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Category:Letter
MONTHYEARIR 05000184/20232012024-01-25025 January 2024 National Institute of Standards and Technology - U.S. Nuclear Regulatory Commission 1st and 2nd Quarter Supplemental Inspection Report 05000184/2023201 ML24023A6182024-01-23023 January 2024 Us Dept. of Commerce, National Institute of Standards & Technology - Nuclear Program Assessments Response and Leadership Accountability ML23257A1972023-12-26026 December 2023 Examination Results Letter No. 50-184/OL-23-02, National Institute of Standards and Technology ML23257A1982023-12-26026 December 2023 Examination Report No. 50-184/OL-23-02, National Institute of Standards and Technology ML23306A1642023-11-0202 November 2023 Examination Report Letter No. 50-182/OL-24-01, University of Missouri - Columbia ML23306A1652023-11-0202 November 2023 Examination Result Letter No. 50-184/OL-24-01, University of Missouri - Columbia ML23207A0402023-07-26026 July 2023 Us Dept. of Commerce, National Institute of Standards & Technology, Nuclear Safety Culture Assessment and Response ML23195A1042023-07-12012 July 2023 NIST Center for Neutron Research (Ncnr), Withdrawal of License Amendment Request of December 11, 2020 ML23104A3002023-04-10010 April 2023 U.S. Dept. of Commerce, National Institute of Standards & Technology (Nist), Transmitted Herewith Is Operations Report No. 74 for the Nbsr for the Cy 2022 ML23089A1132023-03-30030 March 2023 Us Dept. of Commerce - National Institute of Standards & Technology - Non-Availability of Fuel and Funding to Convert Nbsr from HEU to LEU in 2021 ML23086B3832023-03-27027 March 2023 Us Dept. of Commerce, National Institute of Standards & Technology (NIST) - Change of Ncnr Director ML23040A3372023-03-0909 March 2023 NIST Restart Authorization Letter ML23059A0502023-03-0707 March 2023 Examination Confirmation Letter No. 50-184/OL-23-02, National Institute of Standards and Technology IR 05000184/20222022023-03-0707 March 2023 National Institute of Standards and Technology U.S. Nuclear Regulatory Commission 4th 2022 Quarter Supplemental Inspection Report 05000184/2022202 ML23055A3002023-03-0303 March 2023 NIST License Amendment 15 - Core Alternative Reload Methodology Scheme ML23020A9112023-02-0101 February 2023 National Institute of Standards and Technology Issuance of Amendment No. 14 to Renewed Facility Operating License No. TR 5 ML23033A1152023-02-0101 February 2023 Us Dept. of Commerce, National Institute of Standards & Technology, License Amendment Request IR 05000184/20222032023-01-27027 January 2023 National Institute of Standards and Technology - U.S. Nuclear Regulatory Commission Security Inspection Report 05000184/2022203 ML22350A0652022-12-13013 December 2022 Us Dept. of Commerce, National Institute of Standards & Technology (Nist), License Amendment Request ML22322A2182022-11-28028 November 2022 National Institute of Standards and Technology - Report on the Regulatory Audit Re Restart Request Following Exceedance of Cladding Temperature Safety Limit ML22322A2112022-11-17017 November 2022 NIST Center for Neutron Research, License Amendment Request. Response to NRC Questions Regarding the Primary and Effluent Monitoring Systems ML22293B8082022-10-19019 October 2022 National Institute of Standards & Technology (NIST) - License Amendment Request ML22235A1172022-08-23023 August 2022 Us Dept of Commerce, National Institute of Standards & Technology, Transmittal of Draft of a Proposed Presentation of 02/03/2021, Nbsr Event for NRC Review ML22227A1502022-08-15015 August 2022 Us Dept of Commerce, National Institute of Standards & Technology (Nist), Request NRC Permission to Restart the Reactor Upon Completion of Listed Corrective Actions and Recovery Efforts ML22223A1462022-08-11011 August 2022 Docket Number 50-184 and the Nbsr Requalification Plan ML22206A2132022-08-0101 August 2022 Letter to National Institute of Standards and Technology, Center for Neutron Research - Confirmatory Order (EA-21-148) ML22206A0102022-08-0101 August 2022 U.S. Nuclear Regulatory Commission Supplemental Inspection Plan for National Institute of Standards and Technology ML22181A1282022-07-21021 July 2022 National Institute of Standards and Technology - Issuance of Amendment No. 13 to Renewed Facility Operating License No. TR-5 ML22187A1272022-06-29029 June 2022 Nbsr Restart Request ML22160A2852022-06-0808 June 2022 Nbsr License Amendment Request Supplement ML22122A0882022-04-27027 April 2022 Letter for T. 