The Impurity Processing Loop (IPL) of the JET Active Gas Handling System is designed to recover tritium from impurities such as tritiated water and hydrocarbons present in the JET plasma exhaust. All impurities are fully oxidised in a catalytic recombiner, the tritiated water frozen in a cold trap and subsequently decomposed on hot uranium powder. Hydrogen isotopes set free in this reaction are scavenged from the helium carrier gas in a cold uranium bed. The modular design of the IPL permits implementation of advanced processing schemes (eg avoiding solid UO2 waste) in the future without major hardware modifications.