Evaluation of Alternative MGDS Development Strategies

A methodology has been developed to explicitly and quantitatively evaluate acceptable alternative repository development strategies, in terms of the degree to which they are likely to satisfy a specified set of system objectives (e.g., minimizing overall costs through closure, time to initial waste receipt and long-term health effects). An 'acceptable' strategy is one which has a high likelihood of satisfying specified system functions and requirements. Simple but comprehensive system models have been developed to estimate the relevant consequences of any strategy, explicitly considering system uncertainties and contingencies, including the possibility of finding the site to be unsuitable and having to develop a repository elsewhere. Such 'technical assessments', which are appropriately developed by technical experts, can then be combined with separate 'value judgements' regarding preferences and tradeoffs among the consequences, which are appropriately determined by the decision makers/stake holders (rather than by the technical experts), in order to explicitly determine preferences among the acceptable strategies. Implementation of the methodology has been demonstrated by example.