ML031470111

License Amendment, Increase Condensate Storage Tank Minimum Volume Technical Specification Requirements

ML031470111
Person / Time
Site:	Sequoyah
Issue date:	05/27/2003
From:	Marshall M NRC/NRR/DLPM/LPD2
To:	Scalice J Tennessee Valley Authority
Marshall M, NRR/DLPM/301- 415-2734
References
TAC MB7205, TAC MB7206
Download: ML031470111 (13)

Text

May 27, 2003 Mr. J. A. Scalice Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801

SUBJECT:

SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2 - ISSUANCE OF AMENDMENTS REGARDING INCREASING CONDENSATE STORAGE TANK MINIMUM VOLUME TECHNICAL SPECIFICATION REQUIREMENTS (TAC NOS. MB7205 AND MB7206) (TSC 02-06)

Dear Mr. Scalice:

The Commission has issued the enclosed Amendment No. 286 to Facility Operating License No. DPR-77 and Amendment No. 275 to Facility Operating License No. DPR-79 for the Sequoyah Nuclear Plant, Units 1 and 2, respectively. These amendments are in response to your application dated November 15, 2002, as supplemented with letters dated February 28, 2003, March 14, 2003, and April 25, 2003. The Amendments revise the Technical Specification 3.7.1.3, Condensate Storage Water, Limiting Condition for Operation by increasing the required minimum amount of stored water from 190,000 gallons to 240,000 gallons.

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/

Michael L. Marshall, Jr., Senior Project Manager, Section 2 Project Directorate II Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-327 and 50-328

Enclosures:

1. Amendment No. 286 to License No. DPR-77

2. Amendment No. 275 to License No. DPR-79

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

May 27, 2003 Mr. J. A. Scalice Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801

SUBJECT:

SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2 - ISSUANCE OF AMENDMENTS REGARDING INCREASING CONDENSATE STORAGE TANK MINIMUM VOLUME TECHNICAL SPECIFICATION REQUIREMENTS (TAC NOS. MB7205 AND MB7206) (TSC 02-06)

Dear Mr. Scalice:

The Commission has issued the enclosed Amendment No. 286 to Facility Operating License No. DPR-77 and Amendment No. 275 to Facility Operating License No. DPR-79 for the Sequoyah Nuclear Plant, Units 1 and 2, respectively. These amendments are in response to your application dated November 15, 2002, as supplemented with letters dated February 28, 2003, March 14, 2003, and April 25, 2003. The Amendments revise the Technical Specification 3.7.1.3, Condensate Storage Water, Limiting Condition for Operation by increasing the required minimum amount of stored water from 190,000 gallons to 240,000 gallons.

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/

Michael L. Marshall, Jr., Senior Project Manager, Section 2 Project Directorate II Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-327 and 50-328

Enclosures:

1. Amendment No. 286 to License No. DPR-77

2. Amendment No. 275 to License No. DPR-79

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

PUBLIC PDII-2 R/F SMoore AHowe MMarshall BClayton (Hard copy)

GHill (4) OGC ACRS SPeters RDennig, DRIP/RORP SCahill, RII Package: ML ADAMS ACCESSION NO. ML031470111 TS Pages: ML OFFICE PDII-2/PM PDII-2/LA OGC PDII-2/SC NAME MMarshall BClayton AHodgdon AHowe NLO w/comments DATE 5/13/03 5/14/03 5/20/03 5/23/03 OFFICIAL RECORD COPY

TENNESSEE VALLEY AUTHORITY DOCKET NO. 50-327 SEQUOYAH NUCLEAR PLANT, UNIT 1 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 286 License No. DPR-77

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

A. The application for amendment by Tennessee Valley Authority (the licensee) dated November 15, 2002, as supplemented with letters dated February 28, 2003, March 14, 2003, and April 25, 2003, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commissions 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 Commissions 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 Commissions 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. DPR-77 is hereby amended to read as follows:

(2) Technical Specifications The Technical Specifications contained in Appendices A and B, as revised through Amendment No. 286, are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications.

3. This license amendment is effective as of its date of issuance, to be implemented no later than 45 days after issuance.

