At the ‘salt waste treatment’ stage, the salt-loaded zeolite is mixed with fresh zeolite at approximately 500 °C to absorb the free salt, and the mixture is then heated up to approximately 925 °C to convert the salt-loaded zeolite into a more stable sodalite structure, Na8(AlSiO4)6Cl2, with borosilicate glass powder as a bonding material to microencapsulate the grains of soda — lite. The glass-bonded sodalite obtained is referred to as ceramic waste form (CWF). The long-term stability of CWF is expected from the natural ana­logue of sodalite mineral, which contains chloride salt and iodine in its cage structure, in a stable form. Actually, sufficiently stable characteristics to meet Yucca Mountain requirements were reported for CWF based on the extensive studies carried out by ANL and INL from the early 1990s (Ebert, 2005).