Closeout of IE Bulletin 81-01: surveillance of mechanical snubbers

In this period from August 1974 to May 1980, failures of mechanical snubbers were described in event reports issued for nine facilities and in a NRC/IE study of the DOE Fast Flux Test Facility. In most failures, the snubbers were frozen and would not permit free piping motions during thermal transients. In some cases, the failed snubbers no longer provided seismic shock restraint. Because of concern about the reported failures of mechanical snubbers, standard technical specification revisions for snubber surveillance were issued by NRC/DL on November 20, 1980. IE Bulletin 81-01 was issued January 27, 1981 to require examination and testing of mechanical snubbers in safety-related systems at licensed facilities and at selected facilities under construction. Evaluation of utility responses and NRC/IE inspection reports indicates that the bulletin can be closed out per specific criteria for 73 (95%) of the 77 facilities to which it was issued for action. Followup items are proposed for use by NRC/IE to ensure satisfactory completion of corrective action at the remaining four facilities