ML060680230

Comanche Peak 1 & 2, License Amendment, RWST Low Setpoint

ML060680230
Person / Time
Site:	Comanche Peak
Issue date:	03/30/2006
From:	Thadani M C NRC/NRR/ADRO/DORL/LPLG
To:	Blevins M R TXU Power
Thadani M C, NRR/DLPM, 415-1476
Shared Package
ML060680348	List: ML060680230 ML060900019
References
TAC MC2620, TAC MC2621
Download: ML060680230 (13)

Text

March 30, 2006Mr. M. R. Blevins Senior Vice President

& Chief Nuclear Officer TXU Power ATTN: Regulatory Affairs P. O. Box 1002 Glen Rose, TX 76043

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION (CPSES), UNITS 1 AND 2 -ISSUANCE OF AMENDMENTS RE: CHANGES TO TECHNICAL SPECIFICATION TRIP SETPOINT ALLOWABLE VALUES (TAC NOS. MC2620 AND MC2621)

Dear Mr. Blevins:

The Commission has issued the enclosed Amendment No. 125 to Facility Operating LicenseNumbered NPF-87 and Amendment No. 125 to Facility Operating License numbered NPF-89for CPSES, Units 1 and 2, respectively. The amendments consist of changes to the Technical Specifications (TSs) in response to your application dated April 13, 2004, as supplemented byletters dated March 18 and August 31, 2005, and January 6, 2006. The amendments revise TS 3.3.2, "Engineered Safety Feature Actuation SystemInstrumentation," function 7.b, "Refueling Water Storage Tank (RWST)-Level Low Low" trip setpoint allowable value, and revise the frequency for calibration of the level transmitters from 9 months to 18 months.

M. R. Blevins- 2 -A copy of our related Safety Evaluation is enclosed. The Notice of Issuance will be included in the Commission's next biweekly Federal Register notice.Sincerely,/RA/Mohan C. Thadani, Senior Project ManagerPlant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationDocket Nos. 50-445 and 50-446

Enclosures:

1. Amendment No. 125 to NPF-872. Amendment No. 125 to NPF-89

3. Safety Evaluationcc w/encls: See next page A copy of our related Safety Evaluation is enclosed. The Notice of Issuance will be included in the Commission's next biweekly Federal Register notice.Sincerely,/RA/Mohan C. Thadani, Senior Project ManagerPlant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationDocket Nos. 50-445 and 50-446

Enclosures:

1. Amendment No. 125 to NPF-872. Amendment No. 125 to NPF-89

3. Safety Evaluationcc w/encls: See next page DISTRIBUTION

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(Amd) (TS) (Pkg) OFFICENRR/LPL4/PMNRR/LPL4/LAEICB/CHIEFOGCNRR/LPL4/BCNAMEMThadaniDJohnsonAHoweSHamrick (NLOw/c)DTeraoDATE3/22/063/20/063/22/063/28/063/29/06OFFICIAL RECORD COPY TXU GENERATION COMPANY LPCOMANCHE PEAK STEAM ELECTRIC STATION, UNIT NO. 1DOCKET NO. 50-445AMENDMENT TO FACILITY OPERATING LICENSEAmendment No. 125License No. NPF-871.The Nuclear Regulatory Commission (the Commission) has found that:A.The application for amendment by TXU Generation Company LP dated April 13,2004, as supplemented by letters dated March 18 and August 31, 2005, and January 6, 2006, complies with the standards and requirements of the AtomicEnergy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I;B.The facility will operate in conformity with the application, as amended, theprovisions of the Act, and the rules and regulations of the Commission;C.There is reasonable assurance (i) that the activities authorized by thisamendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with theCommission's regulations;D.The issuance of this license amendment will not be inimical to the commondefense and security or to the health and safety of the public; andE.The issuance of this amendment is in accordance with 10 CFR Part 51 of theCommission's regulations and all applicable requirements have been satisfied.2.Accordingly, the license is amended by changes to the Technical Specifications asindicated in the attachment to this license amendment; and paragraph 2.C.(2) of FacilityOperating License No. NPF-87 is hereby amended to read as follows: (2)Technical Specifications and Environmental Protection PlanThe Technical Specifications contained in Appendix A, as revised throughAmendment No. 125 , and the Environmental Protection Plan contained in Appendix B, are hereby incorporated into this license. TXU Generation Company LP shall operate the facility in accordance with the TechnicalSpecifications and the Environmental Protection Plan.3.The license amendment is effective as of its date of issuance and shall be implementedwithin 60 days from the date of issuance.FOR THE NUCLEAR REGULATORY COMMISSION/RA/David Terao, ChiefPlant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Attachment:

