ML060680230

License Amendment, RWST Low Setpoint

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

Text

March 30, 2006 Mr. 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 License Numbered NPF-87 and Amendment No. 125 to Facility Operating License numbered NPF-89 for 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 by letters dated March 18 and August 31, 2005, and January 6, 2006.

The amendments revise TS 3.3.2, Engineered Safety Feature Actuation System Instrumentation, 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 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 Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-445 and 50-446

Enclosures:

1. Amendment No. 125 to NPF-87

2. Amendment No. 125 to NPF-89

3. Safety Evaluation cc 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 Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-445 and 50-446

Enclosures:

1. Amendment No. 125 to NPF-87

2. Amendment No. 125 to NPF-89

3. Safety Evaluation cc w/encls: See next page DISTRIBUTION:

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RidsNrrDirsItsb HLi RidsRgn4MailCenter RidsNrrDorl AHowe Accession No.: (Amd) (TS) (Pkg)

OFFICE NRR/LPL4/PM NRR/LPL4/LA EICB/CHIEF OGC NRR/LPL4/BC NAME MThadani DJohnson AHowe SHamrick (NLO DTerao w/c)

DATE 3/22/06 3/20/06 3/22/06 3/28/06 3/29/06 OFFICIAL RECORD COPY

TXU GENERATION COMPANY LP COMANCHE PEAK STEAM ELECTRIC STATION, UNIT NO. 1 DOCKET NO. 50-445 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 125 License No. NPF-87

1. 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 Atomic Energy 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, 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 license 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. 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-87 is hereby amended to read as follows:

(2) Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A, as revised through Amendment 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 Technical Specifications and the Environmental Protection Plan.

3. The license amendment is effective as of its date of issuance and shall be implemented within 60 days from the date of issuance.

FOR THE NUCLEAR REGULATORY COMMISSION

/RA/

David Terao, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Attachment:

Changes to the Technical Specifications Date of Issuance: March 30, 2006

TXU GENERATION COMPANY LP COMANCHE PEAK STEAM ELECTRIC STATION, UNIT NO. 2 DOCKET NO. 50-446 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 125 License No. NPF-89

1. 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 Atomic Energy 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, 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 license 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. 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-89 is hereby amended to read as follows:

(2) Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A, as revised through Amendment 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 Technical Specifications and the Environmental Protection Plan.

3. This license amendment is effective as of its date of issuance and shall be implemented within 60 days from the date of issuance.

FOR THE NUCLEAR REGULATORY COMMISSION

/RA/

David Terao, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Attachment:

Changes to the Technical Specifications Date of Issuance: March 30, 2006

ATTACHMENT TO LICENSE AMENDMENT NO. 125 TO FACILITY OPERATING LICENSE NO. NPF-87 AND AMENDMENT NO. 125 TO FACILITY OPERATING LICENSE NO. NPF-89 DOCKET NOS. 50-445 AND 50-446 Replace the following pages of the Appendix A Technical Specifications with the attached revised pages. The revised pages are identified by amendment number and contain marginal lines indicating the areas of change.

Remove Insert 3.3-28 3.3-28 3.3-34 3.3-34

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 125 TO FACILITY OPERATING LICENSE NO. NPF-87 AND AMENDMENT NO. 125 TO FACILITY OPERATING LICENSE NO. NPF-89 TXU GENERATION COMPANY LP COMANCHE PEAK STEAM ELECTRIC STATION, UNITS 1 AND 2 DOCKET NOS. 50-445 AND 50-446

1.0 INTRODUCTION

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, Engineered Safety Features Actuation System (ESFAS) Instrumentation, Function 7.b, Refueling Water Storage 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, provided additional information that clarified the application, did not expand the scope of the application as 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).

2.0 REGULATORY 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 limiting trip 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 periodic surveillance testing.

3.0 TECHNICAL EVALUATION

3.1 Background of the Proposed Change The 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 remove decay 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 is injected 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 suction head requirements and prescribed operator response times. The nominal setpoint was previously reviewed and approved by the NRC staff in Amendment 73. The calculations of the AVs 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 Rosemount transmitters 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, the requirement to perform sensor calibration surveillance tests at 9-month intervals can be replaced by the more standard 18-month surveillance test interval. The 9-month test interval only applies to the RWST level low-low trip channels, the 18-month test interval applies to all other trip channels.

3.2 Proposed TS Changes The licensee proposed to revise TS Table 3.3.2-1, Engineered Safety Features Actuation System (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 the performance 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 are no other functions which require its use.

