Research On Deformation Measurement Technology Of Fuel Assembly Based On Line Structured Light Vision

Fuel assembly is one of the most important components in the core of sodium cooled fast reactor.The fast reactor fuel assembly is exposed to strong radiation,large pressure discrepancy and large temperature gradient during operation.Irradiation will result radiation growth,radiation swelling and irradiation creep.Pressure and temperature differences can cause different stresses on different parts of fuel assembly,all of which can cause deformation of fuel assembly.Excessive deformation of fuel assemblies will lead to stuck during refueling and accelerated assembly damage,which will cause great potential safety hazards to the operation of the reactor.Therefore,the measurement,evaluation and research of the deformation of fuel assembly can provide the necessary means for the safe operation of the reactor.In this paper,the deformation measurement technology of fuel assembly is studied,and the deformation measurement system of fuel assembly is developed.The research mainly focuses on the measurement theory and algorithm,the design and experiment of the measurement system.The main work of this paper is as follows:1.A fuel assembly deformation measurement system based on line structured light vision measurement is proposed and designed.Aiming at the measurement of fuel assembly deformation parameters,a new method of deformation measurement of fuel assembly based on structured light measurement and scanning is proposed in this paper.Firstly,point cloud of fuel assembly is obtained by scanning mechanism.Secondly,point cloud is processed to reconstruct the three-dimensional model of fuel assembly.Finally,the parameters of the reconstructed models are measured.In this paper,the main structure of the measurement system is designed and analyzed in detail,and the radiation shielding design is carried out for the influence of radiation on the measurement system.This paper solves the problem of point cloud registration between multiple sensors.2.The influence of the radiation and radiation shielding structure on the deformation measurement system is studied.The correction model of the fuel assembly deformation measurement system is proposed.The correction model is very important for high-precision measurement and point cloud registration.Experiments on the correction model of the measurement system show that the correction error is ±0.05 mm.3.In order to verify the measurement accuracy of the fuel assembly deformation measurement system,we processed the standard part and fuel assembly simulator and carried out the measurement experiments of relevant parameters.The measurement experiments have achieved good results,and measurement error of diagonal distance and opposite edge distance of the standard parts is ±0.05 mm.The measurement error of opposite edge distance of the fuel assembly simulator is ±0.05 mm,and the length and diagonal distances are ±0.1 mm.Finally,the factors that affect the accuracy of the measurement system are studied.