ML110190280

License Amendment, Issuance of Amendment Revising TS 3.7.11, Control Room Emergency Air Temperature Control System (Creatcs)

ML110190280
Person / Time
Site:	Watts Bar
Issue date:	02/08/2011
From:	John Lamb Watts Bar Special Projects Branch
To:	Krich R Tennessee Valley Authority
lamb J, 415-3100
References
TAC ME3429
Download: ML110190280 (12)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 February 8, 2011 Mr. R. M. Krich Vice President, Nuclear Licensing Tennessee Valley Authority 3R Lookout Place 1101 Market Street Chattanooga, TN 37402-2801

SUBJECT:

WAITS BAR NUCLEAR PLANT, UNIT 1 -ISSUANCE OF AMENDMENT REGARDING THE MAIN CONTROL ROOM CHILLER COMPLETION TIME EXTENSION (TAC NO. ME3429)

Dear Mr. Krich:

The U.S. Nuclear Regulatory Commission has issued the enclosed Amendment NO.85 to Facility Operating License No. NPF-90 for Watts Bar Nuclear Plant, Unit 1. This amendment consists of changes to the Technical Specifications (TSs) in response to your application dated February 24,2010, as supplemented September 20,2010, and November 5,2010.

The amendment revises TS 3.7.11, "Control Room Emergency Air Temperature Control System (CREATCS):, Specifically, the proposed change will only be applicable during plant modifications to upgrade the CREATCS chillers. This "one-time" TS change will be implemented during Watts Bar Nuclear Plant, Unit 1 Cycles 10 and 11 beginning March 1, 2011, and ending April 30, 2012.

A copy of our related Safety Evaluation is also enclosed. The Notice of Issuance will be included in the Commission's biweekly Federal Register notice.

Sincerely, Joh Wa Bar Special Projects Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-390

Enclosures:

1. Amendment No.85 to NPF-90

2. Safety Evaluation cc w/encls: Distribution via Listserv

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555*0001 TENNESSEE VALLEY AUTHORITY DOCKET NO. 50-390 WATTS BAR NUCLEAR PLANT, UNIT 1 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 85 License No. NPF-90

1. The Nuclear Regulatory Commission (the Commission) has found that:

A. The application for amendment by the Tennessee Valley Authority (the licensee) dated February 24,2010, as supplemented September 20,2010 and November 5,2010, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in Title 10 Code of Federal Regulations (10 CFR) Chapter I; B. The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C. There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D. The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E. The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.

-2

2. Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 2.C.(2) of Facility Operating License No. NPF-90 is hereby amended to read as follows:

(2) Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendices A and B, as revised through Amendment No. 85 ,and the Environmental Protection Plan contained in Appendix B, both of which are attached hereto, are hereby incorporated into this license. TVA shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.

3. This license amendment is effective as of the date of its issuance, and shall be implemented no later than 90 days from the date of its issuance.

FOR THE NUCLEAR REGULATORY COMMISSION

~~.~

Stephen J. Campbell, Chief Watts Bar Special Projects Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Attachment:

Changes to License No. NPF-90 and the Technical Specifications Date of Issuance: February 8, 2011

ATTACHMENT TO LICENSE AMENDMENT NO. 85 FACILITY OPERATING LICENSE NO. NPF-90 DOCKET NO. 50-390 Replace page 3 of Operating License No. NPF-90 with the attached page 3.

Replace the following page of the Appendix A Technical Specifications with the attached revised page. The revised page is identified by amendment number and contains a marginal line indicating the area of change.

REMOVE INSERT 3.7-25 3.7-25

3 (4) TVA, pursuant to the Act and 10 CFR Parts 30, 40 and 70, to receive, possess, and use in amounts as required, any byproduct, source or special nuclear material without restriction to chemical or physical form, for sample analysis, instrument calibration, or other activity associated with radioactive apparatus or components; and (5) TVA, pursuant to the Act and 10 CFR Parts 30,40 and 70, to possess, but not separate, such byproduct and special nuclear materials as may be produced by the operation of the facility.

