BIOL354 Lecture Notes - Lecture 5: Ionizing Radiation, Depleted Uranium, Subatomic Particle

• School: University of Waterloo
• Department: Biology
• Course: BIOL354
• Professor: Bruce Greenberg

Document Summary

Review: pahs can be anthropogenic or can be naturally emitted through volcanic activity & forest fires. Radioactive elements & isotopes: naturally occurring radioisotopes @ low level, anthropogenic sources: (concern) Mining of the reactor fuel - uranium. Accidental releases from nuclear reactors & power plants. Medical or industrial effluents containing radioactive isotopes. Storage of du @ nuclear cores: uranium (6 isotopes, all radioactive/unstable) Naturally occurring uranium consists of u-238 (99. 2%) & u-235 (0. 72%). U-235 can undergo spontaneous fission; the predominant u-238 is not fissile. Neutron of 1st u-235 strikes the nucleus of the 2nd u-235, 2nd nucleus splits into fission fragments + 2 more neutrons + photons (energy) -> cycle. U-235 self-sustaining nuclear fission chain reaction -> highly exothermic. Uranium enrichment: removal of some u-238 [u-235 + u-238 = 100%] Critical mass: smallest amount of fissile material (u-235) needed to sustain ncr. Slow & long-lasting ncr (nuclear reactor grade): low enriched u-235 (3-4%)