ML23118A228

GEH - Annual Nuclear Test Reactor (Ntr) Operating Report for the Year 2022

ML23118A228
Person / Time
Site:	Vallecitos Nuclear Center
Issue date:	04/27/2023
From:	Smyly J GE-Hitachi Nuclear Energy Americas
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
M230061
Download: ML23118A228 (1)

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( . HITACHI GE Hitachi Nuclear Energy Jeffrey Smyly Regulatory Compliance Manager 6705 Vallecitos Road Sunol, CA 94586 M230061 USA April 27, 2023 T 925-918-6074 Jeffrey.Smyly@ge.com U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555-001

Subject:

GEH Annual Nuclear Test Reactor (NTR) Operating Report for the Year 2022

Reference:

NRC License R-33, Docket 50-73 (NTR)

Enclosed is the Annual Operating Report No. 63 for the GE Hitachi Nuclear Test Reactor (NTR) located at the Vallecitos Nuclear Center in Sunol, California.

If there are any questions regarding this report or additional information required, please contact me at the number above.

Sincerely, Digitally signed by Jeff Smyly DN: cn=JeffSmyly gn=JeffSmyly c=US Jeff United States I=US United States o=GEH ou=VallecHos Nuclear Center Regulatory Compliance e=jeffrey.smyly@ge.com Smyly Reason:lamapprovinglhisdocumenl Location:

Date:2023-04-28 08:48-07:00 Jeffrey Smyly Regulatory Compliance Manager Vallecitos Nuclear Center Attachments: 1) NTR Annual Operating Report Number 63 for the year 2022 cc: D. Hardesty, NRC NRR JS23-005

GE Hitachi

• HITACHI Nuclear Energy Vallecitos Nuclear Center 6705 Vallecitos Rd Sunol, CA 94586 USA NUCLEAR TEST REACTOR ANNUAL REPORT NO. 63 FOR THE YEAR 2022 LICENSE R-33 DOCKET 50-73 APRIL 27, 2023

NTR Annual Report No. 63

• HITACHI April 27, 2023 GE Hitachi Nuclear Test Reactor Annual Report No. 63 This report summarizes the operations, changes, tests, experiments, and major maintenance at the GE Hitachi (GEH) Nuclear Test Reactor (NTR), which were authorized pursuant to LicenseR-33, Docket 50-73, and 10 CFR 50, Section 50.59, for the period of January 1, 2022 through December 31, 2022.

I. General Specific information about the operation of the NTR during the reporting period is presented as follows:

1. In 2022 there were 166 reactor startups with the reactor operating at or above critical for 342.15 hours1.736111e-4 days <br />0.00417 hours <br />2.480159e-5 weeks <br />5.7075e-6 months <br />. Total power generation equaled 334.24 EFPH; equivalent to 1.393 MW days. The majority of this time was spent in the performance of approved experiments, either neutron radiography or small sample irradiations.

2. The highest radiation exposure to any worker at NTR was 0.484 Rem.

3. There were three unscheduled shutdowns of the reactor in 2022 and nine unscheduled shutdowns prior to criticality. See section V.A. for details.

4. URI 05000073/2022-01 was opened as a result of the annual NRC Safety Inspection performed Feb-Mar 2022. The URI relates to potentially failing to meet the minimum staffing requirements of Technical Specification (TS) 6.1.3.1 while the reactor was not secured lAW TS 1.2.20.2 during Safety Rod #4 disassembly/maintenance work. See section V.B. for details.

II. Organization The details of changes in the status of personnel and operator licenses, which occurred during the reporting period, are described as follows:

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NTR Annual Report No. 63

• HITACHI April 27, 2023 A. Personnel

1. The Levell & 2, and the Vallecitos Nuclear Center (VNC) Site Regulatory Compliance managers were unchanged in 2022.

2. The Facility Level 3 Manager was reassigned within GEH and replaced on an interim basis by a qualified on-site manager on April18, 2022.

3. A recently hired VNC Site Manager permanently assumed the duties of Facility Level 3 Manager on January 1, 2023.

B. Operator Licenses

1. On April 25, 2022, an internal candidate was designated an NTR Reactor Operator trainee.

2. On May 5, 2022, a senior reactor operator ended their employment with GEH and their operator license was terminated. License number SOP-503989.