Changes to the Technical SpecificationsDate of Issuance: March 30, 2006 TXU GENERATION COMPANY LPCOMANCHE PEAK STEAM ELECTRIC STATION, UNIT NO. 2DOCKET NO. 50-446AMENDMENT TO FACILITY OPERATING LICENSEAmendment No. 125License No. NPF-891.The Nuclear Regulatory Commission (the Commission) has found that:A.The application for amendment by TXU Generation Company LP dated April 13,2004, as supplemented by letters dated March 18 and August 31, 2005, and January 6, 2006, complies with the standards and requirements of the AtomicEnergy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I;B.The facility will operate in conformity with the application, as amended, theprovisions of the Act, and the rules and regulations of the Commission;C.There is reasonable assurance (i) that the activities authorized by thisamendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with theCommission's regulations;D.The issuance of this license amendment will not be inimical to the commondefense and security or to the health and safety of the public; andE.The issuance of this amendment is in accordance with 10 CFR Part 51 of theCommission's regulations and all applicable requirements have been satisfied.2.Accordingly, the license is amended by changes to the Technical Specifications asindicated in the attachment to this license amendment; and paragraph 2.C.(2) of FacilityOperating License No. NPF-89 is hereby amended to read as follows: (2)Technical Specifications and Environmental Protection PlanThe Technical Specifications contained in Appendix A, as revised throughAmendment No. 125 , and the Environmental Protection Plan contained in Appendix B, are hereby incorporated into this license. TXU Generation Company LP shall operate the facility in accordance with the TechnicalSpecifications and the Environmental Protection Plan.3.This license amendment is effective as of its date of issuance and shall be implementedwithin 60 days from the date of issuance.FOR THE NUCLEAR REGULATORY COMMISSION/RA/David Terao, ChiefPlant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Attachment:

Changes to the Technical SpecificationsDate of Issuance: March 30, 2006 ATTACHMENT TO LICENSE AMENDMENT NO. 125 TO FACILITY OPERATING LICENSE NO. NPF-87AND AMENDMENT NO. 125 TO FACILITY OPERATING LICENSE NO. NPF-89DOCKET NOS. 50-445 AND 50-446Replace the following pages of the Appendix A Technical Specifications with the attachedrevised pages. The revised pages are identified by amendment number and contain marginal lines indicating the areas of change. RemoveInsert3.3-283.3-283.3-343.3-34 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATIONRELATED TO AMENDMENT NO. 125 TOFACILITY OPERATING LICENSE NO. NPF-87AND AMENDMENT NO. 125 TOFACILITY OPERATING LICENSE NO. NPF-89TXU GENERATION COMPANY LPCOMANCHE PEAK STEAM ELECTRIC STATION, UNITS 1 AND 2DOCKET NOS. 50-445 AND 50-44

61.0INTRODUCTION

By letter dated April 13, 2004 (Agencywide Documents Access and Management System(ADAMS) Accession No. ML041110871), as supplemented by letters dated March 18 (ADAMS Accession No. ML050960499), and August 31, 2005 (ADAMS Accession No. ML052550055),

and January 6, 2006 (ADAMS Accession No. ML060130225), TXU Generation Company LP (the licensee) requested changes to the Technical Specifications (TSs) for Comanche Peak Steam Electric Station (CPSES), Units 1 and 2. The amendments revise TS 3.3.2, "EngineeredSafety Features Actuation System (ESFAS) Instrumentation," Function 7.b, "Refueling WaterStorage Tank (RWST) Level - Low Low," trip setpoint allowable value (AV), and revise the frequency for calibration of the level transmitters from 9 months to 18 months. The supplemental letters dated March 18 and August 31, 2005, and January 6, 2006, providedadditional information that clarified the application, did not expand the scope of the applicationas originally noticed, and did not change the staff's original proposed no significant hazards consideration determination as published in the Federal Register on May 11, 2004(69 FR 26193).

