Re: how does boron/cadmium accept neutrons in a nuclear reactor?

The exact reaction that takes place varies.  It is dependent on the energy 
of the neutron and isotope of Boron.  Boron-10 is commonly used in nuclear 
reactors for both detection of neutrons and control of the reaction rate in 
the reactor.  The Boron-10 absorbs a thermal (slow) neutron and produces 
Lithium-7 and an alpha particle.  The Lithium-7 can be produced in either 
its ground state or an excited state.  If it is produced in the excited 
state (which happens about 94% of the time), that excited nucleus will 
eventually dexcite to the ground state.  The reactions would typically be 
written


B-10  +  n   -->  Li-7 + alpha  (Q value 2.792 MeV)

and

B-10  +  n   -->  *Li-7 + alpha  (Q value 2.310 Mev)


where the * indicates Lithium in an excited state.  The later reaction 
occurs 94% of the time and the former 6% of the time.

Michael Baker