ML16112A194

Us Dept. of Commerce, National Institute of Standards & Technology (Nist), Transmittal of 2015 Operations Report No. 68 for the Nbsr

ML16112A194
Person / Time
Site:	National Bureau of Standards Reactor
Issue date:	04/13/2016
From:	Dimeo R M US Dept of Commerce, National Institute of Standards & Technology (NIST)
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML16112A194 (11)

Text

Aprill3,2016 U.S. Nuclear Regulatory Commission Docuinent Control Desk Washington, DC 20555-0001

Subject:

Docket #50-184 Gentlemen:

-UNITED STATES DEPARTMENT OF COMMERCE National Institute of Standards and Technology Gaithersburg, Maryland 20888-Transmitted, herewith is Operations Report No. 68 for the NBSR. The report covers the period January 1, 2015 to December 31, 2015. Sincerely, Q..W WI. hW6* Robert M. Dimeo, Director NIST Center for Neutron Research Enclosure cc: Craig Bassett U.S. Nuclear Regulatory Commission 5523 Preserve Point Flowery Branch, GA 30542 U.S. Nuclear Regulatory Commission ATTN: Xiao song Yin One White Flint North 11555 Rockville Pike, MIS 12-D3 Rockville, MD 20852-2738 NISI NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY REACTOR (NBSR) Docket #50-184 Facility License No. TR-5 Operations Report --#68--January 1, 2015 -December 31, 2015 This report contains a summary of activities connected with the operations of the NBSR. This report fulfills the requirements of section 6.7.1 of the NBSR Technical Specifications for the period from January 1, 2015 to December 31, 2015. The section numbers in the report (such as 6.7.1 (1)) correspond to the sections in the Technical Specifications.

April 13, 2016 Robert M. Dimeo, 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 2015 Operations Report for NBSR (TR-5) [Docket #50-184] Page 1 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, 2015 through December 31, 2015 the reactor was critical for 5716 hours0.0662 days <br />1.588 hours <br />0.00945 weeks <br />0.00217 months <br /> with an energy output of 114, 166 MWH (237.84 full power equivalent megawatt days). Major activities during this period included:

1. Refurbished and replaced the 0-rings for the pneumatic operators of DWV-3,4,5, and 6 primary coolant pump discharge valves; 2. Replaced the diaphragms for DWV-3,4,5, and 6 primary coolant pump discharge .valves; 3. Repaired the # 2 primary coolant pump; 4. Replacing the fan for the #2 cell of the coolant tower; 5. Replaced the mechani.cal seal for the P1008 thermal shield circulating pump and the P101 B thermal shield eductor pump; 6. Replaced 13 motor control center breaker contactors with updated models to prevent premature failure; and 7. Replaced the termini for the pneumatic sample (rabbit) systems, RT-1 and RT-2.

• In addition, 2 operator trainees received their senior reactor operator licenses.

6. 7 .1 (2) Unscheduled shutdowns, including reasons therefore

1. There was a reactor scram .at 1655 on June 3, 2015 from low auxiliary flow when DWV-22 failed open. The micro controller for DWV -22 was rebooted and the reactor was quickly returned to 20 MW in less than an hour. * * *

• 2. The reactor was intentionally shutdown at 1700 on June 4, 2015 td"swap out the Regulating Rod drive system. The reactor was returned.to 20 MW at 0855 June 6,2015. . 3. There was a reactor scram at 1318 on July 30, 2015 from loss of primary flow due to a momentary loss off site power. All primary, secondary flow and ventilation was lo.st. As soon as those systems were restored to operation the reactor was restarted.

The reactor was returned to 20 MW at t339 on July 30, 2015. . 4. On December 19, 2015 at 1904 there was a rundown due to loss of the cold source PLC communications.