2.0REGULATORY EVALUATION

Title 10 of the Code of Federal Regulations (10 CFR) Section 50.36, "Technical specifications,"requires that the limiting safety system setting (LSSS) be included in the TS. Either the limitingtrip setpoint (TSP) value or a reference to the method for determining the limiting TSP value needs to be specified in the TS. At many plants, AVs are identified as LSSS and provide acceptance criteria for determination of instrument channel operability during periodicsurveillance testing.

3.0TECHNICAL EVALUATION

3.1Background of the Proposed ChangeThe refueling water storage tank (RWST) water level low-low trip function initiates the semi-automatic switchover of the emergency core cooling system (ECCS) pump suctions from the RWST to the containment sump. At the end of the injection phase of a loss of coolant accident the RWST will be nearly empty. Continued cooling must be provided by the ECCS to removedecay heat. The source of water for the ECCS pumps is automatically switched to the containment sump. Switchover from the RWST to the containment sump must occur before the RWST empties to prevent damage to the residual heat removal pumps and a loss of core cooling capability. Early switchover must not occur to ensure that sufficient borated water isinjected from the RWST to the reactor core. This ensures that the reactor remains shut down in the recirculation mode.The RWST water level low-low trip function setpoint is selected based on net positive suctionhead requirements and prescribed operator response times. The nominal setpoint was previously reviewed and approved by the NRC staff in Amendment 73. The calculations of theAVs for both units were performed in accordance with WCAP-12123, "Westinghouse Setpoint Methodology for Protection Systems, Comanche Peak [Steam Electric Station,] Unit 1, Revision 1," April 1989. The current difference in the AVs between Unit 1 and Unit 2 is a direct result of the difference in the uncertainties for differential pressure transmitters used for this application. Veritrak transmitters were originally used in Unit 1. Rosemount transmitters were used in Unit 2. Due to the relatively large drift associated with the Veritrak transmitters, Unit 1 was required to perform a sensor calibration surveillance at 9-month intervals. The Rosemounttransmitters have displayed significantly better performance than the Veritrak transmitters with respect to sensor drift. In order to standardize the uncertainty calculation for both units, the licensee conservatively provided a uniform allowance for the sensor drift on Unit 2, based on Unit 1 sensor drift. Thus, the sensor calibration surveillance at 9-month intervals was implemented for both units for this trip function. The Veritrak differential pressure transmitters on Unit 1 have since been replaced with the same model of Rosemount differential pressure transmitters used on Unit 2. As a result, it is not necessary to retain the larger allowance for transmitter drift. A new uncertainty analysis, based on the use of Rosemount transmitters in both units and consistent with the previously reviewed methodology described in WCAP-12123, has been developed. The same nominal trip setpoint and the same allowable value can be used for both units. Due to the stability of the Rosemount differential pressure transmitter, therequirement to perform sensor calibration surveillance tests at 9-month intervals can bereplaced by the more standard 18-month surveillance test interval. The 9-month test intervalonly applies to the RWST level low-low trip channels, the 18-month test interval applies to all other trip channels. 3.2Proposed TS ChangesThe licensee proposed to revise TS Table 3.3.2-1, Engineered Safety Features ActuationSystem (ESFAS) Instrumentation, Function 7.b, Refueling Water Storage Tank (RWST) - Level Low Low, to delete the unique value for Unit 2 and the unit-specific designation for the remaining value, thereby specifying only one value which would be equally applicable to each unit. The proposed change would eliminate the current unit difference in surveillance interval. The proposed change would also delete SR 3.3.2.12 from the Surveillance Requirements (SR)column for Function 7.b and insert SR 3.3.2.9. Both SR 3.3.2.9 and 3.3.2.12 require theperformance of a channel calibration. SR 3.3.2.12 is performed at 9 month intervals while SR 3.3.2.9 is performed every 18 months. SR 3.3.2.12 is deleted from the TS since there areno other functions which require its use.3.3Instrument Setpoint MethodologyThe TS defines the LSSS as an AV. During reviews of industry-proposed license amendmentsthat contain changes to LSSS setpoints, the staff identified concerns regarding the methodused by the licensee to determine the AVs. The AVs are used in the TS as LSSSs to provide acceptance criteria for determination of instrument channel operability during periodicsurveillance testing. The AV is an operability limit in TS. The Bases must state that the limitingtrip setpoint preserves the safety limit and, therefore, the LSSS required by 10 CFR 50.36 ismet. In order for the NRC staff to assess the acceptability of this amendment request, the staffrequested the licensee to provide additional information to address the following issues:(1)For each setpoint to be changed, the licensee was asked to clarify whether it is an LSSSrelated to a variable upon which a safety limit has been placed.(2)The licensee was asked to discuss how the methodology and controls at the plant inplace ensure that the AV associated with an LSSS will not be exc eeded.(3)The licensee was asked how the TS surveillance ensures the operability of theinstrument channel.Additional information was provided to the industry by the NRC staff in a letter dated August 23,2005, from Mr. B. Boger, NRC, to Mr. Marion, Nuclear Energy Institute, "Instrumentation,Systems, and Automation Society (ISA) S67.04 Methods for Determining Trip Setpoints and Allowable Values for Safety-Related Instrumentation." In this letter, the staff discussed the concepts that it felt would satisfactorily address both the staff's and industry's concerns with instrument settings, and ensure compliance with 10 CFR 50.36.Additionally, the staff requested from the licensee additional information associated with theoperability of instrument settings related to the request for amendments. The NRC staff statedthat demonstration of the operability of instruments is needed to ensure compliance with therequirements of 10 CFR 50.36(c)(3), which requires that TS surveillance demonstrates that theplant is operating within its safety limits. The NRC staff also informed the licensee thatverification that the instrument is functioning as required is an integral part of this periodic testing. By supplemental letters dated August 31, 2005, and January 6, 2006, the licensee respondedto the staff's questions and stated that:(1)RWST level low-low trip function (TS ESFAS function 7.b) is not a function provided bythe Reactor Protection System (RPS), does not provide any signal or input which is used to generate a protection signal provided by the Reactor Protection System, anddoes not protect any reactor Safety Limit. Therefore, RWST Level is not a variable for which a LSSS has been specified for protection of a reactor safety limit.(2)The licensee currently assesses the operability and performance of the RWST levellow-low instrumentation, based on as-found instrument setting compared to calibration tolerances and AVs. These values account for uncertainties associated with the test or calibration and instrument drift. If the instrument is found beyond the AV, it is declared inoperable. If it is found outside the calibration tolerance about the nominal trip setpoint but within, or more conservative than, the AV, the channel is evaluated in the correctiveaction program for performance, reliability, and continued long-term operability. Thelicensee will include changes or clarifications to this practice in future licenseamendments. The licensee has committed to the above assertions.(3)The proposed TS changes incorporate a footnote, "The as-left instrument setting shallbe returned to a setting within the tolerance band of the trip setpoint established to protect the safety limit." These provision were already contained in the TS Bases.The staff has examined the TS Bases for the Comache Peak Steam Electric Station (CPSES),Units 1 and 2, TS Section 2.1.1, "Reactor Core Safety Limits." The staff noted that protectingthe fuel design limits is accomplished by having a departure from nucleate boiling design basis. The proper functioning of the RPS and steam generator safety valves prevents violation of the reactor core Safety Limits (SLs). RWST level low-low trip function (TS ESFAS function 7.b) is not a function provided by the RPS, does not provide any signal or input which is used to generate a protection signal provided by the RPS, and does not protect any reactor SL.

