( ( Nuclear fission ) ( ( can ( ( occur ( without ( neutron bombardment ) ) ) ( as ( ( a type ) ( of ( radioactive decay ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Nuclear) (NNP fission)) (VP (MD can) (VP (VB occur) (PP (IN without) (NP (NN neutron) (NN bombardment))) (PP (IN as) (NP (NP (DT a) (NN type)) (PP (IN of) (NP (JJ radioactive) (NN decay))))))) (. .)))
Nuclear fission can occur without neutron bombardment as a type of radioactive decay.
(ROOT (S (NP (DT A) (NN neutron)) (VP (VBZ collides) (PP (IN with) (NP (NP (DT an) (NN atom)) (PP (IN of) (NP (ADJP (JJ u-235) (PP (IN during) (NP (DT the) (JJ basic) (JJ nuclear) (NN fission)))) (NN process)))))) (. .)))
A neutron collides with an atom of u-235 during the basic nuclear fission process.