Even with almost immediate response by the cold source team they were not able to restore functionality of the cold source before the buildup of Xenon prevented the restart of the reactor.

decided 2015 Operations Report for NBSR (TR-5) [Docket #50-184] Page2 to end the cycle because the planned schedule for the cycle end was at 2350 on December 21, 2015, before the Xenon decay would allow a restart. 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). Jan 2 Jan 3 Jan 4 Feb? Feb 16 Feb25 Feb26 Feb 27 Mar 1 Mar2 Mar3 Mara Mar 10 . Mar 12 Mar 14 Mar 15 Mar 19 Mar20 Mar24 Mar25 Apr 16 Apr 17 Maya .May 12 May 17 Tested C02 blow off valve high level set point. Changed and tested position indicators for DWV-32, 33, 34, and 35. Replaced contactor for #1 thermal column pump. Replaced PLC for rack #4 for the cold source. Replaced contactor for SF-11. Replaced contactor for #1 storage pool pump. Replaced contactor for C02 purge fan. Replaced storage pool pumps check valves. Replaced contactor for #1 He blower. Replaced contactor for rabbit blower. Replaced secondary makeup meter. Installed thermal shield educator pump piping support. Replaced seal housing bolt for #1 main D20 pump.

contactor for #1 experimental D20 pump. Replaced contactor for #1 AC shutdown pump. Replaced contactor for #1 experimental Demin pump. Replaced contactor for #1 AC shutdown pump again. Replaced contactor for #1 experimental Demin pump again. Replaced contactor for #2 experimental Demin pump. Replaced contactor for #2 experimental D20 pump. Cooling tower wet door track heaters repaired.

Replaced #3 shim arm shaft seal.

• Installed new thermal shield dosing system . Ducting between ACV-10 and EF-3 repaired.

Completed RT-2 installation.

Changed out storage pool IX resin. Replaced 0-ring for P101 B thermal shield educator pump. Removed standby UPS batteries.

Replaced all 72 standby UPS batteries.

Replaced open limit switch for DWV-21. Repaired HCSC pump VFD. Received diesel fuel delivery.

Replaced secondary bag filter DP switch. Repaired #1 cooling tower east dry door. Cut and capped abandoned thermal shield lines under reactor top decking. 2015 Operations Report for NBSR (TR-5) [Docket #50-184] . Page 3 May 19 May20 Replaced diaphragm for DWV-37. Painted #4 and #5 cooling tower fan gear boxes with rust inhibitor.

All secondary building chain operated valves open/shut stops set. Repaired leaking biocide addition piping. Set open/shut stops on all manual operated secondary valves in the pump house. Jul 13 Jul 14 Jul21 Aug 27 Sep2 Sep8 Oct 21 Oct26 Oct 30. Nov 1 Nov23 Cooling tower gear box #1, 2, and 3 drain lines replaced.

Repaired supply breaker for MCC A2. Replaced contactor for DWV-19. Replaced vibration switch on #1 CT fan. Repaired #2 D20 shutdown pump. Repaired #1 CT fan breaker. New Demin water system installed.

Replaced DP switch for DWV-5. Installed new SCV-7 operator.

Repaired CT fan #1, 2, and 3 gear box oil drain line. Changed oil. Load tested backup UPS. Replaced process room tritium detector on 81. Replaced secondary bag filter housing. Tightened flange bolts for DCV-22, 49, and 52. Aligned HCCP pumps. Replaced DWV-80. Set dip switches for #1 thermal column pump contactor.

Contractor performed maintenance on diesel generators.

Note: the foilowing tabulation of major preventative and corrective maintenance operations are grouped by shutdown periods. There may be some duplication in the by date tabulation above. February-March:

Modifications to Secondary Auxiliary Booster Cooling Pumps (replaced

1. 2 Pump) Replaced secondary isolation valve (SCV-367) to aux. booster pumps Replaced Track Heaters on Cooling Tower Wet Rolling Doors Repaired EF-5 and EF-6 Ductwork (81 Level) Replaced the mechanical seal for the Thermal Shield Eductor Pump "B" Replaced RT-1 and RT-2 Changed Storage Pool IX Resin and Filters

