ML24103A024

GEH - Submittal of Annual Nuclear Test Reactor (Ntr) Operating Report for the Year 2023

ML24103A024
Person / Time
Site:	Vallecitos Nuclear Center
Issue date:	04/12/2024
From:	Smyly J GE-Hitachi Nuclear Energy Americas
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
M240073
Download: ML24103A024 (10)

Text

HITACHI M240073 April 12, 2024 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555-001 GE Hitachi Nuclear Energy Jeffrey Smyly Regulatory Com pliance Manager 6705 Vallecitos Road Sunol, CA 94586 USA T 925-918-6074 Jeffrey.Smyly@ge.com

Reference:

GEH Annual Nuclear Test Reactor (NTR) Operating Report for the Year 2023 NRC License R-33, Docket 50-73 (NTR)

Enclosed is the Annual Operating Report No. 64 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, Jeff Smyly Jeffrey Smyly Digitally signed by Jeff Smyly ON: cn=Jeff Smyly gn=Jeff Smyly c=US United states l=US United States o=GEH ou=Vallecitos Nuclear Center Regulatory Compliance e=jeffrey.smyly@ge.com Reason: I am approving this document location:

Date: 2024--04-1 0 08:55--07:00 Regulatory Compliance Manager Vallecitos Nuclear Center Attachments: 1) NTR Annual Operating Report Number 64 for the year 2023 cc: J.D. Parrott, USNRC/NMSS/DUWP/RDB JS24-005

HITACHI NUCLEAR TEST REACTOR ANNUAL REPORT NO. 64 FOR THE YEAR 2023 LICENSE R-33 DOCKET 50-73 APRIL 10, 2024 GE Hitachi Nuclear Energy Vallecitos Nuclear Center 6705 Vallecitos Rd 5unol, CA 94586 USA

HITACHI GE Hitachi Nuclear Test Reactor Annual Report No. 64 NTR Annual Report No. 64 April 10, 2024 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 License R-33, Docket 50-73, and 10 CFR 50, Section 50.59, for the period of January 1, 2023 through December 31, 2023.

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

1. In 2023 there were 172 reactor startups with the reactor operating at or above critical for 435.25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br />. Total power generation equaled 417.37 EFPH; equivalent to 1.739 MW days. The majority of this time was spent in the performance of approved experiments, either neutron radiography or irradiation experiments in the horizontal facility.

2. The highest radiation exposure to any worker at NTR was 0.658 Rem.

3. There was one unscheduled shutdown of the reactor in 2023 and five unscheduled shutdowns prior to criticality. See section V.A. for details.

4. URI 05000073/2022-01 concerning the securing of the reactor during safety rod maintenance was closed during routine safety inspection number 05000073/2023201.

The conclusion was that no NTR technical specification violation occurred during this evolution. CR 38995 documents preventive actions.

5. NTR ceased reactor operations as of December 21, 2023.

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

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HITACHI A.

Personnel NTR Annual Report No. 64 April 10, 2024

1. The Facility Level 2 & 3, and the Vallecitos Nuclear Center (VNC) Site Regulatory Compliance managers were unchanged in 2023.

2. The Facility Level 1 Manager resigned from GE-Hitachi and was replaced by a qualified on-site manager on May 27, 2023.

B.

Operator Licenses There were no changes in the status of Operator Licenses for the NTR.

C.

Facility License

1. On June 29, 2023, the NRC issued Renewed Facility Operating License No. R-33 for the Nuclear Test Reactor, expiring 20 years from date of issuance.

2. On October 6, 2023, GEH applied for a license action to cease reactor operations and amend the R-33 Facility Operating License to possession-only of the reactor and fuel.

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 three facility Change Authorizations (CA) implemented in 2023 requiring Facility Manager and Regulatory Compliance approval.

1. CA-324 Manual poison sheet modifications were made to maximize the amount of poison in three usable sheets. This is in preparation for ceasing reactor operations and changing to possession-only of the fuel and reactor.

