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| | issue date = 07/31/2012 | | | issue date = 07/31/2012 |
| | title = U.S. Geological Survey Triga Reactor - Response to Question 21 of the Referenced RAI Dated September 29, 2010 | | | title = U.S. Geological Survey Triga Reactor - Response to Question 21 of the Referenced RAI Dated September 29, 2010 |
| | author name = DeBey T | | | author name = Debey T |
| | author affiliation = US Dept of Interior, Geological Survey (USGS) | | | author affiliation = US Dept of Interior, Geological Survey (USGS) |
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Category:Letter
MONTHYEARIR 05000274/20232022023-11-13013 November 2023 U.S. Geological - U.S. Nuclear Regulatory Commission Safety Inpsection Report No. 05000274/2023202 IR 05000274/20232032023-11-0909 November 2023 United States Geological Survey - U.S. Nuclear Regulatory Commission Security Inspection Report No. 05000274/2023203 (Public) IR 05000274/20232012023-02-27027 February 2023 United States Geological Survey - U.S. Nuclear Regulatory Commission Routine Inspection Report No. 05000274/2023201 ML22026A4852022-03-0707 March 2022 Examination Confirmation Letter No. 50-274/OL-22-01, United States Department of Interior Geological Survey ML22053A1872022-02-22022 February 2022 U.S. Geological Survey Triga Reactor, Docket Number 50-274, License Number R-113, Reactor Administrator Succession IR 05000274/20212022021-10-0101 October 2021 U.S. Geological U.S. Nuclear Regulatory Commission Safety Inspection Report No. 05000274/2021202 IR 05000274/20212032021-09-30030 September 2021 United States Geological Survey - Nuclear Regulatory Commission Security Inspection Report No. 05000274/2021203 IR 05000274/20202012021-04-21021 April 2021 United States Geological Survey, U.S. Nuclear Regulatory Commission Routine Inspection Report05000274/2020201 - Cover Letter and Enclosure ML21090A1912021-03-29029 March 2021 U.S. Geological Survey Triga Reactor, Annual Report Submittal in Accordance with Technical Specification 6.7.1 Rev. 00 ML21082A2822021-03-23023 March 2021 Letter to R. Horton, USGS Denver Federal Center, from B. Smith, NRC, NRC Office of Investigations Report No. 4-2019-014 - Release of OI Synopsis IR 05000274/20212012021-03-12012 March 2021 U.S. Geological Survey NRC Non-Routine Inspection Report 05000274/2021201 ML20314A2922020-12-0303 December 2020 USGS Issuance of Amendment No. 14 to Renewed Facility Operating License No. R-113 for the USGS Triga Research Reactor Increasing the Special Nuclear Material Possession Limit ML20336A0202020-12-0101 December 2020 U.S. Geological Survey Triga Reactor - License Amendment Request LAR 14, Supplemental Information Letter 04 Provided in Response to Phone Call with NRC Project Manager at 0854 Mst on 2020-11-30 ML20295A4242020-11-16016 November 2020 Notification of Mailing Address Change Regarding Submittal of Fingerprint Cards ML20310A3352020-11-0505 November 2020 U.S. Geological Survey Triga Reactor, Docket Number 50-274, License Number R-113, Updated Physical Security Plan, Rev. Xxi ML20310A2962020-11-0505 November 2020 U.S. Geological Survey Triga Reactor, Docket Number 50-274, License Number R-113, License Amendment Request LAR 14, Supplemental Information Letter 03 Provided in Resolution of Comments Presented by the State of Colorado During the Public M ML20296A4902020-10-22022 October 2020 U.S. Geological Survey Triga Reactor, Docket Number 50-274, License Number R-113, License Amendment Request LAR 14, Supplemental Information Letter 02 Provided in Response to Audit Visit on 2020-10-15 ML20318A0882020-10-22022 October 2020 U.S. Geological Survey Trig a Reactor, License Amendment Request LAR 14, Supplemental Information Letter 01 Provided in Response to Audit Visit on 2020-10-15 Purpose ML20295A5102020-10-21021 October 2020 U.S. Geological Survey - Regulatory Audit Report Proposed License Amended No. 14 to Increase the Special Nuclear Material Possession Limit ML20233A9962020-10-0909 October 2020 Us Geological Survey - Issuance of Amendment No. 13 to Renewed Facility Operating License No. R-113 to Amend Technical Specifications 3.1.3 and 4.1 for the Us Geological Survey Triga Research Reactor ML20279A5912020-10-0606 October 2020 U.S. Geological Survey - Regulatory Audit Proposed License Amendment No. 14 Tt Increase the Special Nuclear Material Possession Limit ML20279A3052020-10-0505 October 2020 U.S. Geological Survey - Acceptance of the Application for Proposed License Amendment No. 14 Increase in the Special Nuclear Nuclear Material Possession Limit ML20275A2672020-10-0101 October 2020 U.S. Geological Survey Triga Reactor, Docket Number 50-274, License Number R-113, License Amendment Request 2020-02, LAR 14, Rev. 00 ML20199M1672020-07-20020 July 2020 NRC Letter and SER Authorizing USGS to Use an Alternate A2 Value ML20183A1622020-07-0202 July 2020 U.S. Geological Survey - Acceptance of the Application for a License Amendment Exception to