The level of decontamination with regard to uranium and plutonium is a constraint linked to recycling. Required performances to get uranium and plutonium within the norms and standards can be measured through separation or decontamination factors.

The decontamination factor (DF) of an element is defined by the ratio of the specific activities before and after an operation:

DF = (Impurity/Product)m/(Impurity/Product)out The DF requirements are particularity strict, i. e. for f—y decontamination:

DF = 1.5 x 106

U

DF = 7 x 107

PU

These purification factors are much higher than in the ordinary chemical industry.

PUREX enables these specifications to be reached through the use of several extraction stages (generally two for uranium and two for plutonium).

Environmental radioactive releases

Authorized gas and liquid releases are set by the relevant authorities. The assessment of releases makes sense if it is reported against the amount of reprocessed fuel or in relation to the electrical energy produced by the reprocessed fuel expressed in MW. year.

Atmospheric releases primarily concern krypton-85, tritium, halogens and aerosols; for liquid releases it is tritium, ft-у emitters other than tritium, caesium and strontium, and a emitters.