Study On Design And Experiment Of Neutronics Mock-up Of Water Cooled Ceramic Blanket For CFETR

The blanket,as a critical component of the fusion reactor,plays an essential role in tritium production,nuclear heat extraction and neutron shielding.The Water Cooled Ceramic Breeder(WCCB)blanket is one of the candidate blanket concepts of China Fusion Engineering Test Reactor(CFETR).The neutron transport analysis of WCCB was carried out based on Monte Carlo particle transport code MCNP and IAEA fusion evaluation nuclear data library.It turns out that the tritium breeding ratio(TBR)of the WCCB blanket could satisfy the goal of self-sufficiency.In order to evaluate the neu-tron characteristics of the WCCB blanket and the engineering margin of the design,the scaling-down experimental mock-up design and related experimental measurement technology research need to be carried out.The calculated to experimental(C/E)value of the integration parameters,blanket tritium production rate and single nucleon reac-tion rate,were obtained by carrying out the WCCB blanket mock-up neutronics inte-gration experiment and related experimental measurement technology research based on the DT neutron source.The obtained compared result is of great significance for testing the reliability of the blanket concept design and evaluating the overall perfor-mance of the blanket.In this paper,the design of the scaling-down experimental mock-up was carried out based on the feature of the WCCB blanket under 200MW fusion power.The radial layout of the mock-up was set as tungsten,first wall,tritium breeding zone,neutron multiplication zone,cooling plate,tritium breeding zone,neutron multiplication zone,cooling plate based on maintaining the neutron characteristics and the similarity of ge-ometric materials of the original WCCB blanket module.Then the sensitivity analysis of the impact on the thickness of the tritium breeder zone,W armor,database on the critical parameters of the experimental mock-up was carried out.In order to better re-flect the engineering characteristics of the original blanket module using the pebble bed structure,the density of the plate-shaped lithium titanium layer was optimized to the density of lithium titanate as a unit.The geometric size of the experimental mock-up was determined to be 210.0mm(toroidal)× 210.0mm(poloidal)× 193.0mm(radial).The optimized experimental mock-up was analyzed and predicted for the neutron flux and tritium production rate:And the situation of the mock-up after irradiation was esti-mated before the experiment.Subsequently,the theoretical methods involved in the activation method measure-ment technology of the mock-up neutronics experiment were studied.The multi-group cross-section iterative processing program based on NJOY and neutron spectrum un-folding program based on the deconvolution algorithm were developed.Then the ex-periments were conducted under the 252Cf neutron field and the DT neutron field re-spectively.The ratio of C/E of the single nucleon reaction rate under the DT neutron field was 0.96?1.05.The uncertainty measured by the activation method under the DT neutron source was about 5.06%.Combined with the measurement results of the acti-vation method,the unfolding program based on the deconvolution algorithm was used to unfolding the neutron spectrum of the position of the activated foil under the neutron field.Among them,the result of the unfolding spectrum under the graphite moderator of the DT neutron field verifies the reliability of the group cross-section processing and spectrum unfolding program.After verifying the accuracy of the activation method,the neutronics experiment using the activation method in the blanket neutronics experimental mock-up under the DT neutron generator was carried out.Au,In,Al,Ti,Mg,Zr foils were used in the experiment.The reaction rate of the activated foil was measured.The results showed that the C/E ratio of the thermal neutron-dominated reaction,197Au(n,g)198Au had a ranging from 0.93?1.03,and the high-energy neutron-dominated 90Zr(n,2n)89Zr reac-tion ranges between 0.90 and 1.07.The measurement results of the activation method were compared with those of other measurement techniques using small lithium glass detector and lithium titanate ceramics pellet detector.The comparison results showed that the measurement results of the activation method were consistent with those of other measurement techniques.In this paper,the neutronics experiment was carried out for the WCCB scaling-down mock-up.The application of the activation method in the neutronics experiment was studied systematically.The C/E ratio of relevant parameters enhanced the confi-dence of the blanket neutronics design and laid the foundation for the neutron measure-ment based on the activation method in the subsequent neutronics experiment.