C. This license shall be deemed to contain and is subject to the conditions specified in the Commission's regulations set forth in 10 CFR Chapter I and is subject to all applicable provisions of the Act and to the rules, regulations, and orders of the Commission now or hereafter in effect, and is subject to the additional conditions specified or incorporated below.

(1) Maximum Power Level TVA is authorized to operate the facility at reactor core power levels not in excess of 3459 megawatts thermal.

(2) Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A as revised through Amendment No. 85 and the Environmental Protection Plan contained in Appendix B, both of which are attached hereto, are hereby incorporated into this license. TVA shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.

(3) Safety Parameter Display System (SPDS) (Section 18.2 of SER Supplements 5 and 15)

Prior to startup following the first refueling outage, TVA shall accomplish the necessary activities, provide acceptable responses, and implement all proposed corrective actions related to having the Watts Bar Unit 1 SPDS operational.

(4) Vehicle Bomb Control Program (Section 13.6.9 of SSER 20)

During the period of the exemption granted in paragraph 2.0.(3) of this license, in implementing the power ascension phase of the approved initial test program, TVA shall not exceed 50% power until the requirements of 10 CFR 73.55(c)(7) and (8) are fully implemented. TVA shall submit a letter under oath or affirmation when the requirements of 73.55(c)(7) and (8) have been fully implemented.

Amendment No. 85

CREATCS 3.7.11 3.7 PLANT SYSTEMS 3.7.11 Control Room Emergency Air Temperature Control System (CREATCS)

LCO 3.7.11 Two CREATCS trains shall be OPERABLE.

APPLICABILITY: MODES 1, 2, 3, 4, 5, and 6 During movement of irradiated fuel assemblies.

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One CREATCS train A.1 Restore CREATCS train to 30 days*

inoperable. OPERABLE status.

B. Required Action and associated 8.1 Be in MODE 3. 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> Completion Time of Condition A not met in MODE 1, 2, 3, or 4. AND B.2 Be in MODE 5. 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> C. Required Action and associated C.1 Place OPERABLE CREATCS Immediately Completion Time of Condition A train in operation.

not met in MODE 5 or 6, or during movement of irradiated OR fuel assemblies.

C.2 Suspend movement of irradiated fuel assemblies. Immediately (continued)

• An allowance is permitted for one CREATCS train to be inoperable for 60 days. This TS provision is only authorized for one entry per train during modification activities planned for the upgrade of the MCR chillers beginning no earlier than March 1, 2011 and ending April 3D, 2012 and provided compensatory measures are implemented.

Watts Bar- Unit 1 3.7-25 Amendment 35, as

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 85 TO FACILITY OPERATING LICENSE NO. NPF-90 TENNESSEE VALLEY AUTHORITY WATTS BAR NUCLEAR PLANT, UNIT 1 DOCKET NO. 50-390

1.0 INTRODUCTION

By application dated February 24,2010 (Agencywide Document Management Systems (ADAMS) Accession No. ML100570414), as supplemented September 20,2010 (ADAMS Accession No. ML102650043) and November 5,2010 (ADAMS Accession No. ML103120455),

Tennessee Valley Authority (TVA) requested an amendment to Facility Operating License No.

NPF-90 Watts Bar Nuclear Plant (WBN), Unit 1 and Appendix A, Technical Specifications (TSs),

of the Facility Operating License. The proposed change would revise Technical speCification (TS) 3.7.11, "Control Room Emergency Air Temperature Control System (CREATCS)."

Specifically, the proposed change will only be applicable during plant modifications to upgrade the CREATCS chillers. This "one-time" TS change will be implemented during WBN Unit 1 Cycles 10 and 11 beginning March 1, 2011, and ending April 30, 2012.

TVA's supplementary &ubmittals, dated September 20 and November 5,2010, provided clarifying information that did not change the scope of the proposed amendment as described in the original notice of proposed action published in the Federal Register on June 1, 2010 (75 FR 30447) and did not change the initial proposed no significant hazards determination.

2.0 REGULATORY EVALUATION

TVA addressed the regulatory requirements applicable to the proposed amendment in Section 4.1 of Enclosure 1 to the application dated February 24, 2010. As described in the Updated Final Safety Analyses Report (UFSAR), Section 3.1 "Conformance with the U. S.

