Lesson 5 ◆ 5.4 The PUREX Reprocessing Process

The aqueous plutonium stream undergoes further purification. The Pu(III) is first re-oxidised to Pu(IV) using nitrogen oxides, then extracted again into TBP/OK in pulsed columns for further purification.

Plutonium finishing converts the purified plutonium nitrate into plutonium dioxide (PuO₂) powder:

Oxalic acid precipitation followed by calcination:

Pu(NO3)4+2H2C2O4→Pu(C2O4)2+4HNO3\text{Pu}(\text{NO}_3)_4 + 2\text{H}_2\text{C}_2\text{O}_4 \rightarrow \text{Pu}(\text{C}_2\text{O}_4)_2 + 4\text{HNO}_3

Pu(C2O4)2→PuO2+2CO+2CO2\text{Pu}(\text{C}_2\text{O}_4)_2 \rightarrow \text{PuO}_2 + 2\text{CO} + 2\text{CO}_2

PuO₂ powder is stored in triple-encapsulated stainless steel drums in a purpose-built vault.