Review Sheet: Unit 15 Across 3 A nuclear __ controls fission chain reactions to produce useable energy 7 One danger of nuclear reactors is the breakdown of cooling systems to allow _- down. 10 __ nuclei, with mass numbers over 82, are always unstable. 12 reaction occurring when neutrons produced in fission reaction strike illl l: ww.CrosswordWeaver.com Name other nuclei 13 electron emitted when neutron changes into proton in nucleus 16 Splitting of a heavy nucleus 18 When electrical __ between protons is greater than strong forces, the nucleus will be unstable. 20 Fusion occurs on the - 21 protons and neutrons 22 atoms of the some element with different maSSes 23 emission with no mass or charge 24 nuclear bullets used in fission reactions