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36 Nuclear Waste Disposal Crisis closed that the rctc~rn-to-norrrarf spring in the grapple's control circuit had broke After the operator raised the grapple to the fully retracted position and released3' the up-down switch, the switch fell through the neutral position to the down pps1='~ lion due to the broken spring, causing the grapple to lower. January 1974: While transferring an irradiated fuel assembly from the s ~-~ fuel pool to the channel inspection facility at the Pilgrim Nuclear Plant, thee`` assembly became detached from the main grapple and fell approximately 20 ~"~ to the bottom of the spent fuel pool. Examination of the fuel assembly revealed; that its channel slipped down over the nose piece and that the impact rnyShed t~`'~ nose piece and lower end of the channel There were no indications of broken fuel' rods, and the fuel pool liner did not suffer damage. The grapple hook ma "~ have been completely latched under the fuel assembly's handle allowing tlie~ operator to lift the fuel assembly with only a friction grip on its handle." ;~~ January 1977: A fuel assembly was inadvertently released from the at Peach Bottom Unit 3 and fell across the core. The assembly's release was~attrP'1~.+ uted to inadvertent operation of the grapple open switch when the refueling m controls had to be rotated away from the operator in conjunction with a slack cable signal when the fuel assembly nose cone contacted the core as it was being lowered, thereby satisfying all the interlocks for the ~.,~ May 1977: A fuel assembly and mast were inadgveztenltly dropped at DYS ~"~,. Creek while lowering the assembly into a storage rack The fuel and mast move ment were arrested by the able brake drum, without further damage, when the operator released the grapple lower lever. The drop resulted from shearing siz`~ bolts that coupled the refueling mast speed reducer to the cable druai.''c~ Examination indicated that all but two bolts had previously failed." F, t.. December 1979: A new fuel assembly was dropped at Pilgrim while it was; being transferred to its storage location in the spent fuel pool. The assembly wash being transported with the reactor building overhead crane when it struck the top edge of the high-density fuel racks and the latching device on the auxiliary hook failed to retain the fuel assembly lifting bail. The assembly fell, striking the lifting' ~.~"~ bails on four spent fuel assemblies, then coming to rest on the top of the storage .: racks. The four spent fuel assemblies were not damaged. Spent fuel pool water .q samples were analyzed with no discernible change in activity levels detected." ~=> March 1981: During refueling at Millstone Unit 1, a new fuel assembly was dropped onto the upper core grid. It had just been placed in a core location. In the process of removing the fuel grapple and telescoping mast from this fuel assem-~'" blv the latching mechanism did not fullv retract. Upon retraction of the mast, the fuel assembly was removed from the core in an unsecured condition to a point ' just above the upper core grid where it became loose and fell onto the upper core's grid, coming to rest in a diagonal position about 3~~ above the horizontal. The operator failed to detect the fuel assembly on the grappie.because he did not per- form an adequate rotational check of the telescoping mast before raising it. Y ~-~= 16d ~~: `.. -m~L: ~'.,'s, . ¢_~~: , ~:<..: !q~.:,, :~ ~: .`~"~ ~ -~ ti `::-7P ~:L '~ _ a.,, ai