The AGR-like FHR reactor: Assessing the technical limits of the fuel

This work presents the detailed fuel rod simulation with the new TRANSURANUS code in combination with a high fidelity neutronic analysis of an innovative British advanced gas cooled type reactor with new materials by means of Serpent. The Hastelloy cladding material and molten salt properties have been assessed and implemented in our previous work. In this paper, we evaluate the effect of uncertainties on Hastelloy cladding properties in the hottest assembly of a sample AGR. For this purpose, a new cladding limiting criterion based on the Larson Miller Parameter are also introduced to determine safety margins to cladding rupture. The fuel performance of the reference AGR-like FHR is studied in terms of gain in safety margins when using the new materials considering their uncertainties. Further needs for the design optimisation are also outlined on the basis of the sensitivity study.