Americium mono-recycling in PWR: A step towards transmutation

In contrast to the straight final disposal solution, countries like France have opted to reprocess their nuclear reactors spent fuel and defined another way to take care of sensitive elements such as the plutonium or minor actinides. Even in countries which have chosen to reprocess their spent fuel, americium is still considered as a final disposal waste. Among the minor actinides, americium will remain the main contributor to the toxicity and the decay heat of the spent fuel for thousand of years. Therefore it is important to reduce its quantity. At this time, only fast neutron future reactors are accepted to be efficient enough to transmute the americium from the thermal reactors spent fuel. As we can presume these future reactors will not be available before many decades, a new strategy which consists in recycling americium together with plutonium in pressurize water reactors mixed oxide fuel is proposed. In this paper the benefit and after-effect of this waiting strategy is analyzed. It demonstrates that the americium is indeed transmuted in a PWR quite efficiently (transmutation rate of around 43%) however the spent fuel is, as expected, more concentrated in curium of heavier nuclei. The impact on the fuel cycle (transportation, cooling time) is investigated showing that the key point would be the fabrication of the MOx-Am fuel.