sentences: slab / data are formed by nuclear fission
docs: fission is nuclear_reaction. plutonium is fissionable_material. natural_nuclear_fission_reactor is uranium. fissionable_material is nuclear_fuel. nuclear_fission is spewing. uncontrolled_nuclear_fission is nuclear_fission. nuclear_fission is transformation_process. fission is asexual_reproduction. nuclear_fission is nuclear_process. controlled_nuclear_fission is nuclear_fission.