Reliability Analysis Of Nuclear Valve‘s Control System Under Strong Radiation

This text refers to the design technique of electronic valve, preliminary design air duct valve electric control system of nuclear power plant via independent research and development according to the program request. And also states damage effect and mechanism to circuit by nuclear radiation for expanding the application range of the electric control system and making it possible to work normally under nuclear radiation environment.Aiming at the most prone failure electronic unit of the electronic control system and analysis the the influence of irradiation effects on the MOS FET via simulation experiment. Anti-irradiation inverter unit is designed on the basis of radiation- hardened, and total dose radiation effects on traditional inverter and the effect of anti- irradiation inverter unit circuit has been proved through ISE-TCAD software simula- tion. Experiment result indicates inverter unit after strengthening with better anti-radiation effect.Later higher reliability DC/DC converter replaces VRM 7805 CT which is prone to failure in the radiation of this electronic control system. Then vulnerable devices against radiation screening program is designed and based on the quantitative relationship between radiation degradation of VDMOS device and PWM and DC/DC converter degradation as a whole. After that a new concept of reliability engineering, PHM approach has been introduced, and designed prognostic cell of converter. We validated the effect by simulation to show that there is strong practicability of scheme which would further improve the reliability of electric control system.Finally the cold backup and dual fault tolerance system of module level puts forward according to effect of nuclear radiation environment to the electric control system. Some common particle effects failure have summarized in order to design refresh fault tolerant scheme of storage for storage unit of electric control system. Failure analysis of brushless DC motor is made in electric control system and methods of enhance reliable of dual channel brushless DC motor is chosen to solve its common faults. Single particle lock protection circuit are designed to protect storage units of the motor control unit from single event latch up disturb. Finally,resistance to radiation effect achieved by analysis the common radiation shielding material, adding polyethylene coating inside the shell and using lead for skin outside the shell.