ML21088A323

GEH Annual Nuclear Test Reactor (Ntr) Operating Report for the Year 2020

ML21088A323
Person / Time
Site:	Vallecitos Nuclear Center
Issue date:	03/29/2021
From:	Feyrer M GE-Hitachi Nuclear Energy Americas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
M210041
Download: ML21088A323 (10)

Text

• HITACHI GE Hitachi Nuclear Energy Matt J. Feyrer Site Manager, VallecllDs Nuclear Center M210041 6705 VallecilDs Rd Sunol, CA 94586 March 29, 2021 USA T 925 918 6018 U.S. Nuclear Regulatory Commission Matt.foyrer@lge.cm Attn: Document Control Desk Washington, D. C. 20555-001

Subject:

GEH Annual Nuclear Test Reactor (NTR) Operating Report for the Year 2020

Reference:

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

Enclosed is the Annual Operating Report No. 61 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, Matt Feyrer, Site Manager Vallecitos Nuclear Center

Attachment:

NTR Annual Operating Report Number 61 for the year 2020 cc: D. Hardesty, NRC NRR MJF 21-004

GE Hitachi

• HITACHI Nuclear Energy Vallecitos Nuclear Center 6705 Vallecitos Rd Sunol, CA 94586 USA NUCLEAR TEST REACTOR ANNUAL REPORT NO. 61 FOR THE YEAR 2020 LICENSE R-33 DOCKET 50-73 MARCH 25, 2021

NTR Annual Report No. 61

• HITACHI March 25, 2021 GE Hitachi Nuclear Test Reactor Annual Report No. 61 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, 2020 through December 31, 2020.

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

1. In 2020 there were 205 reactor startups with the reactor operating at or above critical for 687.45 hours5.208333e-4 days <br />0.0125 hours <br />7.440476e-5 weeks <br />1.71225e-5 months <br />. Total power generation equaled 671.92 EFPH; equivalent to 2.800 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 0.876 Rem.

3. There was one unscheduled shutdown of the reactor after reaching criticality in 2020 and eight unscheduled shutdowns prior to criticality. See section V for details.

4. There was one self-reported, technical specification violation when the operator requalification program activities were not completed by the required due date. See section V 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. 61

• HITACHI March 25, 2021 A. Personnel The Level 1 & 2, Level 3, and VNC site Regulatory Compliance managers were unchanged in 2020.

B. Operator Licenses

1. On April 10, 2020, a reactor operator ended their employment with GEH thereby terminating their operator license. License number OP-502982.

2. On December 16, 2020, a trainee was issued a senior reactor operator license by the NRC. License number SOP-503989.

III. 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 changes implemented in 2020 requiring Facility Manager and Regulatory Compliance approval.

1. The area radiation monitoring system was replaced with an upgraded system from the same manufacturer as described in Change Authorization (CA)-312. The original system (Model 845) is no longer available and was replaced with Model 945A. This replacement addresses performance and maintenance issues documented in Condition Report (CR) 29656.

2. The rubber stop became detached from the dashpot for safety rod #2. The original adhesive is no longer available. CA-313 justified an equivalent adhesive for this function restoring the components to their as-designed condition.

3. The reactor cell remote area radiation monitor and its designated spare both failed after a short amount of operating time. Because the reactor cell monitor is referenced in Technical Specification Table 4-2, Surveillance Requirements of Reactor Safety System Information Instruments, CA-316 was written to document a 50.59 review. The review concludes that continued operation without the reactor cell radiation monitor is not a violation of technical specifications and is not within applicability of 10 CFR 50.59 in that Page 2 of 8

NTR Annual Report No. 61

• HITACHI March 25, 2021 the installed radiation monitors are for ALARA and therefore covered under 10 CFR 20.

CR 34937 is tracking corrective and preventive actions to address radiation monitor operability.

B. Tests Pursuant to 10 CFR 50.59(a), no special tests were performed during 2020.

C. Experiments Pursuant to 10 CFR 50.59(a), one non-routine and two previously approved experiment types were performed in 2020.

