ML13092A100

Annual Report for Ntr, 2012

ML13092A100
Person / Time
Site:	Vallecitos Nuclear Center
Issue date:	03/29/2013
From:	Mcfadden A GE-Hitachi Nuclear Energy Americas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
AEM 13-06
Download: ML13092A100 (12)

Text

GE Hitachi Nuclear Energy 0 HITACHI Anthony McFadden Site Manager GEH Vallecitos Nuclear Center 6705 Vallecitos Rd Sunol, CA 94586 T - (925) 862-4344 anthony.mcfadden @ge.com Ser: AEM 13-06 March 29, 2013 U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Rockville, Maryland 20852-2738 Attn: Document Control Desk

Subject:

Annual Report for NTR, 2012

Reference:

License R-33, Docket 50-73

Enclosure:

Annual Report No. 53 Enclosed is the Annual Report No. 53 for the GE-Hitachi Nuclear Test Reactor (NTR) located at Vallecitos Nuclear Center in Sunol, California.

Ifyou have questions regarding this request or additional information is required, please contact me using the contact information above.

Sincerely, len Site Manager GEH Vallecitos Nuclear Center cc: Xiaosong Yin, NRC Don Krause, GEH VNC Reg Compliance Daniel Thomas, GEH VNC NTR ba~o

GE Hitachi Nuclear Energy 0HITACHI Vallecitos Nuclear Center 6705 Vollecitos Rd Sunol, CA 94586 USA NUCLEAR TEST REACTOR ANNUAL REPORT NO. 53 FOR THE YEAR 2012 LICENSE R-33 DOCKET 50-73 MARCH 2013

NTR Annual Report No. 53 GE Hitachi Nuclear Test Reactor Annual Report No. 53 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 10CFR50, Section 50.59, for the period of January 1, 2012 through December 31, 2012.

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

IN 2012 there were 240 reactor startups with the reactor operating at or above critical for 846 hours0.00979 days <br />0.235 hours <br />0.0014 weeks <br />3.21903e-4 months <br />. Total power generation equaled 832.6 EFPH; equivalent to 3.47 MW days. The majority of this time was spent in the performance of approved experiments, either neutron radiography or small sample irradiations for forensic evaluations.

The highest radiation exposure to any worker at NTR was 0.679 Rem.

There were three unplanned shutdowns of the reactor in 2012. These shutdowns are discussed in Section V.

There were no occurrences that required notification of the NRC during 2012.

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

Mr. Daniel Thomas continued as Manager NTR performing licensed SRO activities and radiography NDT Level III activities.

> Mr. Edward Ehrlich's license has remained inactive since his retirement in 2008. His license, with an October 6th 2005 effective date, was terminated in 2012. Mr. Ehrlich will not be returning to the NTR.

> Mr. Thomas McConnell continued performing licensed SRO activities. He also worked as a radiographer, NDT Level I.

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NTR Annual Report No. 53 Mr. Dennis Smith's contract was not renewed in 2012. His license expired December 5 th, 2011. GEH and NTR management has made a decision to allow Mr. Smith's license to terminate. There are no plans to have Mr. Smith return to the NTR as an operator.

> Mr. Tim Peterson continued performing licensed SRO activities. He also continues performing his radiography NDT Level III activities.

> Mr. Max Paronable continued performing licensed RO activities. He also continues his radiography NDT Level I activities.

> Mr. George Dumlao continued to perform radiography, and reactor and non-reactor system maintenance tasks under the direction and supervision of the certified NDT personnel and licensed operations staff until in September 2012, a medical condition forced him into accepting a long term disability status. Final determination of Mr.

Dumlao's status will occur later in 2013.

> Mr. Terry Hofer's contract was not renewed in 2012. After working as a part time GEH employee (pensioner) performing radiography and non-reactor system maintenance tasks under the direction and supervision of the certified NDT personnel and licensed operations staff, Mr. Hofer will be permanently retired and will not be asked to support the NTR production efforts in the future.

> Mr. James Graham, under contract as a radiographer, has continued to perform radiography and non-reactor system maintenance tasks under the direction and supervision of the certified NDT personnel and licensed operations staff.

> Ms. Carmen Holmes, under contract as a radiographer, has continued to perform radiography and non-reactor system maintenance tasks under the direction and supervision of the certified NDT personnel and licensed operations staff.

