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| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 57113 | 7 May 2024 21:28:00 | Non | Technical Specification Violation | The following information was provided by the licensee via phone: Per the licensees Technical Specifications (TS) 6.1.3.a, "The minimum staffing when the reactor is not secured shall be: . A reactor operator or the senior reactor operator on duty in the control room. On May 7, 2024, following the reactor shutdown, there was an indication that one control rod was not fully inserted. Both the reactor operator and reactor engineer left the control room to investigate and discovered that one control rod was not fully inserted. The reactor operator leaving the control room violated the minimum control room staffing requirements of TS 6.1.3.a. On May 8, 2024, the licensee determined that the cause for the control rod not being fully inserted was a dislodged plastic buffer at the bottom of the control rod barrel. The NRC Project Manager has been notified. | Control Rod | 05000362/LER-2001-001 |
| ENS 56579 | 31 May 2023 16:30:00 | Non | Technical Specifications Power Limit Violation | The following information was provided by the licensee via phone and email: (Oregon State University Radiation Center is) providing this information as a follow-up with the phone call to the Headquarters Operations Center made today at 1325 EDT (EN-56579). On the morning of 5/31/2023, a senior reactor operator and a trainee operator were performing a square-wave operation to raise power from 100 W to 1 MW. After firing the transient rod, the reactor immediately scrammed on both safety and percent power channels. Review of the chart recorder shows that reactor power likely reached 1.45 MW. This is potentially a violation of Technical Specification 3.1.1 which limits power to 1.1 MW during steady-state operations. Reviewing the power chart recorder, it appears that two immediately adjacent steps required for the square-wave operation were performed inadvertently out of order. The chart's sample rate is 1 Hz, so the resolution on the data is limited. Within 10 seconds, the final procedure steps for square-wave operation were performed (with the mode switch in square-wave mode). Once the transient rod air actuation button was pushed, starting the square-wave, the safety channel shortly thereafter (approximately 1 second) went from 0.02 percent to 145.91 percent of 1 MW. The reactor immediately scrammed and shut down the reactor as the safety and percent power channels exceeded their scram setpoints of 106 percent of 1 MW, which were checked on the daily startup checklist. The cause of the event was that two steps in the procedure were performed out of order, causing the regulating rod to withdraw to match demand power as the transient rod withdrew. As a result, this caused an additional 18 cents of reactivity to be inserted above the planned reactivity insertion of 80 cents. (Oregon State University Radiation Center plans) on following this up with a more thorough report within 14 days. | ||
| ENS 50927 | 25 March 2015 23:00:00 | Non | Research and Test Reactor Technical Specification Violation | We would like to report a potential violation of our Technical Specifications, section 6.7.2.a.8 which states an observed inadequacy in the implementation of administrative or procedural controls such that the inadequacy causes or could have caused the existence or development of an unsafe condition with regard to reactor operations. The details of the event are as follows: - January 14, (2015,) the Reactor Supervisor submitted paperwork for license renewal of an SRO (Senior Reactor Operator) to the director for signature. The director signs the paperwork. It was then assumed that the paperwork would be routed to the NRC for license renewal. The paperwork was signed but not sent to the NRC. - March 10, (2015,) the license for the SRO expires. - March 19, (2015,) the SRO completes the control room portion of the startup checklist. This includes manipulation of console controls and placing the reactor in 'OPERATING' condition. The SRO does not perform the reactor startup. - March 25, (2015,) staff determines that the reactor was placed in an OPERATING condition without a licensed operator at the console on March 19. No other staff was present in the control room during the performance of the startup checklist. - March 26, (2015,) reactor operation was suspended. It has been determined that the SRO did not perform any other license duties after his license had expired. The SRO will not perform license duties until his license is officially renewed.
