ML20147C319

Comment Opposing SRP Section 3.6.3 of NUREG-0800.Utils Endorse Comments by Nuclear Util Group on Equipment Qualification

ML20147C319
Person / Time
Site:	Millstone, Haddam Neck, 05000000
Issue date:	01/06/1988
From:	Mroczka E, Sears C CONNECTICUT YANKEE ATOMIC POWER CO., NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
FRN-52FR32626, RTR-NUREG-0800, RTR-NUREG-800 27086, 52FR32626-00026, 52FR32626-26, B12767, NUDOCS 8801190180
Download: ML20147C319 (5)

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' o I.. hA TFoR . CONNECTICUT 06141 Of7D L L TJ C'[, Ol," C g,",', (203) d65-6:00 LU hlfff January 6, 1988 fQ F){ 33c;g,i Docket Nos. 50-211 50-245  ;

50-336 1 50-423 j B12761 Re: 10CFR50, Appendix A, )

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l U.S. *1aclour Regulatory Commission 8.1.tn Pocument Control Desk ishim .on, D.C. 20555 I Gentlaren:

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Haddam Neck Plant Millstone Nuclear Power Station, Unit Nos. 1, 2, and 3 Comments on Standard Review Plan Section 3.6.5  ;

On August 28, 1987,I I the Nuclear Regulatory Commission (NRC) published for public comment a draf t Standard Review Plkn (SRP) section which will be used by the NRC Staff to evaluate all l submittala from licensees and applicants dealing with implementa-tion of leak-before-break technology under the broad scope amendment to General Design Criterion 4 (GDC-4) of Appendix A, 10CFR Part 50. Connecticut Yankee Atomic Power Company (CYAPCO) and Northeast Huclear Energy company (NNECO) respectfully submit the fo] lowing comments on the draf t SRP Section 3.6.3, "Leak-Before-Dreak Evaluation ?rocedures". In general, CYAPCO and NNECo commend the NRC for tne steps taken thus far to apply leak-before-break technology to selected design basis analysis.

While the entire SRP Section 3.6.3. is open for comment, the NRC Staff has particularly invited comments on the throo items listed below. CYAPCo's ar.d NNEco's response is provided after each item. f 1

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! l (1) 52 Federal Register 32626, August 28, 1987.

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U.S. Nuclear Regulatory commission B12767/Page 2 January 6, 1988 Item 1 With respect to the evaluation of structurns protecting essential equipment as stated in Section 3.6.3.V ("Implementation"),

comment is requested on the need to assume pressurizations associated with an area equivalent to the cross unction of the controlling pipe and linear release time of three seconds in piping which qualifies for leak-before-break.

Resconse, The proposed revision would still require that dynamic effects of postulated pipe breaks be considered. This The is despite an approved leak-before-break evaluation.

revised SRP Section 3.6.3.V.2 introduces a now, overconser-vative, arbitrary loading condition (single-ended guillotine break occurring over 3 seconds) for leak-before-break piping.

Since the intent of this revision is to eliminate arbitrary, overconservative loading, this requirement should be deleted. Instead, the maximum leakage from the postulated stable leak-before-break crack under accident conditions should be uJed. This is both conservative and consistent.

Item 2 With respect to corrosion resistance of piping as stated in Section 3.6.3.III ("Review Procedures"), Item 6, comment is requested on the statement that piping susceptible to inter-granular stress corrosion cracking (IGScc) may qualify for leak-before-break if two mitigating methods are applied within the first two years of service.

Rs.sponsa The proposed revision includes several arbitrary limitations on applicability. It would prohibit leak-before-break ovaluations for individual welds, weld overlays, and inter-granular stress corrosion susceptible welds which have been nitigated (unlosn two techniques were used in the first two years of services).

All of those arbitrary restrictions should be deleted. If the stringent requirements of a leak-before-beak evaluation can be met, no further restrictions are necessary or justi-fled. Individual welds, repaired welds (i.e., weld over-lay), and welds which are no longer susceptible to IGSCC could all benefit from leak-before-break avaluations.

Because the avaluation itself is conservative, making it available in these rituations poses no threat to public health and safety.

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. U.S. Nucicar R gulatory Ccmmiccion >

B12767/Page 3 January 6, 1988

_ Item 3 Regarding the statement in Section 3.6.3.V ("Implementation")

that "Requirements for containment design . . . are not affected," the Staff's current position is that the cited requirements include pressuriaations, pipe whip effects and jet impingement effects from pipe ruptures on containment pressure boundaries and primary structures, and in the case of contain~

monts with pressure suppression design features, the effects of pipe rupturss on those features. The Conaission recognises the needtoaddresswhetherandtowhatextentleg-before-breakcan Comments are be applied to containment design bases.

requested on how containment design bases might be modified together with the associated technical justifications for the proposed modification, particularly with respect to pipe whip effects and jet impingsment effects.

Reneensq The proposed revision is arbitrarily limited to compart-i ments, whipping and jet effects. The support and contain-ment design bases would remain unchanged.

This restriction should be deleted and the largest credible leakage should form the containment and component support' design bases. This leakage would arise from postulated double-ended rupture of piping for which leak-before-break has not been shown or accident condition leakage through the postulated stable crack. This technique would be consistent-a n d_ conservative. i In addition to the three comments provided above, CYAPCo and NNECO have the following comments:

Section III.8 of the proposed SRP 8ection 3.6.3 weuld require that material operates at all times in its ductile temperature range. Operation at low pressure often occurs at lower, more brittle temperatures. This low stress, low temperature operation peces no threat of brittle cleavage-type failure even though the material is not in its "upper shelf." For this reason, the phrase "(that is, the material is on the upper shelf)," should be deleted.

It is recommendud that a footnote be to inserted after the state that the first sentence i MRP Section 3.6.3.I commission recog: 2:e and has requested the Staff to address the inconsistene; : uplying leak-before-break technology.

It also should ': s 1 that the Commission may considr~

(2) 52 Federal Register 26393, July 23, 1987.

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U.S. Nuc1 car RCgu1Ctory C;mmiocicn *

"B12767/Page 4 January 6, 1988 i

relief on a case-by-case basis to apply leak-before-break in the environmental qualification area.

I Several typographical errors should be corrected. These are: ,

j o I.2 - Change "leak are evaluation" to "leak rate l evaluation." l l

o II - Change "sniaytable portion" to "analyzable por-tion."  ;

o III.T - Change "demonsrtrate" to "demonstrate" o VI.4 - Change "EPRI Report NT-4690-SR" to "EPRI Report NP-4690-SR."

o VI.4 - Change "April, 1986" to July, 1986" In addition to our comments, CYAPCO and NNECO endorse the com- l' ments by the Nuclear Utility Group on Equipment Qualification.

We trust that these comments will be useful in the finalization of SRP Section 3.6.3.  ;

very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY NORTHEAST NUCLEAR ENERGY COMPANY l t

. f E. J. Mroczka V Senior Vios President

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By: C. F. Sears '

Vice President j i i cc David L. Meyer, Chief, Rules and Procedures Branch, NRC W. T. Russell, Region I Administrator H. L. Boyle, NRC P/oject Manager, Millstone Unit No. 1 D. H. Jaf fe, NRC Project Manager, Millstons Unit No. 2 R. L. Ferguson, NRC Project Manager, Millstone Unit No. 3 A. B. Wang, NRC Project Manager, Haddam Neck Plant W. J. Raymond, Senior Resident Inspector, Millstone Unit Nos. 1, 2, and 3 J. T. Shedlosky, Resident Inspector, Haddam Neck Plant

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