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MONTHYEARML0703600122007-01-31031 January 2007 E-Mail from W. Kennedy to Dr. Richards of NIST Transmitting the Draft Rais for Re-Licensing of the Nbsr, Docket No. 50-184 (TAC No. MD 3410) Project stage: Draft RAI ML0703200102007-02-0202 February 2007 National Institute of Standards and Technology Test Reactor (Nbsr) - Draft Request for Additional Information (Rai), Regarding Amendment Request for Re-Licensing Project stage: Draft RAI ML0704400432007-02-13013 February 2007 Request for Additional Information Regarding the National Institute of Standards and Technology Test Reactor Application for Re-Licensing Project stage: RAI ML0818302942008-07-0101 July 2008 Request for Additional Information Regarding the National Institute of Standards and Technology Test Reactor Application for License Renewal Project stage: RAI ML0822802192008-08-25025 August 2008 Request for Additional Information Regarding Financial Qualifications and Decommissioning Funding for the National Institute of Standards and Technology Test Reactor Application for License Renewal Project stage: RAI ML0835107542008-09-12012 September 2008 NIST Response to NRC Request for Additional Information (TAC No. MD3410) Dated 07/01/2008 Project stage: Response to RAI ML0828903382008-09-16016 September 2008 NRC Request for Additional Information Re Revised Nbsr Technical Specifications and Nbsr Emergency Plan Project stage: Request ML0830302092008-10-21021 October 2008 Response to NRC Request for Additional Information Financial Qualifications and Decommissioning Funding for the Test Reactor Application for License Renewal Project stage: Response to RAI ML0832307102008-11-19019 November 2008 Request for Additional Information Regarding Emergency Planning for the National Institute of Standards and Technology Test Reactor License Renewal Project stage: RAI ML0903707372009-02-18018 February 2009 National Institute of Standards and Technology Test Reactors - Request for Additional Information Operator Requalification Program Project stage: RAI ML0907001322009-03-0303 March 2009 Us Dept. of Commerce, NIST, Response to Request for Additional Information on Operator Requalification Program Project stage: Response to RAI ML0906100612009-03-0303 March 2009 National Institute of Standards and Technology Test Reactor - Request for Additional Information Advisory Committee on Reactor Safeguards Subcommittee Meeting Follow-up Items (Tac MD3410) Project stage: RAI ML0908903272009-03-19019 March 2009 Submittal of Response to Request for Additional Information Regarding Advisory Committee on Reactor Safeguards Subcommittee Meeting Follow-Up Items and the Revised Nbsr Technical Specifications Project stage: Response to RAI ML0911904642009-04-22022 April 2009 Memo to Bill Kennedy in Response to ACRS Question (April 2, 2009 Meeting) Project stage: Meeting ML0911904512009-04-22022 April 2009 NIST Response to ACRS Question Project stage: Other ML0911700022009-07-0202 July 2009 National Institute of Standards and Technology, Notice of Issuance of Renewed Facility Operating License No. TR-5 Project stage: Approval 2008-08-25
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Category:Graphics incl Charts and Tables
MONTHYEARML22206A0112022-08-0101 August 2022 NIST Supplemental Inspection Table (Attachment) ML0911904642009-04-22022 April 2009 Memo to Bill Kennedy in Response to ACRS Question (April 2, 2009 Meeting) ML0703306132006-07-31031 July 2006 NIST Environmental Available Data from NIST Weather Station Since 2002 2022-08-01
[Table view] 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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MEMORANDUM April 22, 2009 To: Mr. Bill Kennedy Program Manager NIST/NBSR From: Dr. Wade J. Richards Chief, Reactor Operations and Engineering
Subject:
Response to ACRS Question (April 2, 2009 Meeting)
During our analysis of an accident postulated by the ACRS (accidental closing of the valve in the reactor outlet line, DWV-19), we became aware of a possible problem in our original analysis of the transient related to a loss of off-site power. In that analysis, a coast-down curve was derived within RELAP, based upon pump characteristics and the flow geometry. This curve was compared to a coast-down curve measured before initial reactor criticality, and shown to be conservative. However, the original curve was not measured under conditions appropriate to the accident being analyzed.
In the figure below, the flow for the initial few seconds of the new curve is compared to that used in the prior analysis. It should be noted that the minimum Critical Heat Flux Ratio (CHFR) occurs during this time period.
In order to address this issue, the primary coast-down curves were recently measured under various conditions, including the limiting case of no shut-down pump starting. The measured curve for the limiting case was ten used to derive a model as input to RELAP for complete re-analysis of the accident scenarios explored in the original analysis.
From the figure, it is clear that the two curves are almost identical for the first 3 seconds, and this fact is reflected in the analysis using RELAP. The minimum CHFR occurs in the outer plenum approximately 1.5 s after the primary pumps trip, and is 2.17 as compared to 2.19 previously. This result is a direct consequence of the comparison shown in Fig. 1, which is in turn a measure of the conservatism in the coast-down curve used in the prior analysis. It should be noted that the present curve is a conservative representation of the measured curve, and that there is substantial conservatism in the new result (arising from non-local deposition of fission power, neglect of clad and meat thermal conductivity, changes in the distribution of heat deposition for fission product decay, and other terms).
The result of the Loss of Offsite Power accident analysis (and by extension, the Loss of Both Shutdown Pumps) is nearly identical to the initial analysis.
The reactor scram was initiated by low flow to the outer plenum 1.4 seconds after the loss of power. The maximum fuel centerline temperature is 410 K, which occurs at the hot spot at the top of the hottest element in the outer core at the time of the scram. Long term cooling in the case of failed shutdown pumps is bounded by the case of the closure of DWV-19, in which the flow drops to zero just 4 seconds after the scram.
In summary, the new analysis, which is conservative, confirms the earlier analysis and the results presented in the Safety Evaluation Report. It will be included in the revised FSAR, as will all the responses to the previous RAI.
Figure 1. Comparison of the coast-down curve used in the prior analysis to that determined from new measurements.