Application of the analytic hierarchy process in selecting medium-term storage options for spent nuclear fuel in South Africa
Abstract
South Africa is one of the countries using nuclear power and has prospects to expand its use in the near future. The management of spent nuclear fuel (SNF) from nuclear power plants has become a major issue internationally, with South Africa facing the same challenges as other countries (Bunn et al., 2001; Twala, 2007). In 2005 the South African government developed a Radioactive Waste Management Policy and Strategy (RWMP&S) for the Republic of South Africa (hereinafter “the Policy”) for the management of its radioactive waste and SNF (DME, 2005). In the Policy, the government recognises that the practice of storing SNF on-site is not sustainable. Therefore, long-term above-ground storage on an off-site facility is needed to buy time until a permanent solution is found. A number of options for storage systems are available from international vendors. The challenge is to select the most appropriate system for South Africa. The analytic hierarchy process (AHP) is identified as a possible tool to aid the selection process.
The aim of this study is to apply the AHP tool to compare a subset of existing dry storage options currently in use worldwide in a systematic way to decide which of the options is the best to meet South Africa’s needs. The study gives an overview of the existing dry storage options and related facilities. It also identifies relevant specific criteria and sub-criteria from literature to compare these options. Given time constraints, only three cases were chosen to demonstrate the application of the AHP tool using the identified criteria. Pairwise comparisons are conducted and the ranking of the options is determined. The AHP is implemented using a Microsoft Excel program. A code that forms part of the North-West University Reactor Code Suite was used to verify the correctness of the calculations performed on the Microsoft Excel program. The results show that a concrete module with an inner canister stored on a reinforced concrete storage pad open to the environment (ConMod) is the best option to meet South Africa’s needs. These results are in agreement with the initial intuitive judgement of the option by the researcher. On the basis of the results obtained from this study, it was demonstrated that the AHP tool can be applied to decide on the available option that will best meet South Africa’s needs.
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