TXX-4516, Interim Deficiency Rept SDAR-181 Re Branch Feedwater Line Break Which Could Cause Unacceptable Jet & Whip Interaction W/Containment Spray Headers.Pipe Whip Restraint Structure Will Be Designed & Installed

Interim Deficiency Rept SDAR-181 Re Branch Feedwater Line Break Which Could Cause Unacceptable Jet & Whip Interaction W/Containment Spray Headers.Pipe Whip Restraint Structure Will Be Designed & Installed

ML20133E037
Person / Time
Site:	Comanche Peak
Issue date:	07/22/1985
From:	Counsil W TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	Hunter D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
SDAR-181, TXX-4516, NUDOCS 8508070553
Download: ML20133E037 (2)

Text

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Reactor Project Branch 2 U.S. Nuclear Regulatory Commission Office of Inspection & Enforcement 611 Ryan Plaza Drive, Suite 1000 Docket No.: 50-445 Arlington, TX 76012 COMANCHE PEAK STEAM ELECTRIC STATION CONTAINMENT SPRAY HEADERS: FEEDWATER LINE BREAK QA FILE: CP-85-20, SDAR-181 FILE N0.: 10110

Dear Mr. Hunter:

In accordance with 10CFR50.55(e), we are submitting the enclosed written report of actions taken to correct a deficiency regarding a branch feedwater line break which could cause unacceptable jet and whip interaction with the containment spray headers. We have submitted an interim report logged TXX-4487, dated June 3, 1985.

Supporting documentation is available at the CPSES site for your Inspector's review.

Very truly yours, M

W.G. Counsil WGC:tig Attachment cc: NRC Region IV - (0 + 1 copy)

Director, Inspection & Enforcement (15 copies)

U.S. Nuclear Regulatory Commission Washington, DC 20555 8500070553 850722 5 PDR ADOCK 050

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TXX-4516 7/22/85 Page 2 ATTACHMENT CONTAINMENT SPRAY HEADERS: FEEDWATER LINE BREAK Description During the Unit 2 jet and pipe whip interaction analysis, the results of the interaction of a branch feedwater line and the containment spray headers in Unit 1 was referenced. The Unit 1 and Unit 2 configurations for this installation are similar. The Unit 1 analysis had concluded no protection was required. Because of the similarities between Units, a field survey was initiated to re-evaluate prior Unit 1 analysis. As a result, we have identified an unacceptable interaction between the six inch (6") branch feedwater line and the three inch (3") containment spray header. Provisions are required to restrain the pipe whip motion of the larger piping in the event of a break. This issue is applicable only to Unit 1.

Safety Implications In the event the condition had remained undetected, operability of the Unit 1 containment spray headers and the resultant safety effects could not be assured under accident conditions.

Corrective Action A pipe whip restraint structure will be designed and installed to correct the unacceptable interaction. The installation has been identified as a condition prerequisite to fuel load and operation of Unit 1. The design is anticipated to be complete in mid-September with installation to proceed immediately after fabrication.

A review of the interaction program by site engineering has determined the analysis error is an isolated instance. However, in order to assure additional errors do not exist in the analysis, all interaction resolutions will be checked in the process of updating the Unit 1 damage study. Procedures to control this effort are scheduled to be issued no later than September 1, 1985.

Completion of the update is anticipated by December 30, 1985.