ML060960075

License Amendment 61 Regarding the Change in the Steam Generator Narrow-Range Level Requirements to Accommodate the Replacement Steam Generators

ML060960075
Person / Time
Site:	Watts Bar
Issue date:	05/05/2006
From:	Pickett D Plant Licensing Branch III-2
To:	Singer K Tennessee Valley Authority
Pickett , NRR/DLPM, 415-1364
Shared Package
ML061280210	List: ML060960075 ML061280491
References
TAC MC9235
Download: ML060960075 (15)

Text

May 5, 2006Mr. Karl W. Singer Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, Tennessee 37402-2801

SUBJECT:

WATTS BAR NUCLEAR PLANT, UNIT 1 - ISSUANCE OF AMENDMENTREGARDING THE CHANGE IN THE STEAM GENERATOR NARROW RANGE LEVEL REQUIREMENTS TO ACCOMMODATE THE REPLACEMENT STEAM GENERATORS AT WATTS BAR NUCLEAR PLANT, UNIT 1 (TAC NO. MC 9235)

Dear Mr. Singer:

The Commission has issued the enclosed Amendment No. 61 to Facility Operating LicenseNo. NPF-90 for Watts Bar Nuclear Plant (WBN), Unit 1. This amendment is in response to your application dated December 13, 2005 (WB-TS-05-06).The amendment authorizes modification to the Technical Specifications for WBN, Unit 1 toinclude a change in the steam generator (SG) level requirement for Limiting Condition for Operation 3.4.7.b and Surveillance Requirements 3.4.5.2, 3.4.6.3 and 3.4.7.2 from greater thanor equal to () 6 percent (%) to 32% following replacement of the SGs during the Unit 1,Cycle 7 refueling outage, which is currently scheduled to begin in the fall of 2006.A copy of the safety evaluation is also enclosed. Notice of issuance will be included in theCommission's biweekly Federal Register notice. Sincerely,/RA/ Douglas V. Pickett, Senior Project Manager Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationDocket No. 50-390

Enclosures:

1. Amendment No. 61 to NPF-90

2. Safety Evaluationcc w/enclosures: See next page May 5, 2006Mr. Karl W. Singer Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, Tennessee 37402-2801

SUBJECT:

WATTS BAR NUCLEAR PLANT, UNIT 1 - ISSUANCE OF AMENDMENTREGARDING THE CHANGE IN THE STEAM GENERATOR NARROW RANGE LEVEL REQUIREMENTS TO ACCOMMODATE THE REPLACEMENT STEAM GENERATORS AT WATTS BAR NUCLEAR PLANT, UNIT 1 (TAC NO. MC 9235)

Dear Mr. Singer:

The Commission has issued the enclosed Amendment No. 61 to Facility Operating LicenseNo. NPF-90 for Watts Bar Nuclear Plant (WBN), Unit 1. This amendment is in response to your application dated December 13, 2005 (WB-TS-05-06).The amendment authorizes modification to the Technical Specifications for WBN, Unit 1 toinclude a change in the steam generator (SG) level requirement for Limiting Condition for Operation 3.4.7.b and Surveillance Requirements 3.4.5.2, 3.4.6.3 and 3.4.7.2 from greater thanor equal to () 6 percent (%) to 32% following replacement of the SGs during the Unit 1,Cycle 7 refueling outage, which is currently scheduled to begin in the fall of 2006.A copy of the safety evaluation is also enclosed. Notice of issuance will be included in theCommission's biweekly Federal Register notice. Sincerely,/RA/ Douglas V. Pickett, Senior Project Manager Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationDocket No. 50-390

Enclosures:

