Derivation of fuel bundle power limits using fuel element modelling code FUDA

The fuel designs, used in India are 19-element circular geometry and 37-element circular geometry for the 220 MWe PHWR and 540 MWe PHWR, respectively. The fuel bundle design has been evaluated by theoretical analysis, development tests and type tests. The theoretical analysis comprises of fuel bundle sub-channel analysis, fuel element thermo-mechanical analysis and fuel failure analysis during accidents etc. The fuel element thermo-mechanical analysis is carried out using computer code FUDA (Fuel Design Analysis) code. The fuel bundle power limit is derived based on fuel central line temperature, sheath strain and fission gas release parameters. The paper brings out the details of the FUDA code, the typical analysis carried out to estimate these parameters by FUDA code for deriving bundle power limits during operation for 540 MWe PHWR for 37-element fuel bundle.