Nuclear Regulatory Commission (NRC) General Design Cnteria [GDC)," WBN Unit 1 was designed to meet the intent of the "Proposed General Design Criterion for Nuclear Power Plant Construction Permits" published in July 1967. The WBN Unit 1 construction permit was issued on January 23. 1973. The UFSAR provided a discussion of WBN Unit 1 design features and procedures that meet the intent of the NRC GDC published as Appendix A to Title 10 of the Code of Federal Regulations (10 CFR) Section 50 in July 1971.

-2 The regulatory requirements, criteria, and guidance applied by the NRC staff in the review of the proposed change are as follows:

GDC 19, "Control Room," states that, "A control room shall be provided from which actions can be taken to operate the nuclear power unit safely under normal conditions and to maintain it in a safe condition under accident conditions, including loss-of-coolant accidents. Adequate radiation protection shall be provided to permit access and occupancy of the control room under accident conditions without personnel receiving radiation exposures in excess of 5 rem whole body, or its equivalent to any part of the body, for the duration of the accident. Equipment at appropriate locations outside the control room shall be provided (1) with a design capability for a prompt hot shutdown of the reactor, including necessary instrumentation and controls to maintain the unit in a safe condition during hot shutdown, and (2) with a potential capability for subsequent cold shutdown of the reactor through the use of suitable procedures."

Title 10 of CFR 50.36 requires that each licensee operate in accordance with plant TSs.

Title 10 of CFR 50.36(c)(2} specifies that the TSs will include a section on limiting conditions for operation. At WBN Unit 1, the CREATCS falls under this regulation. Further, in 10 CFR 50.59, a licensee is required to submit a license amendment request (LAR) if a change to the TSs is required.

Regulatory Guide (RG) 1.78, "Assumptions for Evaluating the Habitability of a Nuclear Power Plant Control Room During a Postulated Hazardous Chemical Release," provides guidance on methods for maintaining the habitability of control rooms.

TVA referenced Seabrook Station Unit 1 as a precedent for successfully obtaining NRC approval of a similar LAR in the year 1999. The LAR requested, and the NRC approved, an increase in the allowed outage time for the Control Room air conditioning system from 30 days to 60 days, on a one time basis, to allow adequate time for replacing portions of the existing system. The NRC staff's review determined that a similar request was also granted by the NRC to Surry Power Station, Unit Nos. 1 and 2, on January 23, 2008 (ADAMS Accession No. ML073480281). In case of Surry, the chilled water piping needed to be replaced; however, the replacement process resulted in an increased outage time of the control room and emergency switchgear room air conditioning systems.

3.0 TECHNICAL EVALUATION

The heating, ventilation and air conditioning (HVAC) systems for each of the WBN Unit 1 main control room (MCR) and the Shutdown Board Room (SDBR) have two redundant 100-percent capacity subsystems. Each of the subsystems consist of primary equipment such as the water chiller, chilled water pump, air handling units (AHU), piping between the chiller and AHUs, and supporting equipment such as instrumentation and controls, ductwork, dampers, etc. The MCR HVAC system maintains the MCR at a normal temperature of 75 OF, with abnormal excursions of short duration to 104°F maximum and 60°F minimum possible.

-3 The SOBR chillers use refrigerant R-11, and the MCR chillers utilize refrigerant R-22. Executive Order 13148, "Greening the Government Through Leadership in Environmental Management;'

issued April, 2000 requires Federal Agencies to phase out the procurement of Class I ozone depleting refrigerants by Oecember 31,2010. Included in this category is refrigerant R-11, but not R-22. TVA stated that Environmental Protection Agency (EPA) regulations, specifically Title 40"Protection of Environment', Part 82 "Protection of Stratospheric Ozone:' require phasing out the procurement of R-22 by the year 2020. Therefore, the MCR chillers do not need immediate replacement to comply with EPA regulations. However, TVA stated that due to interference issues, the train-A SOBR chiller replacement process will require temporary removal of the train-A MCR chiller. Based on this consideration, equipment reliability, and obsolescence of spare parts, TVA has concluded that it is prudent to undertake permanent replacement of MCR chillers also along with the SOBR chillers.

