TXX-6731, Final Deficiency Rept CP-87-62 Re Use of Nomographs to Design Seismically Supported Class 5 Piping Sys.Initially Reported on 870824.Spec 2323-MS-46B Will Be Revised to Include Appropriate Criteria for Use of Nomagraphs

Final Deficiency Rept CP-87-62 Re Use of Nomographs to Design Seismically Supported Class 5 Piping Sys.Initially Reported on 870824.Spec 2323-MS-46B Will Be Revised to Include Appropriate Criteria for Use of Nomagraphs

ML20235L360
Person / Time
Site:	Comanche Peak
Issue date:	09/30/1987
From:	Counsil W, Keeley G TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
CP-87-62, TXX-6731, NUDOCS 8710050439
Download: ML20235L360 (3)

Text

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M M M-Log # TXX-6731

- 2 File # 10110

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i wmam c. coun n I Esecuts,e Vice Ptruident V. S. Nuclear Regulatory Commission J Attn: Document Control Desk Washington, D. C. 20555 1

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION (CPSES) (

DOCKET NOS: 50-445 AND 50-446 1 CLASS 5 PIPE SUPPORTS I SDAR: CP-87-62 (FINAL REPORT)-

I Gentlemen:

On August 24, 1987, we verbally notified your Mr. H. S. Phillips of design deficiencies identified in the use of nomographs to design seismically supported Class 5 piping systems. A written report was due on September 23, 1987. On September 23, 1987, we verbally requested and received an extension l from your Mr. R. F. Warnick until September 30, 1987. This issue was identified during third party inspections and is addressed in Corrective Action Request (CAR)87-057. A validation program has been enacted to assure the adequacy of the Seismic Category II large bore pipe supports; however, extensive engineering effort would be required to determine if the existing configuration, if left unchanged, would have precluded damaging interaction with seismic Category I components.

Lacking these analyses, we have I conservatively deemed this issue reportable under the provisior,s of i 10CFR50.55(e). j DESCRIPTION Some Class 5 piping has been seismically qualified using.a nomograph method.

I In some cases, this approach resulted in inadequate analysis documentation to support the design basis for Seismic Category II pipe supports and generation of support loads, and insufficient methods for isolating the seismically supported piping from the effects of interconnected non-seismic piping.

The root cause of this condition has been determined to be inadequate engineering requirements in specification 2323-MS-46B, " Piping Haagers (Non- I Nuc l ea r) . " Specifically, the specification did not provide adequate guidelines on proper use of the nomograph for Seismic Category II large bore {

pipe supports.

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• TXX-6731 1 September 30, 1987 Page 2 of 3 The deficiencies identified are generic for the total population of Seismic Category II large bore pipe supports and associated Class 5 piping that are .

not rigorously analyzed as part of the SWEC requalification effort (e.g., high energy piping and extensions to ASME stress problems).

I SAFETY IMPLICATIONS As noted in the description of this deficiency, the methods employed in the -

design of Seismic Category II large bore pipe supports for Class 5 piping could result in failure of these systems during a seismic event. These conditions, if uncorrected, could adversely interact with and affect the operation or functions of safety class systems.

CORRECTIVE ACTION The following measures will be implemented to correct the deficiency:

a) Specification 2323-MS-46B will be revised to include appropriate '

criteria for the use of nomographs.

b) A hardware validation program is being implemented via Field l Verification Method CPE-SWEC-FVM-PS-082, " Validation of Seismic Category II Large Bore Pipe Support Designs," to assure the adequacy of the existing Seismic Category 11 large bore pipe supports for the systems involved in this issue. The program incorporates the following actions.

1) Performance of an engineering walkdown to evaluate the actual i configurations for compliance with piping and pipe support {

drawings, and identify any additional design concerns resultitig i from the previous seismic criteria implementation. I

2) Engineering evaluation, analysis, and resolution of design concerns using an acceptable Category II over I criteria utilizing standard design checklists to assure that Class 5 piping would not damage safety related components. In addition, required modifications will be identified and issued to assure technical adequacy.

3) Documentation for the completed evaluation to establish the design basis for the technical adequacy of the seismically supported piping.

As preventive action, the following measures have been established:

a) Products of the hardware validation program will be documented and controlled by procedure ECE 2.13,'" Retention and Control of Engineering Documents," to provide traceability of the design basis. -

b) Procedure ECE 5.05, " Drawing Control," will be issued to assure that configuration (consistent with the design documentation) is maintained.

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TXX-6731 September 30, 1987 Page 3 of 3 c) Design Basis Document DBD-CS-068, "Non-ASME Piping and Support Design,"

and procedures ECS 5.03-05, "Non-ASME Pipe Stress Analysis," and ECS 5.03-06, "Non-ASME Pipe Support Design," will be issued to assure Seismic Category 11 large bore )ipe supports and the associated Class 5 piping are designed to accepta)le and approved engineering criteria.

COMPLETION DATE The completion schedule for the field verification activities will be commensurate with the schedule for the Post Construction Hardware Validation Program (PCHVP). The PCHVP will be conducted in support of the plant completion plan and scheduled to bring the plant to a fuel load status. The target schedule to be ready for the Unit 1 fuel load is March 1,1988. All applicable specifications and procedures will be revised and/or issued by January 1, 1988.

Records documenting the completion of the above actions will be available for your review at the CPSES site upon completion of the PCHVP.

Very truly yours, W. G. Counsil By: /- , .

l G. S. Keeley i Manager, Nuclea ing  ;

CBCitgj c- R. D. Martin, Region IV l

Resident inspectors, CPSES (3) 1 4

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