1. Amendment No. 61 to NPF-90

2. Safety Evaluationcc w/enclosures: See next page DISTRIBUTION:PUBLICLPL2-2 r/fRidsOgcRpRidsAcrsAcnwMailCenterG. Hill, OIS (2)RidsNrrDorlLpl2-2 RidsNrrLACSolaRidsNrrPMDPickett S. Crane, NRR RidsNrrDssSpwbRidsRgn2MailCenterRidsNrrDorlDprRidsNrrDirsItsbPackage No.: ML061280210TS: ML061280491ADAMS Accession No. ML060960075*No Legal ObjectionNRR-058OFFICELPL2-2/PELPL2-2/PMLPL2-2/LASPWB/BCOGCLPL2-2/BCNAMESCrane:emDPickettRSolaJNakoskiSUttal *MMarshallDATE04/25/0604/24/0604/24/0604/26/0605/02/0605/05/06 OFFICIAL RECORD COPY Mr. Karl W. Singer Tennessee Valley Authority WATTS BAR NUCLEAR PLANT cc:Mr. Ashok S. Bhatnagar, Senior Vice President Nuclear Operations Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Larry S. Bryant, Vice PresidentNuclear Engineering & Technical Services Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801Mr. Robert J. Beecken, Vice PresidentNuclear Support Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Michael D. SkaggsSite Vice President Watts Bar Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Spring City, TN 37381General CounselTennessee Valley Authority ET 11A 400 West Summit Hill DriveKnoxville, TN 37902Mr. John C. Fornicola, ManagerNuclear Assurance and Licensing Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801Ms. Ann P. Harris341 Swing Loop Road Rockwood, Tennessee 37854Mr. Glenn W. Morris, Manager Corporate Nuclear Licensing and Industry Affairs Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801Mr. Paul L. Pace, ManagerLicensing and Industry Affairs Watts Bar Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Spring City, TN 37381Mr. Jay Laughlin, Plant ManagerWatts Bar Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Spring City, TN 37381Senior Resident InspectorWatts Bar Nuclear Plant U.S. Nuclear Regulatory Commission 1260 Nuclear Plant Road Spring City, TN 37381County Executive 375 Church Street Suite 215 Dayton, TN 37321County Mayor P. O. Box 156 Decatur, TN 37322Mr. Lawrence E. Nanney, DirectorDivision of Radiological Health Dept. of Environment & Conservation Third Floor, L and C Annex 401 Church Street Nashville, TN 37243-1532 TENNESSEE VALLEY AUTHORITYDOCKET NO. 50-390WATTS BAR NUCLEAR PLANT, UNIT 1AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 61 License No. NPF-90 1.The Nuclear Regulatory Commission (the Commission) has found that:A.The application for amendment by Tennessee Valley Authority (the licensee)dated December 13, 2005, 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, the provisions of theAct, 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 amendment will not be inimical to the common defense andsecurity 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-90 is hereby amended to read as follows:(2)Technical Specifications and Environmental Protection PlanThe Technical Specifications contained in Appendices A and B, as revisedthrough Amendment No. 61, 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 TechnicalSpecifications and the Environmental Protection Plan.3.This license amendment is effective as of the date of its issuance, and shall beimplemented prior to entering Mode 5 upon restart from the Unit 1 Cycle 7 (U1C7)

Refueling Outage.FOR THE NUCLEAR REGULATORY COMMISSION/RA/Michael L. Marshall, Jr., ChiefPlant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Attachment:

Changes to the TechnicalSpecificationsDate of Issuance: May 5, 2006 ATTACHMENT TO LICENSE AMENDMENT NO. 61FACILITY OPERATING LICENSE NO. NPF-90DOCKET NO. 50-390Replace the following pages of the Appendix A Technical Specifications with the attachedpages. REMOVEINSERT3.4-103.4-103.4-133.4-13 3.4-143.4-14 3.4-153.4-15 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATIONRELATED TO AMENDMENT NO. 61 TO FACILITY OPERATING LICENSE NO. NPF-90TENNESSEE VALLEY AUTHORITYWATTS BAR NUCLEAR PLANT, UNIT 1DOCKET NO. 50-39

01.0 INTRODUCTION

By application dated December 13, 2005 (Agencywide Documents Access ManagementSystem accession number, ML053530127), Tennessee Valley Authority (the licensee) requested changes to the Technical Specifications (TSs) of the license of Watts Bar Nuclear Plant (WBN) Unit 1. Notice of this amendment request was given through the Federal Registeron February 14, 2006 (71 FR 7814).The requested changes provide a revision to the WBN TSs to revise the steam generator (SG)level requirement for Limiting Condition for Operation (LCO) 3.4.7.b and SurveillanceRequirements (SRs) 3.4.5.2, 3.4.6.3 and 3.4.7.2 from greater than or equal to () 6 percent (%)