TVA proposes to replace the chillers with new chiller packages of similar design and plans to implement the changes in three phases, while WBN Unit 1 is at power. Phase 1 will replace the train-B SOBR chiller. Phase 2 will replace the train-B MCR chiller. Phase 1 and Phase 2 work will occur during operating cycle 10. After completion of Phase 2, work will stop during the Cycle 10 refueling outage. Phase 3 work will replace train-A MCR and the train-A SOBR chillers during operating Cycle 11. TVA estimated the times to implement the changes from a minimum of 41 days for Phase 1 to a maximum of 54 days for Phase 3.

The MCR chillers are TS support equipment, governed by TS 3.7.11 "Control Room Emergency Air Temperature Control system (CREATCS):'whereas the SOBR chillers are non-TS support equipment. The current TS 3.7.11 requires the restoration of an inoperable CREATCS train to operable status within 30 days. Since the MCR chiller replacement activities in Phases 2 and 3 take longer than 30 days, TVA is requesting a"one-time'TS change to increase the allowed outage time (AOT) to 60 days, applicable during operating cycles 10 and 11. In letter dated November 5,2010, TVA clarified that the increased AOT is applicable "one-time' in each of phases 2 and 3, and that it would be invoked in the period between March 1, 2011, and April 30, 2012, when the plant is in operation. TVA does not intend to perform the replacement work during refueling outages. Since Phase 1 changes only involve SOBR train-A chiller, the requested TS change is not applicable during this phase. Even though the SOSR chillers are not in the TS, inoperability of these chillers could lead to declaring other TS equipment supported by the SOBR chillers (e.g. Class 1E switchgears, motor control centers) to be inoperable.

3.1 Temporary Air Conditioning Equipment To compensate for the loss of one train of chillers serving the MCR and the SOBRs during each of the phases, TVA is proposing to install temporary chilled water systems. The temporary equipment is intended to mitigate the risk associated with the extended AOT. The temporary chilled water system will be connected and ready to be placed in service if the in-service permanent chiller train fail or become degraded. The major components of the temporary chilled water system will include an air cooled chilled water package, chilled water pump, chilled water pump supply and return hoses, manual isolation valves, demineralized water source, backup diesel generator (OG), power supplies, and cables. To a large extent, these

-4 components are skid-mounted packages on a flat bed trailer in the yard, self contained, completely assembled, thus requiring minimal installation time.

In Phase 1, one temporary chilled water system will be provided to supply chilled water to the train-B AHUs serving the SOBRs. The same chiller package will be reused in Phases 2 and 3.

In Phase 2, it will provide chilled water to the train-B AHU of the MCR. Since Phase 3 replaces both train-A MCR chiller and the train-A SOBR chiller concurrently, an additional temporary chiller package will also be provided in this phase, with one package having the ability to provide chilled water to the train-A AHU serving the MCR and the other package to the train-A AHUs serving the SOBRs. The chilled water supply and return lines from the temporary chiller packages in each phase will be routed to the appropriate AHUs (train-A or train-B) serving the MCR and the SOBRs.

In the LAR, TVA described the system sizing, the precautions and compensatory actions that will be taken during the implementation of the three phases.

3.1.1 System Sizing The temporary chilled water packages have a nominal cooling capacity of 150 tons. In contrast, the design basis loss-of-coolant accident (LOCA) heat loads are 86 tons in the MCR and 116 tons in the SOBR. The only change to the AHUs serving these rooms is to disconnect the permanent chilled water lines and reconnect the temporary chilled water lines from the temporary chilled water packages. The existing ducts to and from the AHUs, and the system dampers will not be affected during the applicable phases of implementation.

The design basis limit for the MCR is 104 OF. Based on calculations performed by TVA, it would take approximately 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> upon loss of cooling before this temperature limit is exceeded. TVA stated that the temporary chilled water system can be placed in service within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. TVA further stated that with LOCA heat loads considered, the temporary chilled water system is capable of maintaining room temperatures below 85°F. Based on this information, the NRC staff concludes that the air flows from the AHUs will be unaffected and the temporary chilled water packages working in conjunction with the AHUs are capable of meeting the cooling needs of the rooms, should the system be called on to operate.

