Proposals of the SCJ report, particularly, the concepts of temporal safe storage and management of total amount, triggered many discussions widely concerning the issue of HLW disposal.

The temporal safe storage is characterized by securing a moratorium period of several dozen or several hundred years to establish appropriate handling measures for the problem. It provides the advantages of using this period to refine techno­logical developments and scientific knowledge, guaranteeing the possibility of creating handling measures that target a longer period; for example, improvement of the durability of containers, development of nuclear transmutation technology to reduce volume and toxicity of HLW, and research related to the stability of geological layers.

In addition, the temporal safe storage makes it possible to keep various options for future generations to choose for final disposal of HLW.

The concept of safe storage, however, still has a wide range of uncertainties in technical specifications; for example, duration of storage, location character­istics such as on ground or underground, and number of storage facilities. The concept ranges from currently available interim storage of spent fuel to retriev­able geological disposal. In fact, the response of Japan Atomic Energy Com­mission mentioned retrievable geological disposal in the context of temporal safe storage.

SCJ had set up a Follow-up Committee as an extension of the Review Commit­tee in August 2013 to clarify the concept of the temporal safe storage.