1. A non-routine experiment type was authorized under CA-314, RIWLM Radiation Test, and performed per Engineering Release (ER) 20-16, TDR Experiment Test Plan. This experiment type approval allowed for the irradiation of a long water level probe in the horizontal test facility. This experiment type was approved by the Facility and Regulatory Compliance Managers and reviewed by the Vallecitos Technological Safety Council (VTSC).

2. Two routine experiment types described as neutron radiography and slide sample irradiations, were properly authorized utilizing experiment authorization forms throughout 2020.

D. Procedure Changes Pursuant to 10 CFR 50.59, an administrative revision of all NTR Standard Operating Procedures (SOP) was effected in 2020. The intent of these revisions was to standardize the format and maintenance of NTR procedures with site wide guidelines under Vallecitos Safety Standard (VSS) 25.1, Document Control. No changes were made that had any safety significance.

In addition to reformatting all procedures, six procedural changes were initiated during 2020 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 2.1, Safety Systems Added two Figures describing the NTR Scram Systems and the Safety Chain that were inadvertently not included in revision 0.

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NTR Annual Report No. 61

• HITACHI March 25, 2021 0 SOP 6.8, Control Room Included an operational check of the North room high Data Sheet radiation area alarm when area used for radiography.

1 SOP 6.8, Control Room Reformatted the associated data sheet (Figure 1).

Data Sheet 0 SOP 7.2, Remote Area Changes made to reflect use of the newly installed Monitoring System Model 945A Area Monitoring System replacing the prior 845 system. System upgrade tracked by the GEH Corrective Action Program, CR 29656.

0 SOP 8.4, Off-Normal Incorporated more conservative gaseous activity action Alarm Response levels (#22) in anticipation of NRC approval of R-33 License Amendment 25. Rewrote seismic trip actions

(#9) to remove duplicity with SOP 8.5.

0 SOP 8.5, Seismic Rewritten to clarify the definition of a seismic Activity occurrence, reference the VNC earthquake procedure, and simplify emergency response for different modes of reactor operation.

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 2020.

1. Identified a small primary leak on the conductivity probe housing On 1/21/20, a small primary coolant leak was found in the reactor cell where the primary flow tubing enters the conductivity probe housing. The leak rate was measured daily and never exceeded 0.01 gal/day. Attempts to repair/patch the leak were unsuccessful. The conductivity probe and housing were replaced in January 2021.

2. Power Instrument Channels insensitive to Neutron Level Changes in shutdown range During startup checks on several days in March and April, signal noise levels prevented reactor power channels #2 and/or 3 to register the required change of 5% or more in response to movement of the installed neutron source. Power and signal cables for #3 were replaced on 4/18/20. Channel #2 detector and cables were replaced on 5/4/20.

3. Safety Rod Drive #2 Page 4 of 8

NTR Annual Report No. 61

• HITACHI March 25, 2021 On 6/10/20, the rubber stop became detached from the dashpot requiring it to be re-glued to restore it to the as built condition.

4. Source Rod Drive On 9/8/20, the drive-in limit switch failed requiring replacement with an identical model switch.

5. Log N Instrument Channel On 10/12/20, replaced the last segment of the high voltage supply and signal cables in the reactor cell. High signal noise levels were causing spurious scrams during reactor startups.

See Section V.A.2.

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

A. Unscheduled Shutdowns

1. Scram Report 20-01 The operator performed an unscheduled shutdown at 11:20 AM on 1/13/20. After reaching critical rod height, the operator observed that the illumination of the fine control rod full out light did not correspond to the expected reading of the continuous position indicator.

Loose wires were found to be obstructing the full out limit switch. The scram report and CR 33499 documented corrective actions.

2. Prior to Criticality On 8 occasions during 2020, noise on the log N instrument channel circuit caused an automatic insertion of safety rods on high period prior to reaching critical rod height. Each time, seating of the Log N (+) and (-) high voltage and signal cable connectors in the reactor control panel was checked, and the log N daily surveillance check was reperformed, satisfactorily. Replaced high voltage power supply and signal cables in the reactor cell for the log N instrument channel on 10/12/20. CR 34089 is being used to document additional actions addressing this issue.

