ML20214R045
| ML20214R045 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 05/28/1987 |
| From: | Jabbour K Office of Nuclear Reactor Regulation |
| To: | Tucker H DUKE POWER CO. |
| References | |
| TAC-61439, TAC-64424, TAC-64425, TAC-64426, NUDOCS 8706050310 | |
| Download: ML20214R045 (4) | |
Text
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o Docket Nos.: 50-413 and 50-414 Mr. H. B. Tucker, Vice President Nuclear Production Department Duke Power Company 422 South Church Street Charlotte, North Carolina 28242
Dear Mr. Tucker:
Subject:
Clarifying Information for Application of Leak-Before-Break Methodology to Auxiliary Lines Catawba Nuclear Station Units 1 and 2 (TACS 64424/64425/64426 and 61439)
By letters dated February 29, May 29, and June 18 and 24,1984, you requested exemptions from the requirements of 10 CFR 50, Appendix A, General Design Criterion 4 regarding postulated pipe breaks for the pressurizer surge line, the accumulator line and the residual heat removal line for Catawba Unit 2.
By letters dated October 8 and 22, 1986, we have identified the additional infonnation required for our review. Your "05000414/LER-1986-014, :on 860518,turbine Trip on hi-hi Steam Generator Level Occurred.Caused by Mfg Not Providing Adequate Calibr Info for Feedwater Control Sys Design. Reactor Manually Tripped & [[system" contains a listed "[" character as part of the property label and has therefore been classified as invalid. Sys Tuned|December 8, 1986, letter]] indicated that you are updating the previous analyses in response to our requests for additional information and that you plan to expand those analyses to include Catawba Unit 1.
We are currently reviewing leak-before-break (LBB) submtitals received from other licensees. From the experience acquired in these reviews, we have developed some general clarifying information that would expedite LBB reviews.
We recommend that you consider the enclosed general clarifying information in the planned update of your analyses.
Please contact ne at (301) 492-7367 if you have any questions regarding this matter.
Sincerely, Kahtan Jabbour, Project Manager Project Directorate II-3 Division of Reactor Projects
Enclosure:
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W ENCLOSURE CLARIFYING INFORMATION FOR APPLICATION OF LEAK-BEFORE-BREAK (LBB) METHODOLOGY TO AUXILIARY LINES DUKE POWER COMPANY CATAWBA NUCLEAR STATION UNITS 1 AND 2 DOCKET NOS. 50-413 8 50-414 MATERIAL INTEGRITY SECTION MATERIALS ENGINEERING BRANCH DIVISION OF ENGINEERING AND SYSTEMS TECHNOLOGY (1) For the fracture mechanics evaluation, a lower-bound material stress-strain relationship will be used.in the crack stability analysis.
The application of the lower-bound relationship is consistent with the intent of ASPE Code to account for material data scatter. For the leakage evaluation, a best estimate material stress-strain relationship will be used in the leakage rate analysis. The application of the best estimate relationship is to provide a realistic evaluation of the leakage rate and not to decrease the effective leakage rate margin.
Furthermore, the material properties selected for the LBB analysis will be demonstrated to be representative of the specific plant materials under review.
(2) For geometrically complex fluid system piping, the functional system for which the application of LBB is being requested will be identified. A thrcughwall flaw will be postulated in each size of pipe comprising the functional system in the LBB analysis.
(Note, these flaws are not postulated simultaneously.) However, a throughwall flaw may.not be postulatedintheicwenergypgrtionofpiping,i.e.,pressurebelow275 psig and temperature below 200 F.
The LBB analysis will include the functional piping system from anchor point to anchor point. If a branch line of another functional system is present for which LBB is not intended to be applied, the branch line may not be included in the LBB analysis. However, if breaks are postulated according to Standard Review Plan (SRP) 3.6.2 for the branch line, the most limiting reaction forces resulting from postulated breaks in the branch line must be included in-the LBB analysis for the functional system involved.
(3) The application of elastic-plastic fracture mechanics in the crack stability analysis is preferred. However, linear elastic fracture mechanics (LEFM), incorporating the Irwin plane-stress plastic zone correction on the half-crack length, may be applied if either of the following conditions is satisfied:
-. ~..
e I (1) Under combined tension and bending loads, the Irwin plane-stress plastic zone size is less than the smaller of (a) 1/5 of the half-crack length "a" or (b) 1/5 of the half-remaining ligament
- length, (Note that the Irwin olastic zone is defined based on the yield strength of the material.)
