ENS 55568
ENS Event | |
|---|---|
06:00 Nov 8, 2021 | |
| Title | Technical Specification Violation |
| Event Description | This is a required notification per University Of Missouri Research Reactor (MURR) Technical Specification (TS) 6.6.c(1) to report to the NRC Operations Center that an Abnormal Occurrence, as defined by MURR TS 1.1, had occurred. MURR was not in compliance with one Limiting Conditions of Operations (LCO). TS 3.2.f states, 'The reactor shall not be operated unless the following rod run-in functions are operable.' Specifically, the rod run-in function that occurs when water level in the anti-siphon system is greater than or equal to 6 inches above the anti-siphon isolation valves was not operable as required by TS 3.2.f.6.
On 11/8/21 while the reactor was shut down for maintenance and conducting surveillance testing on the anti-siphon system high level rod run-in instrument channel, the surveillance testing provided measurement that indicated the rod run-in actuation may not have occurred until water level was slightly greater than 6 inches above the anti-siphon isolation valves. Previously on 4/22/2021, the anti-siphon system high level rod run-in instrument channel activated the rod run-in well below the top of the anti-siphon isolation valves. Troubleshooting revealed the stainless-steel cable that connects the channel's level controller to its suspended displacer (float) had developed loops in it, effectively shortening the cable. The cable with loops made the rod run-in actuation occur at a higher water level than when the cable has no loops in it. The loops in the cable were removed. The instrument channel was retested and documented to be back in compliance with TS 3.2.f.6. On 11/9/21, MURR engineers analyzed the data collected from the 11/8/21 measurement and concluded that prior to removing the loops from the level controller cable, the rod run-in was actuating at a level of approximately 7.3 inches above the anti-siphon isolation valves, which is greater than the maximum of 6 inches above the valves required by TS 3.2.f.6. In accordance with TS 6.6.c(4) before it was known if MURR deviated from TS 3.2.f.6, the Acting Reactor Facility Director was briefed and gave permission to restart the reactor prior to the reactor returning to operation later on 11/8/21. Currently, MURR is operating at 10 MW. A detailed event report will follow within 14 days as required by MURR TS 6.6.c(3). |
| Where | |
|---|---|
| Univ Of Missouri-Columbia (Misc) Columbia, Missouri (NRC Region 0) | |
| License number: | R-103 |
| Reporting | |
| Non | |
| Time - Person (Reporting Time:+41.83 h1.743 days <br />0.249 weeks <br />0.0573 months <br />) | |
| Opened: | Bruce Meffert 23:50 Nov 9, 2021 |
| NRC Officer: | Brian Lin |
| Last Updated: | Nov 10, 2021 |
| 55568 - NRC Website
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University of Missouri-Columbia with Non | |
WEEKMONTHYEARENS 571252024-05-10T05:00:00010 May 2024 05:00:00
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