to 32% following replacement of the SGs during the Unit 1, Cycle 7 refueling outage.During the Unit 1 Cycle 7 refueling outage, the existing WBN Unit 1 Westinghouse Model D3SGs will be replaced with Westinghouse Model 68AXP SGs. The external envelope andinterfaces with existing piping and support structures for the replacement SGs (RSGs) are similar to the old (existing) Steam Generators (OSGs), except that the elevation of several RSGflow and level instrument taps (upper taps and lower narrow range taps) will increase byapproximately 5 feet. The span between the upper taps and lower narrow range taps willremain approximately the same. Internally the RSGs differ from the OSGs in several ways, including increased tube surface area, different tube material, different tube supports, and longer tube length. The tube length increases from just below the lower narrow range taps inthe OSGs to more than 4 feet above the lower narrow range taps in the RSGs.To support use of the RSGs, the licensee has performed numerous analyses and evaluations todetermine the impact of the RSG differences. A calculation performed by Westinghouse to determine the RSG narrow range level instrument uncertainties for Emergency Operating Procedure setpoint applications identified the need to revise the TSs to increase the requiredpercentage of SG narrow range level from 6% to 32% to ensure that the top of the tubes arecovered. This change accounts for the change in relative location of the top of the tubes versusthe lower narrow range taps and the narrow range water level instrument uncertainty.

2.0 REGULATORY EVALUATION

Title 10 of the Code of Federal Regulations (10 CFR) establishes the fundamental regulatoryrequirements with respect to the operability of SGs, which are required for heat transfer. Specifically, the General Design Criteria (GDC) in Appendix A to 10 CFR Part 50 state that "a system to transfer heat from structures, systems, and components important to safety, to anultimate heat sink" (GDC 44), and "to remove residual heat shall be provided" (GDC 34).

Furthermore, it "shall be designed with appropriate margin to assure that specified acceptable fuel design limits are not exceeded during any condition of normal operation, including the effects of anticipated operational occurrences" (GDC 10). To assure SG operability, "instrumentation shall be provided to monitor variables and systemsover their anticipated ranges for normal operation, for anticipated operational occurrences, andfor accident conditions" (GDC 13). The SG narrow range level indicator is an input to the reactor protection system, which "shall be designed (1) to initiate automatically the operation ofappropriate systems including the reactivity control systems, to assure that specified acceptablefuel design limits are not exceeded as a result of anticipated operational occurrences and (2) to sense accident conditions and to initiate the operation of systems and components important tosafety" (GDC 20). Furthermore, "the protection system shall assure that specified acceptable fuel design limits are not exceeded for any single malfunction of the reactivity control systems,such as accidental withdrawal (not ejection or dropout) of control rods" (GDC 25).The LCOs are the lowest functional capability or performance levels of equipment required forsafe operation. If the SG level were to drop below the required percentage of the narrow rangeSG level, the SG would not be operable and would not be able to provide certain safety functions. Therefore, the SG narrow range level is included as an LCO in the plant's TSs that are regulated under 10 CFR 50.36(c)(2) Limiting conditions for operation. To ensure that theLCOs will be met, the SG level is subject to surveillance and meets the requirements of10 CFR 50.36(c)(3) Surveillance requirements

.

3.0TECHNICAL EVALUATION

The function of the SGs is to transfer heat produced by the fission process in the reactor coreto the secondary side of the plant. To assure that the SGs are able to perform this function, the water level on the secondary side of the SG is to be maintained above the tops of SG tubeswhenever the SG is required to be operable. The operability of the SGs is determined by thenarrow range SG level indicator, which provides input to the reactor protection system.The basic function of the reactor protection circuits associated with the low SG water level is topreserve the SG heat sink for removal of long term residual heat. This is of particular importance during Modes 3, 4, and 5 to mitigate the consequences of an inadvertent rodwithdrawal from subcritical, ejection of a control rod, or an accidental boron dilution.WBN will be replacing their SGs during the Cycle 7 refueling outage. The RSGs differ from theOSGs in that the RSG tubes are longer and the elevation of several RSG flow and level instrument taps (upper taps and lower narrow range taps) will increase by approximately 5 feet. The tube length increases from just below the lower narrow range taps in the OSGs to more than 4 feet above the lower narrow range taps in the RSGs, and therefore WBN proposeschanging the required percentage of the narrow range SG level. This will ensure that the RSG level will be maintained above the top of the RSG tubes, which will demonstrate RSGoperability.3.1Proposed ChangesThe proposed amendment would revise the WBN, Unit 1 TS 3.4.5, RCS Loops - MODE 3