Ill. Facility Changes, Tests, Experiments, and Procedure Changes Approved by the Facility Manager In accordance with written procedures, facility manager approval is required for changes to the facility, procedures, tests, and experiments. Specific information about the reporting period is presented as follows:

A. Facility Changes There were two facility Change Authorizations (CA) implemented in 2022 requiring Facility Manager and Regulatory Compliance approval.

1. CA-320 Minor modifications were made to the Safety Rod Magnet (SRM) drawing to make manufacturing and assembly easier. Drawing 6618671 Rev 3 was generated and used to fabricate spare magnets. The Vallecitos Technological Safety Council (VTSC) reviewed the CA.

2. CA-323 Thermopiles used to sense differential temperature across the reactor core, were retired in place and no longer used for the reactor operation heat balance calculations. Thermocouples TC2 and TC5 will provide input to heat balance calculations and were replaced with units capable of being calibration checked at the required periodicity.

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• HITACHI April 27, 2023 B. Tests Pursuant to 10 CFR 50.59(a), no special tests were performed during 2022.

C. Experiments Pursuant to 10 CFR 50.59(a), two previously approved experiment types were performed in 2022.

1. Experiment types described as neutron radiography and slide sample irradiations, were properly authorized utilizing experiment authorization forms throughout 2022.

D. Procedure Changes Pursuant to 10 CFR 50.59, fifteen procedural changes were initiated during 2022 to incorporate editorial or typographical corrections, technical data, and changes to requirements, or to provide for the addition or clarification of information and reliability of performance. Changes were made with Facility Manager and Regulatory Compliance review when required. A summary of the changes is presented in the table below.

Revision Procedure Summary of Changes 1 SOP 1.1, Primary Added symptoms of air in the primary and updated Cooling System figures to reflect recently installed valves.

1 SOP 1.3, Primary Added precautions to ensure correct Radiation Work Coolant Water Permit is used when drawing primary coolant samples.

Chemistry 2 SOP 2.7, Process Added statements retiring use of the thermopiles.

Instrumentation 3 SOP 6.4, Daily Removed references to non-existent procedure steps.

Surveillance Check Sheet 3 SOP 6.5, Monthly Removed thermopile reference. Added comparison of Surveillance Check thermocouple temperatures when shutdown.

Sheet 1 SOP 6.7, Startup Added precaution to ensure primary pump is running Summary before exceeding 100 watts during reactor startup. See section V.A.2.

2 SOP 6.8, Control Room Changed input to heat balance equation from Data Sheet thermopiles to TC2 I TC5. Other administrative changes.

1 SOP 9 .2, Standard Added clarifications on 1) NTR SOP chapters not Operating Procedures applicable to 50.59 review, 2) usage of a Change Pa e 3 of9

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• HITACHI April 27, 2023 Authorization to document 50.59 screenings, and 3) inclusion of a non-applicability statement in revised procedure's Revision Summary page.

2 SOP 9.12, Security Aligned terminology used throughout the procedure with that used in the recently approved revision to the VNC Physical Security Plan.

2 SOP 9.14, Reactor Updated references to the recently approved Dec 2021 Operator Requalification revision to the "Requalification Program for the Program General Electric Nuclear Test Reactor".

1 SOP 12.1, Fine Control Added required calculation of rod withdrawal rate for Rod Drive direct comparison to Technical Specification requirements.

1 SOP 12.2, Coarse Added required calculation of rod withdrawal rate for Control Rod Drives direct comparison to Technical Specification requirements and other administrative changes.

2 SOP 12.3, Safety Rod Added required calculation of rod withdrawal rate for Drives direct comparison to Technical Specification requirements and other administrative changes.

1 SOP 12.34, Core Delta T Procedure rewritten to address calibration check of TC2 and TC5 thermocouples in place of the thermopile calibration.

1 SOP 12.46, Conductivity Added conductivity standards values to the data sheet.

Calibration Added cleanliness steps of using lint free cloth, and rinsing probe before and after tests.