• Replaced Storage Pool Cooling System Check Valves Modified Thermal Shield Level Indication System (Process Room) Installed New Primary Relief Valve Installed Wire and Test New Enclosure for Major SCRAM Relays. Installed Thermal Shield Dosing System (C100 West side of Catwalk) Repaired Automatic Slowdown Valve PAV-2D

• 2015 Operations Report for NBSR (TR-5) [Docket #50-184] Page4 May: Removed SOLA Transformer Number 1 Removed SOLA Transformer Number 2 Cut and cap abandoned Thermal Shield Cooling Lines under Reactor Top Added N16 Detectors RM 3-1 and RM 3-3 to Critical Power Replaced Differential Pressure Switch on Secondary Bag Filter Housing Replaced the mechanical seal for the Thermal Shield Circulator Pump "B" Replaced Secondary MHX'ers Thermocouples Inspected and Verify Accuracy of Primary MHX'ers RTDs July: Leak Detector Monitoring System Hardware and Software Upgrade Installed Startup Prohibit Annunciator AN 5-47 Installed NC-7 Detector Installed NC-7 Drawer and Calibrate c Replaced Cooling Tower Fan Switches (Control Room) Replaced Light Sockets on Cooling Tower Rolling Door Switches (Control Room) Replaced Ultrasonic FR-20

• Replaced Ultrasonic FR-21 Replaced Emergency Cooling Sump Pump Lockout Switch Replaced Storage Pool UV Unit and Isolation Valves Repaired #2 DzO Shutdown Pump Installed C02 Level Indicator (Process Room) Repaired Leaking Thermal Shield Valve PV-1004 Installed l/P Controller on DWV-22 Replaced #1 Blower for RM 3-4 & RM 3-5 Repaired #4 Shim Arm Drive (replaced anti-backlash gear) September:

Replaced Helium Make-up Pressure Low Alarm . Modified Oil Drain Lines on Cooling Tower Fan Gear Boxes (Cells 1-3) Installed Cannon Pool Water System Installed Backflow Preventer between FTV-23 and Cannon Pool Water System Replaced BT-4 Shutter Solenoid Delivery and Installation of Helium Tank (South Side of South Compressor Building)

Cleaned Deicing Nozzles on Cooling Tower Wet Doors Installed SCV-7 valve operator, cooling tower by-pass Replaced DP cell for DWV-5 . Repaired 48V Annunciator AN 5-43 2015 Operations Report for NBSR (TR-5) [Docket #50-184] Page 5 October-November:

Replaced FIA-6 Transmitter and Calibrate Replaced Thermal Shield Ring Header Flow Meters: 1292, 1314, 1330, 1362, 1364, & 1383 Replaced Secondary Cooling Bag Filter Housing Refurbished Helium Bulk Tanks (includes two 200 psig regulators for cold source) Replaced Helium Regulator in A 133 Replaced #2 Cooling Tower Fan Installed New DWV-22 Diaphragm Valve Repaired RM 4-2 indication in ECS Replaced diaphragm and rebuilt air operator on DWV-3 Replaced diaphragm on DWV-6 Repaired micro switch mounts on DWV-4 Repaired Shim Arm Drive in cavity #1 Repaired #2 Main D20 Pump December-January:

Installed Signal Conditioner for FIA-6 and Calibrate Installed Helium Level Indication Rebuilt Air Operator on DWV-6 Rebuilt Air Operators and Replace Diaphragms on DWV-4 and DWV-5 Replaced Flux Controller on NC-5 Replaced RTDs for BTUR measurement In addition to the mechanical and electrical The Reactor Instrumentation Group performed 62 instrument calibrations and 25 corrective maintenance operations during 2015. The calibrations were done using procedures that ensure that the sensors, indication, and controls of the NBSR safety systems are accurate and fully operational.

In addition, the Reactor Instrument Group with the support of the reactor operations and engineering personnel have made corrective actions to some of the instrumentation and control systems at NBSR during 2015. One such project was improving the gas holder indication and control with more robust and reliable components.

