ML20195B921

Forwards Staff Assessment of Fatigue Evaluation,Accepting Licensee 980919 Response to NRC 980916 Request for Certain Plant Specific Design & Installation Details Re Insp & Repair of Plant,Unit 3 Core Spray Sys Piping Internal to Rv

ML20195B921
Person / Time
Site:	Browns Ferry
Issue date:	11/12/1998
From:	Raghavan L NRC (Affiliation Not Assigned)
To:	Scalice J TENNESSEE VALLEY AUTHORITY
References
TAC-MA1970, TAC-MA3610, NUDOCS 9811160313
Download: ML20195B921 (4)

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November 12, 1998 Mr. J. A. Scalice Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, Tennessee 37402-2801

SUBJECT:

BROWNS FERRY NUCLEAR PLANT, UNIT 3 - STAFF EVALUATION OF TVA INSPECTION AND REPAIR PLAN FOR CORE SPRAY INTERNAL PIPING (TAC NOS. MA1970 AND MA3610)

Dear Mr. Scalice.

In a letter dated September 16,1998, the U.S. Nuclear Regulatory Commission (NRC or the staff) requested certain plant specific design and installation details relating to vrur inspection and repair of the Browns Ferry Nuclear Plant Unit 3 core spray system piping haernal to the reactor vessel. By letter dated September 19,1998, you responded to our request. Based on our review, we find your response acceptable. The staff evaluation is enclosed.

This completes our effort under the technical assignment control (TAC) No. MA3610 and the TAC is closed.

Sincerely,

/s/

L. Raghavan, Senior Project Manager Project Directorate 11-3 i Division of Reactor Projects - l/11 )

Docket No. 50-296 Serial No. BFN-98-026

Enclosure:

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54 8849 y p t UNITED STATES 7

[ ] NUCLEAR REGULATORY COMMISSION g WASHINGTON, D.C. 20066-0001

%*****/g November 12,1998 Mr. J. A. Scalice l Chief Nuclear Officer '

and Executive Vice President i Tennessee Valley Authority 6A Lookout Place  ;

1101 Market Street l Chattanooga, Tennessee 37402-2801

SUBJECT:

BROWNS FERRY NUCLEAR PLANT, UNIT 3 - STAFF EVALUATION OF TVA INSPECTION AND REPAIR PLAN FOR CORE SPRAY INTERNAL PIPING (TAC NOS. MA1970 AND MA3610) i

Dear Mr. Scalice:

In a letter dated September 16,1998, the U.S. Nuclear Regulatory Commission ( the staff) requested certain plant specific design and installation details relating to your inspection and repair of the Browns Ferry Nuclear Plant Unit 3 core spray system piping internal to the reactor vessel. By letter dated September 19,1998, you responded to our request. Based on our review, we find your response acceptable. The staff assessment is enclosed.

This completes our effort under the technical assignment control (TAC) No. MA3610 and the TAC is closed.

Sincerely, A

L.Raghavan enior Project Manager Project Directorate ll-3 Division of Reactor Projects - 1/ll Office of Nuclear Reactor Regulation i

Docket No. 50-296 Serial No. BFN-98-026 l

Enclosure:

As stated cc: See next page l

i o

i j-Mr. J. A. Scalice BROWNS FERRY NUCLEAR PLANT Tennessee Valley Authority ,

i f- cc: .

l Senior Vice President Mr. Mark J. Burzynski, Managar 1 Nuclear Operations Nuclear Licensing l Tennessee Valley Authority Tennessee Valley Authority 6A Lookout Place 4X Blue Ridge 1101 Market Street 1101 Market Strer.,t Chattanooga, TN 37402-2801 Chattanooga, TN 37402-2801 i

! Mr. Jack A. Bailey, Vice President Mr. Timothy E. Abney, Manager l Engineering & Technical Services Licensing and Industry Affairs Tennessee Valley Authority Browns Ferry Nuclear Plant 6A Lookout Place Tennessee Valley Authority

! 1101 Market Sirset P.O. Box 2000 j Chattanooga, TN 37402-2801 Decatur, AL 35609 l Mr. Karl W. Singer, Site Vice President Regional Administrator, Region il l

Browns Ferry Nuclear Plant U.S. Nuclear Regulatory Commission Tennessee Valley Authority 61 Forsyth Street, SW., Suite 23T85 P.O. Box 2000 Atlanta, GA 30303-3415

Decatur, AL 35609

! Senior Resident inspector l General Counsel U.S. Nuclear Regulatory Commission

. Tennessee Valley Authority Browns Ferry Nuclear Plant l ET 10H 10833 Shaw Road l 400 West Summit Hill Drive Athens, AL 35611 l Knoxville, TN 37902 State Health Officer Mr. Raul R. Baron, General Manager Alabama Dept. of Public Health Nuclear Assurance 434 Monroe Street Tennessee Valley Authority Montgomery, AL 36130-1701

,. SM Lookout Place

( 1101 Market Street Chairman Chattanooga, TN 37402-2801 Limestone County Commission 310 West Washington Street Mr. Robert G. Jones, Plant Manager Athens, AL 35611 Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609 i

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. . . . . ,o STAFF ASSESSMEN OF FATIGUE EVALUATION BROWNS FERRY NUCLEAR PLANT. UNIT 3 CORE SPRAY PIPING REPAIR Tennessee Valley Authority (TVA or the licensee) letters dated May 20, and September 19, 1998, respectively, described the core spray piping inspection and repairs planned during the September 1998 refueling outage. This description included the fatigue evaluation of replacement components which was performed in accordance with the requirements of American Society of Mechanical Engineers Code (ASME) Section Ill, Subsection NG-3222.4 and Appendix 1. The peak ASME Service level A/B stress intensities for each component were used in the determination of the fatigue stress amplitude. The thermalload cases were determined from the reactor thermal cycle diagram as modified by the recent power uprate.

Also, the peak Service level A/B stresses were increased when necessary by stress concentration factors. In addition, fatigue strength weld reduction factors were utilized on component weld regions. The licensee stated that the fatigue usage for all components was determined to be less than the ASME Code limit of 1.0. In addition, the licensee stated that the potential for flow-induced vibration was addressed. A modal analysis of the core spray line

.between the safe end and the shroud including the effects of the repair was performed. The vortex shedding frequency determination included the effects from increased core flow associated with power uprate. According to the licensee, the lowest first modal frequency was determined to be greater than three times the calculated vortex shedding frequency due to the normal operating flow across the pipe in the annulus. Therefore, the effect of the flow-induced vibration on fatigue was considered negligible.

Based on a review of the core spray line design specifications and the licensee's statements, as discussed above, the staff finds the fatigue and flow-induced vibration evaluations of the replacement components to be in accordance with the design criteria outlined in Sections 7.6 and 7.10 of the Boiling Water Reactor Vessel Internal Project (BWRVIP-16) guidance. The staff has also determined that the materials and fabrication methods selected for the replacement components are acceptable because it follows the guidelines in BWRVIP-16. Therefore, the staff finds the licensee's response acceptable.

Enclosure l

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