ML15084A213
| ML15084A213 | |
| Person / Time | |
|---|---|
| Site: | Technical Specifications Task Force |
| Issue date: | 01/16/2013 |
| From: | Technical Specifications Task Force |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| Download: ML15084A213 (9) | |
Text
1/16/2013
__j_ Technical Specifications Task ForceTSTF A Joint Owners Group ActivityProposed Generic Traveler to Address Inoperable Room Coolers-Technical Specifications Task ForceTSTF A Joint Owners Group ActivityProposed Generic Traveler to Address Inoperable RoomCoolersProblem Statement
-Many plants have cooling equipment that supportsOperability of Technical Specifications (TS) systems,collectively referred to here as "room coolers."
In manycases, the room coolers are not required to be Operable bya TS LCO. When a room cooler is nonfunctional, thesupported systems may be Operable if compensatory measures are implemented.
- However, the supported systems TS do not contain Actions that are appropriate fora nonfunctional room cooler.* The TSTF is developing a Traveler to provide appropriate TSActions for a nonfunctional room cooler.1 1/16/2013 JTechnical Specifications Task ForceTSTF A Joint Owners Group ActivityDesign* Room coolers are used to maintain the environment necessary for TS required equipment to be Operable.
- Room coolers may be heat exchangers using fluid systems(Service Water, Component Cooling Water, Emergency ChilledWater, etc.), refrigeration units, or fans and louvers." Room coolers may or may not be designed to operatefollowing an accident with concurrent loss of offsite power." A single room cooler may support multiple TS systems in asingle train, such as batteries, inverters, and switchgear.
" A nonfunctional room cooler may or may not result in thesupported TS systems being inoperable depending on theenvironmental conditions and compensatory measures.
3I_ Technical Specifications Task ForceTSTF A Joint Owners Group ActivityBackground
" Prior to conversion to the ISTS, some plant TS contained specific Actions for inoperable room coolers.
Duringconversion, most of these Actions were removed." Some licensees believed that the TS Actions for the coolingmedium should be applied (e.g., enter the Service WaterSystem Actions for an inoperable room cooler) as the coolingmedium and the room cooler contributed to the sameobjective.
- In the last few years, several licensees have receivedviolations for entering the cooling medium Actions when theroom cooler (fan, damper, motor, etc.) is nonfunctional.
-e.g., Columbia IR05000397/2012004 2
1/16/2013
-Technical Specifications Task ForceTSTF A Joint Owners Group ActivityBackground
" In response, several licensees submitted License Amendment Requests (LARs) to add Actions in the TS to addressnonfunctional room coolers.-ANO, Callaway, Wolf Creek" These LARs have not been successful.
In the absence of10 CFR 50.49 EQ test data (because supported equipment istypically located in a mild environment),
it is difficult toperform an engineering evaluation of the effects of a loss of aroom cooler on the supported equipment.
" In addition, room temperature rise calculations are inherently plant-specific.
---1_ Technical Specifications Task ForceTSTF A Joint Owners Group ActivityBackground
- Most significant operational impact is for Callaway and WolfCreek, which have an LCO 3.0.3 entry because both inverters on one bus are supported by the same room cooler.* In 2012, Wolf Creek started a TS required shutdown andreached 89% RTP before restoring a nonfunctional roomcooler." The TSTF is pursuing an approach that is generic, and providesappropriate Actions that protect public health and safety.3 1/16/2013 Technical Specifications Task ForceTSTF A Joint Owners Group ActivityLCO 3.0.6 and the Safety Function Determination Program (SFDP)LCO 3.0.6 states:When a supported system LCO is not met solely due to a support systemLCO not being met, the Conditions and Required Actions associated withthis supported system are not required to be entered.
Only the supportsystem LCO ACTIONS are required to be entered.
This is an exception toLCO 3.0.2 for the supported system. In this event, an evaluation shall beperformed in accordance with Specification 5.5.15, "Safety FunctionDetermination Program (SFDP)."
If a loss of safety function is determined to exist by this program, the appropriate Conditions and Required Actionsof the LCO in which the loss of safety function exists are required to beentered.When a support system's Required Action directs a supported system tobe declared inoperable or directs entry into Conditions and RequiredActions for a supported system, the applicable Conditions and RequiredActions shall be entered in accordance with LCO 3.0.2.ITechnical Specifications Task ForceTSTF A Joint Owners Group ActivityLCO 3.0.6 and the Safety Function Determination Program (SFDP)" Why LCO 3.0.6?* From the LCO 3.0.6 Bases:-"This exception is provided because LCO 3.0.2 would require that theConditions and Required Actions of the associated inoperable supported system LCO be entered solely due to the inoperability of thesupport system. This exception is justified because the actions thatare required to ensure the unit is maintained in a safe condition arespecified in the support system LCO's Required Actions."
-"The potential confusion and inconsistency of requirements related tothe entry into multiple support and supported systems' LCOs'Conditions and Required Actions are eliminated by providing all theactions that are necessary to ensure the unit is maintained in a safecondition in the support system's Required Actions."
4 1/16/2013 Technical Specifications Task ForceTSTF A Joint Owners Group ActivityLCO 3.0.6 and the Safety Function Determination Program (SFDP)The Safety Function Determination Program (1/3)-"This program ensures loss of safety function is detected andappropriate actions taken. Upon entry into LCO 3.0.6, an evaluation shall be made to determine if loss of safety function exists.Additionally, other appropriate limitations and remedial orcompensatory actions may be identified to be taken as a result of thesupport system inoperability and corresponding exception to enteringsupported system Condition and Required Actions.
