ML062290485

License Amendment 64, Steam Generator Tube Rupture Accident Control Room Dose Analysis

ML062290485
Person / Time
Site:	Watts Bar
Issue date:	10/04/2006
From:	Pickett D NRC/NRR/ADRO/DORL/LPLII-2
To:	Singer K Tennessee Valley Authority
Pickett D, NRR/DORL, 415-1364
Shared Package
ML062290489	List: ML062290485 ML062850328
References
TAC MD0218
Download: ML062290485 (11)

Text

October 4, 2006 Mr. 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 AMENDMENT REGARDING STEAM GENERATOR TUBE RUPTURE ACCIDENT CONTROL ROOM DOSE ANALYSIS (TAC NO. MD0218)(TS-06-02)

Dear Mr. Singer:

The Commission has issued the enclosed Amendment No. 64 to Facility Operating License No. NPF-90 for Watts Bar Nuclear Plant (WBN), Unit 1. This amendment authorizes revisions to the Updated Final Safety Analysis Report (UFSAR) in response to your application dated February 24, 2006 as supplemented by letter dated May 8, 2006 (TS-06-02).

The amendment authorizes modification to the UFSAR, Section 15.5 dose analysis inputs and results for the Steam Generator Tube Rupture accident. This analysis is being revised for both the current steam generators, and the revised primary and secondary side mass releases associated with the new replacement steam generators, which are scheduled to be installed during the Unit 1 Cycle 7 Refueling Outage in the Fall 2006.

A copy of the safety evaluation is also enclosed. Notice of issuance will be included in the Commission's next 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 Regulation Docket No. 50-390

Enclosures:

1. Amendment No. 64 to NPF-90

2. Safety Evaluation cc w/enclosures: See next page

October 4, 2006 Mr. 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 AMENDMENT REGARDING STEAM GENERATOR TUBE RUPTURE ACCIDENT CONTROL ROOM DOSE ANALYSIS (TAC NO. MD0218)(TS-06-02)

Dear Mr. Singer:

The Commission has issued the enclosed Amendment No. 64 to Facility Operating License No. NPF-90 for Watts Bar Nuclear Plant (WBN), Unit 1. This amendment authorizes revisions to the Updated Final Safety Analysis Report (UFSAR) in response to your application dated February 24, 2006 as supplemented by letter dated May 8, 2006 (TS-06-02).

The amendment authorizes modification to the UFSAR, Section 15.5 dose analysis inputs and results for the Steam Generator Tube Rupture accident. This analysis is being revised for both the current steam generators, and the revised primary and secondary side mass releases associated with the new replacement steam generators, which are scheduled to be installed during the Unit 1 Cycle 7 Refueling Outage in the Fall 2006.

A copy of the safety evaluation is also enclosed. Notice of issuance will be included in the Commission'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 Regulation Docket No. 50-390

Enclosures:

1. Amendment No. 64 to NPF-90

2. Safety Evaluation cc w/enclosures: See next page DISTRIBUTION:

PUBLIC LPL2-2 r/f RidsOgcRp RidsAcrsAcnwMailCenter G. Hill, OIS (2) RidsNrrDorlLpl2-2 RidsNrrLACSola RidsNrrPMDPickett L. Regner, NRR RidsRgn2MailCenter RidsNrrDorlDpr L. Brown, NRR RidsNrrDirsItsb J. McGuire, NRR RidsNrrDraAadb Package No. ML062290489 TS:

ADAMS Accession No. ML062290485 *NLO w/changes NRR-058 OFFICE LPL2-2/PM LPL2-2/PM LPL2-2/LA AADB/BC OGC

• LPL2-2/BC(A)

NAME LRegner DPickett RSola MKotzalas JEM/gah JDixon-Herrity (by memo) (LRaghavan for)

DATE 8/27/06 8/22/06 8/23/06 07/20/06 8/31/06 10/4/06

OFFICIAL RECORD COPY Mr. Karl W. Singer Tennessee Valley Authority WATTS BAR NUCLEAR PLANT cc:

