Introduction

11.30. After about a З-year residence in the core, LWR spent-fuel as­semblies are discharged and stored in an on-site water pool. When most present reactors were built, about a 5-month cooling period was planned, after which the fuel was to be shipped to an off-site interim storage facility or to a reprocessing plant. However, since neither option has become available, spent assembly storage has presented a logistic problem that we will examine.

11.31. Consideration of the options available for managing spent fuel assemblies should begin with a study of such characteristics as their isotopic mix, contributions to radioactivity, heat generation, and physical features.