ML20084K945

AO 50-237/1974-43:on 740901,during Run mode,2B Condensate Booster Pump Vent Line Found Ruptured.Caused by Pipe Nipple Coming Out of Casing Due to Vibration.Similar Nipples Will Be Replaced After hands-on Insp

ML20084K945
Person / Time
Site:	Dresden
Issue date:	09/06/1974
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20084K948	List: ML20084K945 ML20084L443
References
650-74, NUDOCS 8305200051
Download: ML20084K945 (2)

Text

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' CammQcalth Edison

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Chicago, Illinois 60690 BBS Ltr #650-74 Dresden Nuclear Power Station..

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Morris, Illinois 45,ogi^'

V MN September 6, 1974 9

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Mr. James G. Keppler, Regional Director 9

. Directorate of Regulatory Operations-Region III @ (' %

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U. S. Atomic Energy Commission ,

799 Roosevelt Road -L 'X Glen Ellyn, Illinois 60137

SUBJECT:

REPORT OF AENOR>iAL OCCURREJCE PER SECTION 6.6.B 0F THE TECSTICAL SPECIFICATI0HS.

2B CONDa! SATE BOOSTER PUMP VER LINE RUPTURE.

References:

1) Regulatory Guide 1.16 Rev.1 Appendix A

2) Notification of Region III of AEC Regulatory Operations Telephone: Mr. F. Maura, 1320 hours0.0153 days <br />0.367 hours <br />0.00218 weeks <br />5.0226e-4 months <br /> on September'1, 1974 Telegram: Mr. J. Keppler, 0825 hours0.00955 days <br />0.229 hours <br />0.00136 weeks <br />3.139125e-4 months <br /> on September 3, 1974 Report Humber: 50-237/1974-43 -

Report Date: September 6, 1974 Occurrence Date: September 1, 1974 Facility: Dresden Nuclear Power Station, Morris, Illinois IDENTIFICATION OF OCCURRDICE At 0900 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.4245e-4 months <br /> on September 1, 1974, the 2B condensate booster pump vent line was found to be ruptured.

CONDITIONS PRIOR TO OCCURRENCE At 0900 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.4245e-4 months <br /> on September 1,1974, Unit'2 was in the run mode producing 1390 FMt and 428 Mie.

DESCRIPTION OF OCCURRENCE At 0630 hours0.00729 days <br />0.175 hours <br />0.00104 weeks <br />2.39715e-4 months <br /> on September 1, 1974, a condensato pump room flcod alarm was received. A chif t; operator was sont-to investigate the situation. The operator reported approximately 6 inches of water in the room and noted no apparent leakage. It should be'noted at this point that due to radwaste problems, operations had been unable to pump the condensate pump room.

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Mr. James G. Keppler September e, 1974 At 0300 hours0.00347 days <br />0.0833 hours <br />4.960317e-4 weeks <br />1.1415e-4 months <br />, a shift forcoan was sent to the condeneate pump roem to further assess the situation. At thi.s time it was found that the uatcr level had risen to approximately 20 inches. Further invectication revealed that the 2B condensate booster pug vent line was ruptured and water was blcuing out of the line. Atternpts were nade to isolate the pump but the unter sprayin7 out rmde working difficult. It was felt that the pamp could not be isolated in time to prevent the water level from reaching the pump motors and the unit was manually scramned. After the condensate system was shut down, the pump was isolated and the water flow stopped.

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DESIGMATIO?! 0F /tPPARFlR CAUSE OF OCCURilEb!CE (Component Failure)

Upon checking, the cause of the occurrence was failure of the pipe nipple coming out of the casing. Reduction of wall thickness coupled with vibration of the condensate feedwater system appear to be the causes.

ANALYSIS OF OCCURREDICE There were no safety consecuences to the public or plant personnel as a result of thir occu"rme b2cauce Obc ctility to safely shut tha plant d:/n ' .c not impaired and all leakage was c'ontained in the turbine' building basement and processed in the Radwaste facility.

CORRECTIVE ACTION Immediate corrective action was to shutdown the plant and isolate the pump.

Further corrective action consisted of replacing all similar nipplee on Unit 2 conaensste booster pump vent lines. Verified with pump vendor that seal cooling installation was proper. Investigation also underway with Crane Valve Company to determine why valve is so difficult to operate and what can be done. Valve operator is on site brt hand wheels are still needed to make them operable. Also, a work request has been written to inspect the nipples on Unit 3.

FAILURE DATA Previous operating history has revealed numerous problems with leakage for this piping configuration, however, none of these previous problems involved a line severence or separation. In light of this information, all nipples and any other fittings in the vent lines which appeared suspect were replaced.

Sincerely,

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B.~B. S ephenson l Superintendent' EBS:LJD:do g -, _ _ _ _