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 was one Level II ECN that required a license amendment:

ECN 778, Replace T-9 and T-10 UPS. The NRC issued Amendment No. 10 to the NBSR Technical Specification on September 10, 2015. 2015 Operations Reportfor NBSR (TR-5) [Docket #50-184] Page 6 There were three Level II ECNs for which further evaluation was performed using 10 CFR 50.59. None of these required a license amendment.

Level II ECN# 634 TITLE Electrical Substation This ECN covered the installation of the new electrical substation that provides power to loads that do .not affect reactor safety, e.g. cold source compressor and secondary cooling. This change improved power distribution for the facility with increased supply and redundancy of offsite power. The change did not require an amendment to the Technical Specifications.

861 Install I to P Converter on DWV-22 DWV-22 is one of the valves used to control the flow of D20 water in the auxiliary system. This system provides flow for cooling to auxiliary systems such as the cold source cryostats and the pneumatic system (rabbit) termini. It also provides circulation of the primary water for filtration and ion exchange.

This ECN replaced the electronic positioner on DWV-22 with an l/P controller with the intention to provide better control of the flow. The change did not require an.amendment to the Technical Specifications.

936 Change DWV-22 to a Diaphragm Valve This change is a continuation of ECN 861. It was found that the l/P controller did not work as expected because the DWV-22 was a 1-1 /2" ball valve, which was not proportionally controlled.

The l/P controller could only open and close DWV-22. Throttling was achieved by the manually operated 3" diaphragm valve (DWV-185) located next to DWV-22. Originally DWV-22 was a 3" diaphragm valve controlled by an l/P controller.

Over time other plant changes reduced the flow thru DWV-22 making accurate control with a 3" valve difficult.

To alleviate this problem ECN-409 changed the 3" diaphragm valve to a 1-1/2" ball valve which created the problem addressed in ECN 861. Changing the current 1-1 /2" 2015 Operations Report for NBSR (TR-5) [Docket #50-184] Page 7 ball valve to a 1-1/2" diaphragm valve with an l/P controller restored accurate and reliable control to DWV-22. The change in the valve is to a design that was installed originally and has improved performance over the valve change with ECN-409. The change did not require an amendment to the Technical Specifications.

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 During 2015 the gaseous releases to the environs consisted of 1566 Curies of Argon-41, 1241 Curies of Tritium, and 0.01 Curies of other beta-gamma emitters.

All NCNR gaseous radioactive effluent releases were in compliance with 10 CFR 20.1101 (d). The table below summarizes the liquid radioactive effluent releases to the sanitary sewer from Building 235 for calendar year 2015. H-3(1) (STDEV[2s%])

5.00 Ci 0.005 Ci (1) Via Liquid Scintillation Spectroscopy (TRI-CARS).

(2) Via Tennelec instrument (Series 5); includes contributions from gamma radionuclides.

(3) Gamma isotopes were identified using -750 ml samples in Marinelli beakers. The following isotopes were identified , in approximate decreasing order of importance:

Zn-65, Co-60, Cr-51 , Ag-110m , Sb-124, Na-24, Sb-122. (4) STDEV refers the average propagated standard deviation of the instrument concentrations using an Excel© function. For Alpha and Beta activity, 2o is the standard sigma function.

For H-3 and C-14 , 2s% refers to an industry standard function defined by Packard/Perkin Elmer. 2s% is the percent uncertainty in a gross count value (with 95% confidence limits), or 2s%=(100x2x o)/(Total Counts) (5) The alpha activity detected in NCNR samples (this year , 16 µCi , STDEV[2o]=4

µCi) is historically attributed to natural background. All NCNR liquid radioactive effluent releases were in compliance with 1 O-CFR-20.2003 6.7.1(6) Summaries of environmental surveys performed outside the facility Environmental samples of the water, grass, and/or soil showed no licensed radioactive material.