Therefore, RWST Level is not a variable for which a LSSS has been specified for protection of a reactor SL. The staff finds that the proposed setpoint change for the RWST level does not affect the protection of the reactor SL. The additional clarifications in the licensee's responses to NRC's requests for additionalinformation provided the NRC staff with reasonable assurance that the methodology andcontrols at the plant in place will ensure that the AV associated with the RWST level low-low instrumentation will not be exceeded, and the TS surveillance will ensure the operability of theinstrument channel.In addition, the licensee made an explicit regulatory commitment to submit a licenseamendment request to adopt the final Technical Specification Task Force (TSTF) TS changes, as they may be applicable to CPSES, Units 1 and 2, for the first proposed setpoint-related changes occuring more than 120 days after the approved TSTF is made available for adoption via the consolidated line item improvement process.3.4RWST Level Instrument Calibration Frequency ChangeAs stated above, the Veritrak differential pressure transmitters on Unit 1 have since beenreplaced with the Rosemount differential pressure transmitters used on Unit 2. As a result, the licensee has determined that it is not necessary to retain the larger allowance for transmitter drift that was based on the performance of Veritrak transmitters. The licensee has performed a new uncertainty analysis, based on the use of Rosemount transmitters in both units andconsistent with the previously reviewed methodology described in WCAP-12123. The licensee has determined that the nominal trip setpoint and the AVs used for Unit 2 can be used for Unit 1also. In addition, because of the drift stability of the Rosemount differential pressuretransmitters common to both units, the requirement to perform sensor calibration surveillancetests at 9-month intervals can be replaced by the more standard 18-month surveillance testinterval at both units. The NRC staff finds the licensee's conclusions acceptable. The licensee has proposed to delete SR 3.3.2.12 for Function 7.b and insert SR 3.3.2.9. BothSR 3.3.2.9 and 3.3.2.12 require the performance of a channel calibration. SR 3.3.2.12 isperformed at 9-month intervals while SR 3.3.2.9 is performed every 18 months. SR 3.3.2.12 isdeleted from the TS since there are no other functions which required its use. As stated above,the licensee replaced the Veritrak transmitters with the Rosemount transmitters for Function 7.b, RWST level low-low trip function, and previously demonstrated the suitability ofan 18-month surveillance interval for Rosemount transmitters during licensing of Unit 2.

