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Category:Letter
MONTHYEARML24092A1542024-04-0404 April 2024 U.S. Geological Survey - Change of Facility Project Manager ML24092A0422024-03-28028 March 2024 U.S. Geological Survey Triga Reactor Annual Report Submittal in Accordance with Technical Specification 6.7.1 Rev. 00 for 2023 IR 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 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 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 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 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 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 2024-04-04
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S-USGS science for a changing world Department of the Interior US Geological Survey PO Box 25046 MS 974 Denver, CO 80225-0046 January 27, 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 18 of the Referenced RAI Mr. Wertz: Question 18: GSTR SAR Subsection 13.2.5.2 uses a gap release fraction of 1.22x10-4 which is higher than the gap release fraction used in GSTR SAR Subsection 13.2.1.2 for the MHA (1.66x10 5). Please provide an analysis using a consistent gap release fraction.Response:
The Geological Survey TRIGA Reactor (GSTR) Safety Analysis Report (SAR) section 13.2.5.2 calculates the dose to members of the public and GSTR staff in the reactor bay during an accident scenario where the fuel cladding fails in the water. The analysis included work shown in section 13.2.1.1, which was updated in response to RAI question 15.3. Section 13.2.5.2 over-conservatively assumed a fuel temperature of 500 0 C to calculate the gap release fraction; which is unrealistically too high and should actually be the same temperature that was used in section 13.2.1.1 of 350 0 C. The corresponding calculations and explanations are given below in the newly revised section 13.2.5.2, using a consistent gap release fraction of 1.66x10s.13.2.5.2 Accident Analysis and Determination of Consequences All three scenarios mentioned in the previous paragraph result in a single fuel element failure in water.In the unlikely event that this failure occurred in air, it would be the MHA analyzed in Section 13.2.1.2.At various points in the lifetime of the GSTR, fuel elements are moved to new positions or removed from the core. Fuel elements are moved only during periods when the reactor is shutdown.Assumptions for this accident are almost exactly the same as those used for the MHA, except for one thing: the pool water will retain mostof the halogens, resulting in a significant reduction in the halogen dose contribution.
The assumptions for this accident and the method of analysis of this accident Were described in Section 13.2.1.2.
The results for this accident (with water in tank) are given in Tables 13.13 to 13.14.The results of this accident show that under all possibilities the radiation doses to the general public are well below the annual limits in 10 CFR 20, with the maximum dose being 0.015 mrem TEDE at 250 meters from the exhaust stack, for the worst case scenario.
The occupational radiation doses to workers in the reactor room are also well below the occupational annual limits in 10 CFR 20, with the maximum dose being 260 mrem TEDE for a 5-minute exposure.
Five minutes is more than enough time for workers to move the 30 feet or less to evacuate the room if such an accident were to occur.Table 13.13: Occupational CDEThyroid and TEDE in the Reactor Room Following a Single Element Failure in Air and Water Reactorg Rom<2 CEhrod TD CDhyoidoi TED (wtr Occupancy
~ (no water)V (n~o (iwater) TD(rn tern)K (minutes) (mrem) ywater) ...em 2 1534 263 77 0 5 3835 657 192 260 Table 13.14: Radiation Doses to Members of the General Public Following a Single Element Failure in Water Distance CDEThyroid TEDE ( m) I! ( mrem ) (m rem )1 (T 10 0.0 0.0 50 1.6e-8 2.9e-9 100 7.0e-3 1.2e-3 150 0.048 8.3e-3 200 0.078 0.013 250 0.088 0.015 300 0.087 0.014 350 (fence) [ 0.080 0.013 640 (residence) 0.041 6.4e-3 720 (school) 0.035 5.3e-3 Since most of the halogens released from the fuel element will be retained in the primary water, the majority of this activity will end up in the demineralizer tank. The exposure rate from the demineralizer tank can be estimated by DR = 6CEN (R/h at 1 foot), (13.19)where: C = number of halogen curies retained in the demineralizer tank (Ci);E = energy of gamma rays (MeV) = 1; and N = number of gamma rays per disintegration
= 1.
From Table 13.1, the total saturated activity of the halogens is 5,805 curies. Of this, 1.66 x 10-5 is released to the gap (from equation 13.1 using a fuel temperature of 350'C), 0.5 of the gap activity is released to the water, and 0.95 of this remains in the water. Thus, the number of curies retained in the demineralizer tank is 0.046 Ci. The assumption that the average energy of the gamma rays from the halogens is 1 MeV is conservative.
Thus, the dose rate equals 0.27 R/hr at one foot.Surrounding the sides of the GSTR demineralizer tank is 0.5 inch of lead (no shielding on top). The mass attenuation factor for lead is 0.0708 cm 2/g, and the density of lead is 11.34 g/cm 3 [1]. The overall attenuation factor for the lead shield is about 0.361. This reduces the exposure rate to about 97.4 mR/hr at one foot.A fuel loading error is another potential way that a fuel element might overheat and result in a cladding failure. The GSTR Technical Specifications require that if a core containing aluminum-clad fuel is used, the aluminum-clad fuel must be in the outer two rings of the core grid. Loading aluminum-clad fuel in the inner rings of the core could potentially result in cladding failure due to dimensional changes of the element during accident conditions.
[1] Radiological Health Handbook, Revised Edition, U.S. Department of Health, Education, and Welfare, U.S. Government Printing Office, 1970, pp.137-140.
Sincerely, Tim DeBey USGS Reactor Supervisor I declare under penalty of perjury that the foregoing is true and correct.Executed on 1/27/12 Copy to: Betty Adrian, Reactor Administrator, MS 975 USGS Reactor Operations Committee