ML083040104

Request for Additional Information - Watts Bar Emergency Core Cooling System Boron Requirements

ML083040104
Person / Time
Site:	Watts Bar
Issue date:	11/07/2008
From:	John Lamb Watts Bar Special Projects Branch
To:	Campbell W Tennessee Valley Authority
Lamb John G./NRR/DORL, 415-3100
References
TAC MD9396
Download: ML083040104 (5)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 November 7, 2008 Mr. William R. Campbell, Jr.

Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801

SUBJECT:

WATTS BAR NUCLEAR PLANT, UNIT 1 - REQUEST FOR ADDITIONAL INFORMATION - WATTS BAR EMERGENCY CORE COOLING SYSTEM BORON REQUIREMENTS (TAC NO. MD9396)

Dear Mr. Campbell:

By letter dated August 1,2008, Tennessee Valley Authority (TVA) proposed a license amendment to change the Watts Bar Nuclear Plant, Unit 1, Technical Specifications. The proposed request is to revise the boron requirements for cold leg accumulators and refueling water storage tank.

The staff has reviewed the information provided by TVA and has determined that additional information is required to complete its evaluation of the proposed license amendment. The specific question is detailed in the enclosed request for additional information (RAI). Based on discussions with your staff, we understand that you plan to respond to the enclosed RAls within 45 days of the date of this letter.

If you have any questions regarding this issue, please feel free to contact me at (301) 415-3100.

n G. Lamb, Senior Project Manager atts Bar Special Projects Branch ivision of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-390

Enclosure:

RAI cc w/enclosure: Distribution via Listserv

REQUEST FOR ADDITIONAL INFORMATION REGARDING TECHNICAL SPECIFICATIONS REVISIONS EMERGENCY CORE COOLING SYSTEM BORIC ACID CONCENTRATION REQUIREMENTS WATTS BAR NUCLEAR PLANT, UNIT 1 TENNESSEE VALLEY AUTHORITY DOCKET NO. 50-390 By letter dated August 1,2008 (ADAMS Accession No. ML082180091), the Tennessee Valley Authority (TVA), the licensee for Watts Bar Nuclear Plant (WBN) Unit 1, submitted a request to revise the WBN Unit 1 Technical Specifications (TSs) to change the boron requirements for cold leg accumulators and refueling water storage tank (RWST). The U.S. Nuclear Regulatory Commission (NRC) staff is reviewing this request, and has determined that additional information is necessary for the staff to complete its review, as discussed below.

Question - Leak-Before Break (LBB)

In Section 3.2.2, Enclosure 1, of the TSs change submittal regarding boron requirements for cold leg accumulators and RWST dated August 1, 2008 (page E1-8), the licensee stated that "With WBN Unit 1 primary loop qualified under the LBB program, control rod insertion capability need only be evaluated for large break LOCAs [Ioss-of-coolant accidents] due to failure of non-qualified LBB piping such as the piping in the RCS [reactor coolant system] auxiliary branch lines. .. ..

Provide justification to the above statement because the above statement seems to be inconsistent with the staff position.

In the Summary of the Final Rule for General Design Criterion (GDC) 4 (

Reference:

Federal Register, Volume 51, Number 70, April 11, 1986, page 12502), the NRC specifically stated that containment design, emergency core cooling systems (ECCS), and environmental qualification requirements are not influenced by the modification (i.e., LBB) to GDC 4.

In addition, in the response to a public comment (Le., Issue 3) in the Statements of Consideration of the final rule for GDC 4 (70 FR 12502), the NRC stated that it "... acknowledges that the rulemaking will introduce an inconsistency into the design basis by excluding only the dynamic effects of postulated double-ended pipe ruptures in PWR [pressurized-water reactor] primary coolant loops while retaining this postulated accident for ECCS, containment and environmental qualification. The present view is that insufficient technical information is available for applying LBB technology to other aspects of facility design. Further studies must be conducted to develop suitable replacement criteria for the PWR primary coolant loop double-ended pipe rupture if this accident is no longer required for containment design, emergency core cooling or environmental qualification. For the present, the proposed rule allows the removal of plant hardware which it is believed negatively affects plant performance, while not affecting ECCS, containments and environmental qualification of mechanical and electrical equipment. ..."

Enclosure

-2 The above Statements of Consideration for the GOC 4 rule state that double-ended rupture of the largest LBB pipe in the RCS should still be postulated for the purpose of sizing the containment, emergency core cooling systems, and environmental equipment qualification. Therefore, dynamic effects of the double-ended rupture of the largest LBB pipe in the RCS, as well as the non-qualified LBB piping, should be considered for the control rod insertion capability.

ADDITIONAL DISTRIBUTION VIA L1STSERV Mr. Lawrence L. Nanney, Director Tennessee Dept. of Environmental Health & Conservation Division of Radiological Health 3rd Floor, L & C Annex 104 Church Street Nashville, TN 37243-1532

November 7, 2008 Mr. William R. Campbell, Jr.

Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801

SUBJECT:

WATTS BAR NUCLEAR PLANT, UNIT 1 - REQUEST FOR ADDITIONAL INFORMATION - WATTS BAR EMERGENCY CORE COOLING SYSTEM BORON REQUIREMENTS (TAC NO. MD9396)

Dear Mr. Campbell:

By letter dated August 1,2008, Tennessee Valley Authority (TVA) proposed a license amendment to change the Watts Bar Nuclear Plant, Unit 1, Technical Specifications. The proposed request is to revise the boron requirements for cold leg accumulators and refueling water storage tank.

The staff has reviewed the information provided by TVA and has determined that additional information is required to complete its evaluation of the proposed license amendment. The specific question is detailed in the enclosed request for additional information (RAI). Based on discussions with your staff, we understand that you plan to respond to the enclosed RAls within 45 days of the date of this letter.

If you have any questions regarding this issue, please feel free to contact me at (301) 415-3100.

Sincerely, lRAI John G. Lamb, Senior Project Manager Watts Bar Special Projects Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-390

Enclosure:

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