> UCL > SCIENCE AND TECHNOLOGY SECTOR > Institute of Mechanics, Materials and Civil Engineering

Modelling of the mechanical response of polycrystalline graphite in a nuclear reactor environment

(Job opening on Jan. 1st 2013)

Reactor graphite properties change under irradiation and radiolytic oxidation. Graphite behaviour predictions are essential for graphite moderated reactor safety cases and these currently rely on empirical models, which can be proved only for a limited range of reactor operating conditions.

This research is addressing this problem by developing a reliable, physically-based model that relates microstructural changes to macroscopic graphite property changes.

Although there have been numerous attempts over the last 30 years to develop predictive models for graphite property changes in the reactor, a short feasibility study using the current approach has provided the most promising results and fundamental understanding.

Specifically, when exposed to thermal cycles and fast neutron irradiation, polycrystalline components made of highly anisotropic graphite crystals develop huge internal stresses that are partly relaxed by creep or by microcracking. This, in turn, modifies both the macroscopic coefficient of thermal expansion and the irradiation-induced dimensional changes.

In order to pursue its collaboration with the National Nuclear Laboratory (NNL, UK), the division of applied mechanics at University of Louvain (UCL, Belgium) hires a postdoctoral fellow experienced in one or several of the following fields:
‐ fracture mechanics
‐ finite element modelling with user‐defined material law/cohesive elements
‐ continuum damage mechanics
‐ nuclear graphite
‐ crystal plasticity theory / creep

Contact : Pr Laurent Delannay (Laurent.Delannay@uclouvain.be)

(One year contract - Pleasant campus 25km from Brussels - Potential to be employed by NNL in the UK given good performance on the post)