ML25105A095
| ML25105A095 | |
| Person / Time | |
|---|---|
| Site: | National Bureau of Standards Reactor |
| Issue date: | 04/15/2025 |
| From: | Newton T US Dept of Commerce, National Institute of Standards & Technology (NIST) |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| Download: ML25105A095 (1) | |
Text
April 15, 2025 U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555
Subject:
Docket #50184 To whom it may concern:
VOICE (301) 975-6210 FAX (301) 975-9427 Transmitted herewith is Operations Report No. 77 for the NBSR. The report covers the period January 1, 2024 to December 31, 2024.
homas Newton Deputy Director and Chief of Reactor Operations and Engineering NIST Center for Neutron Research Enclosure cc:
Brian Lin U.S. Nuclear Regulatory Commiss.ion 11555 Rockville Pike, M/S 0-12-020 Rockville, MD 20852-2738 U.S. Nuclear Regulatory Commission ATTN: Justin Hudson One White Flint North 11555 Rockville Pike, M/S 0-12-020 Rockville, MD 20852-2738
NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY REACTOR (NBSR)
Docket #50-184 Facility License No. TR-5 Operations Report
-- #77--
January 1, 2024 - December 31, 2024 This report contains a summary of activities connected with the qperations of the NBSR. This report fulfills the requirements of section 6.7.1 of the NBSR Technical Specifications for the period from January 1, 2024 to December 31, 2024.
The section numbers in the report (such as 6.7.1(1)) correspond to the sections in the Technical Specifications.
Deputy Director, NIST Center for Neutron Research
6.7.1 (1) 6.7.1(2) 6.7.1(3) 6.7.1 (4) 6.7.1(5) 6.7.1(6) 6.7.1(7)
TABLE OF CONTENTS Summary of plant operations including the energy produced by the reactor and the hours the reactor was critical Unscheduled shutdowns, including reasons therefore Tabulation of major preventative and corrective maintenance operations having safety significance A brief description, including a summary of the safety evaluations, of changes in the facility or in procedures and of test and experiments carried out pursuant to 10 CFR 50.59 Summary of the nature and amount of radioactive effluents released or discharged to the environs and the sewer beyond the effective control of the licensee as measured at or prior to the point of such release or discharge Summary of environmental surveys performed outside the facility Summary of significant exposures received by facility personnel and visitors 2024 Operations Report for NBSR (TR-5)
[Docket #50-184]
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- 6. 7.1 (1) Summary of plant operations including the energy produced by the reactor and the hours the reactor was critical During the period January 1, 2024, through December 31, 2024, the reactor was critical for 165.1 hours1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> with a thermal energy output of 83.47 MWH (0.17 equivalent full power days). Major activities during this period included:
o Continued efforts directly involved to recoverthe reactor.
Continued operating the reactor to determine the operational impacts and to train non-licensed operators for a licensing exam.
o Training Operated the reactor at a maximum of 200 kW nominal thermal power.
A licensing exam occurred on May 06, 2024.
Shutdown the reactor on August 18, 2024 in preparation for further vessel cleaning efforts to remove fissionable debris.
Efforts to reduce the helium leakage commenced and will continue into calendar year 2025.
Performed fuel handling proficiency training for all operations staff.
Performed pre critical checks proficiency training for all operations staff.
Preformed training on reactor startups and power changes for all operations staff.
o Fuel Transfers Finished removing all fuel elements from the reactor vessel on August 2, 2024.
o Shipments No fuel shipments occurred in 2024.
6.7.1(2) Unscheduled shutdowns, including reasons therefore There were no unscheduled shutdowns in 2024.
2024 Operations Report for NBSR (TR-5)
[Docket #50-184]
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6.7.1(3) Tabulation of major preventative and corrective maintenance operations having safety significance Note: Some of these items may be also listed as Engineering Change Notices (ECN) in section 6.7.1(4).
