SUMMARY

The recent rebirth of the nuclear energy has led to a new orientation in the reactors physics numerical simulation. There is a thrive for high fidelity algorithms, costly effective designs and accurate analysis of the behavior of a nuclear reactor. However, it is a hard task to achieve. A nuclear reactor is a complex machinery where several physical phenomena are coupled together. In order to represent accurately the thermal behavior of a nuclear core, fission events have to be correctly predicted and coupled to the heat transfer through the fuel as well as the heat removal by the coolant. The main focus of this research is the development of a quasi one-dimensional multiphysics algorithm for gas-cooled reactors.At first, a quasi one-dimensional version of the PCICE solution algorithm that employs finite-element discretization is implemented. PCICE is a scheme that solves the thermal-hydraulic behavior of the coolant. Then, a discrete-ordinates method for the neutron transport with a radial correction is coupled to a quasi one-dimensional heat transfer code. Finally, the two sets of codes are coupled together and the formulation verified.