Applied study on optimizing the final disposal of Loviisa NPP spent fuel assemblies

Abstract

In this paper, the optimization of the assignment of spent fuel assemblies into final disposal canisters is considered. This application is of essential importance as the final disposal canisters are expensive and, on the other hand, there exists a limit for the canister-wise total heat load, which must not be exceeded. The study utilizes mathematical optimization algorithms that have been developed by Ranta in his D.Sc. thesis (Tampere University of Technology, 2012). In the applied formulation, the target of the optimization is to minimize the maximum canister-wise decay heat load at the time of canister formation. The optimization algorithms were utilized for analysing a fictional final disposal scenario for present and expected future spent fuel assemblies of Loviisa NPP. The paper concludes that, despite a huge amount of degrees of freedom, the algorithms are capable of finding practically a global optimum for the considered problem. The implemented software tool can be utilized for further final disposal optimization analyses.

Multiobjective Mixed Integer Nonlinear Model to Plan the Schedule for the Final Disposal of the Spent Nuclear Fuel in Finland

“…Another optimization related study to design the disposal facility is in [12] giving the multiobjective MILP problem optimizing the nuclear waste placement in the disposal facility, and in [13], the optimal initial condition for the disposal facility is investigated with multiobjective optimization. The disposal schedule can be utilized, for example, when the loading of canisters is optimized [10,[14][15][16][17]. The final disposal related aspects in terms of optimization is discussed also from several other points of view, like the placement of the disposal repository [18], to route the transfer of the nuclear waste [19,20], to optimize the shut down date of the reactor [21,22], or from the safety point of view: the optimization of the nuclear safeguards [23,24] and the safety assessment of nuclear waste repositories [25].…”