ML14241A384
| ML14241A384 | |
| Person / Time | |
|---|---|
| Site: | National Bureau of Standards Reactor |
| Issue date: | 08/20/2014 |
| From: | O'Kelly S US Dept of Commerce, National Institute of Standards & Technology (NIST) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| TAC MF4420 | |
| Download: ML14241A384 (7) | |
Text
UNITED STATES DEPARTMENT OF COMMERCENational Institute of Standards and Technology
'P4rsof Gaithersburg, Maryland 20899-August 20, 2014ATTN: Document Control DeskU.S. Nuclear Regulatory Commission Washington, DC 20555-0001
Subject:
Statement of no significant hazards resulting from license amendment request datedJune 23, 2014 (ML14196A043)
Reference:
NBSR Facility License TR-5, Docket 50-184, NRC letter dated July 23, 2014(TAC No. MF4420)Sirs:In a license amendment request dated June 23, 2014, the NIST Center for Neutron Research(NCNR) requested an amendment to the facility license Technical Specifications.
As requiredby 10 CFR 50.91(a),
the following analysis is presented to show the proposed amendment doesnot create a significant hazard using the criteria of 10 CFR 50.92(c).
- 1. Does the proposed amendment involve a significant increase in the probability orconsequences of an accident previously evaluated?
No, the proposed amendment would not increase the probability or consequences of an accidentpreviously evaluated.
The proposed amendment modifies maintenance requirements foremergency power systems due to a change in battery technology used in commercially available uninterruptable power supplies (UPS). The proposed amendment will assure the reliability of theemergency power systems utilizing valve-regulated lead acid (VRLA) batteries by increasing thefrequency of performance testing as recommended by the battery manufacturer and the IEEE(Institute of Electrical and Electronics Engineers).
The IEEE recommends the performance testinterval for VRLA batteries (IEEE-I 188) should not be greater than 25% of the expected servicelife or two years, whichever is less, The expected lifespan of a VRLA battery is ten years so atwo year testing interval was selected.
More frequent performance testing will ensure all thestation batteries used for emergency power remain capable of supplying emergency electrical loads for a minimum of four hours as required.
The proposed amendment will also correct atypographical error and add the requirement in the Limiting Conditions for Operations (LCO) forat least one of the two replacement UPS system batteries to be available to operate the reactor.Each UPS battery system is capable of independently supplying the designated emergency electrical loads for a minimum of four hours. Power for larger electrical loads such as primary1NI IN4 L-SDAg~
cooling backup pumps (shutdown pumps) and emergency ventilation fans comes from othersources of emergency electrical power (diesel generators, critical power bus, or 125 VDC stationbattery).
- 2. Does the proposed amendment create the possibility of a new or different kind ofaccident from any accident previously evaluated?
No, the proposed amendment would not create the possibility of a new or different kind ofaccident from any accident previously evaluated.
The replacement UPS utilizes a different battery type (VRLA) which has shorter lifespan than traditional Vented Lead Acid (VLA)batteries.
Increasing the frequency of performance monitoring as recommended by the IEEE:accounts for the shorter lifespan of VRLA batteries and will enable the facility to identify a lossof battery capacity early to permit scheduled replacement of individual system components.
Two identical but redundant UPS systems will each provide for a minimum of four hours at fullyrated emergency power loading (20 kVA). The actual emergency electrical loads on the UPSwill be significantly less because the larger electrical loads will continue to be powered from the125 VDC station battery directly or from one of two emergency diesel generators.
The newsystem will have higher reliability and capacity than the existing emergency power system.3. Does the proposed amendment involve a significant reduction in a margin of safety?No, the proposed amendment would not involve a significant reduction in a margin of safety.More frequent monitoring of the capacity or performance of the VRLA batteries utilized in thereplacement UPS supplying power to critical reactor loads will ensure the UPS performs itsdesign function and loss of battery capacity is detected early before safety margins are reduced.In addition to the above analysis, included as attachments are the following documents:
- 1. Pages 23 and 39 from the existing (Amend. 9) TR-5 Technical Specifications;
- 2. Proposed pages 23 and 39 with changes highlighted by vertical bars in right handmargin.The NCNR appreciates the time required to process these administrative license changes andlooks forward to an approved license amendment in the near future. Please contact me directlyat 301-975-6210 or by email at sean.okellygnist.gov if you have any questions.
Sean YKel , eputy DirectorNIST Center for Neutron Research2 I certify under penalty of perjury that this inform *o is true and coExecuted on AUG 20 ,2014 By: _ -cc: U.S. Nuclear Regulatory Commission ATTN: Xiaosong YinOne White Flint North11555 Rockville Pike, MS 012D20Rockville, MD 20852Susan T. Gray, Program ManagerPower Plant Assessment DivisionMaryland Department of Natural Resources 580 Taylor Avenue (B wing, 3rd floor)Tawes State Office Building, B3Annapolis, MD 21401Attachments 3
3.6 Emergency Power SystemApplicability:
Emergency electrical power suppliesObjective:
To ensure emergency power for vital equipment.
Specification The reactor shall not be operated unless at least one (1) of the diesel-powered generators and the station battery are operable, including associated distribution equipment, and the nuclear instrumentation and emergency exhaust fans can besupplied with electrical power from the diesel generator or the battery.Exception:
In order to provide time for prompt remedial action, the Emergency Powermay be inoperable for a period of no longer than 15 minutes when the specification isnot met or does not exist.BasisOne diesel-powered generator is capable of supplying emergency power to allnecessary emergency equipment.