Results from thermo-luminescent dosimeters located at the NIST fence line showed no statistically significant dose above background levels. 2015 Operations Report for NBSR (TR-5) [Docket #50-184] Page 8 6.7.1(7) Summaries of significant exposures received by facility personnel and visitors Dosimetry results: 1. There were no significant exposures (exceeding regulatory limits) to visitors for this reporting period. 2. There were no significant exposures (exceeding regulatory limits) to facility personnel for this reporting period. 2015 Operations Report for NBSR (TR-5) [Docket #50-184] Page 9 Aprill3,2016 U.S. Nuclear Regulatory Commission Docuinent Control Desk Washington, DC 20555-0001

Subject:

Docket #50-184 Gentlemen:

-UNITED STATES DEPARTMENT OF COMMERCE National Institute of Standards and Technology Gaithersburg, Maryland 20888-Transmitted, herewith is Operations Report No. 68 for the NBSR. The report covers the period January 1, 2015 to December 31, 2015. Sincerely, Q..W WI. hW6* Robert M. Dimeo, Director NIST Center for Neutron Research Enclosure cc: Craig Bassett U.S. Nuclear Regulatory Commission 5523 Preserve Point Flowery Branch, GA 30542 U.S. Nuclear Regulatory Commission ATTN: Xiao song Yin One White Flint North 11555 Rockville Pike, MIS 12-D3 Rockville, MD 20852-2738 NISI NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY REACTOR (NBSR) Docket #50-184 Facility License No. TR-5 Operations Report --#68--January 1, 2015 -December 31, 2015 This report contains a summary of activities connected with the operations of the NBSR. This report fulfills the requirements of section 6.7.1 of the NBSR Technical Specifications for the period from January 1, 2015 to December 31, 2015. The section numbers in the report (such as 6.7.1 (1)) correspond to the sections in the Technical Specifications.

April 13, 2016 Robert M. Dimeo, 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 2015 Operations Report for NBSR (TR-5) [Docket #50-184] Page 1 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, 2015 through December 31, 2015 the reactor was critical for 5716 hours0.0662 days <br />1.588 hours <br />0.00945 weeks <br />0.00217 months <br /> with an energy output of 114, 166 MWH (237.84 full power equivalent megawatt days). Major activities during this period included:

1. Refurbished and replaced the 0-rings for the pneumatic operators of DWV-3,4,5, and 6 primary coolant pump discharge valves; 2. Replaced the diaphragms for DWV-3,4,5, and 6 primary coolant pump discharge .valves; 3. Repaired the # 2 primary coolant pump; 4. Replacing the fan for the #2 cell of the coolant tower; 5. Replaced the mechani.cal seal for the P1008 thermal shield circulating pump and the P101 B thermal shield eductor pump; 6. Replaced 13 motor control center breaker contactors with updated models to prevent premature failure; and 7. Replaced the termini for the pneumatic sample (rabbit) systems, RT-1 and RT-2.

• In addition, 2 operator trainees received their senior reactor operator licenses.

6. 7 .1 (2) Unscheduled shutdowns, including reasons therefore

1. There was a reactor scram .at 1655 on June 3, 2015 from low auxiliary flow when DWV-22 failed open. The micro controller for DWV -22 was rebooted and the reactor was quickly returned to 20 MW in less than an hour. * * *

• 2. The reactor was intentionally shutdown at 1700 on June 4, 2015 td"swap out the Regulating Rod drive system. The reactor was returned.to 20 MW at 0855 June 6,2015. . 3. There was a reactor scram at 1318 on July 30, 2015 from loss of primary flow due to a momentary loss off site power. All primary, secondary flow and ventilation was lo.st. As soon as those systems were restored to operation the reactor was restarted.

The reactor was returned to 20 MW at t339 on July 30, 2015. . 4. On December 19, 2015 at 1904 there was a rundown due to loss of the cold source PLC communications.

