1. The problem statement, all variables and given/known data The radioactive nuclides released into the atmosphere by the Chernobyl nuclear accident in 1986 included both 131I (t 1/2= 8 days) and 137Cs (t 1/2= 30 years). Given that 5 times as many 137 Cs as 131 I are present in the reactor in steady state, and that 131 I is produced in roughly 1% of all fissions, calculate (a) the ratio of activities ACs/AI immediately following the explosion. (b) how many days before the activities are equal. (c) Given that the Chernobyl reactor produced 1000MW of power, estimate AI 4 days after the explosion. 2. Relevant equations it would take me considerable amount of effort to find what means 1% of all fissions produce I 131 . 3. The attempt at a solution it is A level to find that λ= ln2/ (t1/2) and A= λΝ as is probably the whole exercise. which gives Acs/AI easily since 5NI =Ncs is given, b) N=No e^-λt should suffice c) maybe among the other equations P=Po e^-λt has to be used once the power has been found 4 days after the accident , some other equation must be used to find AI ,note that AI initial is not given ,but only as a function of Acs.