alpha emission particle?
helium nucleus

beta decay?
neutron becomes proton and electron

gamma ray?
electromagnetic energy

positron emission?
proton releases positron and becomes neutron

electron capture?
proton combines with electron and becomes neutron

fission `action` fusion `action2`
action: splits
action2: joins

in fission `thing` is fired at uranium isotope `number`
thing: neutron
number: 235

products of fission (besides Barium & Krypton or some other atoms)
neutron

1_0_n + 235_92_U -> `step1` -> `step2` + 94_38_Sr + 2(1_0_n)
step1: 236_92_U
step2: 140_54_Xe

Thing that absorbs neutrons in reactor
control rod

What stops alpha particle
paper

What stops beta particle
water

What stops gamma particle
lead