The second diesel-powered generator is provided topermit outages for maintenance and repairs.The station battery provides an additional source of emergency power for the nuclearinstruments and the emergency exhaust fans. These fans may be powered from AC orDC power supplies.
The battery is capable of supplying this emergency load for aminimum of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. By allowing this amount of time and by requiring operability ofat least one diesel and the station battery, adequate emergency power sources shallalways be available.
3.7 Radiation Monitoring Systems and Effluents 3.7.1 Monitoring Systems and Effluent LimitsApplicability:
Radiation monitoring systemsObjective:
To detect abnormal levels or locations of radioactivity.
Specifications The reactor shall not be operated unless:(1) Two of three gaseous effluent monitors are operable for normal air,irradiated air, and stack air.23 (4) The voltage and specific gravity of each cell of the station battery shall be testedannually.
A discharge test of the entire battery shall be performed once every5 years.Basis(1) The NBSR is equipped with two diesel power generators, each capable ofsupplying full emergency load; therefore, only one of the generators shall berequired.
The diesel generators have proven to be very reliable over decades ofservice.
The quarterly test frequencies are consistent with industry practice andare considered adequate to ensure continued reliable emergency power foremergency equipment.
(2) This testing frequency of the operable generator will ensure that at least one of therequired emergency generators will be operable.
(3) An annual test of the emergency power equipment under a simulated completeloss of outside power will ensure the source will be available when needed.(4) Specific gravity and voltage checks of individual cells are the accepted method ofensuring that all cells are in satisfactory condition.
The annual frequency for thesedetailed checks is considered adequate to detect any significant changes in theability of the battery to retain its charge. During initial installation, the stationbattery was discharge tested to measure its capacity.
Experience has shown thatrepeating this test at the specified interval is adequate to detect deterioration of thecells.4.7 Radiation Monitoring System and Effluents 4.7.1 Monitoring SystemApplicability:
Radiation monitoring equipment Objective:
To operability of radiation monitors.
Specifications (1) The gaseous effluent monitors for normal air, irradiated air and stack airshall be channel tested before startup, after a shutdown of longer thantwenty-four (24) hours, or quarterly.
Each of the above air monitors shallbe channel calibrated annually.
(2) The fission products monitor shall be channel tested monthly and channelcalibrated annually.
39 Proposed Change to Page 23 of TR-5 Tech Spec3.6 Emergency Power SystemApplicability:
Emergency electrical power suppliesObjective:
To ensure emergency power for vital equipment.
Specification The reactor shall not be operated unless at least one (1) of the diesel-powered generators and the station batteries (consisting of at least one (1) batterysupplying a critical power UPS and one (1) battery supplying the 125 VDCbuses) are operable, including associated distribution equipment, and the nuclearinstrumentation and emergency exhaust fans can be supplied with electrical power from the diesel generator or the batteries.
Exception:
In order to provide time for prompt remedial action, the Emergency PowerSystem may be inoperable for a period of no longer than 15 minutes when thespecification is not met or does not exist.BasisOne diesel-powered generator is capable of supplying emergency power to allnecessary emergency equipment.
The second diesel-powered generator is provided topermit outages for maintenance and repairs.The station batteries provide an additional source of emergency power for the nuclearinstruments and the emergency exhaust fans. These fans may be powered from AC orDC power supplies.
The batteries are capable of supplying this emergency load for aminimum of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. By allowing this amount of time and by requiring operability ofat least one diesel and the station batteries, adequate emergency power sources shallalways be available.
3.7 Radiation Monitoring Systems and Effluents 3.7.1 Monitoring Systems and Effluent LimitsApplicability:
Radiation monitoring systemsObjective:
To detect abnormal levels or locations of radioactivity.
.Specifications The reactor shall not b6 operated unless:(1) Two of three gaseous effluent monitors are operable for normal air,irradiated air, and stack air.23 Proposed Change to Page 39 of TR-5 Tech Spec(4) The voltage and specific gravity of each cell of the Vented Lead Acid (VLA)battery shall be tested annually.
A discharge test of the entire battery shall beperformed once every 5 years.(5) A discharge test of the Valve-Regulated Lead Acid (VRLA) batteries shall beperformed once every 2 years.Basis(1) The NBSR is equipped with two diesel power generators, each capable ofsupplying full emergency load; therefore, only one of the generators shall berequired.
The diesel generators have proven to be very reliable over decades ofservice.
The quarterly test frequencies are consistent with industry practice andare considered adequate to ensure continued reliable emergency power foremergency equipment.
(2) This testing frequency of the operable generator will ensure that at least one of therequired emergency generators will be operable.
(3) An annual test of the emergency power equipment under a simulated completeloss of outside power will ensure the source will be available when needed.(4) Specific gravity and voltage checks of individual cells are the accepted method ofensuring that all cells of a VLA battery are in satisfactory condition.
The annualfrequency for these detailed checks is considered adequate to detect any significant changes in the ability of the battery to retain its charge. During initial installation, the station batteries were discharge tested to measure their capacity.
Experience has shown that repeating these tests at the specified intervals is adequate to detectdeterioration of the cells and loss of battery capacity.
4.7 Radiation Monitoring System and Effluents 4.7.1 Monitoring SystemApplicability:
Radiation monitoring equipment Objective:
To operability of radiation monitors.
.Specifications (1) The gaseous effluent monitors for normal air, irradiated air and stack airshall be channel tested before startup, after a shutdown of longer thantwenty-four (24) hours, or quarterly.
Each of the above air monitors shallbe channel calibrated annually.
(2) The fission products monitor shall be channel tested monthly and channelcalibrated annually.
39