IR 05000312/1972001

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Inquiry Rept 50-312/72-01 Re B&W Advisement That 10 of 40 Control Rod Drive Motor Tubes for Top Head of Reactor Questionable Due to Discovery of Hot Tears on Inside Surface of Tubes.B&W Perfecting Procedure for Ultrasonic Testing
ML19319E238
Person / Time
Site: Rancho Seco
Issue date: 05/03/1972
From: Dodds R
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:
Shared Package
ML19319E210 List:
References
50-312-72-01, 50-312-72-1, NUDOCS 8003310745
Download: ML19319E238 (1)


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UNITED STATES g

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DIVISION OF COMPT.!ANCF

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REGION V

2111 BANCROFr V.Y BERKELEY, CALIFORNIA 94704 rnam== e4i.s 2:

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May 3,1972 CO Inquiry Report No. 050-0312/7201

Subject: Sacramento Municipal Utility District (Rancho Seco)

Sacramento County, California Construction Permit No. CPPR-56 963 Mwe PWR, B & W

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Prepared by:

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R. T. Dodds,. Reactor Inspector Date A.

Date and Manner AEC Was Informed j

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Mr. Vincent P. McMahon, SMUD Quality Assurance Director, telephoned j

.R. T. Dodds on April 27, 1972.

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Description of Significant Construction Deficiency Babcock & Wilcox has advised SMUD that 10 o'f 40 control rod drive motor tubes (number of tubes in the B & W shop) for the top head of the reactor were questionable because " hot tears" had been discovered on

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the inside surface of 0.he tubes. The tears were chevron like in appear-L

- ance and were 'about one inch long, 40 mils wide and 15 mils deep. The tears ran as a continuous series the entire length inside the tube.

The defect was initially discovered when a repair was being made on a

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- ferritic-to-stainless steel junction.. All of the tubes had previously been 100% ultrasonically tested. The tubes were forged by Sandvik (Sweden), shipped to Royal. Industries (Santa Ana, Californid for machining and then to Diamond Power, a subsidiary of B & W.

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-Action-by Licensee

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The B & W Research. Center in Alliance, Ohio, is perfecting a procedure for UT testing the tubes. Once this has been accomplished, the tubes

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that are at Rancho Seco will be sent.to Royal Industries for examination.

Defective tubes will be rejected as appropriate.

SMUD will send 'a. report on the deficiency to the Director of Regulatory -

Operations within 30 days.

Mr. McMahon was not sure if the deficiency O

was applicable to other facilities.

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