Therefore, the staff finds the 18 months interval acceptable for Unit 1.3.5Summary ConclusionsBased on the above review of the licensee's submittals, the staff finds that the licensee hasproperly addressed the instrument setpoint methodology concerns. The staff finds the licensee's determination that the RWST Level is not a variable for which an LSSS has been specified for protection of a reactor SL, acceptable. There is reasonable assurance that the methodology and controls in place at the plant will ensure that the AV associated with theRWST level low-low instrumentation will not be exceeded. There is reasonable assurance thatthe TS surveillance will ensure the operability of the instrument channel. The licensee hasprovided analyses during the plant license stage that support the use of Rosemount transmitters with an 18-month surveillance frequency. Therefore, the staff finds the proposed request for TS changes acceptable.

4.0STATE CONSULTATION

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

5.0ENVIRONMENTAL CONSIDERATION

The amendments change a requirement with respect to installation or use of a facilitycomponent located within the restricted area as defined in 10 CFR Part 20 and changes surveillance requirements. The NRC staff has determined that the amendments involve nosignificant increase in the amounts, and no significant change in the types, of any effluents thatmay 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 amendments involve no significant hazards consideration, and there has been nopublic comment on such finding published May 11, 2004 (69 FR 26193). The amendment also relates to changes in recordkeeping, reporting, or administrative procedures or requirements.

Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in10 CFR 51.22(c)(9) and 10 CFR 51.22(c)(10). Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.

6.0CONCLUSION

The Commission has concluded, based on the considerations discussed above, that: (1) thereis reasonable assurance that the health and safety of the public will not be endangered byoperation 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 thecommon defense and security or to the health and safety of the public.Principal Contributor: H. Li Date: March 30, 2006 December 2004Comanche Peak Steam Electric Station cc:Senior Resident InspectorU.S. Nuclear Regulatory Commission P. O. Box 2159 Glen Rose, TX 76403-2159Regional Administrator, Region IVU.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011Mr. Fred W. Madden, DirectorRegulatory Affairs TXU Generation Company LP P. O. Box 1002 Glen Rose, TX 76043George L. Edgar, Esq.Morgan Lewis 1111 Pennsylvania Avenue, NW Washington, DC 20004County Judge P. O. Box 851 Glen Rose, TX 76043Environmental and Natural Resources Policy Director Office of the Governor P. O. Box 12428 Austin, TX 78711-3189Mr. Richard A. Ratliff, ChiefBureau of Radiation Control Texas Department of Health 1100 West 49th Street Austin, TX 78756-3189Mr. Brian AlmonPublic Utility Commission William B. Travis Building P. O. Box 13326 1701 North Congress Avenue Austin, TX 78701-3326Ms. Susan M. JablonskiOffice of Permitting, Remediation and Registration Texas Commission on Environmental Quality MC-122 P. O. Box 13087 Austin, TX 78711-3087Terry Parks, Chief InspectorTexas Department of Licensing and Regulation Boiler Program P. O. Box 12157 Austin, TX 78711