The following list is significant I &G maintenance tasks:
32 regularly scheduled calibrations o 01/26/2024 SR-1 relay test o 03/25/2024 NC-6 o
03/26/2024 NC-4 o 03/27/2024 NC-7 o 03/28/2024 FIA-40 o
03/28/2024 LIA-40 o
03/28/2024 TRA-2 o
04/02/2024 RD3-4 o 04/04/2024 RD4-1 o
04/08/2024 RD4-2 o
04/08/2024 RD3-5 o
04/08/2024 NC-2 o 04/08/2024 BTU R o
05/14/2024 TIA-40A o
06/17/2024 RD 3-3 o
06/24/2024 RM4-5 o 06/24/2024 RM4-6 o
07/05/2024 NC-1 o 07/15/2024 NC-3 o
07/30/2024 NC-2 o 08/06/2024 PC-3 o 08/06/2024 PC-150 o
08/06/2024 PS-150 o 08/07/2024 RM1-15 o 08/08/2024 NC-5 o 08/13/2024 FRC-3 o
08/13/2024 FRC-4 o 08/27/2024 RM3-1 o 10/02/2024 PT-27 o
10/16/2024 NC-7 o
11/19/2024 LCA-19 2024 Operations Report for NBSR (TR-5)
[Docket #50-184]
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o 12/19/2024 LIA-3 The following maintenance occurred during the unscheduled/scheduled shutdowns.
o 1/03/2024 Completed replacement of #2 5k tank pump for ECN 1289.
o 1/23/2024 Unit 2 Vacuum Pump "A" was swapped with a Vacuum Scroll Pump and Unit 2 Vacuum Pump "B" Diaphragm pump was replaced due to bad seal.
o 2/06/2024 Replaced "A" diesel water pump.
o 2/08/2024 Replaced bolts on "A" and "B" diesel exhaust flanges.
o 2/08/2024 Replaced "B" diesel selector switch.
o 2/28/2024 Replaced SCV-22, #2 Strainer Inlet Valve.
o 3/06/2024 Resealed with caulk EF-5/EF-6 charcoal filter covers.
o 3/12/2024 Replaced SCV-25, HCSC Motor operated Backwash Line.
o 3/15/2024 Completed installation and testing of SCV-12 per ECN 1313.
o 3/20/2024 Replaced overheated wire and tightened terminals in electric bucket for #2 D2O shutdown pump.
o 3/26/2024 Replaced contactor for #1 Storage Pool Pump.
o 4/03/2024 Replaced SCV-28, #3 Strainer Inlet Valve.
o 4/23/2024 Repaired B-1 door after it was difficult to shut the door.
o 5/10/2024 Replaced fuel transfer hose for diesel day tank.
o 5/10/2024 Replaced alarm module EE53 for PIA-50D.
o 5/16/2024 Replaced EF-2 contactor.
o 5/20/2024 Completed MP 5.79.2 Shim Arm Maintenance: Drive Mechanism Removal &
Installation for #3 Shim Arm.
o 5/23/2024 Completed MP 5.79.2 Shim Arm Maintenance: Drive Mechanism Removal &
Installation for #4 Shim Arm.
o 5/29/2024 Completed MP 5.79.2 Shim Arm Maintenance: Drive Mechanism Removal &
Installation for #1 Shim Arm.
o 5/31/2024 Completed MP 5_792 Shim Arm Maintenance: Drive Mechanism Removal &
Installation for #2 Shim Arm.
o 6/11/2024 Repaired concrete for piping support pad by #1 Main Secondary Pump.
o 6/18/2024 Adjusted dampers on B1 for contamination control.
o 6/21/2024 Completed replacement of #1 5k tank pump for ECN 1358.
o 6/27/2024 Completed test plan for FRC-4 tripping prematurely.
o 7/05/2024 Completed ECN-1372 NC-1 Temporary Power Supply Rebuild.
o 7/09/2024 Replaced and tested COV-8 per MP 5.89.
o 7/09/2024 Replaced C 100 truck door roll up door motor.
o 7/11/2024 Replaced log signal conditioner on NC-3.
o 7/23/2024 Updated software for storage pool and C100 ARM's.
o 7/24/2024 Updated software for C200 ARM's.
