ML20215L309

Forwards Request for Addl Info Re Alternative Pipe Break Criteria for RHR Lines Per GDC 4.Requests That Westinghouse Agree to Release Any Info Designated Proprietary to Support SER Conclusions

ML20215L309
Person / Time
Site:	Catawba
Issue date:	10/22/1986
From:	Jabbour K Office of Nuclear Reactor Regulation
To:	Tucker H DUKE POWER CO.
References
NUDOCS 8610280572
Download: ML20215L309 (5)

Text

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06cket No.: 50-414 82 OCT 1986 Mr. H. B. Tucker, Vice President Nuclear Production Department Duke Power Company 422 South Church Street Charlotte, North Carolina 28242

SUBJECT:

CATAWBA NUCLEAR STATION, UNIT 2 - REQUEST FOR ADDITIONAL INFORMATION ON ALTERNATIVE PIPE BREAK CRITERIA FOR THE RESIDUAL HEAT REMOVAL (RHR)

LINES By letter dated June 27, 1984, you requested an exemption to the requirements of 10 CFR 50, Appendix A, General Design Criterion (GDC)-4 for the RHR line pipe breaks. The staff has reviewed your request and finds that additional information, identified in the Enclosure, is needed for completion of its review.

In addition, we request that the vendor, Westinghouse Electric Corporation, agree to release for these lines the system parameters, margin numbers, specific system moments and forces, references to analytical methods, leak rates and reference crack sizes, which have been designated as proprietary. This in-formation must be included in the NRC staff's safety evaluation to support its conclusions.

Your response to the enclosure is requested within 60 days from the date of this letter. Please contact me at (301) 492-7367 if you have questions regarding

the enclosure or are unable to meet the requested respense date.

Sincerely, Kahtan Jabbour, Project Manager i PWR Project Directorate #4 1 Division of PWR Licensing-A

Enclosure:

As stated cc: w/ enclosure See next page DISTRIBUTION:

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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, Cook, 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 19745 P.O. Box 29513 Raleigh, North Carolina 27626-0513 Regional Administrator, Region II U.S. Nuclear Regulatory Commission, L.L. Williams 101 Marietta Street, NW, Suite 2900 Area Manager, Mid-South Area Atlanta, Georgia 30323 ESSD Projects Westinghouse Electric Corp.

FNC 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 Fanagement 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 Boston, Massachusetts 02109

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ENCLOSURE REQUESTFORADDITIONALINFORMATION

1. Material Characterization a) For the base and held Iretal actually in the Catawba RHR lines provide the rr,echanical properties (e.g., ultimate and yield strengths) or other significant rr.aterial properties that will characterize the material.

b) Indicate the type weld and post weld heat treatment used to fabricate the welds in the RHR lines.

c) Provide a materials evaluation to demonstrate that the material stress-strain curve in Figure 5-8, JIc, and the J-R curve used in the analyses are representative of the material in the Catawba RHR lines. This evaluation should follow the general guidelines in

- NUREG-1061, Vol. 3, and include a comparison of the traterial properties for the RHR lines to the material properties for test data.

2. History of Cracking and Dynamic Loading a) Section 2.0 of WCAP 10577 should include references to the NUREG-0691 and NUREG-0521 reports where applicable.

b) A water hammer event, which resulted in significant leakage, has occurred previously at McGuire Unit 2 (LER 370/84-017). Provide additional justification that water hammer is not a credible event at Catawba Unit 2 for the purpose of applying leak before break analysis to the RHR lines.

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c) Describe the criteria and action associated with RC pump shaft vibration limits to ensure that the RHR lines will not experience unacceptable fatigue damage.

3. Loads a) List individual axial load and bending moment components used to determine the resultant axial forces and bending moments indicated on Page 3-5 of WCAP 10577.

b) Provide a qualitative discussion of why a circumferential flaw in a straight pipe section is more limiting than a longitudinal flaw in an elbow or other component.

4. Stability Analysis

. Confirm that the margins on load and flaw size in Sections 5.2 (h) and (1) and factor of 10 on leakage discussed in Section 5.7 of NUREG-1061, Vol. 3 are demonstrated by the stability analyses for the pipe and attachment weld materials.

5. Leak Rate Analysis l Section 3.2 of WCAP 10577 indicates that the total axial force used in the leak rate computation is the absolute value of the sum of the axial deadwight, thermal and pressure compcnents. Provide justification for not using the algebraic sun. of the axial load components for the leak rate computations.

6. Validation of Con.putational Methods i

Describe the method of validating (bench marking) each computer code used in the leak rate and fracture mechanics calculations.

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7. Fatigue Crack Growth Analysis a) The data cited in Reference 8-2 as the basis for the fatigue crack growth rote should be included in the report in graphical form that would illustrate and justify the fatigue crack growth rate constants in equation 8-3 of WCAP 10577. These equations should represent the fatigue crack growth rate of the material characterized in Item 1.

b) The applicant must perform as realistic analysis as possible using service level A and B loads. The aspect ratio for the postulated crack in the fatigue evaluation should be 6. The aspect ratio should remain constant tt.roughout the analysis. Unless otherwise justified, the maximum allowable flaw depth is the smaller of:

(1) 60% of the wall thickness, or (2) the depth at which the plastic zone is equal to the remaining ligament.

c) The length of the fatigue crack must be less than both:

j (1) the length of the instability thru-wall crack at 1.4 (N+SSE) and (2) 1/2 (instability thru-wall flaw at N+5SE)

The applicant is requested to confirm that the fatigue analysis includes the items listed in b) and c), above.

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