Spent nuclear fuel with a hybrid heat pipe for electricity generation and thermal management

The global warming resulting from the emission of the greenhouse gases has led to tightened restrictions on the use of fossil. Therefore, renewable energy for new energy sources is being widely investigated. However, renewable energy has limitations such as location, environmental conditions, and the potential construction of a new electricity grid. Spent nuclear fuel (SNF) is one of the potential new energy candidates that does not emit the greenhouse gases or suffer from limitations of other renewable energy sources. In this research, generating electricity by using SNF is suggested with a hybrid heat pipe system. Thermal energy from SNF worldwide is ∼750 MWth; however, this energy is not used as an energy source but just removed by chilling in water or in air in storage facilities. To achieve electricity generation from SNF, a dry storage cask with heat pipes and a Stirling engine (UCAN, UNIST CANister) are designed. Using a 1/10-scale test facility, the experimental test of heat transfer and electricity generation as the module of the storage system is conducted. The results yield good agreement with those predicted by the thermal resistance network model, and the electricity generation of the Stirling engine is in the range from 2.3% to 3.2% of the total heat load. The calculated temperature distributions are a good agreement, deviating within 12.2%, and the cooling efficiencies range from 17.51% to 26.33%. The results show the advantages of the use of SNF and its effects, focusing on thermal management and energy generation. The amount of SNF will gradually increase because of the continued operation of nuclear power plants. The usable heat from the SNF is generated due to the decay of fission products during at least several hundred years, which enables to use the SNF as one of the energy sources.