2024 Operations Report for NBSR (TR-5)
[Docket #50-184]
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o 7/26/2024 Replaced NC-2 detector and cables.
o 8/28/2024 Removed upper doughnut after earlier removal of hold down tubes, shield plugs, regulator rod and VT's.
o 8/07/2024 Replaced "Control and Non-operate card (A7) on NC-5.
o 8/28/2024 Installed new 4A fuse and overload heaters for #1 5k tank pump.
o 9/2024 Commenced upgrades of NG-5, 6, and 7 per ECN-1347 NG-5 thru NG-7 Guide Upgrade Confinement Configuration, 1367 NG-5 thru NG-7 Guide Configuration Upgrade, 1368 NG-5 thru NG-7 Facility Upgrades, 1369 NG-5 thru NG-7 Neutron/Gamma Ray Shutter Upgrade, and 1370 NG-5 thru NG-7 Facility Upgrade -
Shielding Configuration Change.
o 9/04/2024-9/9/2024 Performed MP 5.69 Reactor Top Helium Leak Identification.
o 9/11/2024 Installed new 4A fuse and overload heaters for #2 5k tank pump.
o 9/30/2024 Replaced diaphragms for HEV-66 and HEV-67.
o 10/07/2024 Replaced diaphragms for HEV-6, 68, 69, 70, and 75.
o 10/08/2024 Replaced diaphragm for HEV-7.
o 10/08/2024 Changed Helium blower breakers from 15A to 7 A.
o 10/21/2024 Tested Fl-30 after removing and cleaning the Orifice Plate.
o 10/22/2024 A hole was made in the North Vestibule wall for neutron guide laser work. A metal cover was mounted on the inside of the vestibule.
o 10/28/2024 Replaced diaphragm for operator on HEV-6.
o 10/30/2024 Rethreaded truck door dogging bolts.
o 11/01/2024 Replaced ultrasonic unit for HE-1A secondary flow.
o 11/08/2024 Completed repairs on HEV-8 per MP 3.26.
o 11/19/2024 Changed #3 CT gear box.
o 11/20/2024 Replaced OEM electronic drain valves for 235-P air compressor.
o 11/22/2024 Completed installation and testing of new helium blowers per ECN 1190, MP 5.93 and TSP 4.3.1 (2).
o 11/27/2024 Disassembled, cleaned, and lubricated the lock mechanism including the tumbler plates for the process room door.
o 11/27/2024 Added gaskets to the bellows flanges for the diesels.
- 6. 7.1 (4)
A brief description, including a summary of the safety evaluations, of changes in the facility or in procedures and of test and experiments carried out pursuant to 10 CFR 50.59 There were 7 Level II Engineering Change Notifications (ECN) for which further evaluation was performed using 10 CFR 50.59.
2024 Operations Report for NBSR (TR-5)
[Docket #50-184]
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ECN 1208 ECN 1231 ECN 1330 ECN 1347 ECN 1355 This ECN installs the new Noise Monitoring System (NMS)which linear Nuclear automates the quantification of oscillations of nuclear channel Channel indications, with the aim of reducing the burden on operators and Mechanical errors due to perception differences. This ECN will also entail Anomaly Detection updating the Reactor Startup procedure that will include the NMS's System Signal-Noise Ratio (SNR) calculations in the shutdown triggers listed above.
TSP 4.1.2 currently relies on an analog calibration method. This T.S.P 4.1.2 method has been updated to a digital tool to aide the operator in Procedure Updates the calibration process. The tool significantly reduces the time and Excel Tools requirement of performing the calibrations and makes the calibration more accessible to ROE staff.
This ECN will serve to document and validate procedural changes to MP 5.79 the shaft seal replacement procedure, as well as to Shim Arm Shaft provide an engineering basis for the torque specification provided Seal Replacement in the procedure. It will also document a basis for the selection of Procedure fastener material. Regarding the extent of condition, establishing Corrections MP whether the remaining three (shim #1,2,3) shaft seals' fasteners 5.79 can be relied on for continued operation will be completed via CAP 279 Non-Conforming Item: "Over Torqued Fasteners in Shim Arm
- 1-3 Shaft Mechanical Seals". CAP 213 completes a Root Cause Analysis and other corrective actions.
