The decay heat removal analysis is considered as one of the four items of dry storage system safety analysis in addition to criticality analysis, confinement analyses and radiation protection analysis. This paper has illustrated the related standards and rules to be followed, and demonstrated the CFD simulation of a vertical spent fuel dry storage cask. Furthermore, the thermal analysis is applied in developing new materials, and the optimization of loading schemes in one operation. The above applications have proved that thermal analysis plays critical role in the design and operation of spent fuel dry storage system.

To solve the problem of low thermal safety margin, bad heat conductivity and lack of experiment data for performance against accumulative radiation in current concrete developed for spent fuel dry storage all over the world, a specific high performance concrete material with three mixed components and high tension steel fibre has be proposed and developed. It is proved by the experiment data that 1) the concrete material can withstand 180 °C for long term, 300 °C for 168 hours and 800 °C (as an accidental case) for 20 minutes, after which there is no observable cracks and flakes; 2) the heat conductivity of the material can be enhanced 27%, with the help of steel fibre inserted, which can significantly enhance the heat load of spent fuel assemblies to be loaded in dry storage container; 3) the material can withstand a total neutron dose of 1 × 1017n/cm2 and gamma dose of 2.4 × 107Gy, which is expected during 60 years of spent fuel storage. The performance of the material is better than that of current concrete material used for spent fuel dry storage all over the world. The material enhances the thermal safety, structural safety and radiation protection safety during spent fuel dry storage, which can be applied at the same time in other technical area with high temperature and high radiation conditions.

Rock cavity disposal is regarded as a preferred option of radioactive waste final disposal solutions with less disturbance to surface and better isolation from people and surface environment which facilitates the long term surveillance and control of facility both during operation and after closure. This paper provides the research progress of key aspects of rock cavity disposal technology, such as site selection criteria, engineering design scheme of disposal vaults, technique process design of the handling of waste packages, research & development of intelligent control system and equipment of waste transportation, documentation of safety case and supporting safety assessment, numerical simulation of radionuclides migration process, and etc. The first practice of rock cavity disposal in China is also discussed. It shows that developing the rock cavity technology is reasonable, feasible and has significant potential in China. Finally, this paper looks forward to the research focus in the next stage. It is suggested to study the compatibility between the complexity level of engineering barrier measures and the waste hazards and to improve the reliability of future evolution and scenario assumption. The nuclides migration behavior study and migration parameter determination involving more key nuclides in waste from other origins are also of importance.