Design Of Nuclear Fuel Elements Deformation Measurement System

At nuclear power plant, Nuclear Fuel Elements of pressurized water reactor core work in high temperature, high-pressure and intense radiation circulating water. For some reason such as assembly stress and thermal stress, fuel rod and fuel elements will distort, graveness transmogrification will endanger nuclear reactor. So it is necessary to check fuel elements. The paper expatiates design of Nuclear Fuel Elements deformation measurement system principle prototype, including mechanical driving equipment, laser scanning system design, circuit system design and data processing software system. Through detecting simulative Nuclear Fuel Elements to prove the correctness of philosophy of measurement and check the accuracy in measurement of the system.The system's fundamental is laser scanning. Laser have characteristic with small divergence angle and high intensity. So laser scanning is a kind of excellent non-contact measurement methods with high-precision, wide dynamic range and anti-jamming. The thesis introduces a method of comparative measurement to eliminate the error that resulted from velocity discontinuity of electromotor used in laser scanning set and improve measure precision.The transmission gear of this measurement system is openloop servo system composed of step motor, worm reducer and synchronous belt. Synchronous belt have characteristic with accurate transmission ratio, high transmission efficiency, high transmission power and Synchronous belt made up of neoprene can work in water.Circuit and data acquisition system use high performance "Mega" series singlechip of AVR and hardware counter circuit to measure signal pulse width with pulse stuffing method. Data acquisition system deals with original signal with half-wave sampling edge signal detection method to reduce infection of level variation.At last, we propose using BP neural network to compensate and correct non-linear error, and eliminate the effect of mismachining tolerance of optical device,and improve measuring accuracy more.