Extending Spent Fuel Storage until Transport for Reprocessing or Disposal

Spent fuel (SF) must be stored until an end point such as reprocessing or deep geological disposal is implemented. Selection and implementation of an end point for SF depends upon legislation, future funding, licensing and other factors that cannot be predicted with certainty. Past presumptions related to the availability of an end point have often been wrong and resulted in missed opportunities for properly informing SF management policies and strategies. For example, dry cask storage systems were originally conceived to free up needed space in reactor SF pools and also to provide SF storage for up to 40 years until reprocessing and/or deep geological disposal became available. Hundreds of dry cask storage systems are now employed throughout the world and will be relied upon well beyond the originally envisioned design life.Given present and projected rates for the use of nuclear power coupled with projections for SF reprocessing and deep geological disposal capacities, one concludes that SF storage will be prolonged, potentially for several decades. The US Nuclear Regulatory Commission has recently considered 300 years of storage to be appropriate for the characterization and prediction of ageing effects and ageing management issues associated with extending SF storage and subsequent transport.This paper, a summary of a forthcoming IAEA Technical Report (see reference), encourages addressing the uncertainty associated with the duration of SF storage by design – rather than by default. It suggests ways that this uncertainty may be considered in design, licensing, policy, and strategy decisions, and proposes a  framework for safely, securely, effectively, and sustainably storing and maintaining transportability of SF until it can be transported for reprocessing or deep geological disposal – regardless of how long that may be. The paper however is not intended to either encourage or facilitate needlessly prolonging SF storage durations.