TS 3.1.3 and 4.1 to Allow Fewer than 110 Fuel Elements When Either Shutdown or Operating at a Power Level Not Greater than 5 Kilowatts ML20177A6102020-06-25025 June 2020 U.S. Geological Survey Triga Reactor, Docket Number 50-274, License Number R-113, License Amendment Request 2020-01, Supplemental Information Provided in Response to ML20176A465 ML20161A1272020-06-0404 June 2020 U.S. Geological Survey Triga Reactor, Docket Number 50-274, License Number R-113, License Amendment Request 2020-01, Revision 01 ML20134J1082020-05-13013 May 2020 U.S. Geological Survey Triga Reactor, Docket Number 50-274, License Number R-113, License Amendment Request 2020-01 ML20157A0752020-05-0707 May 2020 U.S. Geological Survey Triga Reactor, Docket Number 50-274, License Number R-113, Reactor Supervisor Appointment ML20136A3362020-04-21021 April 2020 Us Dept. of Interior, Geological Survey (Usgs), Submittal of Corrected 2019 Annual Report ML20134J1162020-04-10010 April 2020 7 of the Emergency Plan for the U.S. Geological Survey Triga Reactor (Gstr) Facility (License R-113, Docket 50-274) ML20087H0192020-03-0202 March 2020 Us Dept of Interior, Geological Survey (USGS) - Submittal of 2019 Annual Report ML19206A0622019-07-11011 July 2019 Us Dept of the Interior, Us Geological Survey Follow-Up on August 9, 2018 Letter Request for Approval for Use of Alternative A2 Value for Isotope Br-80m Under Appendix a to 10 CFR 71 ML19066A0542019-02-25025 February 2019 U.S. Dept of the Interior, Geological Survey, Reply to a Notice of Violation: EA-18-031 and EA-18-111 ML19044A3732019-01-31031 January 2019 Us Dept. of Interior, Geological Survey - Submittal of 2018 Annual Report ML18354B1702018-12-31031 December 2018 U.S Geological Survey-Notice of Violation and Proposed Imposition of Civil Penalty ML18324A5752018-11-16016 November 2018 United States Geological Survey (Usgs), Transfer of Reactor Supervisor Responsibilities. Position of Reactor Supervisor for Triga Facility Has Been Transferred from Mr. Brycen Roy to Mr. Christopher Farwell, Effective October 26, on Interim ML18324A5742018-11-16016 November 2018 United States Department of the Interior - Transfer of Reactor Administrative Responsibilities ML18325A1462018-11-0707 November 2018 U.S. Dept. of Interior, Geological Survey - Response to Apparent Violations Associated with NRC Investigation Reports 4-2017-027 and 4-2018-005; IA-18-038 IR 05000274/20182022018-08-15015 August 2018 United States Geological Survey - U.S. Nuclear Regulatory Commission Routine Inspection Report No. 50-274/2018-202 ML18236A5512018-08-0909 August 2018 Request for Approval for Use of Alternative A2 Value for Isotope Br-80m Under Appendix a to 10 CFR 71 IR 05000274/20182032018-07-17017 July 2018 United States Geological Survey - U.S. Nuclear Regulatory Commission Security Inspection Report 05000274/2018203 ML18016A0512018-01-11011 January 2018 2017 Annual Report for the U.S. Geological Survey Triga Non-Power Reactor Facility ML17355A1472017-12-18018 December 2017 Establishing a Quality Assurance Program at the U.S. Geological Survey Triga Reactor Facility (License R-113, Docket 50-274) IR 05000274/20172012017-05-17017 May 2017 United States Geological Survey NRC Routine Inspection Report No. 50-274/2017-201 ML17074A6472017-04-19019 April 2017 United States Geological Survey TRIGA Reactor Closure of Confirmatory Action Letter No. NRR-03-005 on Site-Specific Compensatory Measures Implementation Plan ML17067A3942017-03-22022 March 2017 U.S. Geological Survey - Non-Power Reactor Closeout of Generic Letter 2016-01, "Monitoring of Neutron Absorbing Materials in Spent Fuel Pools," for the U.S. Geological Survey Training Reactor And Isotopes Production, General Atomics Research Reactor ML17046A3632017-02-17017 February 2017 Examination Report No. 50-274/OL-17-01, United States Geological Survey ML17030A0362017-01-0909 January 2017 Us Dept. of the Interior, Geological Survey - Submittal of 2016 Annual Report ML16326A1462016-12-0101 December 2016 Us Geological Survey - Amendment No. 11 to Indemnity Agreement Amendment No. D-10 2023-02-27
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Text
E"USGS science for a changing world Department of the Interior US Geological Survey PO Box 25046 MS 974 Denver, CO 80225-0046 July 31, 2012 U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555
Reference:
U.S. Geological Survey TRIGA Reactor (GSTR), Docket 50-274, License R-113, Request for Additional Information (RAI) dated September 29, 2010
Subject:
Response to Question 21 of the Referenced RAI Mr. Wertz: Question: 21. GSTR TS Section 14.2.2, "Limiting Safety System Setting," states that the limiting safety system setting shall be a steady state thermal power of 1.1 MW when there are at least 100 fuel elements in the core (including fuel-followed control rods) and a steady state thermal power of 0. 1 MW if there are less than 100 fuel elements in the core and any of the core fuel elements are aluminum-clad.