IV. Major Preventative or Corrective Maintenance During this reporting period, all routine preventive maintenance and surveillance checks were completed as scheduled.

The following lists the noteworthy corrective maintenance activities performed in 2022.

1. 1/7/22 Replaced the startup source drive belt During maintenance, the startup source could not be withdrawn from the reactor within the required timeframe. The drive belt was replaced and all re-tests per SOP 12.4 completed satisfactorily.

2. 1/11/22 Replaced Safety Rod (SR) #4 magnet S-13 with magnet AE004 Pa e 4 of9

NTR Annual Report No. 63

• HITACHI April 27, 2023 During annual safety rod maintenance, SR #4 failed the residual force test of NTR SOP 12.41.

Replaced magnet S-13 with AE004. All retests were completed satisfactorily.

3. 7/6/22 New thermocouple wires Pulled three new thermocouple wires from the control room panel into the reactor cell in preparation for replacing thermocouples TC2 and TC5. Work performed under ER 2022-08.

4. 8/31/22 Safety Rod #4 magnet/anvil interface adjustment Investigating the cause of pre-critical shutdowns due to SR #4 under ER 2022-09 and CR 40368, it was found that the interface between the magnet and anvil surfaces was less than optimal. Adjustments were made and retests completed in accordance with NTR SOP 3.2 and 4.2. See Section V.A.4.

5. 10/10/22 Safety Rod #4 "drive in" limit switch After making the interface adjustment in item #4 above, it was discovered that SR #4 was being driven too hard into the dash pot. Adjusted the location of the SR #4 "drive in" limit switch to address this condition.

6. 10/18/22 Reactor Cell Area Radiation Monitor (ARM)

Installed a refurbished ARM in the reactor cell after the initial monitor lasted approximately three months before receiving an error code. The preamp for the refurbished monitor was re-located to an area with lower background radiation in an attempt to extend its life. The digital readout failed after one week but bar readout and alarm features are still functional.

Continuing to work with the manufacturer to restore full functionality. CR 34937

7. 11/14/22 Installed new thermocouples Installed and calibration checked new thermocouples TC2 and TC5 in accordance withER 2022-06 and NTR SOP 12.46. These replace the thermopiles as input to the reactor power heat balance calculation and must be periodically calibration checked. CR 32562

8. Spurious high stack particulate alarms Late January 2022 thru early June 2021 and November and December 2022 Continued to receive frequent high stack particulate activity alarms that are determined to be spurious in the winter and spring seasons. Efforts were documented in CR 36408 to troubleshoot and correct this condition but the issue still exists and continues to be tracked.

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NTR Annual Report No. 63

• HITACHI April 27, 2023 V. Unscheduled Shutdowns During the reporting period, there were three unscheduled reactor shutdowns after reaching criticality and nine unscheduled shutdowns prior to reaching criticality.

A. Unscheduled Shutdowns

1. Scram Report 22-01 An unscheduled shutdown occurred at 12:36 on 4/5/2022 during a reactor startup. A Reactor Safety System scram was automatically inserted just after reaching criticality during a reactor startup with the reactor safety system in 1 out of 2 coincidence logic mode. The scram occurred while the operator was re-positioning PICO #3 linear power meter range selector switch which temporarily spiked the meter and caused a high power scram.

Inspection and cleaning of the switch contacts and the return to normal 2 out of 3 coincidence logic resolved the condition. Actions documented under CR 39286.

2. Scram Report 22-02 An unscheduled shutdown occurred at 10:35 AM on 4/28/2022 during a normal reactor startup as the 100 watt power level was approached. A Reactor Safety System scram was automatically inserted due to low primary coolant flow. The primary pump had been secured while reactor cell activities were in progress. Reactor startup checks had already been completed and the pump was not reenergized prior to commencement of a reactor startup. The scram report and CR 39446 documented corrective actions.

3. Scram Report 22-03 An unscheduled shutdown occurred at 11:00 AM on 12/1/2022 while the reactor was operating steady at 100% power. A Reactor Safety System scram was automatically inserted due to a momentary loss of site power. Reactor operations were suspended and recommenced the following day.