3.1.2 Equipment Staging The temporary chiller packages will be stationed in the yard and the chilled water lines run from the chiller packages to the AHUs. Final connection of the chilled water lines to the AHUs will occur when the chiller train to be replaced is taken out of service. All necessary hardware will be staged at the AHUs for rapid deployment to disconnect and reconnect the chilled water lines and perform filling and venting operations. This process minimizes the time when the SOBR and the MCR would be without the benefit of the backup cooling system, albeit, a temporary system.

- 5 3.1.3 Power Supplies The temporary chiller packages will be stationed in the yard area and will be powered from nonsafety related 480 volt alternating current sources located within that area. Each of the temporary chiller packages will also be equipped with a non-safety related DG with sufficient kilovolt-ampere rating, to provide backup power to the temporary cooling system. The DG fuel oil tank is sized to last for 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, which is adequate time to take replenishing measures from sources located onsite.

3.1.4 Testing and Training Qualified personnel will be provided with training to operate the temporary cooling system training, including the backup power supply. The training will be conducted by supervisors and field engineers by using material such as vendor instructions, start-up procedures, work instructions, and on the job training. Post modification testing of the temporary cooling system and the newly installed chillers will be performed before declaring the systems operational. In addition, the first newly installed MCR chiller (train-B) will be operated for a minimum of 2 weeks prior to removing the train-A MCR chiller from service. Since the only available safety-related chiller will be the train-B MCR chiller during train-A MCR chiller replacement, the 2 week test provides a measure of confidence on the availability and reliability of the train-B chiller.

3.2 Control Room Habitability The MCR HVAC system together with the Main Control Room Habitability System (MCRHS) provides for the safe uninterrupted occupancy of the MCR Habitability Zone (MCRHZ) during an accident and subsequent recovery period. TVA stated that at WBN Unit 1, the MCRHZ is also referred to as the MCRHS area. The MCRHS area includes all rooms on Elevation 755 feet of the Control Building (CB).

As stated in Section 9.4.1 of the UFSAR of WBN Unit 1, MCRHS area isolation signal can be generated by a safety injection signal, high radiation or smoke concentration in the normal outside air intake. Upon the actuation of a MCRHS area isolation signal, the following conditions occur:

Automatic isolation valves in the AHU outside air intake ducts close and the emergency air cleanup system operates to recirculate a portion of the MCR air conditioning system return air through high efficiency particulate air (HEPA) filters and charcoal adsorbers.

The CB emergency pressurizing air supply fans operate to supply a reduced quantity of outside air to the MCR to keep the MCRHCS area pressurized. The intake air is routed through the emergency cleanup system.

All non safety-related ventilation fans in the CB that could impact the MCR pressurization and leakage characteristics will cease to operate, and the isolation valves and dampers in the ducts communicating with outside close.

-6 The MCRHZ is unaffected by the temporary chilled water system. There are no changes to the ductwork, AHU characteristics, or the various system air flows serving the MCRHZ. There are no changes to the emergency air cleaning system. There is no impact to post accident dose analysis. TVA stated that temporary equipment such as hoses, pipe, and fittings are qualified for adequate pressure to protect against rupture and pipe whip. The valves at the penetrations are qualified for seismic retention. TVA performed a transient combustible loading evaluation to verify that the fire severity indices of the spaces are not impacted by the temporary hoses.

TVA also stated that the temporary cooling system and associated devices will be designed such that safety related features will not be prevented from performing their safety function.

Plant components and their set points that could impact the ability to respond to accident conditions will not be altered by the temporary system. Based on the information provided by TVA, the NRC staff concludes that the temporary chiller packages and associated equipment will have no interface with the MCRHZ isolation, and therefore, will not impact the ability to isolate the MCRHZ or the ability of the emergency air cleanup system to function as designed.

