ML20105A794

Forwards Presentation from 850104 Meeting Re Theoretical Basis & Application of Coupling of Multiple Degrees of Freedom Computer Program

ML20105A794
Person / Time
Site:	Hope Creek
Issue date:	01/11/1985
From:	Buchholz R NUTECH ENGINEERS, INC.
To:	Vassallo D Office of Nuclear Reactor Regulation
Shared Package
ML20105A766	List: ML20105A762 ML20105A778 ML20105A794
References
RHB-85-002, RHB-85-2, NUDOCS 8502040512
Download: ML20105A794 (3)

Text

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9038 VIA DEL OAo e SAN JOSE. CALIFORNIA 96119 e PHONE (408) 829 9000 o TELEX 352002 January 11, 1985 RHB-85-002 U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, DC 20555 Attention: Mr. D. B. Vassallo, Chief Operating Reactors Branch No. 2

Subject:

Mark I Containment Program Transmittal of Presentation, "CMDOF Review Meeting", dated January 4, 1985 Gentlemen:

On January 4, 1985 Mark I Owners' Group representatives met with NRC Staff and consultants to discuss the theoretical This basis and application of the CMDOF computer program.

letter is written to transmit 10 copies of the presentation material discussed in the meeting. It is submitted by NUTECH on behalf of Northern States Power, Iowa Electric Light &

Power, Public Service Electric & Gas, and Commonwealth Edison Company.

CMDOF (Coupling of Multiple Degrees of Freedom) was used in the analysis of torus attached piping systems to more accurately represent the effects of torus shall motions caused by the postu-l laced Mark I Long Term Program hydrodynamic loads. During the presentation it was stated that CMDOF is not a newly developed l program, nor is its use unique to the Mark I Program. The concept

! on which CMDOF is based was identified in the 1960's and programs utilizing these concepts have been routinely used since 1969.

CMDOF, itself, is a rigorously based mathematical formulation and does not incorporate any compromises in accuracy for the sake of expediency. It was acted that the coupled solutions l generated using CMDOF are more accurate than uncoupled solutions.

l In fact, CMDOF was utilized expressly to insure that totally un-

necessary modifications were not made to the torus penetrations and attached piping systems.

l Based on the discussion with the Staff and its consultants following the presentation, it is our understanding that the theoretical basis for CMDOF is acceptable. In addition, there are no specific tech-nical issues still outstanding with regard to its Mark I application.

Notwithstanding, the Staff and its consultants indicated that they l

are desirous of further verification and validation for the Mark I application.

8502040512'050131 PDR ADOCK 05000354 A PDR

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Jcnu3ry 11, 1985 Mr. D. 3. Vassallo RHB-85-002 U.S. Nuclear Regulatory Cosen.

d.

The affected utilities consider that this request is not fully justifiable and consider that it will lead to an unnecessary expenditure of resources and delay to Mark I Program closure.

As was experienced earlier in the Mark I program, the performance of an accurate single-pass, fully-coupled torus / piping system analysis is not practicable; snd further, its probability of Instead, the success on a reasonable time frame is unlikely.

l affected utilities request that the CMDOF review be concluded on the following technical bases:

o CMDOF has been adequately verified and validated using the sample problems to strenuously test 4

program accuracy. In addition, the program has been applied to a free-standing steel Mark III

• containment, where 20 actual piping systems were analyzed. Note, for this case where the pre- .

cision of CMDOF results was rigorously demon-strated, the reductions in the reactions at the i

point of piping system attachment were comparable to those observed for the Mark I.

o The entire Mark I containment reevaluation was conducted on a conservative basis. In addition l to the conservatisms identified specifically in  ;

i- the Mark I Imad Definition Report and those in-  !

herent when ASME Code requirements are met, two ,

additional specific conservatisms should be considered first, the applied load frequency was adjusted to match that of the piping system l frequency characteristic so as to produce the ,

maximum responser and second, the damping factors utilized for the piping system (Reg. Guide 1.61) ,

were substantially below that currently suggested i

in the Pressure Vessel Research Council (PVRC) t recommendations.

}

l In susunary, it is felt that these considerations, together with i the sound theoretical formulation of CMDOF, are sufficient bases '

upon which to conclude CMDOF review.

l. j

M 29 '85 0 P. 7 7 6 3 0 i

January 11, 1985 Mr. D. B. Vassallo RHB-85-002 U.S. Nuclear Regulatory Consa.

l Please contact Mr. G. Nails at (612) 330-6052 or the undersigned at (408) 281-6146 if any questions or issues requiring clarifica-tion arise during review of this submittal.

Very truly yours, hlM uckMob R. H. Buchholz Project !!anager 8/pc Enclosure cc: B. Siegel (NRC)

G. Neils (NSP)

H. Shearer (IEL&P)

A. Kao (PSE&G)

B. Rybak (CECn) t p.

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