2. CA-325 This Experiment Type Approval authorized an irradiation test in the horizontal facility of a time-domain reflectometry probe. A 50.59 Screening was performed resulting in a 50.59 Evaluation not being required.

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HITACHI NTR Annual Report No. 64 April 10, 2024

3. CA-326 This Experiment Type Approval authorized an irradiation test in the horizontal facility of a gamma thermometer probe prototype. A 50.59 Screening was performed resulting in a 50.59 Evaluation not being required.

B.

Tests Pursuant to 10 CFR 50.59{a), no special tests were performed during 2023.

C.

Experiments Pursuant to 10 CFR 50.59{a), two previously approved experiment types were performed in 2023.

1. Experiment types described as neutron radiography and irradiation in the horizontal facility, were properly authorized utilizing experiment type approvals and experiment authorization forms throughout 2023.

D.

Procedure Changes Pursuant to 10 CFR 50.59, nineteen procedural changes were initiated during 2023 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 3

SOP 1.3, Primary Implemented a less restrictive conductivity limit for Coolant Water the primary coolant. Per revision 6 of the technical Chemistry specifications issued March 2023.

1 SOP 2.3, Log N and Administrative changes updating internal document Period Amplifier references and formatting.

1 SOP 5.2, Stack Gas Administrative changes updating internal document references.

1 SOP 6.1, Staffing Administrative changes updating definitions and Requirements requirements per revision 6 of the technical specifications issued March 2023.

2 SOP 6.7, Startup Added precautions to limit the performance of Summary surveillances and other work after daily startup checks have been completed.

1 SOP 7.2, Area Radiation Aligned administrative terminology throughout the Monitoring System procedure.

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HITACHI 2

SOP 7.13, Reactor Cell Entry 1

SOP 8.3, Abnormal Operation 1

SOP 9.1, Safety Responsibilities and Authority 1

SOP 9.6, Quality Assurance 4

SOP 9.12, Security 1

SOP 10.1, Experiment Type Approval 1

SOP 10.4, Explosives Handling 1

SOP 12.12, Primary Flow Transmitter 1

SOP 12.15, Primary Chemistry 1

SOP 12.30, Stack Particulate Monitor 2

SOP 12.32, Area Radiation Monitoring System 1

SOP 12.41, Safety Rod Magnets 2

SOP 12.46, Conductivity Calibration NTR Annual Report No. 64 April 10, 2024 Updated references from local procedures to GE wide documents. Security changes related to ceasing of operations implemented.

Administrative changes to update external document references and internal section references.

Implemented technical specification section references to align with revision 6 of the technical specifications issued March 2023.

Updated references to the current March 2023 revision of the technical specifications. Removed reference to unused implementing procedures.

Removed redundant motion sensing system.

Implemented security changes dictated by ceasing of reactor operations.

Implemented changes required by revision 6 of the technical specifications issued March 2023.

Updated North room explosives limits, use of cell phones and radios, and Safety Analysis Report references required by revision 6 of the technical specifications issued March 2023.

Added two valve protection when isolating the instrument for maintenance.

Newly installed conductivity instrument can be calibrated - removing the need to perform a calibration check with the analyzed coolant sample.

Update a section reference in an external procedure.

Terminology changes to align with other NTR procedures.

Increased periodicity this procedure is performed.

Added the recording of additional step details to the PM sheet.

Added more detailed steps to this maintenance procedure to ensure system cleanliness and avoid cross-contamination of reference standards.

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HITACHI NTR Annual Report No. 64 April 10, 2024 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 2023.

1. 2/3/23 Cleaned Log N drawer "operate" and "ramp" switches The Log N instrument failed to pass daily surveillance checks. The site l&C technician found that the "operate" switch was causing erroneous responses. The "operate" and "ramp" switches were removed and cleaned to the extent possible. Normal Log N behavior observed after switches re-installed.

2. 2/15/23 Replaced the primary coolant pump Increased operating noise and lower flow indicated that the primary pump failed. Pump replaced and required retests completed satisfactorily.

