ML19259C871

Responds to IE Bulletin 79-07 Re Seismic Stress Analysis of safety-related Piping.Clarifies Safety Significance of Safety Relief Valve Discharge Piping Discussed in 790629 Ltr

ML19259C871
Person / Time
Site:	Cooper
Issue date:	07/18/1979
From:	Pilant J NEBRASKA PUBLIC POWER DISTRICT
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
NUDOCS 7908160034
Download: ML19259C871 (2)

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July 18, 1979 got flir N r/ o Y "O wh :\',A .

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Mr. Karl V. Seyf rit , Director

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U.S. Nuclear Regulatory Core 11ssion '

Office of Inspection and Enforcenent t-

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Region IV '

611 Ryan Plaza ' 9,,

Suite #1000 '4 111* 7' ,

Arlington, TX 76011 Subj ect : IE Bulletin No. 79-07 Seisnic Stress Analysis of Safety-Related Piping a u

Dear Mr. Seyfrit:

Our partial response to the subject bulletin submitted June 29, 1979 contained the results of a re-evaluation of the Safety / Relief Valve (SRV) discharge piping at Cooper Nuclear Station. This re-evaluation was perforced because Iten No. 1 of the bulletin required that we consider " safety systems (or portions thereof) af fected" by the comp'tter code nethods speci'ied.

Our in-depth response discussing this re-evaluation has led to sub-sequent discussions with the Staff regarding the possible safety issues involved. This letter is written to further clarify the safety signit-icance of the SRV discharge line which was found to have one pipe support structure in an overstressed condition.

The SRV discharge piping is not a safety-related system and is thiu.

classified as a Seismic Class IIS system at CNS. Section XII-2.1.1 of the FSAR for Cooper Nuclear Station defines a Class II system as follows:

"This class includes those structures, equipment, and components which are important to reactor operation, but are not essential for preventing an accident which would endanger the public health and safety, and are not essential for the nitigation of the consequences of these accidents. A Class II designated iten shall not degrade the integrity of any item designated Class I." QSi'u j 7008160 0 U1

• - ' Mr. Karl V. Seyf rit July 18,1979 Page 2 Because failure of the SRV discharge piping system nust not degrade the integrity of any Class I system, its pipe supports were originally analyzed using the ADLP:PE Computer Program as described in our previous response. Even though *his one pipe support structure could be in an overstressed condition during a SRV blowdown transient, it will not lose functica and fall to meet the original safety criterion as specified in the FSAR.

If you have any questions or require additional information, please do not hesitate to contact ce.

Sincerely yours, M

u d. Pilant Director of Licensing and Quality Assurance

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JDU/cnk cc: U.S. Nuclear Regulatory Commission Office of Inspection and Enforcement Division of Reactor Operations Inspection Washington, DC 20555 0 b b.). . 7 8

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