> Mr. Stephen Neel, under contract as a radiographer, has continued to perform radiography and non-reactor system maintenance tasks under the direction and supervision of the certified NDT personnel and licensed operations staff.

> Ms, Maralynn Segars, under contract as a radiographer, has continued to perform radiography and non-reactor system maintenance tasks under the direction and supervision of the certified NDT personnel and licensed operations staff.

> Ms, Rose Bagnas, under contract as a radiographer, has continued to perform radiography and non-reactor system maintenance tasks under the direction and supervision of the certified NDT personnel and licensed operations staff.

> Mr. Michael Leedle was hired as a full time specialist in July to perform radiography and non-reactor system maintenance tasks under the direction and supervision of the certified NDT personnel and licensed operations staff. Mr. Leedle resigned his employment in November 2012.

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NTR Annual Report No. 53 Mr. Jorge Garcia was hired as a full time specialist in July to perform radiography and non-reactor system maintenance tasks under the direction and supervision of the certified NDT personnel and licensed operations staff.

Mr. Martin Whitman was hired as a full time specialist in July to perform radiography and non-reactor system maintenance tasks under the direction and supervision of the certified NDT personnel and licensed operations staff.

Mr. Earl Saito became the Vallecitos Nuclear Center Manager for EHS and RC in September with overall EHS responsibilities for the Vallecitos site, including NTR.

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 Pursuant to 10CFR50.59(a), the following facility changes were implemented in 2012 requiring Facility Manager, Regulatory Compliance and VTSC approval. The following process changes and associated activities were comprehensively reviewed using a 50.59 analysis.

CA-301-NTR Fine Control Rod Drive Split-Nut Assembly Replacement-It was found that the threads on the drive nut for the fine control rod drive were stripped preventing rod motion. There were no spares for this manufactured item and the drawings could not be located. Drawings were developed and materials were specified using information gained from similar drive mechanisms at the NTR. The part was successfully manufactured and placed in the system. The drive system was tested and returned to service. An enhanced surveillance program was initiated on the drive unit focusing on the split-nut assembly.

> CA-302-Reactor Startup on One Good, One Replaced, and One Noisy Reactor Power Instrument-One of the three power instruments was replaced due to excessive detector noise. SOP requires that the replaced instrument remain in a tripped condition during the subsequent startup until it is determined that the instrument is properly tracking with the other calibrated instruments. This forces the scram logic from 2 out of 3 into a 1 out of 2 trip mode. It was determined however, that a startup under these conditions would not be feasible due to detector noise which developed on the second calibrated reactor power instrument. A one-time use procedure was approved to make possible a safe startup using the one remaining stable calibrated instrument and the one recently maintained stable instrument in 1 out of 2 scram logic mode. The third noisy calibrated instrument was initially placed in the trip Page 3 of 10

NTR Annual Report No. 53 condition. Strict boundaries to verify instrument tracking were enforced along with an enhanced monitoring regiment. The noisy instrument would be kept in the tripped condition (still able to use the detector in the scram logic) until reactor power rose to a level such that the detector output signal overcame the noise. As expected, once reactor power increased above source count level by greater than a decade, the noise signal in the instrument was negated by the stronger detector signal, and the instrument noise became insignificant enough to allow placing the detector into the scram logic. As power increased however, it was found that the power indication of the noisy detector was tracking at a level at least 1/2 decade below expectations. It was decided to abort the startup and re-evaluate. See CA-303.

CA-303-Reactor Startup Subsequent to Dual CIC Replacements-Because of the aborted startup during the use procedure of CA-302, the decision was made to replace the remaining noisy detector and to write a procedure to perform a startup using the one known calibrated power instrument and the two power instruments with replaced detectors. A one-time use procedure was approved to make possible a safe startup using the one remaining stable calibrated instrument and one of the two recently maintained stable instruments in 1 out of 2 scram logic mode. The other recently maintained instrument was left in the trip condition. Again, strict boundaries to verify instrument tracking were enforced along with an enhanced monitoring regiment. The startup was successful and the two instruments with replaced detectors were calibrated to thermal power.

B. Tests Pursuant to 10CFR50.59(a), no special test were performed during 2012 with Facility Manager, Regulatory Compliance and VTSC approval.

C. Experiments Pursuant to 10CFR50.59(a), there were no new experiments in 2012 requiring Facility Manager, Regulatory Compliance and VTSC approval. The two routine experiment types described as neutron radiography and Schafer slide sample irradiations were properly authorized utilizing experiment authorization forms throughout 2012.