Even with almost immediate response by the cold source team they were not able to restore functionality of the cold source before the buildup of Xenon prevented the restart of the reactor.

decided 2015 Operations Report for NBSR (TR-5) [Docket #50-184] Page2 to end the cycle because the planned schedule for the cycle end was at 2350 on December 21, 2015, before the Xenon decay would allow a restart. 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). Jan 2 Jan 3 Jan 4 Feb? Feb 16 Feb25 Feb26 Feb 27 Mar 1 Mar2 Mar3 Mara Mar 10 . Mar 12 Mar 14 Mar 15 Mar 19 Mar20 Mar24 Mar25 Apr 16 Apr 17 Maya .May 12 May 17 Tested C02 blow off valve high level set point. Changed and tested position indicators for DWV-32, 33, 34, and 35. Replaced contactor for #1 thermal column pump. Replaced PLC for rack #4 for the cold source. Replaced contactor for SF-11. Replaced contactor for #1 storage pool pump. Replaced contactor for C02 purge fan. Replaced storage pool pumps check valves. Replaced contactor for #1 He blower. Replaced contactor for rabbit blower. Replaced secondary makeup meter. Installed thermal shield educator pump piping support. Replaced seal housing bolt for #1 main D20 pump.

contactor for #1 experimental D20 pump. Replaced contactor for #1 AC shutdown pump. Replaced contactor for #1 experimental Demin pump. Replaced contactor for #1 AC shutdown pump again. Replaced contactor for #1 experimental Demin pump again. Replaced contactor for #2 experimental Demin pump. Replaced contactor for #2 experimental D20 pump. Cooling tower wet door track heaters repaired.

Replaced #3 shim arm shaft seal.

• Installed new thermal shield dosing system . Ducting between ACV-10 and EF-3 repaired.

Completed RT-2 installation.

Changed out storage pool IX resin. Replaced 0-ring for P101 B thermal shield educator pump. Removed standby UPS batteries.

Replaced all 72 standby UPS batteries.

Replaced open limit switch for DWV-21. Repaired HCSC pump VFD. Received diesel fuel delivery.

Replaced secondary bag filter DP switch. Repaired #1 cooling tower east dry door. Cut and capped abandoned thermal shield lines under reactor top decking. 2015 Operations Report for NBSR (TR-5) [Docket #50-184] . Page 3 May 19 May20 Replaced diaphragm for DWV-37. Painted #4 and #5 cooling tower fan gear boxes with rust inhibitor.

All secondary building chain operated valves open/shut stops set. Repaired leaking biocide addition piping. Set open/shut stops on all manual operated secondary valves in the pump house. Jul 13 Jul 14 Jul21 Aug 27 Sep2 Sep8 Oct 21 Oct26 Oct 30. Nov 1 Nov23 Cooling tower gear box #1, 2, and 3 drain lines replaced.

Repaired supply breaker for MCC A2. Replaced contactor for DWV-19. Replaced vibration switch on #1 CT fan. Repaired #2 D20 shutdown pump. Repaired #1 CT fan breaker. New Demin water system installed.

Replaced DP switch for DWV-5. Installed new SCV-7 operator.

Repaired CT fan #1, 2, and 3 gear box oil drain line. Changed oil. Load tested backup UPS. Replaced process room tritium detector on 81. Replaced secondary bag filter housing. Tightened flange bolts for DCV-22, 49, and 52. Aligned HCCP pumps. Replaced DWV-80. Set dip switches for #1 thermal column pump contactor.

Contractor performed maintenance on diesel generators.

Note: the foilowing tabulation of major preventative and corrective maintenance operations are grouped by shutdown periods. There may be some duplication in the by date tabulation above. February-March:

Modifications to Secondary Auxiliary Booster Cooling Pumps (replaced

1. 2 Pump) Replaced secondary isolation valve (SCV-367) to aux. booster pumps Replaced Track Heaters on Cooling Tower Wet Rolling Doors Repaired EF-5 and EF-6 Ductwork (81 Level) Replaced the mechanical seal for the Thermal Shield Eductor Pump "B" Replaced RT-1 and RT-2 Changed Storage Pool IX Resin and Filters

• Replaced Storage Pool Cooling System Check Valves Modified Thermal Shield Level Indication System (Process Room) Installed New Primary Relief Valve Installed Wire and Test New Enclosure for Major SCRAM Relays. Installed Thermal Shield Dosing System (C100 West side of Catwalk) Repaired Automatic Slowdown Valve PAV-2D

