# Decay Rates ,Radioactivity ,Half life easy question

## Homework Statement

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.

## Homework Equations

it would take me considerable amount of effort to find what means 1% of all fissions produce I 131 .

## 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.

phyzguy
AI initial can be calculated given the reactor power level and the fact that "131 I is produced in roughly 1% of all fissions". I suggest you put in the "considerable amount of effort" to figure out what that statement means.

Ok
What about the other questions.Does anyone know the equation for power?

phyzguy