FOR THE NUCLEAR REGULATORY COMMISSION

/RA/

Allen G. Howe, Chief, Section 2 Project Directorate II Division of Licensing Project Management Office of Nuclear Reactor Regulation

Attachment:

Changes to the Technical Specifications Date of Issuance: May 27, 2003

ATTACHMENT TO LICENSE AMENDMENT NO. 286 FACILITY OPERATING LICENSE NO. DPR-77 DOCKET NO. 50-327 Replace the following page of the Appendix A Technical Specifications with the attached page.

The revised page is identified by amendment number and contains marginal lines indicating the areas of change.

REMOVE INSERT 3/4 7-7 3/4 7-7

TENNESSEE VALLEY AUTHORITY DOCKET NO. 50-328 SEQUOYAH NUCLEAR PLANT, UNIT 2 AMENDMENT TO FACILITY OPERATING LICENSE Amendment No. 275 License No. DPR-79

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

A. The application for amendment by Tennessee Valley Authority (the licensee) dated November 15, 2002, as supplemented with letters dated February 28, 2003, March 14, 2003, and April 25, 2003, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commissions 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 Commissions 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 Commissions 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. DPR-79 is hereby amended to read as follows:

(2) Technical Specifications The Technical Specifications contained in Appendices A and B, as revised through Amendment No. 275, are hereby incorporated in the license. The licensee shall operate the facility in accordance with the Technical Specifications.

3. This license amendment is effective as of its date of issuance.

FOR THE NUCLEAR REGULATORY COMMISSION

/RA/

Allen G. Howe, Chief, Section 2 Project Directorate II Division of Licensing Project Management Office of Nuclear Reactor Regulation

Attachment:

Changes to the Technical Specifications Date of Issuance: May 27, 2003

ATTACHMENT TO LICENSE AMENDMENT NO. 275 FACILITY OPERATING LICENSE NO. DPR-79 DOCKET NO. 50-328 Replace the following page of the Appendix A Technical Specifications with the attached page.

The revised page is identified by amendment number and contains marginal lines indicating the areas of change.

REMOVE INSERT 3/4 7-7 3/4 7-7

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 286 TO FACILITY OPERATING LICENSE NO. DPR-77 AND AMENDMENT NO. 275 TO FACILITY OPERATING LICENSE NO. DPR-79 TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT, UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328

1.0 INTRODUCTION

By application dated November 15, 2002, as supplemented by letters dated February 28, 2003, March 14, 2003, and April 25, 2003, the Tennessee Valley Authority (the licensee, TVA) proposed an amendment to the Technical Specifications (TSs) for Sequoyah Nuclear Plant (SQN), Units 1 and 2. The requested changes would revise the TS 3.7.1.3, Condensate Storage Water, Limiting Condition for Operation by increasing the required minimum amount of stored water from 190,000 gallons to 240,000 gallons. The February 28, March 14, and April 25, 2003 letters provided clarifying information that did not change the initial proposed no significant hazards consideration determination or expand the scope of the application.

2.0 REGULATORY EVALUATION

Section 50 of Title 10 of the Code of Federal Regulations (10 CFR 50), Appendix A, General Design Criteria for Nuclear Power Plants, Criterion 34, Residual Heat Removal, requires that a system be provided to remove fission product decay heat and other residual heat from the reactor core. This heat removal prevents violation of the specified acceptable fuel design limits and the design conditions of the reactor coolant pressure boundary.

Consistent with the current licensing basis at SQN, the essential raw cooling water (ERCW) system provides this function with an unlimited source of safety grade water. But for the preferred source of auxiliary feedwater (AFW) supply, the current licensing basis for SQN requires that the condensate storage tank (CST) supply be capable of holding the unit in hot standby for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, followed by a cooldown to residual heat removal (RHR) entry condition (hot shutdown) within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

TVA plans to replace the SQN, Unit 1 steam generators (SGs) in the spring of 2003. Because of physical differences between the original and replacement SGs (i.e., greater structural mass), the new generators require more water to cool down. Therefore, TVA reanalyzed the supply requirements for the replacement SGs and proposed an increase from 190,000 to 240,000 gallons. To assure that SQN continues to meet its licensing basis for CST volume with Enclosure 3

the new generators, the staff will verify that the proposed volume is adequate to hold the unit in hot standby for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, followed by a cooldown to RHR entry conditions (hot shutdown) within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

