TXX-4762, Interim Deficiency Rept CP-86-07 Re Weld Failure & Coating Degradation in Svc Water Sys.Initially Reported on 860124. Connected Pipe Nipple Lengthened to Add Flexibility & Eliminate Stress Riser.Final Rept Expected by 860730

Interim Deficiency Rept CP-86-07 Re Weld Failure & Coating Degradation in Svc Water Sys.Initially Reported on 860124. Connected Pipe Nipple Lengthened to Add Flexibility & Eliminate Stress Riser.Final Rept Expected by 860730

ML20203P511
Person / Time
Site:	Comanche Peak
Issue date:	04/11/1986
From:	Counsil W TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	Johnson E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
CP-86-07, CP-86-7, TXX-4762, NUDOCS 8605070380
Download: ML20203P511 (2)

Text

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Log # TXX-4762 File # 10110 909.2 TEXAS UTILITIES GENERATING COMPANT NKD WAY TOWER . 400 NORT16 OBJVE 9FTMENT tott. El e IRAl.8.AN. TEM AS 78303 April 11, 1986 E C E S IIT fj , l l Mr. Eric H. Johnson, Director I Division of Reactor Safety and Projects i ppg j gl986 l, f U.S. Nuclear Regulatory Commission LL 611 Ryan Plaza Drive, Suite 1000 N 'Q ,

Arlington, TX 76012

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION DOCKET NOS. 50-445 AND 50-446 SERVICE WATER SYSTEM LEAKAGE

-SDAR: CP-86-07 (INTERIM REPORT)

Dear Mr. Johnson:

On January 24, 1986, we verbally notified you of a deficiency regarding weld failure and coating degradation in the Service Water System. We submitted an interim report TXX-4711 dated February 24, 1986. We have concluded that this deficiency is reportable under the provision of 10CFR50.55(e). We anticipate evaluation of all corrective action and completion of our final report by July 30, 1986.

i Very truly yours, llg 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 8605070380 e60411 PDR ADOCK 05000445 S PDR.

g -3'lM NN A DIV1480N OF TEXAM UTil2TIEN ELEtTNit' COMPANY k

ATTACHMENT SERVICE WATER SYSTEM LEAKAGE DESCRIPTION AND CORRECTIVE ACTION The following is a description and corrective action for weld failure and coating degradation deficiencies associated with the Station Service Water System.

The repeated weld failure in the vicinity of ISW-026 is caused from vibration fatigue. The lumped mass of instrument isolation valve ISW-026 is excited from flow induced vibration at flow control valve ISW-022 and restricting orifice CPI-SWORFR-05. The short nipple connecting the valve and orifice flange has little flexibility and is a stress riser. The corrective action will be to lengthen the connected pipe nipple to add flexibility and thereby eliminate the stress riser.

In relation to the weld at the junction of 24-SW-003-150-3 and 1-SW-1-021-150-3, and the weld in the vicinity of valve 1SW-023, it was established that erosion-corrosion associated with the cavitation across valve ISW-023 created the weld and pipe failure. In order to eliminate the erosion-corrosion concerns, the carbon steel pipe spool downstream of valve ISW-023 will be replaced with a flanged 316 stainless steel spool.

Field weld 10A in stainless steel line 2-SW-1-302-150-3 has been radiographed and an ultrasonic test performed on the surrounding area. The test results showed several small indentations existing in the pipe wall and a small cylindrical hole existing within its vicinity. A complete failure analysis will be performed on the weld when Train B is out of service. The expected completion date of this analysis is June 1986. This weld has been temporarily patched to reduce water spray.

In regard to deterioration of the plastic coating, the piping will be repaired or recoated as necessary using a Belzona lining. The exact extent of the lining repair in Train A will be established from the recently completed lining inspection of Train A. The remaining portion of the Unit 1 SW system piping will be inspected when Train B is out of service. Any required corrective action will be identified and documented by July, 1986.

SUMMARY

OF EVENTS

Date Discovered

December 26, 1985 Date NRC Notified as Potentially Reportable: January 24, 1986 Date Determined Reportable: April 11, 1986 SAFETY IMPLICATION Normally pipe coating failure or corrosion are not considered a safety issue. The periodic in-service inspection of the class 3 piping would detect any loss of integrity of the piping. However, due to the significant erosion-corrosion associated with the cavitation across valve ISW-023 and rapid loss of integrity of the piping, these deficiencies should be considered as reportable, pursuant to 10CFR50.55(e).

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