TXX-4658, Deficiency Rept CP-85-46 Re Unacceptable Pressurizer Surge Line Interactions Involving Potential LOCA & Damage to Secondary Side Lines.Initially Reported on 851029.Addl Analyses Will Be Completed Prior to Fuel Load

Deficiency Rept CP-85-46 Re Unacceptable Pressurizer Surge Line Interactions Involving Potential LOCA & Damage to Secondary Side Lines.Initially Reported on 851029.Addl Analyses Will Be Completed Prior to Fuel Load

ML20151M653
Person / Time
Site:	Comanche Peak
Issue date:	12/20/1985
From:	Beck J, Counsil W TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	Johnson E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
CP-85-46, TXX-4658, NUDOCS 8601020647
Download: ML20151M653 (2)

Text

. -

Log # TXX-4658 TEXAS UTILITIES GENERATING COMPANY Fi1e # 10110 NKYW AY TOWER . 400 NORTH OIJVE STREET. I.B. A t . DAtl.AN. TEXAN 7S201 E Ufc?UUA December 20; 1985 -

.g{S, Mr. Eric H. Johnson, Acting Director O

d mmJ '~ ~__ . . _

II Division of Reactor Safety and Projects ~ ~

3 U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 1000 _

Arlington, TX 76012 (((7 _

.i-~

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION i n ,_

DOCKET NOS. 50-445 AND 50-446 t.lEC L 0ISdb DAMAGE STUDY EVALUATION OF WESTINGHOUSE 'i I

SDAR: CP-85-46

_}

Dear Mr. Johnson:

In accordance with 10CFR50.55(e), we are submitting the enclosed written report of actions taken to correct a deficiency involving high energy piping analyzed by Westinghouse. Postulated longitudinal line breaks were not evaluated by the damage study group. Evaluation of this issue has identified a reportable condition under the provisions of 10CFR50.55(e) involving interactions in the pressurizer surge line.

Very truly yours, LJ. G. &-A W. G. Counsil By: M.

Jt/W. Beck Vice President JCH/grr Attachment c- NRC Region IV (0 + 1 copy)

Director, Inspection & Enforcement (15 copies)

U. S. Nuclear Regulatory Commission Washington, D.C. 20555 8601020647 PDR 851220 S ADOCK 05000445 PDR lE-1]

i

\g a nuvssion or rexas ununes etecraic couraur y 04

o -

ATTACHMENT DAMAGE STUDY EVALUATION OF WESTINGHOUSE ANALYZED PIPING DESCRIPTION In the analysis (by Westinghouse) of high-energy piping, circumferential and longitudinal breaks were assumed to occur at high intermediate stress points. Programmatically, the site Damage Study Group has evaluated circumferential pipe breaks. The site evaluation of i

longitudinal breaks has occured only in the instances in which these

, breaks have been specifically identified by the analysis organization.

Based upon a review of previous analysis results, Westinghouse was requested to' provide clarification regarding a number of specific longitudinal breaks. The response resulted in a site Damage Study evaluation and the identification of unacceptable pipe break interactions.

Additional detailed analysis by Westinghouse indicated unacceptable interactions exist in the pressurizer surge line which originates at the reactor coolant loop and terminates at the pressurizer. The interactions involve a possible loss-of-coolant incident and damage to secondary side lines (SG blowdown and feedwater).

The concern is applicable to Unit 1 only.

SUMMARY

OF EVENTS Date Discovered: October 28, 1985 by DRR-117 Date NRC Notified as Potentially Reportable: October 29, 1985 Interim Report to NRC: November 20, 1985 Date Determined Reportable: December 19, 1985 SAFETY IMPLICATION In the event the conditions had remained undetected and the unanalyzed

-longtidinal breaks had occurred, the operator's ability to safely control plant operations during accident conditions could be impaired.

CORRECTIVE ACTION Evaluations are currently underway to resolve the unacceptable interaction through additional analysis techniques or'the incorporation of physical protective structures. These efforts have been identified as a prerequisite to Fuel Load and will be completed accordingly. l i

4

- --., , ~ g-- - ,--g,-