PROBLEM 1. a) What is the period for a thermal reactor with prompt neutron lifetime 4.8510-6 s if the reac- tivity is 0.0115? What is the reactor period if instead the reactivity is 0.00115? b) Suppose a thermal reactor is operating at a power level of 230 MWe. Control rods are removed to give a reactivity of 0.00042. Neglecting temperature feedback, calculate the time required to go to a power of 290 MWe.