'Mind the Gap' between old and new nuclear qualified cable: Lessons learned from aging, historical adverse events and other nuclear cable issues

摘要

Nuclear-qualified cable designs have been availablesince the 1970s. Though their polymeric formulations maystill be considered as sophisticated today, compounds arepresently being formulated to meet more rigorousrequirements or due to restrictions in compoundingredient use. The Technical and Quality requirementsof Environmental Qualification have also evolved asimprovements to reduce risk, sometimes initiated inresponse to adverse events involving cables or perhaps tomeet the rigors of new advanced reactor designs. Legacyplants have qualified, aged cable near retirement or lifeextension and may require condition monitoring. Some ofthe new cable designs have improved materials,construction and advancements. Regulations have beendeveloped and improved upon for various reasons tobetter assure public safety. There have been examples ofgaps - but still in compliance - in considering theTechnical or the Quality requirements of theEnvironmental Qualification to which the cable isqualified, how well the Environment was defined, how itthe cable was installed. Examples discussed include risksfrom shipping, storage or installation of cable, cablesubmergence as an unforeseen environment and the postLOCA severe accident condition. This paper will reviewthe history of US nuclear cable use and issues. The authorsuggests mindfulness in gaps and cable-specificrecommendations for use at the new, advanced reactordesigns.