This programimplements the requirements of LCO 3.0.6. The SFDP shall contain thefollowing:
- a. Provisions for cross train checks to ensure a loss of the capability toperform the safety function assumed in the accident analysis doesnot go undetected,
- b. Provisions for ensuring the plant is maintained in a safe condition ifa loss of function condition exists,Technical Specifications Task ForceTSTF A Joint Owners Group ActivityLCO 3.0.6 and the Safety Function Determination Program (SFDP)The Safety Function Determination Program (2/3)c. Provisions to ensure that an inoperable supported system'sCompletion Time is not inappropriately extended as a result ofmultiple support system inoperabilities, andd. Other appropriate limitations and remedial or compensatory actions.A loss of safety function exists when, assuming no concurrent singlefailure, no concurrent loss of offsite power, or no concurrent loss of onsitediesel generator(s),
a safety function assumed in the accident analysiscannot be performed.
For the purpose of this program, a loss of safetyfunction may exist when a support system is inoperable, anda. A required system redundant to the system(s) supported by theinoperable support system is also inoperable, orb. A required system redundant to the system(s) in turn supported bythe inoperable supported system is also inoperable, or105 1/16/2013 I Technical Specifications Task ForceTSTF A Joint Owners Group ActivityLCO 3.0.6 and the Safety Function Determination Program (SFDP)" The Safety Function Determination Program (3/3)c. A required system redundant to the support system(s) for thesupported systems (a) and (b) above is also inoperable.
The SFDP identifies where a loss of safety function exists. If a loss of safetyfunction is determined to exist by this program, the appropriate Conditions and Required Actions of the LCO in which the loss of safetyfunction exists are required to be entered.
When a loss of safety functionis caused by the inoperability of a single Technical Specification supportsystem, the appropriate Conditions and Required Actions to enter arethose of the support system.* All plants that have converted to ISTS haveimplemented an SFDRTechnical Specifications Task ForceTSTF A Joint Owners Group ActivityLCO 3.0.6 and the Safety Function Determination Program (SFDP)LCO 3.0.6 and the SFDP ensure that only a single train ofequipment is inoperable and that the facility can respond toan accident.
If Train A, System 2 "MIAis inop, then loss of -ITrain B Systems 2, -*4, 5, 8, 9, 10, or 11 " ,.can result in a loss Iof a safety function.
I ,,SupportIi..Supported 126 1/16/2013 ITechnical Specifications Task ForceTSTF A Joint Owners Group ActivityLCO 3.0.6 and the Safety Function Determination Program (SFDP)* LCO 3.0.6 only applies when the support system is required tobe Operable by a TS LCO.* During the development of the ISTS and LCO 3.0.6, it wasrecognized that LCO 3.0.6 does not apply for nonfunctional support systems that do not have a TS LCO, such as roomcoolers.-The industry did not see this as a problem for the reasonsdiscussed above.13I_ Technical Specifications Task ForceTSTF A Joint Owners Group ActivitySafety Justification
- A very short Completion Time or immediate shutdown are notappropriate for nonfunctional room coolers as the supported equipment is functional.
- Engineering judgment suggests that the likelihood of an eventoccurring during a forced shutdown would be greater thanoperating for a short period of time with an inoperable roomcooler, because should an accident occur during theCompletion Time:-offsite power (and other cooling equipment) is available,
-The heat load in the room may be less than the conservative assumptions in the accident
- analysis,
-The accident may not be the limiting event for the equipment in theroom.147 1/16/2013 Technical Specitications Task ForceITechnical Specifications Task ForceTSTF A Joint Owners Group ActivityRegulatory Analysis* The proposed LCO would satisfy 10 CFR 50.36(c)(2)(ii)
Criterion 2 (initial condition) or Criterion 3 (mitigating equipment).
- 10 CFR 50.36(c)(2) states:"When a limiting condition for operation of a nuclear reactor is not met,the licensee shall shut down the reactor or follow any remedial actionpermitted by the technical specifications until the condition can be met."* No other regulation governs licensee actions when a TS LCO isnot met.15I Technical Specifications Task ForceTSTF A Joint Owners Group ActivityConclusion
" Recent inspection activity has pointed out that the historical approach to addressing an inoperable room cooler is inappropriate.
" Plant-specific engineering LARs to allow time to performpreventative and corrective maintenance have been unsuccessful, leading some plants to forego online maintenance, even whenwarranted.
" The TSTF proposes to add a new LCO to the TS on room coolers thatcontains appropriate Conditions and Required Actions." LCO 3.0.6 and the SFDP will ensure that appropriate actions will betaken if a nonfunctional room cooler results in a loss of function.
168 1/16/2013 Technical Specifications Task ForceITechnical Specifications Task ForceTSTF A Joint Owners Group ActivityDiscussion
" Does the NRC staff see any "fatal flaws" in the proposedapproach?
" What aspects of the justification should be emphasized in theTraveler?
- Is there any regulatory guidance (Regulatory Guides, StandardReview Plan sections, Branch Technical Positions, etc.) notidentified by the TSTF that should be considered in creatingthe Traveler?
17Technical Specifications Task Force__I_ Technical Specifications Task ForceTSTF A Joint Owners Group ActivityNext Steps* Draft the TSTF Traveler* Need for another presubmittal meeting?* Submit the Traveler189