3.2.1 Protection from Hazardous Chemical Releases The current licensing basis for protection from hazards created by accidental release of potentially toxic chemicals is contained in Section 6.4.4.2 of the UFSAR for WBN Unit 1. The UFSAR states that no hazard to control room habitability is posed by any of the chemicals stored on site, offsite within a 5-mile radius, or transported by the site by barge, rail, or road within a 5-mile radius. The guidelines in RG 1.78 address the in-leakage of hazardous materials. They have no bearing on control room cooling. The modification would not require any new penetrations to the MCRHZ. Therefore, the NRC staff finds that the proposed LAR satisfies the recommendations of RG 1.78.

3.3 Technical Specifications TS 3.7.11 "Control Room Emergency Air Temperature Control System:' Action A.1 requires restoration of CREATCS train to OPERABLE status, if one CREATCS train is inoperable, with a completion time of 30 days. In its letter dated February 24, 2011, TVA proposed to add an asterisk (*) next to the completion time and explain the asterisk as follows:

• An allowance is permitted for one CREA TCS train to be inoperable for 60 days. This TS provision is only applicable provided compensatory measures are implemented during modification activities planned for the upgrade of the MCR chillers beginning December 1, 2010, and ending January 29, 2012.

In the NRC staffs jUdgment, the explanation under the asterisk did not adequately describe the LAR sought by TVA. The requested increase in the allowable outage time (AOT) to 60 days should be applicable one time only, during each of the Phases 2 and 3. The explanation, as proposed, could be interpreted in a way that the increased AOT can be applied multiple times (Le., greater than 2 times) during the effective period between December 1, 2010, and January 29, 2020. In response to an RAI by the NRC staff, TVA proposed a modified explanation in a letter dated November 5, 2010, as follows:

-7

• An allowance is permitted for one CREA TCS train to be inoperable for 60 days. This TS provision is only authorized for one entry per train during modification activities planned for the upgrade of the MCR chillers beginning no earlier than March 1, 2011, and ending April 30, 2012, and provided compensatory measures are implemented.

The proposed note is acceptable to the NRC staff as it appropriately reflects the intent of the LAR and eliminates the potential for applying the increased AOT to situations beyond the intent of the LAR.

The design basis of the CREATCS is to maintain the control room temperature for 30 days of continuous occupancy. The 30 day Completion Time is based on the low probability of an event requiring control room isolation, the consideration that the remaining train can provide the required protection, and that alternate safety or nonsafety related cooling means are available.

TS 3.7.11 is applicable during MODES 1, 2,3,4,5, and 6, and during movement of irradiated fuel assemblies. Limiting Condition of Operation (LCO) 3.7.11 states "two CREATCS trains shall be operable." Action A.1 requires restoration of CREATCS train to OPERABLE status, if one CREATCS train is inoperable during Modes 1,2,3, or 4 (Le., Condition A), with a completion time of 30 days. TVA intends to install the replacement chillers during normal operations (i.e., Mode 1,2,3, or 4). TVA stated that if the operating CREATCS train becomes inoperable during the installation of the replacement chillers (i.e. the plant in action statement A.1, but with an increased AOT of 60 days), the plant will enter LCO 3.0.3 immediately as required TS 3.7.11, Action E. Therefore, insofar as the TS is concerned, there is no difference in how the condition of both the CREATCS trains inoperable is treated between the current TS 3.7.11 and proposed "one-time" AOT change to 60 days, thus assuring that the temporary chiller packages are not proposed as safety related substitutes for the permanent chiller being replaced during the extended AOT.

