ENS 56331
ENS Event | |
|---|---|
08:00 Jan 31, 2023 | |
| Title | Limiting Condition of Operation Not Met |
| Event Description | The following information was provided by the licensee via email:
[University of California, Davis McClellan Nuclear Research Center] MNRC received its new 20 year operating license from the NRC on November 21, 2022. As part of the new license, several new conditions in the technical specification were added for consistency with other non-power reactors and to give greater assurances of public safety beyond the previous technical specifications. The license condition involved in this event is Technical Specification 3.3 specification 4 concerning the maximum allowable activity of radionuclides in MNRC's primary cooling water with half-lives greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The specific requirement is that these radionuclide concentrations shall be less than the 10 CFR 20 Appendix B table 3 values for the reactor to be operated. When agreeing to this new technical specification, MNRC staff looked at the historical values for all non-tritium nuclides having half-lives greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. These nuclides are assayed at MNRC via high resolution gamma-ray spectroscopy. For these nuclides MNRC is able to meet the new [limiting condition of operation] LCO limit easily. Separately, MNRC staff evaluated the tritium activity that was provided to MNRC via a 3rd party laboratory. The latest result from the 3rd party laboratory appeared to confirm that MNRC would meet the new tritium limit of 0.01 uCi/ml by having a tritium concentration of approximately 1/40th of this value. On January 31, 2023, during the planning for the required surveillance of technical specification 3.3 item 4, it was discovered that the 3rd party laboratory result was incorrect and they mistakenly underreported tritium concentrations by a factor of 100. At approximately 1600 (PST) on the same day, it was verified that MNRC's primary water tritium concentration was approximately 2.5 times the new technical specification limit given in section 3.3 item 4, resulting in not being able to meet an LCO. A more thorough data review shows that historical concentrations of the tritium in MNRC's primary coolant are very constant (except for the misreported data used to evaluation MNRC's ability to meet the new technical specification 3.3 item 4). Therefore, failing to meet this LCO is a condition that has likely existed since the issuing of the new license on November 21, 2022. MNRC was not operating at the time of this discovery and has not resumed reactor operations. There has likely been no increase in the amount of tritium in MNRC's primary cooling water nor has any primary cooling water been released from the reactor tank since the new technical specification took effect. There are no safety or security concerns generated as a result of this event. The facility license holder (level 1 management), the chair of the MNRC safety committee, MNRC's NRC program manager, assistant program manager, and inspector have been notified of this event. The ultimate resolution of this issue will need to be a license amendment increasing the permissible tritium concentration in the primary cooling water as a condition for reactor operation as it is physically impossible to lower the tritium concentration in order to meet the LCO. |
| Where | |
|---|---|
| McClellan Nuclear Research Center Sacramento, California (NRC Region 0) | |
| License number: | R-130 |
| Reporting | |
| Non | |
| Time - Person (Reporting Time:+32.85 h1.369 days <br />0.196 weeks <br />0.045 months <br />) | |
| Opened: | Wesley Frey 16:51 Feb 1, 2023 |
| NRC Officer: | Brian P. Smith |
| Last Updated: | Feb 1, 2023 |
| 56331 - NRC Website
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University of California-Davis with Non | |
WEEKMONTHYEARENS 566432023-07-27T22:00:00027 July 2023 22:00:00
[Table view]Non Fuel Element Inspection Failure ENS 563312023-01-31T08:00:00031 January 2023 08:00:00 Non Limiting Condition of Operation Not Met 2023-07-27T22:00:00 | |