ML19224D741

Responds to IE Bulletin 79-07 Re Methods of Combination of Seismic Directional Response.None of Computer Programs Used for Seismic Analysis of safety-related Piping Use Algebraic Techniques Described

ML19224D741
Person / Time
Site:	Bailly
Issue date:	05/21/1979
From:	Shorb E NORTHERN INDIANA PUBLIC SERVICE CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
NUDOCS 7907160242
Download: ML19224D741 (3)

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- NII*SCII F-Northern Indiana Puh!!c Service Company

-y Genera! Offces l 5265 Hohman Avenu e / I:ammond. Ind,ana 46325 l Tel: 853 5200 (219)

%h EUGENE M. SHORD

= ' = c ac5mr~' May 21, 1979 Mr. James Keppler, Director Nuclear Regulatory Commission Region III 799 Poosevelt Road Glen Ellyn, Illinois 60137 Re: NRC I. E. Bulletin No. 79-07

Dear Mr. Keppler:

1. E. Bulletin No. 79-07, dated April 14, 1979 raises questic'o concerning the methods of combination of earthquake directional response used for piping ana lys is for safety-related piping systems in both opereting nuclear plants and plants under construction.

Northern Indiana Public Service Company (NIPSCO) has retained Sargent &

Lundy Engineers as Architect Engineer for the Bailly ating Station Nuclear 1. The "DYNAPIPE" and "PIPSYS" computer prog . used by Sargent

& Lundy it. their seismic analysis of piping system- were developed inde-pendently of computer programs used by other AEs and other programs thrc were and are commercially available. The Sargent & Lundy programs worn first with each direction of response (X, Y, or Z) and combine modal responses for a given direction in accordance with applicable regulatory guide requirements. The combined responses for each direction are then added by the SRSS method. Thus the cancelling effect experienced in other piping analyses does not occur in the Sargent & Lundy seismic analysic.

I. E. Bulletin No. 79-07 requests responses to four specific action items regarding the seismic analysis of safety-related piping. NIPSCO's response is as follows:

NRC Iten (1) The DYNAPIPE and PIPSYS computer programs used by Sargent &

Lundy for the response spectra seismic analysis of safety-related piping do not employ algebraic summation routines for comoining responses, either intermodal or for any other 357 193 7907160 SUN 2.j 1979

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Mr. James Keppler, Directo; llammond , Iadiana Nuclear Regulatory Commission May 21, 1979 Page 2 component or response. Sargent & Lundy does not use the time history method for the seismic analysis of piping.

NRC itan (2) None of the computer progrnes used by Sargent & Lundy for the seismic analysis of safety-related piping employ the algebraic technio es des cribed in Item (1) of I. E.

Bulletin No. 79-07.

NRC Item (3) The S&L computer program DYNAPIPE (09.7.052) and PIPSYS (09.5.065) were used in piping scismic analyses. These programs have a long history of use within S&L - e.g. ,

DYNAPIPE since 1969 and PIPSYS since 1972. They have been validated several times since that time. For the seismic portions of the program, this has been done by checking computer results by hand calculations and check-ing results against the computer programs referenced below. Each new version of the program is extensively checkeu against the older version through a series of test problems. The following validation procedure was performed for the initial validation:

A. Check Acainst DYNAL(1) (1969)

A typical hot rehe t piping system was analyzed on DYNAPIPE and DYNAL 1 The element forces for a specified response spectra were compared and found to be corparable. The frequencies of modes 1 through 6 were also in close agreement.

B. Check Acainst MEC-21 (2) (1969)

In 1969, no public-domain seismic analysis code had the capability of curved elements to model pipe elbows. To validate this feature of the S&L pro-grams, the piping system given in cxample problem No. 2 of the MEC-21 computer code was analy7ed by the S&L program. Seismic analysis was performed using tre response spectrum method. Member forces, joint displacements, and joint inertia forces were p*inted for each mode. The same system was then analyzed using the MEC-21 code with a static load equal to the modal inertia free forces, and joinc displacements obtained from the two cod- were compared and found to be in good agreem '.

C. PIPSYS & DYNAPIPE Comparison (1972)

In 1972, when the PIPSYS program was developed, it 357 19A

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Mr. James Koppler, Director Hammond Indiana Nuclear Regulatory Commission May 21, 1979 Page 3 was extensively benchmarked against the DYNAPIPE program. Typical piping systems were run on the two programs and found to yield the same responses on the two codes.

s. PIPSYS & DYNAPIPE Check against DYNAL(1) and NASTRAN(3) (1972)

In 1972 the modal periods and time history of response to pipe transients using the modal time history method on PIPSYS and DYNAPIPE were checked against those ob-tained from DYNAL and NASTRAN. Good agreement was obtained in responses from the four codes.

In addition, NIPSCO and Sargent & Lundy would welcome a generic review of our piping program by the NRC Licensing Staff. This review could most effectively be conducted at the S&L offic<.s where all documenta-tion and ks personnel would be available to the Staff.

NRC Item (4) None of the computer programs used by Sargent & Lundy for seismic analysis of safety-related piping employ the alge-braic techniques described in Item (1) of I.E. Bulletin No. 79-07, therefore no reanalysis of any safety-related piping is necessary.

References:

1. ICES DYNAL User 's Manual, Mcdonald-Douglas Automation Co.

2. MEC-21, 7094, "A Piping Flexibility Analysis Program for the IBM '090 and 7094", Los Alamos Scientific Laboratory, University of Calift 'a, 1964.

3. NASTRAN User's Manual, NASA SP-221.

Very truly yours ,

I EMS:bw cc: Office of Inspection and Enforcement Division of Reactor Construction Inspection U. S. Nuclear Regulatory Commission Washington, D.C. 20555 -

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