Bulletin 74-012: Incorrect Coils in Westinghouse Type SG Relays at Trojan
BL74012 RO BULLETIN NO. 74-12 Date: 10/21/74 INCORRECT COILS IN WESTINGHOUSE TYPE SG RELAYS AT TROJAN We recently received information from the Portland General Electric Company describing incorrect relay coils supplied as component parts of the 4kV and 12kV switchgear that were discovered during preoperational testing at the Trojan nuclear power plant. The information provided is as follows: A. Description of Circumstances Eleven (11) Westinghouse type SG293-B255A20 relays supplied by ITE in the 4kV and 12kV switchgear were determined to have incorrect coils during Trojan field preoperational testing. The relays were found to have 48V dc coils rather than 125V dc coils. The resistance of 48V dc coils is 725 ohms; the resistance of 125V dc coils is 4650 ohms). The relays were found to have been labeled incorrectly as being 125V dc relays by the subvendor, Westinghouse. Five of the 11 incorrect relays are located in engineered safety features (ESF) circuits - three of which (27-A1, 27-D1, 27-D2) are potential monitor relays whose only function is to alarm; the other two (162-108X and 162-208X) perform an ESF function. The licensee's evaluation showed that these relays with 48V dc coils could fail in either of two ways - burn open or short to ground when subjected to 125V dc. B. Action Requested of Licensees It is requested that you notify this office in writing within 30 days: (1) whether or not similar circumstances or the potential for similar circumstances described above exist at your facility for Class IE equipment, or (2) the date(s) when action to determine whether similar circumstances exist will be completed. If the findings as a result of the action above indicate that similar circumstances exist, the specific findings together with a description of the corrective action taken or planned, including the scheduled completion date of planned corrective action, should be submitted to this office within 30 days of the findings. If there are no such relays at your facility(ies) a negative report is requested.
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