TXX-4656, Initial Deficiency Rept CP-85-49 Re Unevaluated Fluid Transient in Two Main Steam Piping Sys.Initially Reported on 851206.Piping Sys Will Be Redesigned to Include Sloping & Addl Drain Pots

Initial Deficiency Rept CP-85-49 Re Unevaluated Fluid Transient in Two Main Steam Piping Sys.Initially Reported on 851206.Piping Sys Will Be Redesigned to Include Sloping & Addl Drain Pots

ML20151M700
Person / Time
Site:	Comanche Peak
Issue date:	12/20/1985
From:	Counsil W TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	Johnson E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
CP-85-49, TXX-4656, NUDOCS 8601020666
Download: ML20151M700 (2)

Text

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Log # TXX-4656 TEXAS UTILITIES GENERATING COMPANY File # 10110 SKYWAY TOWER

• 400 NORTH OLIVE STREET.1 B. e t

• DAILAS. TEXAM 75301 EAN50?SMAS December 20, 1985 %g@@QQ DEC 2 3 S85 f

!\Ni Mr. Eric H. Johnson, Acting Director .-

J' Division of Reactor Safety and Projects

! U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 1000 Arlington, TX 76012

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION DOCKET N05. 50-445 AND 50-446 MAIN STEAM LINE FLUID TRANSIENT SDAR: CP-85-49

Dear Mr. Johnson:

In accordance with 10CFR50.55(e), we are submitting the enclosed written report of actions taken to correct a deficiency regarding the Auxiliary Feedwater (AFW) turbine steam supply line. On December 6,1985 we verbalb notified your Mr. S. Phillips of this potentially reportable issue.

Evaluation of this issue has identified a reportable condition under the provisions of 10CFR50.55(e) involving the piping and support systems for the main steam supply line to the AFW turbine.

Very truly yours,

f. V/lds W. G. Counsil JCH/grr Attachment c- NRC Region IV (0 + 1 copy)

Director, Inspection & Enforcement (15 copies)

U. S. Nuclear Regulatory Commission Washington, D.C. 20555 ck $$f LE - 27 I

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r ATTACHMENT MAIN STEAM LINE FLUID TRANSIENT DESCRIPTION In the process of evaluating a problem report issued by operations engineering regarding damaged snubbers, a design concern was observed in two (2) main steam piping systems. As a result of steam condensation and inadequate provisions for draining, moisture accumulation creates an unevaluated fluid transient (or waterhammer).

The specific lines are installed in parallel originating at the steam generator (numbers 1 and 4) main steam headers upstream of the main steam isolation valves. The piping terminates at the auxiliary feedwater pump turbine. Thermal movement resulting from the fluid transient could exceed design stresses considered in the piping and support design, and result in damage to attached components.

The concern is applicable to Units 1 and 2.

SUMMARY

OF EVENTS Date Discovered: May 16, 1985 by Problem Report 85-297 Date Identified as Potentially Reportable: November 6, 1985 Date NRC Notified as Potentially Reportable: December 6, 1985 Date Determined Reportable: December 18, 1985 SAFETY IMPLICATION In the event the condition had remainea undetected, the capability of the piping and associated support system to perform the intended safety functions could not be assured.

CORRECTIVE ACTION It order to implement measures to remove moisture accumulation, the piping systems will be redesigned to include sloping and additional drain pots. Reanalysis of the piping and support scheme will be performed in cos.innction with the issue of system rework documents.

The Unit I and 2 engineering efforts are scheduled for completion in May and July of 1986 respectively. Construction activities will follow immediately in Unit 1 and as determined in the construction schedule for Unit 2.