ML20205L994

Forwards Request for Addl Info Re GDC 4 Exemption Request on Elimination of Dynamic Effects of Postulated Pressurizer Surge Line Ruptures from Design Basis

ML20205L994
Person / Time
Site:	South Texas
Issue date:	03/27/1987
From:	Kadambi N Office of Nuclear Reactor Regulation
To:	Goldberg J HOUSTON LIGHTING & POWER CO.
References
NUDOCS 8704020240
Download: ML20205L994 (6)

Text

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March 27, 1987 Docket Nos. 50-498 Distribution and 50-499 (MM32y ACRS (10)

Mr. J. H. Goldberg NRC/ Local PDR MRushbrook Group Vice President, Nuclear PAD #5 Reading RPerch Houston Lighting & Power TNovak PKadambi P.O. Box 1700 OGC-Beth EJordan Houston, Texas 77001 BGrimes JPartlow Gray File 3.6a NThompson

SUBJECT:

RE0 VEST FOR ADDITIONAL INFORMATION ON GDC-4 EXEMPTION RE00EST ON PRESSURIZER SURGE LINE The staff has reviewed your exemption request on elimination of dynamic effects of postulated pressurizer surge line pipe ruptures from the. design basis for South Texas, and found that additional information, as indicated in the enclosure, is required. The staff is continuing the review of your submittals on the similar exemption request relative to the accumulator injection lines and is preparing a request for information with similar or identical questions.

These will be ready in about two weeks.

In providing your responses to the enclosed request, please include information regarding the accumulator injection lines which addresses the concerns represented in each question.

Please call me at (301) 492-7272 is you have any questions.

Sincerely, I

/s/.

N. Prasad Kadambi, Project Manager PWR Project Directorate No. 5 Division of PWR Licensing-A

Enclosure:

As stated cc: See next page l

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8704020240 870327 PDR ADOCK 0500 8

Mr. J. H. Goldberg Houston Lighting and Power Company South Texas Pro,iect cc:

Brian Berwick, Esc.

Resident Inspector / South Texas Assistant Attorney General Project Environmental Protection Division c/o U.S. Nuclear Regulatory Commission P. O. Box 12548 P. O. Box 910 Capitol Station Bay City, Texas 77414 Austin, Texas 78711 Mr. Jonathan Davis Mr. J. T. Westenneir Assistant City Attorney Manager, South Texas Project City of Austin Houston Lighting and Power Company P. O. Box 1088 P. O. Box 1700 Austin, Texas 78767 Houston, Texas 77001 Ms. Pat Coy Mr. H. L. Peterson Citizens Concerned About Nuclear Mr. G. Pokorny Power City of Austin 5106 Casa Oro P. O. Box 1088 San Antonio, Texas 78233 Austin, Texas 78767 Mr. Mark R. Wisenberg Mr. J. B. Poston Manager, Nuclear Licensing Mr. A. Von Rosenberg Houston Lighting and Power Company City Public Service Boad P. O. Box 1700 P. O. Box 1771 Houston, Texas 77001 San Antonio, Texas 78?96 Mr. Charles Halligan Jack R. Newman, Esq.

Mr. Burton L. Lex Newman & Holtzinger, P.C.

Bechtel Corporation 1615 L Street, NW P. O. Box P166 Washington, D.C.

20036 Houston, Texas 77001 Melbert Schwartz, Jr., Esq.

'Mr. E. R. Brooks Baker & Botts Mr. R. L. Range One Shell Plaza Central Power and Light Company Houston, Texas 77002 P. O. Box 2122 Corpus Christi, Texas 78403 Mrs. Peggy Buchorn Executive Director Citizens for Equitable Utilities, Inc.

Route 1, Box 1684 Brazoria, Texas 77422 i

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f Houston Lighting & Power Company South Texas Pro.iect cc:

Regional Administrator, Region IV U.S. Nuclear Regulatory Commission Office of Executive Director for Operations 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76011 Mr. Lanny Sinkin, Counsel ior Intervenor Citizens Concerned about Nuclear Power, Inc.

Christic Institute 1324 North Capitol Street Washington, D.C.

20002-a Licensing Representative Houston Lighting and Power Company Suite 1309 7910 Woodmont Avenue Bethesda, Maryland 90814 l

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ENCLOSURF REQUEST FOR ADDITIONAL INFORMATION ON ELIMINATION OF POSTULATED PRESSURIZER SURGE LINE RUPTURES AS A DESIGN BASIS HOUSTON LIGHTING & POWER COMPANY SOUTH TEXAS PROJECT UNITS 1 AND 2 DOCKET NOS. 50-498 & 50-499 4

MATERIALS ENGINEERING SECTION ENGINEERING BRANCH DIVISION OF PWR LICENSING-A (1) Figure 7-2 in WCAP-10489 shows that the pressurizer surge line pipe (SA376 TP316) is welded to a nozzle safe-end forging (SA182 GR F316L) via a stainless steel weldment, and the nozzle safe-r id is welded to the cladded nozzle furging (SA508 Class 2A) via an Inconel weldment.

