Inventory Estimation for Accident Waste Generated at the Fukushima Daiichi NPS

Conclusion: • Inventory estimation for waste generated in the severe accident of reactor was discussed. •At early stage, in which development of accident is not clear and analytical data is insufficient, it is important to make a calculation model, which describes transport of radioactive nuclides from source term to waste by using knowledge from past accidents. •Once analytical data is collected, uncertainty in estimation decreases by improving model parameters; branchings and their ratios. •As D&D progresses, waste generation will be well predicted, analytical data will be accumulated and thus, it is expected to decrease uncertainty in inventory estimation.