Modeling of decay heat removal from CONSTOR RBMK-1500 casks during long-term storage of spent nuclear fuel

Management of spent nuclear fuel is a very important part in the whole cycle of nuclear energy generation. Ignalina nuclear power plant operated two RBMK-1500 reactors that are now being decommissioned. After careful consideration “dry” storage technology in casks was selected for the interim storage of spent nuclear fuel (SNF) for up to 50 years. SNF after pre-storage time in water pools for not less than 5 years is loaded into cast-iron or metal-concrete casks. In this paper decay heat removal was modelled from specific GNB (Gesellschaft für Nuklear Behälter GmbH) metal-concrete (CONSTOR RBMK-1500) casks for the long-term storage period up to 300 years. The ALGOR code was used for the numerical modeling of the distribution of the heat fluxes and temperatures in a loaded cask placed in an open type storage facility in both summer and winter taking into account local environmental conditions. A local sensitivity analysis of the impact of fuel parameter uncertainties is also performed.