3.0 TECHNICAL EVALUATION

The current CST minimum water volume of 190,000 gallons met the licensees previous cooldown requirements. These requirements included maintaining the reactor coolant system (RCS) in hot standby for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> with steam discharge to the atmosphere and a concurrent loss of off-site power, followed by a reduction to hot shutdown conditions within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

To determine the new CST water volume requirements, the licensee performed steady state heat balance calculations following the first law of thermodynamics, similar to the original water volume calculation. Several assumptions from the original water volume calculation remained in this updated version, including the loss of all reactor coolant pumps and the cooldown period of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. Because these assumptions follow the original licensing basis, the U.S. Nuclear Regulatory Commission (NRC) staff finds them acceptable.

However, the following assumptions changed: (1) The structural mass of the replacement SGs increased, (2) the AFW temperature increased from 100 oF to 120 oF, and (3) the new calculations include the volume of water needed to refill the SGs. All three of these changes are conservative and provide for an increase to the required CST water volume to account for the changes in the plant. Because these changes are conservative, the NRC staff finds them acceptable.

The licensee changed its original decay heat model from the 1970 Westinghouse decay heat model to the 1994 American Nuclear Society (ANS) standard decay heat model. In the calculation, the licensee used the 1994 ANS simplified method for determination of the decay heat power and uncertainty. In addition, to estimate the contribution to decay heat from heavy actinides, TVA employed a Babcock & Wilcox (B&W) Heavy Actinide model. To verify the validity of the B&W model, the staff compared it to the 1994 ANS standard model for actinides.

During the comparison the NRC staff identified three concerns.

(1) Over the 8-hour period assumed in the analysis the B&W model predicted an actinide contribution that is nearly 1 percent lower than that predicted by the 1994 ANS model.

(2) Additionally, Research Information Letter (RIL) 0202 identified that over the first 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of modeling, the 1994 ANS standard could be up to 6 percent nonconservative for the decay heat contribution of the actinides.

(3) Furthermore, RIL 0202 also identified that the simplified method of the 1994 ANS standard contained an error (i.e., Equation 13) for determining the decay heat power uncertainty.

The staff determined that correcting the first concern would increase the CST volume requirement by 161 gallons. The second concern was addressed by the licensee including a 6-percent uncertainty to its B&W decay heat model that would increase the CST volume

requirement by 949 gallons. The licensee stated that correcting the third concern would increase the CST volume requirements by 3589 gallons. So, the licensees calculation underpredicts CST volume requirements by roughly 4700 gallons. However, the licensees calculations show that SQN has a margin of 12,000 gallons between the calculated requirements and the proposed TS value. Because the licensee accounted for the NRC staff identified concerns with the 1994 ANS decay heat standard, and because the proposed TS limit bounds the necessary energy removal requirements, the staff finds the limit acceptable.

The NRC staff audited the licensees calculations against the cooldown requirements of Branch Technical Position (BTP) RSB 5-1. In its response, TVA indicated that it meets BTP RSB 5-1 by having an adequate alternate seismic Category 1 AFW supply, the ERCW system. The staff evaluated whether the system could actually cool the plant down according to the SQN assumptions (i.e., 2-hour hold followed by a 6-hour cooldown), and by following this cooldown curve, the calculated CST volume would not be exceeded. TVA indicated that its AFW system would exceed the flow requirements for the above cooldown period, even with one of the AFW pumps inoperable. Therefore, the flow rate would be adequate to meet the cooldown requirements. Additionally, TVA indicated that, for the fixed time period, the energy removal requirements from hot standby to hot shutdown remain independent of cooldown rate.

Therefore, over the 8-hour period, the required volume of CST water would be equivalent regardless of the rate of cooldown. SQN would not exceed the calculated CST volume by following the cooldown curve. Because the AFW system provides sufficient flow to follow the cooldown curve, and because the calculated CST volume will be adequate for the cooldown assumptions, the staff finds the SQN cooldown assumptions acceptable.