(ii) The variation in the stress intensity "X", under combined tension and bending loads, calculated with and without the Irwin plane stress plastic zone correction is less than 15%.
(Note that both "a" and "F(a)" in the "K" expression vary with the plastic zone correction.)
(4)
In order to complete our safety evaluation, the staff needs to evaluate the line for potential degradation during service (see NUREG-0927, NUREG-0679, NUREG-0691, and NUREG-0582). Therefore, the licensee should identify the potential for intergranular stress corrosion cracking, vibratory fatigue (socket welds, if any), flow stratification (and associated low and high cycle thermal fatigue), thermal aging of cast stainless steel, wall thinning by erosion / corrosion, creep and water hammer. Also, discuss the experience of the specific line of similar plant design with respect to in-service degradation.
(5) Relative to the system (s) that would be relied upon in this LBB application, provide a discussion of the leakage detection system (s),
procedures for detection and corresponding operator action at the plant.
For inside containment, NUREG-1061, Volume 3 recomends a minimum detectable unidentified leakage rate of 1 gpm.
If a minimum detectable unidentified leakage rate less than 1 gpri, is selected for LBB analysis, justify this selection. Where information was previously provided, a specific reference is acceptable.
(6)
In order to complete our safety evaluation, the staff needs to evaluate the potential of pipe degradation or failure from indirect causes such as fire, missiles, and component support failure as prevented by design, fabrication, and inspection. Therefore, the licensee should for corrpleteness provide a discussion on compliance with Standard Review Plan 3.4.1, 3.5.1.2, 3.9.3, 3.9.6, and 9.5.1.
Where information was previously provided, a specific reference is acceptable.
(7) The application of a bi-linear stress-strain curve in the crack stability analysis may be nonconservative. Thus, the application of a multi-linear stress-strain curve or a Ramberg-Osgood stress strain relationship is recomended.
I Mr. H. B. Tucker Duke Power Company Catawba Nuclear Station CC*
A.V. Carr, Esq.
North Carolina Electric Membership Duke Power Company Corp.
422 South Church Street 3400 Sumner Boulevard Charlotte, North Carolina 28242 P.O. Box 27306 Raleigh, North Carolina 27611 J. Michael McGarry, III, Esq.
Bishop. Liberman, Cock, Purcell Saluda River Electric Cooperative, and Reynolds Inc.
1200 Seventeenth Street, N.W.
P.O. Box 929 Washington, D. C.
20036 Laurens, South Carolina 29360 North Carolina MPA-1 Senior Resident Inspector Suite 600 Route 2, Box 179N 3100 Smoketree Ct.
York, South Carolina 29745 P.O. Box 29513 Raleigh, North Carolina 27626-0513 Regional Administrator, Region II U.S. Nuclear Regulatory Connission, L.L. Williams 101 Marietta Street, NW, Suite 2900 Area Manager, Mid-South Area Atlanta, Georgia 30323 ESSD Projects Westinghouse Electric Corp.
MNC West Tower - Bay 239 P.O. Box 355 Pittsburgh, Pennsylvania 15230 Mr. Heyward G. Shealy, Chief Bureau of Radiological Health South Carolina Department of Health and Environmental Control 2600 Bull Street Columbia, South Carolina 29201 County Manager of York County York County Courthouse Karen E. Long York South Carolina 29745 Assistant Attorney General N.C. Department of Justice Richard P. Wilson, Esq.
P.O. Box 629 Assistant Attorney General Raleigh, North Carolina 27602 S.C. Attorney General's Office P.O. Box 11549 Spence Perry, Esquire Columbia, South Carolina 29211 General Counsel Federal Emergency Management Agency Piedmont Municipal Power Agency Room 840 100 Memorial Drive 500 C Street Greer, South Carolina 29651 Washington, D. C.
20472 Mr. Michael Hirsch Federal Emergency Management Agency Office of the General Counsel Room 840 500 C Street, S.W.
Washington, D. C.
20472 Brian P. Cassidy, Regional Counsel Federal Emergency Management Agency, Region I J. W. McCormach P0CH Coston, Massachusetts 02109