A report to the NRC is required within one working day and will be made by 1700 EDT by phone on 6/2/23, as required by TS 6.7.1. Also as required by TS 6.7.1, a written report to the NRC is due in 14 days (6/16/23). |
Where | |
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North Carolina State University (Ncsu) Raleigh, North Carolina (NRC Region 0) | |
License number: | R-120 |
Reporting | |
Non | |
Time - Person (Reporting Time:+0.98 h0.0408 days <br />0.00583 weeks <br />0.00134 months <br />) | |
Opened: | Gerald Wicks 13:17 Jun 2, 2023 |
NRC Officer: | Brian Lin |
Last Updated: | Jun 2, 2023 |
56553 - NRC Website
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North Carolina State University with Non | |
WEEKMONTHYEARENS 571962024-06-27T14:37:00027 June 2024 14:37:00
[Table view]Non Technical Specification (Ts) Reportable Occurrence ENS 565532023-06-02T12:18:0002 June 2023 12:18:00 Non Unscheduled Shutdown ENS 557472022-02-17T18:46:00017 February 2022 18:46:00 Non Technical Specification Violation ENS 527482017-05-10T21:00:00010 May 2017 21:00:00 Non Research Test Reactor - Technical Specification Violation ENS 464842010-12-13T20:00:00013 December 2010 20:00:00 Non Research Reactor Radiography Incident ENS 449912009-04-10T13:30:00010 April 2009 13:30:00 Non Violation of Limiting Conditions in Technical Specification 3.5B 2024-06-27T14:37:00 | |