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Bowen, Nrc/Nrr/Danu, NRC Office of Investigations Report No. 1-2022-005 - Release of OI Synopsis ML22094A1082022-04-0404 April 2022 Transmittal of Operations Report No. 74 for the Nbsr for January 1, 2021 to December 31, 2021 ML22084A4082022-03-30030 March 2022 NIST - Non-availability of Fuel and Funding to Convert Nbsr from HEU to LEU in 2021 IR 05000184/20222012022-03-16016 March 2022 National Institute of Standards and Technology - Us Nuclear Regulatory Commission Special Inspection Report No 05000184-2022201 ML22012A0902022-01-11011 January 2022 Nbsr License Amendment Request, Revised No Significant Hazard Consideration Determination ML21349A3772022-01-0404 January 2022 December 7, 2021, Summary of Mtg with Nist to Discuss Proposed Technical Specification Changes at the National Bureau of Standards Reactor EPID L-2021-LLN-0000 ML21361A2472021-12-23023 December 2021 Nbsr License Amendment Request ML21355A2752021-12-21021 December 2021 Us Dept. of Commerce, National Institute of Standards & Technology, Nbsr Response to Request for Supplemental Information on Request to Restart the Nbsr ML21355A2742021-12-20020 December 2021 Us Dept. of Commerce, National Institute of Standards & Technology, Supplement to October 1, 2021 Report and Restart Request ML21340A0092021-12-0303 December 2021 Nbsr Response to Request for Supplemental Information on Request to Restart the Nbsr ML21294A2772021-11-18018 November 2021 National Institute of Standards and Technology - Supplemental Information Needed for the Request to Restart the National Bureau of Standards Reactor ML21294A3732021-10-21021 October 2021 National Institute of Standards and Technology - Submittal of Supplement to October 1, 2021 Report and Restart Request ML21288A5552021-10-15015 October 2021 Us Dept. of Commerce, National Institute of Standards and Technology (NIST) - Supplement to October 1, 2021 Report and Restart Request ML21274A0272021-10-0101 October 2021 Nbsr Report on February 3, 2021 Fuel Failure Event, Root Causes, Corrective Actions, and Restart Readiness ML21265A4352021-09-24024 September 2021 National Institute of Standards and Technology - Change of Facility Project Manager ML21153A4162021-06-15015 June 2021 National Institute of Standards and Technology - Acceptance of the Application for a License Amendment Request for License Amendment and Addjustment of Tritium Effluent Values for D2 Cold Source Under Title 10 of the Code of Federal Regulat ML21153A3962021-06-0202 June 2021 Us Dept of Commerce, National Institute of Standards & Technology (NIST) - Docket Number 50-184 and the Nbsr Requalification Plan ML21133A2662021-05-13013 May 2021 Us Dept. of Commerce, National Institute of Standards & Technology, Follow-Up to Event Report ML21130A6042021-04-30030 April 2021 Us Dept of Commerce, National Institute of Standard & Technology - Non-Availability of Fuel and Funding to Convert Nbsr from HEU to LEU in 2021 IR 05000184/20212012021-04-14014 April 2021 National Institute of Standards and Technology U.S. Nuclear Regulatory Commission Interim Special Inspection Report No. 05000184/2021201 2024-01-25
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UNITED STATES DEPARTMENT OF COMMERCE National Institute of Standards and Technology Gaithersburg, Maryland 20899-February 16, 2020 Document Control Desk U.S. Nuclear R~gulatory Commission Washington, DC 20555-0001
Subject:
Report ofNCNR declaration of Alert Ref: NRC Event Report 55094, Docket 50-184, Facility License TR-5 Sirs and Madams:
On February 3, 2021, the NCNR (NIST Center for Neutron Research) declared an alert as a result of detecting fission products in the helium sweep gas above the reactor and elevated readings on the ventilation stack monitor. An initial report to the NRC Operations Center was made that day in accordance with TR-5 TS 6.7.2(1)h and TR-5 Emergency Plan 7 .1. There was no time in which any technical specification was violated. This letter is a 14-day report of that occurrence, as required by TS 6. 7.2(1 ).
