23.2.1 Sources, types and classification of radioactive waste

In Japan, RAW is categorized as shown in Table 23.14 . In May 2007, the Nuclear Safety Commission of Japan (NSC) issued a document which pro­vides for upper bounds of concentration of radioactive elements in waste packages from power reactors and in TRU waste packages. The upper bounds of concentration of radioactive elements are so decided, that the

Classification Origin of Disposal method High-level radioactive waste Reprocessing plant Deep geological disposal (>300 m) Low-level radioactive waste Waste power reactor Relatively higher level Nuclear power plant Sub-surface disposal (50-100 m) Lower level Near-surface disposal with artificial barrier Very low level Near-surface disposal without artificial barrier TRU Reprocessing plant, MOX fuel fabrication plant Deep geological, sub-surface and near-surface disposal Uranium waste Enrichment plant, fuel fabrication plant and conversion and refining plant Not yet decided Rl and research waste Research facility Rl utilizing facility Deep geological, sub-surface and near-surface disposal

public exposure due to waste packages is well within the reference value, and that the upper bounds conform to the latest knowledge in the interna­tional community. Based on these concepts, disposal of RAW is categorized into Category 1 Waste disposal (geological disposal) and Category 2 Waste disposal (sub-surface disposal, near-surface disposal with artificial barrier and near-surface disposal without artificial barrier).

Concerning the waste that does not need to be dealt with as RAW, the NSC has studied the clearance level of radionuclide concentrations and its calculation method, by reference to the ICRP document (Pub. 46, 1985) and IAEA-TECDOC-855, respectively.