NuFuel & MMSNF 2015

First Workshop on Research into Nuclear Fuel in Europe
and Materials Modeling and Simulation for Nuclear Fuels Workshop
Karlsruhe, Germany, November 16th to 18th, 2015

Updated: Tue 08 Dec 2015, 14:27

Talk 6.6: Modeling and simulation of fast reactor minor actinide bearing oxide fuels in support of MABB and MADF concepts

Sergei Lemehov1, Rolando Calabrese2, Fabienne Delage3, Alexander Fedorov4, Manuel Pouchon5, Paul Van Uffelen6 .
  • 1 SCK•CEN - Belgium
  • 2 ENEA - Italy
  • 3 CEA - France
  • 4 NRG, Netherlands
  • 5 PSI - Switzerland
  • 6 JRC-ITU Germany

Abstract

The European FP–7 project PELGRIMM addresses the development of Minor-Actinide (MA) bearing oxide fuels for Sodium-cooled Fast Reactors. MA homogeneous and heterogeneous recycling options are investigated in this project. Work-Package 3 (WP3) addresses modelling of minor actinide enriched fuels under irradiation regarding both MADF and MABB compositions - spherepacked or pelletized – in order to establish reliable predictive capabilities of existing fuel performance codes with respect to specific issues of MADF/MABB fuels.

The concept of MABB – Minor Actinide Bearing Blanket fuels – stands for use of depleted UO2 with incorporated Am in elevated quantities (up to 10–15 wt.%) in radial blanket on the periphery of the outer core in fast reactors. Such (U,MA)O2 fuels can also be doped with Np to accelerate the rate of plutonium build-up and to keep (U,MA)O2 fuel longer in the reactor for deeper transmutation of Americium. In the complementary concept MADF – Minor Actinide Driver Fuel – compositions are manufactured with high initial content of PuO2 for use in the core of a fast reactor to generate power and neutron flux.

Most of fuel performance codes have been originally developed, verified and validated to model standard LWR or SFR types of fuels made of enriched uranium dioxide or a mixture of uranium and plutonium oxides (MOX). Implementation of new compositions and fuel forms (pellets or spherepac) is naturally made by correction of existing models and correlations for standard fuels. Such approach is practical; however, validity of it still shall be tested. Many in-pile properties of fuels depend on temperature – the higher centre-line temperature the higher scale/rate of all temperature dependent processes and properties. Thus, thermal properties of MADF and MABB fuels under consideration are to be reviewed and analyzed first. The objective of the study performed in the FP7-PELGRIMM project and its WP3 is an assessment and a comparative evaluation of the fuel performance codes and their ability to model the behavior of fuel pins with either sphere-pac or pellets.

Several fuel performance codes (MACROS – SCK•CEN, TRANSURANUS – ENEA, NRG, JRC-ITU, GERMINAL -CEA) have been used by participants to cover the WP3 scope of work and particular tasks.

The PELGRIMM WP3 work started with the general model evaluations of material properties of MADF and MABB dedicated compositions and reference irradiation experiments – SUPERFACT and SPHERE. The efforts that participants of the WP3 made so far cover aspects of modeling such as helium production and release under a fast neutron spectrum; plutonium, americium and oxygen redistribution; influence of MA and fission products (i.e. burnup effects) on melting temperature; evolution rate of fuel restructuring, columnar grain growth and central void formation; and, finally, some predictive behavior simulations have been made for the SPHERE irradiation test.

There is a good understanding based on carried out work that concepts of MADF and MABB fuels open promising prospective for safety assessments and design efforts underway in the WP4 which addresses problematics of core physics.