,TS 3.4.6, RCS Loops -MODE 4, and TS 3.4.7, RCS Loops - MODE 5 , Loops Filled, to changethe SG level requirement for LCO 3.4.7.b and SRs 3.4.5.2, 3.4.6.3, and 3.4.7.2 from 6% to 32% following replacement of the SGs. In addition, symbols (i.e., , <, etc.) on affected pages are being spelled out as anadministrative change. Revision bars are not shown for these changes.The TS changes affect the following sections:

Section 3.4.5, RCS Loops - MODE 3 - Revise SR 3.4.5.2 to read: "Verify steam generatorsecondary side water levels are greater than or equal to 32% narrow range for required RCS loops."Section 3.4.6, RCS Loops - MODE 4 - Revise SR 3.4.6.3 to read: "Verify SG secondary sidewater levels are greater than or equal to 32% narrow range for required RCS loops."Section 3.4.7, RCS Loops- MODE 5, Loops Filled - Revise LCO 3.4.7.b to read: "Thesecondary side water level of at least two steam generators (SGs) shall be greater than or equal to 32% narrow range."Section 3.4.7 - Revise SR 3.4.7.2 to read: "Verify SG secondary side water level is greater thanor equal to 32% narrow range for required SGs."In summary, the above changes revise the value of the secondary side narrow range waterlevel from 6% for the OSGs to 32% for the RSGs. This change will assure that the secondaryside water level in the RSGs is high enough to cover the tubes.3.2Technical Justification of Proposed TS ChangesThe proposed TS changes address the SG narrow range level requirements during Modes 3, 4,and 5. For SG operability, the top of the SG tubes must be covered. Since the tubes arelonger in the RSGs than the OSGs, the level tap elevations are greater in the RSGs than theOSGs, and the elevation of the top of the SG tubes relative to the level taps is greater for theRSGs than the OSGs, the required percentage of the SG narrow range level would need to be revised so that the top of the RSG tubes remain covered.The licensee performed a series of calculations and analyses to determine the appropriate required percentage of the SG narrow range level for the RSGs. The SG narrow range level instrumentation uses the differential pressure between the vessel and the reference leg todetermine level. This type of instrumentation is subject to errors due to density changes in the vessel contents or the reference leg. The two main sources of error are 1) pressure and temperature changes in the vessel resulting in a change in the differential pressure across the vessel and 2) a temperature change in the environment around the reference leg. To determine the required narrow range level for the RSGs (including instrument uncertainties),the process pressure uncertainty, reference leg temperature uncertainty, and narrow range level channel uncertainty were added to the minimum narrow range level without uncertainties.

The result was rounded up to 32% to define an easily readable value on the indicator and add some additional conservatism. This value accounts for the change in relative location of the top of the tubes versus the lowernarrow range taps and the narrow range water level instrument uncertainty. The change in the required percentage of the SG narrow range level from 6% to 32% accounts for thedifferences in SG design between the OSGs and RSGs and ensures the operability of theRSGs for the Mode 3, 4, and 5 accidents and transients that rely upon SG operability. The newvalue will be used in the same manner as the old one to assess SG operability.The proposed change in the required percentage of the SG narrow range level from 6% to 32% ensures that the RSGs are operable and available to act as a heat sink for both normaloperations and anticipated operational occurrences. Furthermore, the same acceptance criteria is being used for the RSGs as was used for the OSGs, so that there is no reduction in the margin of safety. This change does not affect whether the instrumentation used to monitor SG level will be available, nor does it affect the transmission of the level signal to the reactorprotection circuitry. Therefore, this change does not affect the ability of the protection systemto mitigate accident and transient consequences. The proposed TS changes meet the requirements of the applicable GDCs in Appendix A to 10 CFR Part 50. In addition, since the new minimal required percentage of the SG narrow range level will be used in the same manner as the old one, it is necessary to include the newvalue in the LCO and SR sections of the TSs, which are regulated under 10 CFR 50.36. For these reasons, the staff finds the aforementioned TS changes acceptable.

4.0 STATE CONSULTATION

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

5.0 ENVIRONMENTAL CONSIDERATION

The amendment changes 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 amendment 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 amendment involve no significant hazards consideration, and there has been no publiccomment on such finding (71 FR 7814). Accordingly, the amendment meet the eligibility criteriafor 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) 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 theCommission's regulations, and (3) the issuance of this amendment will not be inimical to thecommon defense and security or to the health and safety of the public.Principal Contributor: Samantha Crane Date: May 5, 3006