• 2015 Operations Report for NBSR (TR-5) [Docket #50-184] Page4 May: Removed SOLA Transformer Number 1 Removed SOLA Transformer Number 2 Cut and cap abandoned Thermal Shield Cooling Lines under Reactor Top Added N16 Detectors RM 3-1 and RM 3-3 to Critical Power Replaced Differential Pressure Switch on Secondary Bag Filter Housing Replaced the mechanical seal for the Thermal Shield Circulator Pump "B" Replaced Secondary MHX'ers Thermocouples Inspected and Verify Accuracy of Primary MHX'ers RTDs July: Leak Detector Monitoring System Hardware and Software Upgrade Installed Startup Prohibit Annunciator AN 5-47 Installed NC-7 Detector Installed NC-7 Drawer and Calibrate c Replaced Cooling Tower Fan Switches (Control Room) Replaced Light Sockets on Cooling Tower Rolling Door Switches (Control Room) Replaced Ultrasonic FR-20

• Replaced Ultrasonic FR-21 Replaced Emergency Cooling Sump Pump Lockout Switch Replaced Storage Pool UV Unit and Isolation Valves Repaired #2 DzO Shutdown Pump Installed C02 Level Indicator (Process Room) Repaired Leaking Thermal Shield Valve PV-1004 Installed l/P Controller on DWV-22 Replaced #1 Blower for RM 3-4 & RM 3-5 Repaired #4 Shim Arm Drive (replaced anti-backlash gear) September:

Replaced Helium Make-up Pressure Low Alarm . Modified Oil Drain Lines on Cooling Tower Fan Gear Boxes (Cells 1-3) Installed Cannon Pool Water System Installed Backflow Preventer between FTV-23 and Cannon Pool Water System Replaced BT-4 Shutter Solenoid Delivery and Installation of Helium Tank (South Side of South Compressor Building)

Cleaned Deicing Nozzles on Cooling Tower Wet Doors Installed SCV-7 valve operator, cooling tower by-pass Replaced DP cell for DWV-5 . Repaired 48V Annunciator AN 5-43 2015 Operations Report for NBSR (TR-5) [Docket #50-184] Page 5 October-November:

Replaced FIA-6 Transmitter and Calibrate Replaced Thermal Shield Ring Header Flow Meters: 1292, 1314, 1330, 1362, 1364, & 1383 Replaced Secondary Cooling Bag Filter Housing Refurbished Helium Bulk Tanks (includes two 200 psig regulators for cold source) Replaced Helium Regulator in A 133 Replaced #2 Cooling Tower Fan Installed New DWV-22 Diaphragm Valve Repaired RM 4-2 indication in ECS Replaced diaphragm and rebuilt air operator on DWV-3 Replaced diaphragm on DWV-6 Repaired micro switch mounts on DWV-4 Repaired Shim Arm Drive in cavity #1 Repaired #2 Main D20 Pump December-January:

Installed Signal Conditioner for FIA-6 and Calibrate Installed Helium Level Indication Rebuilt Air Operator on DWV-6 Rebuilt Air Operators and Replace Diaphragms on DWV-4 and DWV-5 Replaced Flux Controller on NC-5 Replaced RTDs for BTUR measurement In addition to the mechanical and electrical The Reactor Instrumentation Group performed 62 instrument calibrations and 25 corrective maintenance operations during 2015. The calibrations were done using procedures that ensure that the sensors, indication, and controls of the NBSR safety systems are accurate and fully operational.

In addition, the Reactor Instrument Group with the support of the reactor operations and engineering personnel have made corrective actions to some of the instrumentation and control systems at NBSR during 2015. One such project was improving the gas holder indication and control with more robust and reliable components.

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 was one Level II ECN that required a license amendment:

ECN 778, Replace T-9 and T-10 UPS. The NRC issued Amendment No. 10 to the NBSR Technical Specification on September 10, 2015. 2015 Operations Reportfor NBSR (TR-5) [Docket #50-184] Page 6 There were three Level II ECNs for which further evaluation was performed using 10 CFR 50.59. None of these required a license amendment.

