ENS 56878
ENS Event | |
|---|---|
17:24 Dec 1, 2023 | |
| Title | Safety System Malfunction |
| Event Description | The following information was provided by the licensee via phone and email:
[The following is a report of] reactor safety system component malfunction under Missouri University of Science and Technology Reactor (MSTR) Technical Specification (TS) 6.7.2.c)iii) At 1124 [CST], on December 1, 2023, with the MSTR at 180 kW, a `150 Percent Full Power' scram signal was received from one safety amplifier, and the reactor scrammed automatically. Based upon other nuclear instrumentation, at no point was reactor power at, above, or near the MSTR 300-kW Limiting Safety System Setting (LSSS), nor was any transient underway that could have yielded such a situation. Power was within the 2 percent automatic control setpoint window of 180 kW, and power dropped rapidly as expected following a scram. At the time of the event, the console operator observed that the affected safety amplifier went blank, and following an approximate 0.5 second delay, returned to a normal status tracking the decay power with a scram indicator illuminated. At no point was the health and safety of the public or MSTR in doubt. Due to ongoing reviews and replacement component sourcing, the MSTR has not operated since the event. Per MSTR TS 6.7.2.c)iii), `[the license shall make a report for] a reactor safety system component malfunction that renders or could render the reactor safety system incapable of performing its intended safety function unless the malfunction or condition is discovered during maintenance tests or periods of reactor shutdowns.' Following a thorough review of the scram logic and documented failure modes and effects analysis (FMEA) provided in the system's `Operation and Maintenance Manual' (Imaging & Sensing Technology Report 021-2103, Rev. 00), in the MSTR's opinion, the safety system malfunctioned but was able to complete its safety function. The event is being reported pending further review by facility staff and discussions with Nuclear Regulatory Commission facility project management. This report is being made under the provisions of MSTR Technical Specification 6.7.2, requiring a report by telephone to the NRC Headquarters Operations Center no later than the following working day. Under the provisions of MSTR Technical Specification 6.7.2, a written follow-up report will be submitted to the Commission within 14 days. Additional replacement parts will need to be secured and repairs performed to restore operability. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: This event has been entered into the licensee's corrective action program. |
| Where | |
|---|---|
| Missouri U Of Science &Amp; Tech (Mist) Rolla, Missouri (NRC Region 0) | |
| License number: | R-79 |
| Reporting | |
| Non | |
| Time - Person (Reporting Time:+73.62 h3.068 days <br />0.438 weeks <br />0.101 months <br />) | |
| Opened: | Ethan Taber 19:01 Dec 4, 2023 |
| NRC Officer: | Ernest West |
| Last Updated: | Dec 4, 2023 |
| 56878 - NRC Website | |
with Non | |
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