On March 26, 2015, the Oregon State TRIGA Reactor staff self-reported a potential violation of Technical Specifications, section 6.7.2.a.8 which states 'an observed inadequacy in the implementation of administrative or procedural controls such that the inadequacy causes or could have caused the existence or development of an unsafe condition with regard to reactor operations.' The report was submitted due to the fact that the license of an SRO had expired on March 10, 2015, but that the operator performed licensed duties including placing the reactor in the 'operating' state on March 19, 2015. This individual did not perform any other license duties between the date his license expired and the date that a new license was issued. The initial notification e-mail sent by the reactor staff on 3/26/2015 (event notification 50927) informed the NRC of the event. In retrospect, we (Oregon State University) believe this event falls well below the threshold that would constitute a violation of Technical Specification 6.7.2.a.8. The individual has been a licensed operator of the Oregon State TRIGA Reactor for six years. None of the activities he (the operator) performed during the short period that his license was expired could realistically be construed as 'development of an unsafe condition with regard to reactor operations.' All duties that were performed during the event were reviewed by a licensed SRO as part of the daily start-up checklist. A new license was issued on April 2, 2015 (SOP-70794, Docket# 55-70933). The staff currently tracks all licensee due dates and it has been emphasized that maintenance of one's license is the responsibility of each licensed operator as well. The staff intends to add a tracking item to verify that 1) a license renewal is submitted at least 2 months prior to license expiration and 2) a license renewal is received at least one month prior to license expiration. It is expected that this information will reviewed during our (Oregon State University) next normally scheduled NRC inspection. No other follow-up or remedial actions are planned. This letter serves to retract the initial self-reported potential technical specification violation. Since it is deemed that a violation did not actually occur, there will be no subsequent 14-day written report. Notified NRR PM (Adams) | ||
| ENS 46738 | 6 April 2011 07:00:00 | Non | Violation of Limiting Condition of Operation 3.8.1, Reactivity Limits | Summary of Events: The Oregon State University TRIGA� Reactor (OSTR) staff is designing a new experiment which will utilize reactivity oscillation to measure reactor parameters. During attempts to measure the maximum worth of the oscillating absorber on Wednesday, April 6, it was determined that the worth of the preliminary test absorber is $0.60 at the mid-plane of the core. Technical Specification 3.8.1, Reactivity Limits states in part that 'The absolute value of the reactivity worth of any single unsecured experiment shall be less than $0.50.' Measurements were taken in a manner such that the apparatus qualifies as a movable experiment, and moveable experiments are taken to be a subcategory of unsecured experiments. A neutron absorber was fabricated by crushing an existing � inch segment of B4C absorber and placing 29.8 grams of the material in a sealed aluminum TRIGA� tube. The reactivity of the absorber was not formally calculated, but it was believed that the worth of the absorber would be less than $0.20. This was based on the fact that a full length control rod absorber (15 inch) is worth about $2.00, depending on position in the core. Past experience has also shown that several grams of Cadmium, a very strong thermal neutron absorber, have a reactivity worth of ~$0.20 in the B-1 position where the absorber was being tested. To characterize the worth of the absorber, the reactor was first taken critical with the In-Core-Irradiation-Tube (ICIT) installed in the B-1 position. Critical rod heights were measured and core excess was calculated. The reactor remained critical at 15 watts in automatic mode. The absorber was then manually lowered to the bottom of the ICIT by an operator using a length of nylon line. The regulating rod was observed to behave as anticipated, automatically withdrawing until some maximum worth position near core center was reached by the absorber, and then automatically inserting as the absorber was lowered to the bottom of the core. The worth of the absorber when resting at the bottom of the core was estimated to be less than $0.07. When power and reg rod position were stable, the absorber was slowly withdrawn 7.5 inches to the geometric center of the core. The reg rod automatically withdrew to compensate. The difference between reg rod position with no absorber present and reg rod position with the absorber at core center indicated that the worth of the absorber at core center was $0.60. As soon as absorber worth was determined, the reactor was shut down and the absorber was withdrawn from the ICIT. Although oscillatory operation was not planned, the fact that the absorber was moved while the reactor was critical qualified the experiment as a moveable experiment. Since $0.60 is in excess of L.C.O. 3.8.1, reactor operation was secured in accordance with Technical Specification 6.6.2.a. |