A planned facility upgrade to the cold neutron facility involves NG-5 thru NG-7 replacing a major portion of the NG-5 through NG-7 neutron guide Guide Upgrade system. The new configuration, while different from what currently Confinement exists, provide redundant seals and employ only sealing methods Configuration that are functionally identical to what has been proven to be effective in maintaining confinement in the past Diesel Generator The diesel engine starting batteries will be replaced with Battery Change to commercial-grade Absorbent Glass Mat (AGM) batteries AGM Batteries and Replacement of Battery Chargers 2024 Operations Report for NBSR (TR-5)
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ECN 1180 ECN 1190 The existing system and its human machine interface (HMI} have been determined to be difficult to maintain both in short and long terms. To imf?rove the usability of these RSS critical systems, an NBSR Radiation upgrade to the area radiation monitors (ARMs} and their respective Monitoring System Data Acquisition (DAQ) system is necessary. The other radiation monitoring systems, the Effluent and Exhaust monitors, are to be integrated into this upgraded data acquisition and display system, to be referred to as the Radiation Monitoring Data Acquisition and Display System (RMDADS).
Two helium blowers, type Nash Compressor MD-673, are original plant equipment from 1967. The blowers are liquid ring seal pumps that use a circular rotor within a water-filled elliptical case. These blowers pump approximately 21 cfm (9.9 liters/sec) of helium at a Replace Blowers in discharge pressure of approximately 1 psi, in accordance with the Helium Sweep system design documentation. These blowers are equipped with a System mechanical shaft seal at the drive input. Due to limited support for a model that has been out of production since the 1980s, it is no longer possible to service this seal. The installed seals are beyond expected life and the blowers are leaking an excessive amount of D2O into the process room when operated.
2024 Operations Report for NBSR (TR-5)
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6.7.1 (5) Summary of the nature and amount of radioactive effluents released or discharged to the environs and the sewer beyond the effective control of the licensee as measured at or prior to the point of such release or discharge The table below summarizes NCNR tank releases of ~110,970 gallons, and one separate Cooling Tower Basin (aka secondary") release of ~108,000 gallons.
Slowdown releases are not considered here.
H-3(1) c.14(1)
Beta(2)
Gamma(2, 3)
Alpha(2, S)
(STDEVf2s%1) (4)
(STDEVf2s%]) (4)
(STDEV[2s]) (4)
(STDEV[2sl) (4)
(STDEV[2s]) (4) 0.302 Ci (0.001 1.6E-3 Ci (0.5E-3 21 0 µCi (50 µCi) 2 µCi (1 µCi) 8 µCi (17 µCi)
Ci)
Ci}
- 1. v,a L1qu1d Sc1nt1llahon Spectroscopy (TRI-GARB).
- 2. Gamma column is from a one-hour count on a Mirion HPGe gamma spectrometer. Beta and Alpha columns are from 15-minute counts from Tennelec/Mirion Model 6 type-instruments Beta activity includes contributions from gamma radionuclides. 'Negative* disintegration/minute values for Mirion counters are assigned the value of zero (and hence the statistics are skewed upwards).
- 3. The gamma isotope samples size was ~921 g (s - 100 g) in 1000 ml Marinelli beakers. The 2024 total activities of detected gamma emitters were, in decreasing order, Co-60, Ce-144/Pr-144, and Cs-137.
- 4. STDEV refers to the average propagated standard deviation using an Excel" function. For Alpha and Beta activity, 2s is two times the standard sigma function. For H-3 and C-14, 2s% refers lo a Packard/Perl<in Elmer industry standard function, where 2s% is the percent uncertainty in a gross count value (with 95% confidence limits), or 2s% = (100 X 2 X s)I (Total Counts).
- 5. Alpha has historically been attributed to natural background Gaseous releases from the NBSR Reactor Stack for the Calendar year of 2024 included Tritium (H-3), Argon-41 (Ar-41) and gaseous fission products. These releases are summarized in the table below.
The reactor startups in 2024 were done for the purpose of low power testing but also to give reactor operators and trainees time on the console. Two hundred kilowatts is the highest power level that the reactor achieved during this testing.
2024 total Activit* Releases from the Reactor Stack Gaseous Effluents (Ci)
H-3 Ar-41 361 2.28 0.084 0.352 0.297 0.045 0.567 H-3 releases were calculated in the usual manner, a routine (as often as weekly) reactor stack cold trap.