TVA stated that during the replacement of the chillers, no planned maintenance activity that could impact the operability of the permanent plant DGs that provide emergency power to the operable chiller train will be performed. However, surveillance requirements (SR) 3.8.12, "DG Auto Start," SR 3.8.13, "DG Load Capacity Test," and SR 3.8.1.7, "DG Fast Auto Start" will continue to be performed on all permanent plant emergency DGs. In response to an NRC staff request for additional information (RAI), TVA stated in letter dated November 5,2010, that when these SRs are in progress, the available chiller train would remain OPERABLE per TS 3.8.1, "AC Sources - Operating," provided two qualified offsite circuits are available. If one offsite power source is lost, the plant would enter LCO 3.8.1, Required Action A.2, "Declare required feature(s) with no offsite power available inoperable when its required redundant feature(s) is inoperable." This action would necessitate the available chiller train to be declared inoperable (if offsite power cannot be restored). Since both chiller trains would be inoperable under this scenario, TS 3.7.11, Required Action E, would subsequently enter TS 3.0.3 immediately. TVA further stated that if the DG that provides backup power to the qualified chiller in service becomes inoperable, LCO 3.8.1, Required Action B.2, and LCO 3.7.11, Required Action E, would force the plant to enter TS 3.0.3 immediately. Based on TVA's response, the NRC staff is satisfied that no credit is being taken for the temporary chillers in TS space.

-8 The SDBR chillers are not TS support equipment. In Section 2.1.3 of Attachment 1 to the LAR dated February 24,2010, TVA stated that"lftrain-B SDBR chiller were to fail during the installation of the new train-A SDBR chiller package, the plant will evaluate the impact and enter the appropriate TS action if required:' In a letter dated October 8,2010, TVA was requested to elaborate on the processes in place that would lead the applicant from the time SDBR chiller failures are discovered to when the determination is made that TSs are impacted. In a letter dated November 5,2010, TVA provided the requested explanation. TVP\s response is summarized as follows:

The SDBR chillers are designed such that one train of the SDBR cooling system can maintain the environmental conditions of both trains of the supported systems (i.e., Class 1E Distribution Systems) within design limits for all DBAs

[design basis accidents]. Loss of one SDBR chiller, as in the replacement process, does not result in a loss of safety function for the supported systems.

However, during the SDBR chiller replacement, the supported systems are vulnerable due to failure of the support system to meet the single failure criteria.

To compensate for this potential failure mode, TVA performs a risk assessment in accordance with the maintenance rule, 10 CFR 50.65(a)(4) to determine the appropriate AOT for one support system operable. The risk informed AOT for the SDBR chiller will have a duration of 60 days based on the AOT estimate provided in the LAR.

In the event both trains of SDBR chillers become inoperable during Phase 1 or Phase 3, the plant will conduct an operability evaluation of the supported equipment in accordance with the guidance in NRC Inspection Manual 9900. If the evaluation determines that the supported equipment is inoperable, the plant will enter LCO 3.8.9, Condition E of TS 3.8.9"Distribution Systems-Operating;'

which requires that the plant enter LCO 3.0.3 immediately. Condition Estates

'two trains with one or more inoperable distribution subsystems that result in a loss of safety function:'

The NRC staff finds that 10 CFR 50.36(c)(2) is satisfied even if the non-TS support SDBR chiller failures are discovered, because TVA has sufficient processes and procedures in place to determine if TSs are impacted.

3.4 Compensatory Measures TVA included the proposed compensatory measures (e.g., temporary chilled water system) in the revised bases of TS 3.7.11. TVA also included some of the requirements as licensee commitments. The commitments were included in Enclosure 3 of the LAR, dated February 24, 2010, and read as follows:

1. If a temporary chilled water system hose breaks in the Control Building during the time frame that the temporary equipment is installed, the two manual isolation ball valves located at the MCRHZ boundary will be closed immediately. Qualified personnel will be capable of closing the valves and will be stationed in the area whenever the valves are in the "Operl' position and the temporary cooling system is in service.

- 9

2. If a temporary chilled water system hose breaks in the Auxiliary Building or Shutdown Board Room during the timeframe that the temporary equipment is installed, the manual isolation valves will be closed immediately. Qualified personnel will be capable of closing the valves and will be stationed in the area whenever the valves are in the"Opeo' position and the temporary cooling system is in service.

3. Due to lack of operating data, the availability or reliability of the new MCR chiller packages are unknown. To compensate for this uncertainty the new train-B chiller packages will be operated for a minimum of 2 weeks prior to removing the train-A MCR chillers from service for replacement.

4. During replacement of the MCR chillers, no planned maintenance activity, except for SRs 3.8.12,3.8.1.3, and 3.8.1.7, that could impact the OPERABILITY of the DGs that provide emergency power to the OPERABLE MCR chiller train will be performed.

