Integrated Lead-bismuth Cooled Spallation Target Structural Design And Analysis

Integrated Lead-bismuth spallation target with window is one of the most promising targets for accelerator driven sub-critical system (ADS), which has a high neutron yield, simplified structure, good safety characteristics and good maintainability. The target window faces the problem of high irradiation and heat flux. In order to ensure the safety of the target system, flow section of target window design needs optimization to reduce the maximum temperature and the temperature gradient on the target. In this thesis, an integrated lead-bismuth cooled window target was designed, and the3D thermal-hydraulic analysis was carries out on the ADS target system.Grid model was set up and carried for the sensitivity analysis, which selected optimal calculation model. In order to understand the influence of the coolant flow channel field on the spallation target coolant system, a three flow channel model was established to calculate. The calculated results showed that the central region of flow velocity on flow field of the target area had remarkable improvement for heat transfer. The entrance total flow was constant, In order to improve the target area in thermal efficiency, target inlet velocity should be set to non-uniform flow field distribution. At the same time,2mm thick target window and improved coolant entrance total flow would have better heat transfer effect, when increased intensity of proton beam.According to the above conclusion redesigned lead bismuth coolant inlet flow channel, adopted the design of variable cross-section turbulence structure, the upper guide tube diameter remained, the lower narrow diameter, between upper and lower nozzle USES tapered tube structure. In order to deeper understand the turbulence structure on the target window in thermal efficiency, the influence of the inlet section in different size to taken on the design, including the target window bottom nozzle diameter D and height h, comparing different flow channel design. Results shown that, on the premise of structure stability, could try to get variable cross-section near the target window. The results shown that the non-straight structure compared to the straight, could improve target coolant flow velocity near the window, decreased the temperature of the target window.When using variable cross-section design of nozzle diameter, the proton beam under operation condition under a variety of conventional load and with load combination, would result in complex stress field, therefore, on the stress intensity evaluation was an important content of spallation target design. Structure stress analysis based on ANS YS Workbench platform, for integrated stress analysis of the proton beam under the condition of the steady state. Preliminary results show that the proton beam under various loading stress intensity satisfied the requirement of ASME specifications.This paper aimed to carry out the numerical simulation of window spallation target and structure optimization, it is concluded that the spallation target structure and change rule of heat-exchange spallation target structure, which lay a foundation for the ADS spallation target to engineering application.