ENS 55516

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v t e ENS Event
05:00 Oct 11, 2021
Title	One Primary Coolant LOW Pressure Instrument Channel Scram Setpoint Found Below Technical Specification Required Minimum
Event Description	[This notification is required] 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 (1) Limiting Conditions of Operations (LCO). TS 3.2.g. which states, 'The reactor safety system and the number (N) of associated instrument channels necessary to provide the following scrams shall be operable whenever the reactor is in operation..' TS 3.2.g.6 requires four (4) Primary Coolant Low Pressure reactor safety system instrument channels provide a reactor scram when the primary coolant pressure corresponding to the pressurizer during normal flow drops below 75 psia. Surveillance testing on 10/11/2021 revealed that one (1) of the four (4) channels was not operable. On 10/11/21 while the reactor was shutdown for maintenance and conducting surveillance testing on the reactor core outlet pressure channels, the surveillance testing revealed that the reactor core outlet pressure channel associated with pressure transmitter 944B did not provide a reactor scram at an appropriate TS low pressure setpoint. On 10/11/21, the Primary Coolant Low Pressure reactor safety instrument channel 944B scram setpoint was calculated to be 74.43 psia which is slightly below the required 75 psia minimum. Previously on 4/12/2021, the Primary Coolant Low Pressure reactor safety instrument channel 944B scram setpoint was calculated to be 76.94 psia which is within the TS-required setpoint range. So, sometime between 4/12/2021 and 10/11/2021, the reactor possibly operated while one (1) of the four (4) instrument channels deviated from TS 3.2.g.6. Troubleshooting revealed the component in instrument channel 944B that caused the setpoint deviation. That component was replaced with an exact spare, and the instrument channel was retested and documented to be back in compliance with TS 3.2.g.6. In accordance with TS 6.6.c(4), permission from the Reactor Facility Director was obtained prior to the reactor returning to operation later on 10/11/21. 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).

ENS 55516 +/-
Where
Univ Of Missouri-Columbia (Misc) Columbia, Missouri (NRC Region 0)
License number:	R-103
Reporting

Non
Time - Person (Reporting Time:+32.2 h1.342 days <br />0.192 weeks <br />0.0441 months <br />)
Opened:	Bruce Meffert 13:12 Oct 12, 2021
NRC Officer:	Donald Norwood
Last Updated:	Oct 12, 2021
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v • d • e

v t e Emergency Notification System
University of Missouri-Columbia with Non
WEEKMONTHYEAR2024-05-10T05:00:00 [Table view]
[ENS list for University of Missouri-Columbia]

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