Explain the principle of `:` ltbr. `a.` Activation analysis
`b.` Breeder reactor

Explanation

`a.` Neutron activation analysis is a method for determining the presence of element present in trace quantities in a sample. The sample under examination is bombarded with neutrons in a reactor when the stable isotope of the element to be investigated is converted into its radioisotope which can then be detected, and its quantitative measurement is made by measuring its radioactivity with the help of Gieger `-` Muller counter. ltbr. `b.` A breeder reactor products more fissionable nuclei than what is consmed during the generation of energy. For example, in a breeder reactor when one atom of uranium `-235` undergoes fission three neutrons are produced of which only one neutron is used to propagate the fission chain of `U-235` . The other two neutrons are allowed to react with two atoms of non`-`fissionable `U-238` to generate two fissionable `Pu-239` nuclei. Thus, two fissionable `Pu-239` are produced for one nucleus of `U-235` consucmed.
A breeder reactor is one which produces more fissionable nuclei than it consumes.
`i. ``._(92)U^(238)+``._(0)n^(1)rarr ``._(92)U^(239)`
`ii. ``._(92)U^(238)rarr ``._(93)Np^(239)+``._(-)e^(0)`
`iii. ``._(93)Np^(239)rarr ``._(94)Pu^(239)+``._(-1)e^(-0)`