5. Sodium treatment

At the end-of-life of an RNR, the sodium coolant is considered nuclear waste. However, given the reactivity of sodium with water and air, any part in contact with metallic sodium, or any reactor sodium, cannot be considered as standard nuclear waste. Decommissioning RNRs therefore involves a specific sodium and sodium waste treatment stage. This involves transforming potentially reactive metallic sodium into a chemically stable compound: in the first stage, soda ash or sodium carbonate, and then, if necessary, appropriate conditioning.