The licensee based its calculation on a heat balance with an assumed control volume and fixed heat inputs. However, the staff noted that the calculations did not include all of the possible mixing volumes and heat inputs, specifically, the possible mixing water volumes upstream of the AFW entry point and the heat added by the reactor coolant pumps during coastdown and the AFW pumps during the cooldown period. TVA stated that the added energy requirements from feedwater upstream of the AFW entry point would add 435 gallons to the required CST inventory, whereas the reactor coolant pump coastdown and AFW pump heat would add 449 gallons and 1435 gallons respectively. The licensees calculations show that SQN would only need 228,000 gallons of CST inventory for the RCS cooldown. With the added volume requirement of 2319 gallons, the 240,000 gallon proposed TS limit would still be bounding.

Because the proposed TS limit bounds the necessary energy removal requirements, the staff finds the limit acceptable.

Because of standpipe locations, pump vortexing, net positive suction head requirements, and level instrumentation automatic switchover with uncertainty, CSTs typically contain a large volume that is unusable. The NRC staff assessed whether TVA adequately accounted for the unusable volume in the calculations to ensure that the usable volume would be adequate to meet the cooldown requirements. TVA indicated that the standpipe locations, pump vortexing levels, and net positive suction head level requirements all fall below the 0-percent level indicated on the CST level instrumentation. At the 0-percent level approximately 18,600 gallons of CST water volume will be unusable. The CST would automatically switch over prior to reaching the 0-percent level to the Category I ERCW system. The proposed wording of the TS accounts for the unusable volume:

[a] condensate storage tank system (CST) shall be OPERABLE with a water level of at least 240,000 gallons of water.

Since the proposed wording of the TS accounts for the unusable portion of the CST volume, the NRC staff finds that TVA adequately accounted for the unusable CST volume.

In summary, TVAs calculations show that the minimum required CST water level would be 228,000 gallons. When including the heat sources of the reactor coolant pump coastdown and the AFW pumps, available water volumes upstream of the AFW entry point, and conservative decay heat values, the minimum required CST water volume would be approximately 236,000 gallons. Given that the proposed CST level of 240,000 gallons bounds this value and that the TSs account for unusable CST volume, the NRC staff finds that the licensees proposed CST water level will provide adequate supply to meet the SQN licensing basis cooldown requirements and to hold the unit in hot standby for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, followed by a cooldown to RHR entry conditions (hot shutdown) within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. Therefore, the staff finds the proposed TS changes acceptable.

4.0 STATE CONSULTATION

In accordance with the Commission's 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 (68 FR 5682). 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.

5.0 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 amendment will not be inimical to the common defense and security or to the health and safety of the public.

Principal Contributor: Sean E. Peters, NRR Dated: May 27, 2003

Mr. J. A. Scalice SEQUOYAH NUCLEAR PLANT Tennessee Valley Authority cc:

Mr. Karl W. Singer, Senior Vice President Mr. Pedro Salas, Manager Nuclear Operations Licensing and Industry Affairs Tennessee Valley Authority Sequoyah Nuclear Plant 6A Lookout Place Tennessee Valley Authority 1101 Market Street P.O. Box 2000 Chattanooga, TN 37402-2801 Soddy Daisy, TN 37379 Mr. James E. Maddox, Vice President Mr. D. L. Koehl, Plant Manager Engineering & Technical Services Sequoyah Nuclear Plant Tennessee Valley Authority Tennessee Valley Authority 6A Lookout Place P.O. Box 2000 1101 Market Street Soddy Daisy, TN 37379 Chattanooga, TN 37402-2801 Senior Resident Inspector Mr. Richard T. Purcell Sequoyah Nuclear Plant Site Vice President U.S. Nuclear Regulatory Commission Sequoyah Nuclear Plant 2600 Igou Ferry Road Tennessee Valley Authority Soddy Daisy, TN 37379 P.O. Box 2000 Soddy Daisy, TN 37379 Mr. Lawrence E. Nanney, Director Division of Radiological Health General Counsel Dept. of Environment & Conservation Tennessee Valley Authority Third Floor, L and C Annex ET 11A 401 Church Street 400 West Summit Hill Drive Nashville, TN 37243-1532 Knoxville, TN 37902 County Executive Mr. Robert J. Adney, General Manager Hamilton County Courthouse Nuclear Assurance Chattanooga, TN 37402-2801 Tennessee Valley Authority 6A Lookout Place Ms. Ann P. Harris 1101 Market Street 341 Swing Loop Road Chattanooga, TN 37402-2801 Rockwood, Tennessee 37854 Mr. Mark J. Burzynski, Manager Nuclear Licensing Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801