Part 21 Report - 1997-510

LICENSEE: MGP INSTRUMENTS, INC. SITE: MGP INSTRUMENTS, INC. EN NUMBER:32725 DOCKET: EVENT DATE: 06-12-97 RX TYPE: EVENT TIME: 00:00 VENDORS: NOTIFY DATE: 08-05-97 EMERGENCY CLASS: N/A REGION: 2 STATE: GA TIME: 14:57 OPS OFFICER: LEIGH TROCINE 10 CFR SECTION: CDEG 21.21(c)(3)(i) DEFECTS/NONCOMPLIANCE 10 CFR PART 21 NOTIFICATION REGARDING THE DISCOVERY THAT A RADIATION MONITORING SYSTEM POWER SUPPLY CIRCUIT BOARD IS SUBJECT TO PREMATURE ELECTRONIC COMPONENT FAILURE MGP INSTRUMENTS, INC., LOCATED IN SMYRNA, GEORGIA, REPORTED A POTENTIAL SAFETY-RELATED DEFECT INVOLVING DIODES IN RADIATION DETECTION MEASUREMENT EQUIPMENT WHICH WAS SUPPLIED TO SOUTHERN CALIFORNIA EDISON FOR USE AT SAN ONOFRE. DIODE VD9 (MODEL #1N4148) WAS INSTALLED ON PROPRIETARY POWER SUPPLY BOARDS, AND THIS DIODE IS SUSCEPTIBLE TO FAILURE DURING EQUIPMENT START-UP. THE FAILURE IS DUE TO THE INSUFFICIENT RATING OF THE DIODE UNDER TRANSIENT CONDITIONS (NON-REPETITIVE PEAK FORWARD CURRENT). FAILURE OF THIS DIODE COULD ULTIMATELY RESULT IN THE INABILITY OF THE LOCAL PROCESSING UNIT TO RESTART WITH CORRECT OPERATING PARAMETERS. THE SAFETY-RELATED APPLICATION OF THIS DEVICE IS LIMITED TO ITS INSTALLATION IN 28 LOCAL PROCESSING UNITS AT SAN ONOFRE. MGP INSTRUMENTS, INC., STATED THAT A RECENT INQUIRY OF THE UTILITY INDICATED THAT THE AFFECTED EQUIPMENT HAD NOT BEEN COMMISSIONED AND IS NOT YET IN SERVICE. PLANS ARE BEING MADE TO REPLACE THE DIODES WITH APPROPRIATE COMPONENTS PRIOR TO THE COMMISSIONING OF THE EQUIPMENT. (REFER TO THE HOO LOG FOR CONTACT NAMES AND TELEPHONE NUMBERS.)

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