The
Missouri University of Science and Technology Reactor (
MSTR) is required by facility
Technical Specification 3.3.2 to maintain pool water resistivity above 0.2 MOhm-cm so long as fuel elements are in the pool.
TS 3.3.2 continues that 'This requirement may be waived for a period of up to 3 weeks once every 3 years.' On September 13, 2021, pool resistivity dropped below the 0.2 MOhm-cm threshold, triggering the three-week waiver to support water deionization system maintenance. Ion exchange resins for this system were replaced, but the system was not able to be restored to an operational status prior to exceeding the three-week waiver. It is noted that pool resistivity recovered above 0.2 MOhm-cm by September 14, 2021 and was maintained until the system was removed from service to replace the resins (September 28, 2021).
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. It is anticipated that full compliance with
TS 3.3.2 will be restored within two weeks (by October 19, 2021).