Linear heat generation rate for breaking plastic strain limit of cladding in a BWR fuel rod type

Highlights: • Determine the maximum rate of linear heat generation which limit 1.1% plastic strain on the cladding is reached. • Establish part of the methodology for setting operational limits of a BWR fuel rod type. • We make use FEMAXI-VI code to evaluate fuel rods performance from fuel assemblies. - Abstract: The linear heat generation rate (LHGR) is calculated for a BWR fuel rod type as a burnup function that breaks the plastic strain circumferential limit of cladding in nominal operation and steady state. The evaluation of the LHGR as a burnup function of fuel rod is performed under the condition of which the values of the circumferential plastic strain of the cladding exceed in a 10% of the limit value operation of 1%. The results show that for burn up between 0 and 16,000 MWd/tU there is 160.8 W/cm as minimum margin between LHGR peak for maximum operation (439.6 W/cm) and LHGR calculated to reach 1.1% of circumferential plastic cladding strain, considering a factor peaking power of 1.40. For a burn up of 20,000 MWd/tU and 60,000 MWd/tU there are margins of 150.3 and 298.6 W/cm, respectively. The calculations are carried out with codes FEMAXI-VI and RODBURN.