Minimizing the repository volume for spent nuclear fuel

When minimizing the size of the spent nuclear fuel repository, two parameters are important: the required total number of canisters and distance between neighbouring canisters (the canister array pitch). If the latter is kept fixed, the Canister Filling Problem arises. On the other hand, if the former is assumed minimal, we come across the Alternative Canister Filling Problem. Both problems are NP-hard. Constructive heuristics followed by remove and reinsert local optimization are considered. The obtained results have shown that constructive heuristics give satisfactory results for realistic input data, although there is still some room for improvements.