Mr. Ashok S. Bhatnagar, Senior Vice President Mr. Glenn W. Morris, Manager Nuclear Operations Corporate Nuclear Licensing Tennessee Valley Authority and Industry Affairs 6A Lookout Place Tennessee Valley Authority 1101 Market Street 4X Blue Ridge Chattanooga, TN 37402-2801 1101 Market Street Chattanooga, TN 37402-2801 Mr. Larry S. Bryant, Vice President Nuclear Engineering & Technical Services Mr. Paul L. Pace, Manager Tennessee Valley Authority Licensing and Industry Affairs 6A Lookout Place Watts Bar Nuclear Plant 1101 Market Street Tennessee Valley Authority Chattanooga, TN 37402-2801 P.O. Box 2000 Spring City, TN 37381 Mr. Robert J. Beecken, Vice President Nuclear Support Mr. Jay Laughlin, Plant Manager Tennessee Valley Authority Watts Bar Nuclear Plant 6A Lookout Place Tennessee Valley Authority 1101 Market Street P.O. Box 2000 Chattanooga, TN 37402-2801 Spring City, TN 37381 Mr. Michael D. Skaggs Senior Resident Inspector Site Vice President Watts Bar Nuclear Plant Watts Bar Nuclear Plant U.S. Nuclear Regulatory Commission Tennessee Valley Authority 1260 Nuclear Plant Road P.O. Box 2000 Spring City, TN 37381 Spring City, TN 37381 County Executive General Counsel 375 Church Street Tennessee Valley Authority Suite 215 ET 11A Dayton, TN 37321 400 West Summit Hill Drive Knoxville, TN 37902 County Mayor P. O. Box 156 Mr. John C. Fornicola, Manager Decatur, TN 37322 Nuclear Assurance and Licensing Tennessee Valley Authority Mr. Lawrence E. Nanney, Director 6A Lookout Place Division of Radiological Health 1101 Market Street Dept. of Environment & Conservation Chattanooga, TN 37402-2801 Third Floor, L and C Annex 401 Church Street Ms. Ann P. Harris Nashville, TN 37243-1532 341 Swing Loop Road Rockwood, Tennessee 37854

TENNESSEE VALLEY AUTHORITY DOCKET NO. 50-390 WATTS BAR NUCLEAR PLANT, UNIT 1 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 64 License No. NPF-90

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

A. The application for amendment by Tennessee Valley Authority (TVA, the licensee) dated February 24, 2006, as supplemented on May 8, 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, 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. Accordingly, by Amendment No. 64, Facility Operating License No. NPF-90 is amended to revise the design and licensing basis Design Basis Event for the Steam Generator Tube Rupture accident dose analysis described in the amendment application of February 24, 2006, as supplemented by letter dated May 8, 2006, and evaluated in the associated safety evaluation by the Commissions Office of Nuclear Reactor Regulation.

3. This amendment is effective as of its date of issuance. Implementation of the amendment is the incorporation into the next Updated Final Safety Analysis Report update made in accordance with 10 CFR 50.71(e), of the changes to the description of the facility as described in TVAs application dated February 24, 2006, as supplemented by letter dated May 8, 2006, and evaluated in the staffs Safety Evaluation attached to this amendment.

FOR THE NUCLEAR REGULATORY COMMISSION

/RA/

L. Raghavan, Chief Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Date of Issuance: October 4, 2006

ATTACHMENT TO LICENSE AMENDMENT NO. 64 FACILITY OPERATING LICENSE NO. NPF-90 DOCKET NO. 50-390 Replace page 3 of Operating License No. NPF-90 with the attached page 3.

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 64 TO FACILITY OPERATING LICENSE NO. NPF-90 TENNESSEE VALLEY AUTHORITY WATTS BAR NUCLEAR PLANT, UNIT 1 DOCKET NO. 50-390

1.0 INTRODUCTION

By letter received February 24, 2006 (Agencywide Documents Access and Management System (ADAMS) No. ML060660041), and supplemented by letter dated May 8, 2006 (ADAMS No. ML061310159), the Tennessee Valley Authority (TVA, the licensee), requested a license amendment for Watts Bar Nuclear Plant (WBN) Unit 1. The proposed change will revise the Updated Final Safety Analysis Report (UFSAR) Section 15.5 dose analysis inputs and results for the steam generator tube rupture (SGTR) accident. In addition, the existing steam generators at WBN will be replaced during the Cycle 7 Refueling Outage scheduled for the Fall 2006. The replacement steam generators will result in changes to primary and secondary side mass releases and the time sequence of the releases subsequent to a SGTR accident. As a result, the licensees revised accident dose analysis addressed both the current and replacement steam generators.