3.3 Instrument Setpoint Methodology The TS defines the LSSS as an AV. During reviews of industry-proposed license amendments that contain changes to LSSS setpoints, the staff identified concerns regarding the method used 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 periodic surveillance testing. The AV is an operability limit in TS. The Bases must state that the limiting trip setpoint preserves the safety limit and, therefore, the LSSS required by 10 CFR 50.36 is met. In order for the NRC staff to assess the acceptability of this amendment request, the staff requested 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 LSSS related 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 in place ensure that the AV associated with an LSSS will not be exceeded.

(3) The licensee was asked how the TS surveillance ensures the operability of the instrument 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 staffs and industrys concerns with instrument settings, and ensure compliance with 10 CFR 50.36.

Additionally, the staff requested from the licensee additional information associated with the operability of instrument settings related to the request for amendments. The NRC staff stated that demonstration of the operability of instruments is needed to ensure compliance with the requirements of 10 CFR 50.36(c)(3), which requires that TS surveillance demonstrates that the plant is operating within its safety limits. The NRC staff also informed the licensee that verification 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 responded to the staffs questions and stated that:

(1) RWST level low-low trip function (TS ESFAS function 7.b) is not a function provided by the 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, and does 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 level low-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 corrective action program for performance, reliability, and continued long-term operability. The licensee will include changes or clarifications to this practice in future license amendments. The licensee has committed to the above assertions.

(3) The proposed TS changes incorporate a footnote, "The as-left instrument setting shall be 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 protecting the 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 licensees responses to NRC's requests for additional information provided the NRC staff with reasonable assurance that the methodology and controls 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 the instrument channel.

In addition, the licensee made an explicit regulatory commitment to submit a license amendment 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.

3.4 RWST Level Instrument Calibration Frequency Change As stated above, the Veritrak differential pressure transmitters on Unit 1 have since been replaced 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 and consistent 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 1 also. In addition, because of the drift stability of the Rosemount differential pressure transmitters common to both units, the requirement to perform sensor calibration surveillance tests at 9-month intervals can be replaced by the more standard 18-month surveillance test interval at both units. The NRC staff finds the licensees conclusions acceptable.

The licensee has proposed to delete SR 3.3.2.12 for Function 7.b and insert SR 3.3.2.9. Both SR 3.3.2.9 and 3.3.2.12 require the performance 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 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 of an 18-month surveillance interval for Rosemount transmitters during licensing of Unit 2.

Therefore, the staff finds the 18 months interval acceptable for Unit 1.

3.5 Summary Conclusions Based on the above review of the licensees submittals, the staff finds that the licensee has properly addressed the instrument setpoint methodology concerns. The staff finds the licensees 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 the RWST level low-low instrumentation will not be exceeded. There is reasonable assurance that the TS surveillance will ensure the operability of the instrument channel. The licensee has provided 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.

4.0 STATE CONSULTATION

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

5.0 ENVIRONMENTAL CONSIDERATION

The amendments change a requirement with respect to installation or use of a facility component 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 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 amendments involve no significant hazards consideration, and there has been no public 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 in 10 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.

6.0 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 Contributor: H. Li Date: March 30, 2006

Comanche Peak Steam Electric Station cc:

Senior Resident Inspector Mr. Brian Almon U.S. Nuclear Regulatory Commission Public Utility Commission P. O. Box 2159 William B. Travis Building Glen Rose, TX 76403-2159 P. O. Box 13326 1701 North Congress Avenue Regional Administrator, Region IV Austin, TX 78701-3326 U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Ms. Susan M. Jablonski Arlington, TX 76011 Office of Permitting, Remediation and Registration Mr. Fred W. Madden, Director Texas Commission on Environmental Regulatory Affairs Quality TXU Generation Company LP MC-122 P. O. Box 1002 P. O. Box 13087 Glen Rose, TX 76043 Austin, TX 78711-3087 George L. Edgar, Esq. Terry Parks, Chief Inspector Morgan Lewis Texas Department of Licensing 1111 Pennsylvania Avenue, NW and Regulation Washington, DC 20004 Boiler Program P. O. Box 12157 County Judge Austin, TX 78711 P. O. Box 851 Glen Rose, TX 76043 Environmental and Natural Resources Policy Director Office of the Governor P. O. Box 12428 Austin, TX 78711-3189 Mr. Richard A. Ratliff, Chief Bureau of Radiation Control Texas Department of Health 1100 West 49th Street Austin, TX 78756-3189 December 2004