The off situ accurate reconstruction of the core neutron field is an important step in realizing real-time reactor monitoring.The existing off situ reconstruction method of the neutron field is only applicable to case...The off situ accurate reconstruction of the core neutron field is an important step in realizing real-time reactor monitoring.The existing off situ reconstruction method of the neutron field is only applicable to cases wherein a single region changes at a specified location of the core.However,when the neutron field changes are complex,the accurate identification of the individual changed regions becomes challenging,which seriously affects the accuracy and stability of the neutron field recon-struction.Therefore,this study proposed a dual-task hybrid network architecture(DTHNet)for off situ reconstruction of the core neutron field,which trained the outermost assembly reconstruction task and the core reconstruction task jointly such that the former could assist the latter in the reconstruction of the core neutron field under core complex changes.Furthermore,to exploit the characteristics of the ex-core detection signals,this study designed a global-local feature upsampling module that efficiently distributed the ex-core detection signals to each reconstruction unit to improve the accuracy and stability of reconstruction.Reconstruction experiments were performed on the simulation datasets of the CLEAR-I reactor to verify the accuracy and stability of the proposed method.The results showed that when the location uncertainty of a single region did not exceed nine and the number of multiple changed regions did not exceed five.Further,the reconstructed ARD was within 2%,RD_(max)was maintained within 17.5%,and the number of RD≥10%was maintained within 10.Furthermore,when the noise interference of the ex-core detection signals was within±2%,although the average number of RD≥10%increased to 16,the average ARD was still within in 2%,and the average RD_(max)was within 22%.Collectively,these results show that,theoretically,the DTHNet can accurately and stably reconstruct most of the neutron field under certain complex core changes.展开更多
Purpose Self-powered neutron detectors(SPNDs)with rhodium emitters exhibit high thermal neutron sensitivity and extensively equipped in nuclear reactors for core monitoring.The neutron sensitivity of SPND is the most ...Purpose Self-powered neutron detectors(SPNDs)with rhodium emitters exhibit high thermal neutron sensitivity and extensively equipped in nuclear reactors for core monitoring.The neutron sensitivity of SPND is the most significant criterion that directly determines the measured neutron flux and power and thereby needs to be accurately calibrated.Methods In this presented paper,the physical characteristics of rhodium SPND and its reaction mechanism with in-core neutrons were described thoroughly.Based on the inherent space electric field of concentric cylindrical SPND,three formulas with different approaches were proposed to quantitatively calculate the effective signal of SPND.The neutron sensitivity of rhodium SPND was then calculated quantitatively using the Monte Carlo(MC)methods.In order to expand the application scope of rhodium SPND,its sensitivity performance in four different types of pressurized water reactors(PWRs)was also been simulated and compared.Results and improvements The effectiveness and correctness of the model have been verified through experiments and comparisons with previous studies.The methods proposed in this paper have been successfully applied to industrial applications of reactor monitoring,and have demonstrated considerable reliability and accuracy.展开更多
基金supported by the National Natural Science Foundation of China(No.12305344)the 2023 Anhui university research project of China(No.2023AH052179).
文摘The off situ accurate reconstruction of the core neutron field is an important step in realizing real-time reactor monitoring.The existing off situ reconstruction method of the neutron field is only applicable to cases wherein a single region changes at a specified location of the core.However,when the neutron field changes are complex,the accurate identification of the individual changed regions becomes challenging,which seriously affects the accuracy and stability of the neutron field recon-struction.Therefore,this study proposed a dual-task hybrid network architecture(DTHNet)for off situ reconstruction of the core neutron field,which trained the outermost assembly reconstruction task and the core reconstruction task jointly such that the former could assist the latter in the reconstruction of the core neutron field under core complex changes.Furthermore,to exploit the characteristics of the ex-core detection signals,this study designed a global-local feature upsampling module that efficiently distributed the ex-core detection signals to each reconstruction unit to improve the accuracy and stability of reconstruction.Reconstruction experiments were performed on the simulation datasets of the CLEAR-I reactor to verify the accuracy and stability of the proposed method.The results showed that when the location uncertainty of a single region did not exceed nine and the number of multiple changed regions did not exceed five.Further,the reconstructed ARD was within 2%,RD_(max)was maintained within 17.5%,and the number of RD≥10%was maintained within 10.Furthermore,when the noise interference of the ex-core detection signals was within±2%,although the average number of RD≥10%increased to 16,the average ARD was still within in 2%,and the average RD_(max)was within 22%.Collectively,these results show that,theoretically,the DTHNet can accurately and stably reconstruct most of the neutron field under certain complex core changes.
文摘Purpose Self-powered neutron detectors(SPNDs)with rhodium emitters exhibit high thermal neutron sensitivity and extensively equipped in nuclear reactors for core monitoring.The neutron sensitivity of SPND is the most significant criterion that directly determines the measured neutron flux and power and thereby needs to be accurately calibrated.Methods In this presented paper,the physical characteristics of rhodium SPND and its reaction mechanism with in-core neutrons were described thoroughly.Based on the inherent space electric field of concentric cylindrical SPND,three formulas with different approaches were proposed to quantitatively calculate the effective signal of SPND.The neutron sensitivity of rhodium SPND was then calculated quantitatively using the Monte Carlo(MC)methods.In order to expand the application scope of rhodium SPND,its sensitivity performance in four different types of pressurized water reactors(PWRs)was also been simulated and compared.Results and improvements The effectiveness and correctness of the model have been verified through experiments and comparisons with previous studies.The methods proposed in this paper have been successfully applied to industrial applications of reactor monitoring,and have demonstrated considerable reliability and accuracy.