Circumstances Prior to Event Tue NCNR research reactor (NBSR) operates 24/7 on a nominal 38-day fuel cycle. On February 3, the NBSR was undergoing a routine startup following a normal maintenance and refueling period. Startup of the reactor began at 0816 and reactor power was taken to 10 MW (half power) at 0900, as is routinely done during a startup.
Circumstances of Event At 0906, the operator began raising power to go to full power. At 0907, when the reactor power had just reached 15 MW, there was a sudden drop in power, down to about 7 MW,
, followed less than a minute later by sudden increases on several radiation monitors, including the stack radiation monitor, RM 4-1. At 0909, the stack monitor reached its setpoint of 50kcpm, tripping a major scram, which scrams the reactor and seals the confinement building, preventing the possibility of any further release. Based on the fact that the fission product monitor in the helium sweep gas system indicated well above the 50lccpm criteria for an alert, the reactor shift supervisor recognized the potential for a fuel cladding failure and declared an Alert at 0916, in accordance with NBSR Emergency Instruction 0.3 2.2.2.
At 0910, because of increasing radiation levels in the confinement building, the building '
was evacuated of all personnel (a total of eight people) except for the reactor shift NISI
a supervisor and Chief of Reactor Operations (CRO), who stayed behind few minutes to assure that the reactor was in a safe condition. The CRO contacted the Chief of Reactor Operations and Engineering (CROE) at 0921. The CROE contacted the NCNR Director at 0927 and notified the NRC of the Alert declaration at 0929.
Of the personnel present in the confinement at the initiation of the event, six were either in the control room or near the reactor top and exposed to the release. Their clothing was found to be contaminated. In addition, four individuals entered the confinement later at 1205 wearing protective clothing to align the reactor systems for a shutdown configuration.
Site boundary radiation surveys began at 0912 and continued throughout the event. Air grab samples and charcoal/particulate samples, both at the 400 m EPZ boundary and from the stack were taken throughout the day. All stack samples taken showed the presence of fission product gases. Initially Cs-138 and Xe-138 were the primary isotopes seen on the stack samples, with later stack samples showing primarily Xe and Kr isotopes. No iodine isotopes were seen on any air sample. The initial air sample taken at the boundary at 1040 showed a very small concentration of Cs-138 at 0.5% of 10CFR20 Appendix B Table 2 values. All other boundary air samples did not show the presence of any radioisotopes, with the exception of one taken on Feb 4, which showed very minute concentrations(< 0.1 % EC) ofXe-133 and Xe-135.
Due to the difficulty of ascertaining the quantities ofKr-83m and Kr-85 (which are pure beta emitters), it was necessary to extrapolate stack measurements to try and quantify the potential dose at the boundary. We were able to determine that all isotopes were below our detection limits at the fence line which allowed for the downgrading from an Alert to a Notice of Unusual Event (NOUE) and NRC was notified at 1532. Further analysis during the day was able to better quantify the maximum levels and at 193 5 we were able to determine that all isotopes were below 50 EC, at which point we terminated the NOUE.
Discussion Initial internal and external dose assessments based on electronic personal dosimeters (EPD) worn at the time were made on the ten exposed individuals. Results showed that the maximum external dose was on the individuals leaving the control room last, being 200 mrem. Based on initial assessments, internal doses are low. Further analysis and sampling are ongoing and will be used to further refine doses to personnel.
Radiation dose monitors at the NIST fence line did not show an increase in the dose rate during this event. An analysis of all air samples taken indicate the dose at the 400m boundary as a result of this event was less than 0.5 mrem.
In a review of this event so far, indications are that no regulatory limits for NIST personnel or members of the public were exceeded, that all reactor protection systems and instrumentation performed as designed, and that personnel responded appropriately and adroitly.
Cause of Event Determination of the cause of this event is under investigation. Imaging equipment has been obtained to ascertain the state of reactor fuel. Once this is done, a root cause investigation will be performed, and corrective actions implemented before the reactor will be authorized for restart. Results of this investigation will be shared with NRC.
Please feel free to contact the undersigned if you have any questions.
Respectfully submitted, Robert Dimeo omasNewton Director Deputy Director and Chief of Reactor Operations and Engineering NIST Center for Neutron Research NIST Center for Neutron Research