The proposed changes will revise the following UFSAR Chapter 15 tables:

• Table 15.5-14, Atmospheric Dilution Factors at the Control Building

• Table 15.5-18, Parameters Used in Steam Generator Tube Rupture Analysis

• Table 15.5-19, Doses from Steam Generator Tube Rupture (separate tables are proposed for both the current and replacement steam generators)

The supplement dated May 8, 2006, provided additional information that clarified the application, did not expand the scope of the application as originally noticed, and did not change the U.S. Nuclear Regulatory Commission (NRC) staffs original proposed No Significant Hazards Consideration Determination as published in the Federal Register on April 25, 2006 (71 FR 23962).

2.0 REGULATORY EVALUATION

This safety evaluation addresses the impact of the proposed changes on previously analyzed design basis accident (DBA) radiological consequences, and the acceptability of the revised analysis results. The regulatory requirements for which the NRC staff based its acceptance are Enclosure

the accident dose guidelines of Title 10 of the Code of Federal Regulations (10 CFR) Section 100.11, as supplemented by accident-specific criteria in Section 15 of the Standard Review Plan (SRP), and 10 CFR Part 50 Appendix A, General Design Criterion 19 (GDC-19), Control Room, as supplemented by SRP Section 6.4. The NRC staff also considered relevant information in the WBN UFSAR.

The regulatory framework for requesting this licensing action is based on Regulatory Guide (RG) 1.195, Methods and Assumptions for Evaluating Radiological Consequences of Design Basis Accidents at Light-Water Nuclear Power Reactors. Additionally, License Amendment 56, dated March 10, 2005, and License Amendment 40, dated September 23, 2002, were referenced. The changes requested would amend Operating License NPF-90 for WBN. This amendment would revise the UFSAR Chapter 15, Tables 15.5-14, -18, and -19 for both the current and replacement steam generators.

3.0 TECHNICAL EVALUATION

The licensee has identified an error in the computer modeling used to calculate the dose consequences to plant personnel in the main control room (MCR) subsequent to an accident.

The fuel handling accident (FHA), loss-of-coolant accident (LOCA), main steam line break (MSLB) accident, and SGTR accident analyses are all affected by the computer modeling input errors and result in small increases in dose to plant personnel in the MCR.

The Nuclear Energy Institute (NEI) has published industry guidance document NEI 96-07, Revision 1, Guidelines for 10 CFR 50.59 Implementation. NEI 96-07, which has been reviewed and endorsed by the NRC staff, provides industry guidance regarding the use of 10 CFR 50.59. NEI 96-07 recommends that changes to the licensing basis can be implemented pursuant to 10 CFR 50.59 provided that any increase in the dose consequence is less than ten percent above the previously approved limit. Dose consequences greater than ten percent above the previously approved limit need to be submitted to the NRC staff for review and approval pursuant to 10 CFR 50.90.

The dose consequences for the FHA and LOCA analyses result in small increases to plant personnel in the MCR. Since the increases are less than the ten percent criteria of NEI 96-07, the changes to the FHA and LOCA analyses in the UFSAR will be made pursuant to 10 CFR Section 50.59 and are not addressed in this safety evaluation. The dose consequences for the MSLB accident analysis exceeds the NEI 96-07 criteria of ten percent for the current steam generators but will be significantly reduced from the current UFSAR values for the replacement steam generators due to reduced post accident steam generator leakage assumptions (3 gallons per minute (gpm) for the current steam generators as opposed to 1 gpm for the replacement steam generators). Since the current steam generators will be replaced in the Fall 2006, TVA has chosen to track this item as a nonconforming condition under the WBN Corrective Action Program as opposed to requesting staff approval for the interim period prior to the steam generator replacement. The staff finds this acceptable because the steam generators will be replaced in the near term and the WBN UFSAR will be revised to reflect the MSLB accident doses for the replacement steam generators when the replacement steam generators are installed.

The dose consequences for the SGTR accident analysis exceed the NEI 96-07 recommended ten percent criteria for MCR plant personnel for both the current and replacement steam

generators. As a result, the licensee has submitted proposed WBN UFSAR changes to the NRC staff for review and approval pursuant to 10 CFR 50.90.

