Application ofa Microprocessor BasedSolidStateProgrammable LogicSystem forControl ofClass1EComponents andDevices

DESIGNDESSCRIPTION ANDHARDWARE The paperdiscussesthe microprocessor based TheCRBRPdesignencompassed threesafetydiviSolidStateProgrammable LogicSystem(SSPLS) sionsthatwerephysically separated andelectridesigned fortheClinchRiverBreederReactorPlant callyindependent, and providedforredundancy of (CRBRP) whichwas terminated in December 1983by nuclearsafetyrelatedplantequipment. TheClass1E U.S.Congress.Eventhoughprocurement ofequipment equipment associated withthesafetydivisions were did not takeplace,the topicsdiscussed here controlled by three(3)separateandfunctionally reflect theadvanced engineering anddesigncomple- redundant SSPLSdivisions.Thedistributed SSPLS tion(85percent) on theprojectandtheauthors architecture selected forCRBRPhadensureddivision feel that the informationpresentedreflects compatability withcomplete physical andelectrical worthwhile experience associated withtheimplemen- independence betweenredundantdivisionsand the tationof thestate-of-the-art technology andmay failureof one division willnotaffectanycombenefitfuturedesignsas wellas theindustry in pone or equipment ofth ot afety con. general.Topicspresented includediscussion on onent oreuiPment of theothersafetydivision. designdescription andhardware, programming, vern- Thetpaired sSPLSgcabinetsc(terminationlogi ficationand validation, licensing concernsand cabinet)werestrategically locatedin separate requirements on reliability and maintainability.celso e plant. Thepaperdescribes licensing interaction withthe A typical SSPLSlogiccabinetcontainsthe NuclearRegulatory Commission(NRC)Staffat the necessary control logic, signalconditioners, auxiconstruction permitstageand outlines additional liarycircuits, powersupplies andcircuitisolation details thatwouldbeneededatanoperating license devicesto controlup to 50 components, plusthe permitstage.