D. Procedure Changes Pursuant to 10CFR50.59, there were no procedural changes initiated during 2012.

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NTR Annual Report No. 53 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 2012.

Fine Control Rod Drive

> The split-nut was replaced on the fine control rod drive. This replacement was authorized by CA-301 and implemented by ER-12-03.

Log-N power supply The Log-N system provides log scale readout of reactor power and related functions including the high power and period scrams. On three occasions in 2012, work was performed on either the power supply or the instrument drawer. On the first occasion, the work was in response to abnormal fluctuations observed by the operator prior to startup. On the second and third occasions, the work was in response to an intermittent instrument failure causing a reactor scram from 100%

power. Refer to Section V of this report and the description for Scram 12-02 and 12-03.

Radiation Monitoring Instrumentation (Victoreen)

On two occasions, performed corrective maintenance on the Radiation Monitors involving the replacement of one or more PC boards and a detector. This is a continuing effort to maintain the system with no change in the trend that would indicate a system wide concern.

Source Rod Drive System On two occasions, performed corrective maintenance on the Source Rod drive system, once involving the replacement of one drive belt due to normal wear and tear, and once involving the replacement of the full-in limit switch due to normal wear and tear. This is a continuing effort to maintain the system with no change in the trend that would indicate a system wide concern.

Reactor Power Instrumentation On two occasions, performed corrective maintenance on the Reactor Power Instrumentation. Both occasions were in response to the development of an overpowering noise signal while low in the source power range. This noise is a result of arcing at the connectors to the high voltage cables at the detector. This is part of a continuing effort to maintain the system with no change in the trend that would indicate a system wide concern.

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NTR Annual Report No. 53 Reactor Chemistry Analysis Unusually high Strontium concentrations were being found and tracked in the primary coolant and with the recommendation of the VTSC, additional coolant samples were taken and analyzed to attempt to determine the cause. It was recommended that the resin filter be changed as a first step, as resin break-through was considered a possibility. After the cleanup system's filter and resin were changed, the levels returned to normal.

V. Unscheduled Shutdowns During the reporting period, there were three unscheduled reactor shutdowns after reaching criticality.

Scram Report 12-01 Sequence of Events At 12:05 PM on Monday the 9th of January 2012, an unplanned shutdown occurred 43 minutes into the second reactor startup of the year.

Cause of Event The unplanned shutdown was caused by one of the four safety rod separation switches opening.

This resulted in a process scram signal being sent to the protection system causing all safety rods to automatically scram to the full-in position. All control rods and the source rod drove in automatically to the full-in position.

Corrective Actions Working under ER 12-01, Safety Rod Separation Switch Investigation, an abnormal gap was found between the anvil and magnet faces on safety rod #4. Adjustments made to the magnet position and drive-in limit switch position achieved normal contact between the anvil and magnet faces and normal operation of the system. Subsequent scram time and magnet drop-out current tests were satisfactory.

Conclusions Scram time and drop-out current tests were satisfactory after the annual PMs were performed. This has historically been our go no-go test as to whether the rods will function properly. Discussed with the staff the need to visually check the anvil/magnet face contact to ensure no abnormal gap exists. NTR was authorized for restart.

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NTR Annual Report No. 53 Scram Report 12-02 Sequence of Events At 12:06 PM on Tuesday the 16th of October 2012, an unplanned shutdown occurred while operating at 100% power. Alarm lights illuminated on the control room alarm panel were:

Log N CIC trip, fast period and safety rod disconnect. The Reactor Operator observed all normal indications of a reactor scram and shutdown. Manager, NTR and VNC Regulatory Compliance were notified of the scram.

Cause of Event The unplanned shutdown was caused by an electronic failure of the Log N power supply. All safety rods automatically scrammed to a full in position. All control rods drove in automatically to the full-in position.

Corrective Actions The Log N, startup high voltage scram test was performed with satisfactory results. A Log N instrument power supply was found to be "bad". The power supply was replaced and PMs 12-24 and 12-25c were performed to "align" the Log N drawer. Both PMs were completed with satisfactory results.

Conclusions This scram was caused by an electronic failure of the Log N power supply. All appropriate actions were taken in response to the unplanned shutdown. The maintenance actions taken to correct the cause of the scram were appropriate. The Log N instrument was fully tested after completing the maintenance and is returned to service. NTR was authorized for restart.