The NRC staff reviewed the regulatory and technical analyses, as related to the radiological consequences of the SGTR accident, performed by TVA in support of its proposed license amendment. The NRC staff reviewed the assumptions, inputs, and methods used by TVA to assess these impacts. The findings of this safety evaluation input are based on the descriptions of the licensees analyses in the original request and supplemental information contained in their letter dated May 8, 2006.

The licensee evaluated the impact of the computer model input errors on the SGTR accident.

Current licensing basis assumptions were used for all parameters with some exceptions. The following input and assumptions were revised: 1) rather than assume a single failure of a Control Room Emergency Ventilating System (CREVS) train, the licensee used the worse case of either one or two train operation of the CREVS, 2) the licensee used a corrected CREVS recirculation flow rate, and 3) the licensee changed the modeling of the MCR isolation time sequence. All revised analysis inputs and assumptions are in accordance with the regulatory guidance found in RG 1.195, and are acceptable to the NRC staff.

The licensee evaluated the impact of the replacement steam generators on the radiological consequences of the SGTR accident analyses. With the replacement steam generators, the following inputs changed: 1) primary side mass release, 2) secondary side mass release, and

3) time sequence of the releases subsequent to a SGTR accident. The methodology used by the licensee to determine the replacement steam generator mass releases was the LOFTTR2 program. This methodology is the same that was used to calculate the mass and energy releases for the current steam generators and is further discussed in Section 15.1.9.7 of the WBN UFSAR. All other inputs and assumptions remained unchanged. The licensee determined that only the control room thyroid dose for the pre-accident initiated iodine spike with a 21 FCi/gm maximum peak would increase. All other doses would decrease for the SGTR accident.

The NRC staff performed calculations to confirm the conclusions reached by the licensee for the SGTR accident for the replacement steam generators. The NRC staffs independent confirmatory calculations agreed with the licensees analysis that control room operator thyroid doses would be less than the criteria of SRP 6.4. The tables below list the results from the SGTR analyses for the replacement steam generators.

Pre-Accident Initiated Iodine Spike (21 F Ci/gm maximum peak)

(rem) 2 hr EAB 2 hr EAB 30 Day LPZ 30 Day LPZ MCR MCR WBN Limit WBN Limit WBN Limit Gamma 3.298E-01 25 8.43E-02 25 1.284E-01 5 Beta 1.912E-01 --- 4.86E-02 --- 1.464E00 30 Thyroid 1.249E01 300 2.967E00 300 2.309E01 30 Accident Initiated Iodine Spike (0.265 F Ci/gm steady state)

(rem) 2 hr EAB 2 hr EAB 30 Day LPZ 30 Day LPZ MCR MCR WBN Limit WBN Limit WBN Limit Gamma 3.587E-01 2.5 8.753E-02 2.5 1.281E-01 5 Beta 1.933E-01 --- 4.919E-02 --- 1.419E00 30 Thyroid 3.996E00 30 9.771E-01 30 2.343E00 30 The licensee used previously generated control room exclusion area boundary (EAB) and low population zone (LPZ) atmospheric dispersion factors (/Q values) to evaluate the radiological consequences of the SGTR dose assessment described above. These /Q values were previously submitted by the licensee as part of a license amendment request related to tritium production that included a SGTR dose assessment. The NRC staff found these /Q values acceptable for the reasons presented in the safety evaluation supporting Watts Bar Amendment No. 40 dated September 23, 2002 (ADAMS No. ML022540925).

The licensees letter of May 8, 2006, stated that the duration of effluent release for the SGTR accident is 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> and, therefore, control room /Q values for time periods subsequent to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> are not needed. For the reasons discussed above, the NRC staff has concluded that the control room, EAB and LPZ /Q values are acceptable for use in the SGTR dose assessment associated with this license amendment request.

The NRC staff concludes that the current DBA dose analyses remain bounding for the installation of the replacement steam generators. The staff finds with reasonable assurance that the licensees estimates of the EAB, LPZ, and control room doses will continue to comply with the applicable regulatory criteria identified in Section 2.0 of this safety evaluation.

Therefore, the staff finds the proposed changes to the UFSAR acceptable.

4.0 STATE CONSULTATION

In accordance with the Commissions regulations, the Tennessee State official was notified of the 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 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 (71 FR 23962). 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

Based on the preceding discussion, the NRC staff finds 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 Commissions regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

Principal Contributors: Joshua McGuire Leta Brown Lisa Regner Date: October 4, 2006