Level II ECN# 634 TITLE Electrical Substation This ECN covered the installation of the new electrical substation that provides power to loads that do .not affect reactor safety, e.g. cold source compressor and secondary cooling. This change improved power distribution for the facility with increased supply and redundancy of offsite power. The change did not require an amendment to the Technical Specifications.

861 Install I to P Converter on DWV-22 DWV-22 is one of the valves used to control the flow of D20 water in the auxiliary system. This system provides flow for cooling to auxiliary systems such as the cold source cryostats and the pneumatic system (rabbit) termini. It also provides circulation of the primary water for filtration and ion exchange.

This ECN replaced the electronic positioner on DWV-22 with an l/P controller with the intention to provide better control of the flow. The change did not require an.amendment to the Technical Specifications.

936 Change DWV-22 to a Diaphragm Valve This change is a continuation of ECN 861. It was found that the l/P controller did not work as expected because the DWV-22 was a 1-1 /2" ball valve, which was not proportionally controlled.

The l/P controller could only open and close DWV-22. Throttling was achieved by the manually operated 3" diaphragm valve (DWV-185) located next to DWV-22. Originally DWV-22 was a 3" diaphragm valve controlled by an l/P controller.

Over time other plant changes reduced the flow thru DWV-22 making accurate control with a 3" valve difficult.

To alleviate this problem ECN-409 changed the 3" diaphragm valve to a 1-1/2" ball valve which created the problem addressed in ECN 861. Changing the current 1-1 /2" 2015 Operations Report for NBSR (TR-5) [Docket #50-184] Page 7 ball valve to a 1-1/2" diaphragm valve with an l/P controller restored accurate and reliable control to DWV-22. The change in the valve is to a design that was installed originally and has improved performance over the valve change with ECN-409. The change did not require an amendment to the Technical Specifications.

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 During 2015 the gaseous releases to the environs consisted of 1566 Curies of Argon-41, 1241 Curies of Tritium, and 0.01 Curies of other beta-gamma emitters.

All NCNR gaseous radioactive effluent releases were in compliance with 10 CFR 20.1101 (d). The table below summarizes the liquid radioactive effluent releases to the sanitary sewer from Building 235 for calendar year 2015. H-3(1) (STDEV[2s%])

5.00 Ci 0.005 Ci (1) Via Liquid Scintillation Spectroscopy (TRI-CARS).

(2) Via Tennelec instrument (Series 5); includes contributions from gamma radionuclides.

(3) Gamma isotopes were identified using -750 ml samples in Marinelli beakers. The following isotopes were identified , in approximate decreasing order of importance:

Zn-65, Co-60, Cr-51 , Ag-110m , Sb-124, Na-24, Sb-122. (4) STDEV refers the average propagated standard deviation of the instrument concentrations using an Excel© function. For Alpha and Beta activity, 2o is the standard sigma function.

For H-3 and C-14 , 2s% refers to an industry standard function defined by Packard/Perkin Elmer. 2s% is the percent uncertainty in a gross count value (with 95% confidence limits), or 2s%=(100x2x o)/(Total Counts) (5) The alpha activity detected in NCNR samples (this year , 16 µCi , STDEV[2o]=4

µCi) is historically attributed to natural background. All NCNR liquid radioactive effluent releases were in compliance with 1 O-CFR-20.2003 6.7.1(6) Summaries of environmental surveys performed outside the facility Environmental samples of the water, grass, and/or soil showed no licensed radioactive material.

Results from thermo-luminescent dosimeters located at the NIST fence line showed no statistically significant dose above background levels. 2015 Operations Report for NBSR (TR-5) [Docket #50-184] Page 8 6.7.1(7) Summaries of significant exposures received by facility personnel and visitors Dosimetry results: 1. There were no significant exposures (exceeding regulatory limits) to visitors for this reporting period. 2. There were no significant exposures (exceeding regulatory limits) to facility personnel for this reporting period. 2015 Operations Report for NBSR (TR-5) [Docket #50-184] Page 9