3. 4/25/23 Replaced the separation switch on Safety Rod #4 Safety Rod #4 caused a pre-critical unscheduled reactor shutdown when its separation switch malfunctioned. Switch replaced, actuator pin inspected and cleaned, and all retests completed satisfactorily. Work performed under ER 2023-06.

4. 8/11/23 Reactor Cell Area Radiation Monitor (ARM)

Replaced the reactor cell ARM (s/n 4765002) with s/n 4765001 due to error code E0012 being locked in. Calibration performed satisfactorily and unit placed in-service.

5. Spurious high stack particulate alarms Late January 2023 thru early June 2023 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.

V. Unscheduled Shutdowns During the reporting period, there was one unscheduled reactor shutdown after reaching criticality and five unscheduled shutdowns prior to reaching criticality.

A. Unscheduled Shutdowns

1. Scram Report 23-01 Pa e 5 of8

HITACHI NTR Annual Report No. 64 April 10, 2024 An unscheduled shutdown occurred at 11:42 on 2/6/2023 during a reactor startup. A Reactor Safety System scram was automatically inserted due to a Log-N instrument high power scram signal. This scram setpoint was inadvertently adjusted to a below normal value during the performance of a monthly surveillance check completed after the daily reactor startup checks. Corrective Actions documented under CR 41624.

2. Prior to Criticality On 5 occasions during 2023, issues with the safety rods precluded a reactor startup:

Three 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 was identified.

One was caused by a failed limit switch on SR #4. The switch was found to be intermittently "sticky" and not operating as designed. CR 42370 documented investigative and corrective actions.

One was caused by SR #1 drive belt slippage. Replacing the drive belt corrected the issue.

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

VI. Summary of Radioactive Discharges and Environmental Surveys The data below are from sample and dosimeter results collected during the 2023 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 2023 are as follows:

Alpha Particulate: 1.37E-08 Ci (predominantly radon-thorium daughter products)

Beta-Gamma Particulate: 4.36E-07 Ci lodine-131: 4.16E-06 Ci Noble Gases: 7.19E+0l Ci 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.

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HITACHI B.

Gamma Radiation NTR Annual Report No. 64 April 10, 2024 Site perimeter environmental monitoring dosimeters showed radiation dose levels consistent with normal environmental background levels.

C.

Vegetation and Sediment Vegetation and sediment sample radioactivity levels were below local action levels and showed no increased radioactivity levels attributable to VNC operations.

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, Column 2. All water sample radioactivity levels were below local action levels and showed no increased radioactivity levels attributable to VNC operations.

E.

Air Sampling There was no release of radioactivity in the air greater than the limits specified in 10 CFR 20, Appendix B, Table 2, Column 1.

There were two periods of time in 2023 where environmental air samples exceeded gross beta radioactivity local action levels established by VNC. Both observations were recorded in the GEH corrective action program. All samples were recounted and analyzed further with gamma spectroscopy in accordance with VNC procedures. The results showed the increased radioactivity levels were not attributable to VNC operations.

VII. Radiation Exposure In 2023, the highest annual exposure to any fulltime radiation worker at NTR was 0.658 Rem and the lowest exposure for this category of worker was 0.102 Rem. The average radiation exposure for the eight workers involved was 0.334 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 two workers receive between 25% and 50%, and two workers receive between 50% and 70%, of the 1 Rem/yr value.

The 2023 total radiation exposure for all workers while performing work at NTR was 2.668 Rem.

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HITACHI VIII. Conclusion NTR Annual Report No. 64 April 10, 2024 GE Hitachi's NTR facility has ceased reactor operations that began in 1957 and continued through 2023. NTR is currently staffed to safely possess the reactor and fuel with the reactor safety systems in the possession-only license shutdown configuration, as required by R-33 License Amendment 26 and the associated technical specifications.

GE-Hitachi Nuclear Energy Americas LLC Vallecitos Operations Digitally signed by Thomas McConnell Reason: Approved Date: 2024-04-1 O 09:35-07:00 Thomas J. McConnell, Manager, Nuclear Test Reactor Pa e 8 of8