Design aspects of metallic fuel for research reactors and ceramic fuel for boiling water reactors

The performance of reactor fuel under normal operation, transient and abnormal conditions is the key factor for the success of the nuclear reactors. Therefore, the development of analytical capability for the fuel design and in predicting its behaviour under various conditions continues to draw high degree of attention and pursuit to R and D work. Computer codes developed for fuel design need to be bench-marked against well characterised data generated by out-of-pile and in-pile experimentations and post irradiation examinations. Natural uranium metal fuel clad in aluminium is being used in Indian research reactors whereas for power reactors uranium dioxide fuel clad in zircaloy is used. Our experience with power reactor fuel includes fuel for boiling water reactors (BWR) and pressurised heavy water reactors (PHWR). The capabilities in various aspects of the fuel design such as physics, thermal hydraulics, mechanical design and safety analysis etc. have been developed in various groups in the DAE family. Specialised efforts have been put into the various development aspects required for fabrication of the fuel. The interplay of experience and capabilities developed in the various fields is used to optimise the fuel design. Apart from work conducted in design and analysis of reactor fuel to meet various operation requirements, this paper includes the studies carried out resulting in the incorporation of design changes to improve fuel performance and also to evolve remedial measures for the problems faced during the operation of TAPS reactor. (author) 13 refs., 4 figs., 1 tab