Thermal Safety Analysis Of CNSC-24 Spent Fuel Transportation And Storage Cask

The amount of spent fuel assemblies is increasing along with the operation and construction of NPPs.It is foreseen that the accumulated spent fuel assemblies will reach 7500 tons by the year 2020.Based on the capability of onsite spent fuel pools,800 tons vacancy of offsite storage is a problem faced by post-process policy in China.The dry storage technology has been well developed and implemented in American and European countries.Comparing to wet storage such as pools,the dry storage is more safe,convenient and economic,but less storage density.In three main paths of dry storage technology,vault/metal cask/concrete cask,the metal cask could be designed as dual functions including transportation and storage,which requires less operation.Based on the domestic research of dry storage,the company author works for is now developing CNSC-24 dual function cask,to meet the demand of offsite storage in the future.Author gathers the practice experience and CFD tools of foreign company in thermal safety analysis of dry storage equipments and facilities,lists the detail of domestic international regulations in thermal safety analysis of transportation and dry storage of spent fuel,and forms the executable environment conditions of numerical evaluation.Based on the design characteristic of CNSC-24,author gives the temperature limit of main functional parts of the cask,as the safety criteria of thermal evaluation.The thermal evaluation is conducted by ICEM code for mesh and CFX code for numerical simulation of different conditions.Calculation shows the cask can maintain the temperature limits are not exceeded for the cask in normal transportation and storage;The cask can maintain its function in 800? fire burning condition for 30 minutes due to its thermal inertia.The remedy is not necessary for 3 days in an insulation condition of being buried.