Index | Site Map | FAQ | Facility Info | Reading Rm | New | Help | Glossary | Contact Us |
ACCESSION #: 9504110082 TO: NRC OPERATIONS CENTER FROM: MAINE YANKEE ATOMIC POWER CO. SUBJECT: CRACKED ROLL PIN HOUSING IN CAM FOLLOWER (GE TYPE SBM CONTROL AND TRANSFER SWITCH) TIME OF EVENT : FEBRUARY 28, 1995 , 1145 HRS. WE HAVE EXAMINED 20 CONTROL SWITCHES ON THE MAIN CONTROL BOARD IN THE CONTROL ROOM. EACH SWITCH HAS SOME TYPE OF PROBLEM WITH A CRACK THAT IF THE CRACK PROPAGATES TO A BREAK, POTENTIALLY ALLOWS THE CONTACT TO DETACH FROM THE CAM FOLLOWER. IN ADDITION, A NEW SWITCH FROM STOCK WAS EXAMINED AND IT ALSO HAD EVIDENCE OF CRACKING. THESE SWITCHES ARE SAFETY CLASS AND NON-SAFETY CLASS AND HAD THEY BEEN FOUND DEFECTIVE (COMPLETE SEPARATION) WHILE THE REACTOR WAS AT POWER, IT COULD HAVE RESULTED IN THE PLANT BEING SERIOUSLY DEGRADED THAT SIGNIFICANTLY COMPROMISED PLANT SAFETY. (10CFR50.72(b)(2)(i). PRESENTLY THE PLANT IS IN A SHUTDOWN CONDITION WITH REACTOR DEFUELED. SPENT FUEL POOL COOLING IS IN SERVICE AND WITHOUT PROBLEMS. OUR OUTAGE RISK MANAGEMENT PROGRAM HAS CONTINGENCY PLANS IN PLACE TO COMPENSATE FOR ANY PROBLEMS WITH SPENT FUEL COOLING. (THE TIME TO BOIL IS 18 HOURS WITH A LOSS OF COOLING.) ADDITIONAL INFORMATION WILL BE SENT TO NRC VIA AN LER AS REQUIRED BY 50.73 (a)(2)(ii) AND 10CFR PART 21. THE RESIDENT NRC INSPECTOR HAS BEEN INFORMED OF THE EXISTING PROBLEM. PSS: WILLIAM BAXTER STA: DAN McDOUGOLD GE INSTRUCTIONS GEH-2038A SUPERCEDES GEH 2038 CONTROL AND TRANSFER SWITCH TYPE S B M Figure omitted SWITCHGEAR DEPARTMENT GENERAL ELECTRIC PHILADELPHIA, PA. Figure 1 "Exploded View of Type Switch SBM Switch" omitted. *** END OF DOCUMENT ***