Scram Report 12-03 Sequence of Events On Wednesday the 14th of November 2012 at 09:13 AM, an unplanned shutdown occurred while operating at 100% power. The Reactor Operator (RO) observed all normal indications of a reactor scram and the reactor shutdown. The Manager, NTR and VNC Regulatory Compliance were notified of the scram.

Cause of Event The unplanned shutdown was caused by an electronic failure of the Log N instrument. All safety rods automatically scrammed to a full in position. All control rods drove in automatically to their full-in positions.

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NTR Annual Report No. 53 Corrective Actions Investigation as to the cause of the shutdown started immediately and troubleshooting of scram instrumentation lasted two days. Eventually the cause was focused on the Log N Amplifier drawer. All four modules were replaced in the Log N Amplifier drawer. As found and As Left voltages were recorded. The four modules were marked as suspect and taken to the shop for further investigations. The modules are identified as the Pre-Regulator, the Voltage Regulator, and both the positive and negative High Voltage Power modules. The rebuilding and calibration of the Log N Amplifier as was completed. An instrument run-in test was run through the night and completed with satisfactory results. No trips were received with the simulated 100% power signal applied. A meeting of the VTSC was called. A quorum of the VTSC unanimously voted to authorize the restart of NTR.

Conclusions This scram was likely caused by an electronic failure of the Log N instrument. All appropriate actions were taken in response to the unplanned shutdown. Maintenance activities were implemented as follows:

1. Log N CIC cable replaced

2. Insulators on the high voltage terminals for the Log N CIC detector were replaced

3. The pre regulator and regulator in the Log N Amplified Drawer were replaced

4. The positive and negative high voltage power supplies in the Log N Amplifier Drawer were replaced

5. On overnight run-in test was completed giving satisfactory results

6. The calibration checks lAW PM 12-24 were completed with satisfactory results

7. The daily surveillance checks were completed with satisfactory results

8. A cursory inspection of the wiring in the control panel associated with the Log-N instrument was completed with no findings.

The Log N Instrument was declared operational and the NTR Manager authorized its restart.

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NTR Annual Report No. 53 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 2012 reporting period. Except for the NTR stock data, these data are for the entire VNC site and include the effects of operations other than the NTR.

A. NTR Stack Total airborne releases (stack emissions) for 2012 are as follows:

Alpha Particulate: 1.51E-06 Ci (predominantly radon-thorium daughter products)

Beta-Gamma Particulate: 2.56E-06 Ci Iodine-131: 7.10E-06 Ci Noble Gases: 2.70E+2 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. Air Monitors (Yearly average of all meteorological stations.)

Four environmental air-monitoring stations are positioned approximately 90 degrees apart around the operating facilities of the site. Each station is equipped with a membrane filter, which is changed weekly and analyzed for gross alpha and gross beta-gamma.

Alpha Concentration:

Weekly Maximum, 9.21E-14 kICi/cc Weekly Average, 2.09 E-14 jiCi/cc Beta Concentration:

Weekly Maximum, 4.10 E-14 pCi /cc Weekly Average, 7.78 E-15 [tCi/cc C. Gamma Radiation The yearly dose results for the year 2012 as determined from evaluation of site perimeter environmental monitoring dosimeters showed no departure from normal stable backgrounds.

D. 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.

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NTR Annual Report No. 53 E. 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.

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

VII. Radiation Exposure In 2012, the highest annual exposure to any one of the eight full time GEH workers while working at NTR was 0.679 Rem and the lowest exposure for this category of worker was 0.271 Rem. The average radiation exposure for the full time GEH-NTR workers was approximately 0.423 Rem per person.

In 2012, the highest annual exposure to any one of the five part time contract NTR workers was 0.573 Rem and the lowest exposure for this category of worker was 0.006 Rem. The average radiation exposure for the part time contract NTR workers was approximately 0.274 Rem per person.

The 2012 collective radiation exposure for all workers while performing work at NTR was 4.750 Person-Rem.

VIII. Conclusion GE Hitachi concludes that the overall operating experience of the NTR reflects another year of safe and efficient operations. There were no reportable events.

GE-Hitachi Nuclear Energy Americas LLC Vallecitos Operations Daniel M.Thomas, Manager Nuclear Test Reactor Page 10 of 10