4. Prior to Criticality On 9 occasions during 2022, issues with safety rods or the log N instrument precluded a reactor startup:

Four were related to SR #2 separating and causing a shutdown upon failing to initially pull out of the dash pot. Investigation and retests found the rod drive performing as designed and no reproducible cause for the shutdowns.

Four caused by SR #4 separating while being pulled in support of normal reactor startups. The cause was found to be a combination of 1) less than optimal mating of the Pa e 6 of9

NTR Annual Report No. 63

• HITACHI April 27, 2023 magnet and anvil faces and 2) a need to adjust the position of the "drive in" limit switch.

CR 40368 documented investigative and corrective actions.

One shutdown was due to electronic "noise" on the Log Nat very low neutron flux levels in the core causing a high period scram when period spiked momentarily.

All occurrences were investigated, repaired and the affected components retested satisfactorily. The Facility Manager authorized reactor restarts.

B. NTR Safety Inspection Unresolved Issue (URI)

NRC Inspection Report 2022-201 cited a URI for failing to meet the minimum staffing requirements of Technical Specification (TS) 6.1.3.1 while the reactor was not secured lAW TS 1.2.20.2.c. during work performed on SR #4 in June 2021.

Work on SR #4 under ER 21-17 removed the SR from the reactor for inspection and cleaning.

After removal, the work was secured overnight with no licensed operator remaining at the facility. The NRC believes that the proper interpretation of the above referenced TSs is that any work on core components remains "in progress" until the component is reinstalled and design configuration restored. NTR Staff believes that the intent of these TSs is to ensure no activities are taking place that could change reactivity in the core without an operator present and therefore not applicable to core components worked outside the core if adequate shutdown margin is maintained. CR 38995 documents preventive actions.

VI. Summary of Radioactive Discharges and Environmental Surveys The data below are from sample and dosimeter results accumulated during the 2022 reporting period. Except for the NTR stack data, the data below covers the entire VNC site and include the effects of operations other than the NTR.

A. NTR Stack Total airborne releases (stack emissions) for 2022 are as follows:

Alpha Particulate: 1.54E-08 Ci (predominantly radon-thorium daughter products)

Beta-Gamma Particulate: 5.65E-07 Ci lodine-131: 2.69E-06 Ci Noble Gases: 6.69E+01 Ci Pa e 7 of9

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• HITACHI April 27, 2023 Noble gas activities recorded from the NTR stack integrate both background readings and the actual releases. Background readings may account for as much as 50% of the indicated release.

B. Gamma Radiation The yearly dose results for the year 2022 as determined from evaluation of site perimeter environmental monitoring dosimeters showed no departure from normal backgrounds.

C. Vegetation One vegetation sample was slightly above an internal action level for alpha activity, which resulted in the initiation of Condition Report #41680 to investigate the cause. No regulatory limits were exceeded.

D. Water There was no release of radioactivity in water or to groundwater greater than the limits specified in 10 CFR 20, Appendix B, Table 2, and Column 2.

E. Sediment and Air Sampling Stream bottom sediment samples and ambient air monitoring showed no increased activity levels attributable to VNC operations.

VII. Radiation Exposure In 2022, the highest annual exposure to any fulltime radiation worker at NTR was 0.484 Rem and the lowest exposure for this category of worker was 0.018 Rem. The average radiation exposure for the ten workers involved was 0.197 Rem per person. GEH Work Instruction Wl-27-105-02 states that the initial dose constraint for personnel at GEH facilities is 1 Rem/yr. NTR had 3 workers receive between 25% and 50% of this value.

The 2022 total radiation exposure for all workers while performing work at NTR was 1.966 Rem.

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( . HITACHI April27, 2023 VIII. Conclusion GE Hitachi concludes that the NTR is staffed and organized for efficient operations. Extensive use of our Corrective Action Program will continue contributing to making us a more safe and compliant operation.

GE-Hitachi Nuclear Energy Americas LLC Vallecitos Operations Digitally signed by Thomas McConnell Reason : Approved Date: 2023-04-27 12:15-07:00 Thomas J. McConnell, Manager Nuclear Test Reactor Pa e 9 of9