Modelling Weibull Distributions in Peridynamics for Nuclear Fuel

Lloyd Jones1

Thomas Haynes2, Mark Wenman2

1National Nuclear Laboratory; 2Imperial College London.


Peridynamics is a non-local continuum mechanics modelling method, often utilised in modelling brittle fracture. The integral form of its foundational equations offers an advantage over local continuum mechanics methods, the partial differential equations of which tend to break down at discontinuities such as crack tips. The fracture strength of brittle materials is determined by the size of the critical flaw, the random distribution of which can be characterised by a Weibull distribution. A method of accurately recreating Weibull distributions of fracture strengths, having been developed first in simple 1D and 2D tensile test models, was applied to peridynamics models of pressurised water reactor fuel pellets. The resulting number of radial cracks at given linear power ratings were compared to PIE data. A Weibull modulus value of 5 – 10 was determined to be a sensible range for use in modelling UO2 fuel, since these values produced the closest fit to the post-irradiation examination data, although artificial crack nucleation at sites away from the pellet surface occurred when a Weibull modulus of 5 was used.

Event Timeslots (1)

Thursday – 16th September 2021
Lloyd Jones