Please explain or clarify the following observations:
21.1 Please explain whether the statement should read "or any of the core fuel elements are aluminum-clad." 21.2 The LSSS discusses "steady state" power whereas the subject of the LSSS is the limiting power to be used for automatic protective circuits.
Please explain.21.3 License Amendment 4 (January 1988) eliminated the allowance to exceed licensed power for purposes of testing SCRAM circuits.
The safety analysis presented in the GSTR SAR provides no basis for an LSSS above 1.0 MW.Response: Preliminary results of the neutronic/thermal hydraulic analyses show that the most limiting core, with aluminum-clad fuel in the F and G rings, will not exceed any safety limits if at least 110 fuel elements are present in the core. The GSTR currently operates with about 123 fuel elements in the core and there is no reasonable expectation that this will decrease by any significant amount. The original proposed limit of 0.1 MW when the core has <100 fuel elements in the core seems to be confusing and causing significant additional analyses, so we will be changing M our submission to require that the GSTR core always have at least 110 fuel elements in the core, for any operation.
The safety analyses will be performed for a limiting core configuration of 110 fuel elements and a maximum analyzed power of 1.1 MW. The details of this submission cannot be finalized until the neutronic/thermal hydraulic analyses are finished.
This change should eliminate the RAI questions 21.1 through 21.3.Neutronic/thermal-hvdraulic analysis: The most recent update (mid-July, 2012) for the neutronic/thermal hydraulic analyses is provided as an attachment to this document.
This update infers that the full-power model analyses may be completed in August. In a recent verbal discussion with the CSM principal investigator, it was felt that answers to all existing RAI questions could be provided to the NRC by the end of August. Accordingly, we do not expect to need another extension on our RAI response deadline at this time.Sincerely, ADe Tim DeBey USGS Reactor Supervisor I declare under penalty of perjury that the foregoing is true and correct.Executed on 7131112 Attachment Copy to: Betty Adrian, Reactor Administrator, MS 975 USGS Reactor Operations Committe Safety Analysis Support for the USGS Research Reactor Battelle Energy Alliance Award #00114253 (CSM # 400305)June 2012 Progress Report -Revised Nicolas Shugart and Jeffrey King Work this June focused on the RELAP model and re-defining the GSTR limiting core. The RELAP model is very sensitive to the gap thickness between the fuel and cladding.
The model uses a RELAP defined material for the cladding gas, which provides a very conservative temperature rise across the gap. Decreasing the size of the gap lowers the fuel temperature in the model, and adjusting the gap thickness to match the model's temperature to experimental data from the GSTR corrects the gap material bias. The thermocouples available at the GSTR have a temperature uncertainty of at least +/-30 K, which makes an accurate validation difficult.
Alternative methods of validation the RELAP model are under consideration.
The first first version of the RELAP model used the published gap thicknesses
(-0.5 mm) as a worst-case scenario, and provides very conservative temperature approximations.
Analyzing the limiting core under these conditions predicts fuel temperatures in excess of 1000 K for the hot-rod of the GSTR limiting core. Further analysis of the literature produced by OSU and other TRIGAs using similar RELAP models indicates that a much smaller gap (0.1 mm) accurately characterizes TRIGA fuel.With a 0.1 mm gap, the predicted fuel temperatures for the limiting core still exceed the established limits, so the identification of a new limiting core is underway based on three criteria: an excess reactivity limit of $7.00, a minimum fuel rod number (to be determined), and filling both the B and C rings with fresh 12 wt% uranium fuel. To further define the new limiting core, fuel outside of the B and C-Rings would be old 8.5 wt% uranium fuel (at various stages of burnup), to promote a peaked core. These criteria lead to two possible limiting cores, a 110-element and a 105-element core. While both of these options maintain a high power factor in the hot-rod, the extra elements decrease the rod power to -20 kW (compared to -27 kW for the previous limiting core containing 80 fuel elements).
This should allow the hot rod to function safely during normal operations.
The GSTR staff has no strong preference on which limiting core to use, which prompted the analysis to focus on the 110-element core, which has a slightly lower rod power, and therefore a lower chance of fuel damage.Part of the new limiting core analysis will included an examination of the dependence of the reactivity feedback coefficients on core configuration.
These analyses will be completed in July, and the limiting core will be ready for the final stage of the re-licensing analysis:
the transient analysis using the PARET code.