Ar-41 releases are calculated based on the reactor stack monitoring system that employs a GM tube in the stack that reports back to a Ludlum 375. With the addition of gaseous fission products (attributed to tramp uranium in the reactor vessel because of the February 3, 2021 incident) in the effluent not usually seen in past years of reactor operations, a fraction of the counts seen in the stack monitor can be attributed to the fission products and not Ar-41. As a conservative estimate, the full counts were used to 2024 Operations Report for NBSR (TR-5)
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determine the Ar-41 releases without any attempt to account for counts from fission products. This method is considered an overestimation of the Ar-41 released and is done to assure compliance with NRC release limits.
In the past, fission product releases were measured using reactor stack charcoal and particulate filter analysis. The analysis of these filters in 2024 showed no detectable isotopes. Stack Marinelli grab sampling was also conducted on various days for the purpose of identifying and quantifying gaseous fission products. These Marinelli samples were taken after the reactor had reached an equilibrium state at maximum power level for the day just prior to reactor shutdown. Marinelli sampling was conducted on multiple days but not on all days that the reactor had restarted. Samples were collected at every novel power level. On days where a sample wasn't collected, a previous day's data was used to estimate fission product release that had been measured at the same power level. Total release activities for fission products were calculated for each day the reactor was operated. As a conservative estimate the maximum concentrations measured are used to estimate the releases based on the time frame where counts in the reactor stack monitoring system were seen above background after reactor startup to the time where they fell back to background levels after the reactor was shut down. This method is considered an overestimation of the fission products released and is done to assure compliance with NRC release limits.
An analysis of this effluent release was performed using the EPA COMPLY Code software. This analysis showed that the effective dose to a member of the public would be no greater than 5.2E-2 mrem for the year.
It is noted that two errors were discovered in the 2023 report. The first error involved the total Argon-41 release for 2023. The value given in the original memo stated the amount to be 0.298 Ci when the real value was 23.4 Ci. The second error involves the release value for Ar-41 used in the 2023 EPA COMPLY report. A value of 29.8 Ci was used in generating the EPA COMPLY report and not the true value 23.4Ci. The original Effective dose equivalent from the 2023 COMPLY report was 0.1 mrem/yr. The EPA COMPLY code was rerun using 2023 release data including the true value for Ar-41 and the Effective dose equivalent calculated did not change.
2024 Operations Report for NBSR (TR-5)
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6.7.1(6) Summaries of environmental surveys performed outside the facility Below are the environmental results for 2024 NIST Environmental Sample Anslysis Resu/t3 for 2024 Cs-137 Month typical mda =>>
8.00E-09 8.00E-09 2.00E-08 2.00E-08 Soil Be-7 Cs-137 The typical MDA is an estimate made by viewing the MDAs for each count Co-60 Zn-65 9.00E-09 3.00E-08 Except for 1*131 (short halflife) there is not a large variation in the MDAs for each nuclide Water 1-131 Cs-137
µGeml None Det.
None Del.
None Det.
None Det.
None Det.
None Det.
None Det.
None Det.
None Det.
None Det.
None Del.
None Det.
B.OOE-10 Co-60 Zn-65 1-131
µCi/ml
µCerni uCi/ml None Det.
None Det.
None Det.
None Det.
None Det.
None Del.
None Det.
None Del.
None Oet.
None Det.
None Det.
None Det.
None Del.
None Det.
None Det.
None Del.
None Det.
None Det.
None Det.
None Det.
None Del.
None Oet.
None Det.
None Det.
None Det.
None Del.
None Det.
None Del.
None Det.
None Det.
None Det.
None Del.
None Del.
None Det.
None Det.
None Det.
6.00E-1 0 2.00E-09 1.00E-09 6.7.1(7) Summaries of significant exposures received by facility personnel and visitors Dosimetry results:
The exposure reports have not been finalized as of April 3, 2025. This section will be amended, and the Annual Report will be resubmitted when the exposure reports are complete.
2024 Operations Report for NBSR (TR-5)
[Docket #50-184]
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