Power ramp analysis for 37 element fuel bundle of 500 MWe pressurised heavy water reactor

In the reactor, the fuel bundles experience power ramp due to on-power refueling and movement of reactivity devices. Many cases have been analysed to estimate the bundle power ramp. The ramped power and power increases were compared with corresponding threshold values for graphite coated bundles and CAFE power curves. For all the cases the ramped power was less than the threshold value, while power increase was more than its threshold value for few cases. Since both ramped power and power increase have to exceed the corresponding threshold values for fuel failure to occur, no failure due to power ramp is expected. Based on the CAFE equation, for the ramped power and power increase for all the cases, failure probability is quite less than 1%. (author). 5 refs., 2 figs., 2 tabs