Provide justification for using the pipe stress-strain and the stainless steel weld fracture toughness relationships as the Ifmiting material conditions.

(Note that the nozzle safe-end has a lower Code minimum yield than the pipe and the ferritic nozzle forging has a lower fracture toughness than the pipe.) This response should include a more comprehensive listing of material properties than currently submitted, i

Also, is the subject surge line of a constant 16-inch diameter and cross-sectional dimension?

(2) The Ifmiting weld is identified as the stainless steel weld between the surge line pipe and the nozzle safe-end (i.e. location 10). As stated in WCAP-11256 (Supplement 1), the weldment is not SAW. Describe the process of fabrication of the limiting weld. Provide justification for using the thermally-aged cast stainless steel in WCAP-10456 for the limiting weld.

Specifically, compare the base metal, weld metal, and welding process parameters between the limiting weld and the welds considered in WCAP-10456 Furthermore, W4P-10456 reports that th; worst case end-of-life cast stainless steel J of 570 in-lb/in and T of 40.

ThesevaluesarelowerthanthevaI6esusedinWCAP-11256(Nhplement1).

Explain this difference.

(3) The room temperature tensild values for the base metal are given in WCAP-11256 (Supplement 1). The values are supposed to be lower bound data extracted from Table 1(a)-1 in WCAP-11256. We assume that the data are from Certified Material Test Reports (CMTRs) specific for the South Texas Project pressurizer surge line. A room temperature yield of 46,100 psi was selected as the minimum yield for the pipe. However, as observed in Table 1(a)-1 in WCAP-11256, the elbows have a roora temperature yield

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o of 40,100 psi. Provide.iustification for selecting the pipe and not the elbow as the limiting material.

(4) From the room tempgrature tensile data, WCAP-11256 (Supplement li indicates that 650 F tensile data were obtained by ratioing with temperature data in typical SA376 TP316 primary loop pipin Then, from estimates of yield and ultimate, WCAP-11256 (Supplement 1)g. indicates that 6

a modulus of 25.1 x 10 psi and a stress-strain relationship were selected based on the Nuclear Systems Materials Handbook. Describe how the modulus was obtained. Also, describe how the entire stress-strain relationship was obtained from only two values, i.e., the yield and the ultimate. Provide justification for using the literature data to represent the subject surge line.

(5) In order to complete our safety evaluation, NRC needs to evaluate the surge line for potential degradation during service. Therefore, the applicant should provide a discussion on the potential and preventive measure for water hammer (e.g., relief valve discharge loads), vibratory fatigue, flow stratification (and associated low cycle thermal fatigue),

wall thinning by erosion, and creep.

(See NUREG-0582, NUREG-0679, and NUREG-0927) Also, state whether there has been any service cracking in pressurizer surge line of Westinghouse design.

(6) If the sequence of transients in the fatigue crack growth analysis was not selected randomly, provide the specific sequence used in the analysis.

(7) Figures 2.4-7, 2.4-8 and 2.4-9 in WCAP-11256 (Supplement 1) apparent 1v show mass flux data. Convert the mass flux data into leak rate and present the leak rate in English units (i.e., gpm). Also, provide English units for Tables 2.4-1 and 2.4-2 in WCAP-11256 (Supplement 1).

Discuss whether cracks or machined slits were used in cenerating the i

Table 2.4-2 data. Also, describe the materials (i.e., ferritic steel or austenitic stainless steel) considered in Figures 2.4-7, 2.4-8, and 2.4-9, and Table 2.4-2.

The data in Table 2,4-1 were plotted in Figures j

2.4-7 and 2.4-8 based on the "BH" and "FHG" models, respectively.

However, the "BH" and "FHG" models depend on the "L/D " ratio. The data in Table 2.4-1 may have various "L/Du" ratios. Thus,gonly a portion of the data entries in Table 2.4-1 appl'fes to either of the "8H" and "FHG" models. However, the number of data points plotted in each of Figures

2. 4-7 and 2.4-8 appears to be similar to the number of data entries in Table 2.4-1.

Provide a discussion as to the use of Table 2.4-1 data in generating these figures.

(81 Relative to the system (si that would be relied upon in this application, I

provide additional discussion of the leakage detection system (s) at South Texas and operating experience at Westinghouse plants. Describe the backaround unidentified average leakage rate expected at South Texas and the basis for this prediction.

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4 -(9) In order to complete our safety evaluation, NRC 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 applicant should for completeness provide a discussion on the compliance with Standard Review Plan 3.4.1, 3.5.1.2, 3.9.3, 3.9.6, and 9.5.1.

(10) It appears that a lower-bound stress-strain relationship was used in estimating the crack-opening area and thus, the leakage rate. The staff considers it more appropriate to use the average stress-strain relationships in estimating leakage rates. Provide,iustification that a lower-bound stress-strain relationship gives a conservative estimate of the leakage rate.

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