Nuclear, Enea studies fuel recycling to reduce waste

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Improve the sustainability and performance of fourth generation nuclear reactors by promoting the recycling of fuel already used, to reduce long-lived waste. This is the objective of the Pumma (Plutonium Management for More Agility) project which involves 20 partners from 12 European countries, including Enea for Italy. The project, co-financed by the Euratom programme, aims to evaluate the impact of the high plutonium content (around 40%) in the nuclear fuel of fast reactors and to examine the possible implications on safety and performance, but also the integration scenarios of technology with those currently in use, for increasingly sustainable nuclear power.

From Mox more sustainable nuclear fuel

«From the use of Mox, a fuel composed of a mixture of uranium oxide and plutonium, it is possible to obtain a more sustainable nuclear fuel available in large quantities – explains Alessandro Del Nevo, head of the Enea Experimental Engineering Division at the Nuclear Department and project contact -. However, it is a fuel whose behavior must continue to be studied, to improve its performance and guarantee the adequate safety of the plant”.

I test

The activities related to the project include both simulations through modeling and software and experimental analyses. The tests used data already available on MOX with a high plutonium content, irradiated and analyzed using destructive and non-destructive tests. «The preliminary results are promising, but we need to improve our models based mainly on data from experiments on traditional water reactors» clarifies Del Nevo. Specifically, Enea contributes together with seven other partners to simulation and modeling activities to increase knowledge on the behavior of the materials used during the operation of the reactor.

The “tablets”

The “tablets” of nuclear fuel, stacked inside cylindrical rods, represent, together with the external sheath of the rod itself, the first barriers against the release of fission products. «Understanding how the materials of which the “tablets” are made can be deformed or damaged by irradiation activity is essential to increase reliability and prolong the useful life of the fuel, without compromising safety margins» adds Del Nevo.

«During the project, a significant milestone was achieved by replicating the behavior of nuclear fuel through FEM (Finite Element Method) analysis, the simulation technique that allows the structural behavior of a complex system to be calculated by breaking it down into a large number of elements that can be resolved in a simpler way” concludes Del Nevo.