B. Technical Specification Violation Page 5 of 8

NTR Annual Report No. 61

• HITACHI March 25, 2021 On February 23, 2021, it was discovered that two licensed operators had manipulated the plant between April 30, 2020 and July 20, 2020, without being fully qualified - having exceeded the due dates for their annual operating and biennial written tests. This constitutes a deviation from the facility's Technical Specification 6.1.3.1 - 'Minimum staffing. During that period the reactor was operated normally, there were no unusual occurrences and at no time did the loss of qualifications cause the existence or development of an unsafe condition with regard to reactor operations. Both operators performed and passed the requisite tests by July 20, 2020.

Immediate Action Taken

- reactor operations were suspended to investigate the extent of the issue (2 days).

- event reported to the NRC the following working day as required by NTR Technical Specification (TS) Section 6.6.2 (NRC Event 55113).

Corrective/Preventive Actions

- Condition Report 36312 was initiated in the GEH Corrective Action Program to track additional investigation findings, causes, and corrective and preventive actions.

- in accordance with TS 6.6.2(a)(2), Special Reports, a written follow-up report concerning EN 55113 was submitted to the NRC on 3/10/21.

- created annual compliance calendar reminders for all operators to review and complete all requalification program requirements.

- created annual compliance calendar item for NTR Manager to schedule and complete requalification program requirements.

- created annual compliance calendar item for an independent review of NTR operator requalification program.

- revise SOP 9.14, Reactor Operator Requalification Program, to specify that a calendar based tracking system be used to ensure timely completion of all program requirements.

- hold training for all licensed operators on program requirements of SOP 9.14, ANSI/ANS 15.4, and NUREG-1478.

This violation will be addressed in NRC Safety Inspection report 2021-201.

VI. Radiation Levels and Sample Results at On-Site and Off-Site Monitoring Stations The data below are from sample and dosimeter results accumulated during the 2020 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.

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NTR Annual Report No. 61

• HITACHI March 25, 2021 A. NTR Stack Total airborne releases (stack emissions) for 2020 are as follows:

Alpha Particulate: 1.18E-08 Ci (predominantly radon-thorium daughter products)

Beta-Gamma Particulate: 7.07E-07 Ci Iodine-131: 1.47E-05 Ci Noble Gases: 1.37E+02 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.

B. Gamma Radiation The yearly dose results for the year 2020 as determined from evaluation of site perimeter environmental monitoring dosimeters showed no departure from normal stable backgrounds.

C. Vegetation No alpha, beta, or gamma activity attributable to activities at the NTR facility was found on or in vegetation in the vicinity of the site.

D. Water There was no release of radioactivity in water or to groundwater greater than the limits specified in 10CFR20, Appendix B, Table 2, and Column 2.

E. Off-Site The results of samples collected from off-site locations indicate normal background for the regional area.

VII. Radiation Exposure In 2020, the highest annual exposure to any fulltime radiation worker while working at NTR was 0.876 Rem and the lowest exposure for this category of worker was 0.021 Rem. The average radiation exposure for the twelve workers involved was 0.384 Rem per person.

The 2020 total radiation exposure for all workers while performing work at NTR was 4.607 Rem.

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NTR Annual Report No. 61

• HITACHI March 25, 2021 VIII. Conclusion GE Hitachi concludes that the NTR is staffed and organized for efficient operations. Our Corrective Action Program will continue contributing to making us a more safe and compliant operation.

GE-Hitachi Nuclear Energy Americas LLC Vallecitos Operations Thomas Digitally signed by Thomas McConnell DN: cn=Thomas McConnell, o=GE Hitachi, ou=NTR, email=thomas.mcconnell@ge.com, McConnell c=US Date: 2021.03.25 07:19:19 -07'00' Thomas J. McConnell, Manager Nuclear Test Reactor Page 8 of 8