TVA stated and the NRC staff agrees that the temporary chiller packages are not intended as substitutes for the potential loss of the remaining OPERABLE MCR and SDBR chiller during replacement activities concurrent with a DBA. However, the proposed compensatory measures provide additional defense-in-depth during the replacement activities when only one train of an OPERABLE chiller is available. The safety related MCR cooling systems are support systems that control the temperature in the MCRHZ area to assist in maintaining a habitable environment for personnel and to protect the equipment qualification of safety related components in the control room area. The MCR cooling system does not perform actions required to mitigate the consequences of an accident. The functionality, and isolation capability of the MCRHZ, and the ability of the emergency air cleanup system to perform as designed are not affected by the proposed change. The proposed change ensures suitable environmental conditions for the control room and equipment, whenever one train of the CREATCS is inoperable for an interim period of time. If such conditions cannot be maintained, an immediate unit shutdown in accordance with TS 3.0.3 will be required. Therefore, the NRC staff finds that GDC-19 is satisfied.

3.5. Technical Conclusion Based on the foregoing evaluation, the NRC staff finds that there are no significant reductions in safety resulting from the requested AOT extension. The NRC staff finds that the "one-time' AOT change to 60 days is acceptable based on the compensatory measures and the low probability of an event requiring control room isolation, the consideration that the remaining train can provide the required protection, and that alternate safety or nonsafety related cooling means are available. The NRC staff finds that GDC-19 is satisfied. Therefore, based on a review of the information contained in the application, the NRC staff finds the proposed'bne time' increase of the AOT from 30 to 60 days in TS 3.7.11 is acceptable.

- 10

4.0 STATE CONSULTATION

In accordance with the Commission's regulations, the Tennessee State official was notified of the proposed issuance of the amendments. The State official had no comments.

5.0 ENVIRONMENTAL CONSIDERATION

The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (75 FR 30447). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.

6.0 CONCLUSION

The Commission has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.

Principal Contributors: Nageswara R. Karipineni Victor Cusumano Matt Hamm Date: February 8, 2011

Mr. R. M. Krich Vice President, Nuclear Licensing Tennessee Valley Authority 3R Lookout Place 11 01 Market Street Chattanooga, TN 37402-2801

SUBJECT:

WATTS BAR NUCLEAR PLANT, UNIT 1 - ISSUANCE OF AMENDMENT REGARDING THE MAIN CONTROL ROOM CHILLER COMPLETION TIME EXTENSION (TAC NO. ME3429)

Dear Mr. Krich:

The U.S. Nuclear Regulatory Commission has issued the enclosed Amendment No. 85 to Facility Operating License No. NPF-90 for Watts Bar Nuclear Plant, Unit 1. This amendment consists of changes to the Technical Specifications (TSs) in response to your application dated February 24,2010, as supplemented September 20,2010, and November 5,2010.

The amendment revises TS 3.7.11, "Control Room Emergency Air Temperature Control System (CREATCS)." Specifically, the proposed change will only be applicable during plant modifications to upgrade the CREATCS chillers. This "one-time" TS change will be implemented during Watts Bar Nuclear Plant, Unit 1 Cycles 10 and 11 beginning March 1, 2011, and ending April 30, 2012.

A copy of our related Safety Evaluation is also enclosed. The Notice of Issuance will be included in the Commission's biweekly Federal Register notice.

Sincerely, IRA!

John G. Lamb, Senior Project Manager Watts Bar Special Projects Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-390

Enclosures:

1. Amendment No. 85 to NPF-90

2. Safety Evaluation cc w/encls: Distribution via Listserv NRC Distribution: See next page ADAMS Accession No ML110190280 *via memorandum

~

OFFICE NRR/LPWB/PM NRR/LPWB/LA DSS/SCVB/BC DIRS/ITSB/BC NRR/LPWB/BC NAME JLamb BClayton RDennig' RElliott* SCampbell DATE 02/08/11 02/08111 01/19/11 01/25/11 I 02/07/11 02/08/11 OFFICIAL AGENCY RECORD