Nuclear Chemistry at Work The First Atomic Bombs Jennifer Christensen Kristoffer Gerik Bryan Wagner November 25, 2008

Agenda Introduction Nuclear Chemistry Discoveries Manhattan Project Background Fission 239Pu Manhattan Project Nazi Regime Attempts Atomic Bomb Mechanisms Gun Type Implosion Type Conclusion

Introduction Political Front: Scientific Front: World War II Largest world conflict in history Race for nuclear weapons United States vs. Nazi Regime Military superiority Political consequences Scientific Front: Nuclear chemistry Beginnings of understanding Application of theories Nuclear reactors Nuclear weapons http://www.mbe.doe.gov/me70/manhattan/images/FatMan.gif http://upload.wikimedia.org/wikipedia/commons/thumb/e/e0/Nagasakibomb.jpg/509px-Nagasakibomb.jpg

Nuclear Chemistry Discoveries: Background 1932: James Chadwick discovers neutrons Bombardment of beryllium with alpha particles from a polonium source Joliot-Curies discover artificial radioactivity 1934: Enrico Fermi uses high energy neutron beam to bombard elements Bombardment of uranium hypothesized to produce transuranic elements http://th.physik.uni-frankfurt.de/~jr/gif/stamps/sm_chadwick1.jpg http://recherche-technologie.wallonie.be/servlet/Repository?IDR=1113 http://www.anl.gov/Science_and_Technology/History/Fermi_stamp_cap.html

Nuclear Chemistry Discoveries: Fission 1934-1939: Ida Noddack questions Fermi’s theory Otto Hahn & Fritz Strassmann recreate Fermi’s experiment Cannot isolate ‘radium’ isotope from barium carrier Lise Meitner & Otto Frisch confirm discovery of fission Other scientists analyzed uranium properties Discovered 235U fissioned with thermalized neutrons Must isolate 235U isotope for nuclear weapons

Nuclear Chemistry Discoveries: 239Pu 1940-1941: University of Berkley scientists & researchers discover transuranic element, plutonium Bombardment of uranium with neutrons 239Pu Mass production potential 238U reactant Separation techniques High fission cross section

Nuclear Chemistry Discoveries: Pile Reactor 1942: Fermi lead team to build first nuclear reactor Fuel: Natural uranium 235U fission produces neutrons to ensure chain reaction of 238U Successful production of 239Pu President Franklin D. Roosevelt pledged government support Manhattan Project http://www.atomicarchive.com/History/firstpile/Images/Reactor.jpg

Manhattan Project Started in August of 1942 Robert Oppenheimer Manhattan, New York City Colonel Leslie Richard Groves Robert Oppenheimer Main physicist http://content.answers.com/main/content/wp/en-commons/thumb/2/2a/250px-Groves_Oppenheimer.jpg

Manhattan Project continued… Three main sites: Oak Ridge, Tennessee 235U production Hanford, Washington 239Pu production Los Alamos, New Mexico Assembly site & testing http://a.abcnews.com/images/TheLaw/ap_oak_ridge_070719_ms.jpg http://www.pas.rochester.edu/~tobin/pictures/ligo/Hanford_Site_sign.jpg http://www.mphpa.org/classic/IM/los_alamos_emblem.jpg

Oakridge: 235U Enrichment Main purpose: Upgrade natural uranium into ~90% 235U product Enrichment techniques: Gaseous diffusion Electromagnetic separation Liquid thermal diffusion http://www.chemcases.com/nuclear/nc-07.htm

Hanford: 239Pu Production Produced in reactor, X-10 Separated from fission products One part of fissionable byproducts to 107 parts plutonium Bismuth phosphate process Selective, co-precipitation of plutonium from acid solution Oxidation-reduction reactions utilized for greater purification

Testing 100-ton test “The Gadget” Exploded on July 16, 1945 Plutonium (Implosion type) Exploded on July 16, 1945 First and only full test before the use of “Little Boy” and “Fat Man” on Japan http://library.thinkquest.org/C005271F/oatomic001p1.jpg

German Side Conflicting data Major scientists: Werner Heisenberg Electric power for U-boats Kurt Diebner Nuclear reactor project in Stadtilm, Leipzig http://www.learn-math.info/history/photos/Heisenberg_13.jpeg http://www.cfo.doe.gov/me70/manhattan/images/DiebnerLarge.jpg

German Reactors Germans were using heavy water as a moderator for their reactors Their main manufacturing plant in Norway was sabotaged, so they never had enough heavy water to support the reactor They also never had enough 235U to sustain a reaction

Atomic Bomb Mechanisms Gun Type Implosion Type Fat Man Little Boy

Gun Type – Little Boy First mechanism designed Not feasible for 239Pu Excess neutron production from 240Pu side reaction Two subcritical, fissile pieces Projectile Target Supercritical mass after collision High confidence level with 235U No test needed http://mesikammen.files.wordpress.com/2008/01/nuclear-bomb-badger350.jpg

Gun Type – Little Boy 6.5 inch diameter barrel 6 feet long High alloy steel case (5000 lb) Fused by four radar units Measured bomb height above ground Set to detonate at 1850ft above ground www.freewebs.com

Gun Type www.freewebs.com

Implosion Type Subcritical amount of enriched 239Pu Neutron initiator to ensure start of chain reaction Detonation device same as gun type Conventional explosives encased in steel sphere to cause severe inward compression on fissile material Subcritical material compressed to supercritical Neutron initiator released

Implosion Type – Explosives 1/32 inch tolerances Prevent irregularities in compressive shock wave Constructed of hexagonal and pentagonal blocks –much like a soccer ball www.nuclearweaponarchive.org

Implosion Type www.freewebs.com

Little Boy Contained 135 lbs of 90% 235U enriched uranium Dropped on Hiroshima on August 6, 1945 Created 16,000 ton TNT equivalent blast Killed approximately 200,000 people Fissioned 2 lbs of enriched uranium

Fat Man Contained 12 pounds of enriched 239Pu Dropped on Nagasaki on August 9, 1945 Created explosion equivalent to 22,000 tons of TNT Killed approximately 70,000 people immediately and eventually a total of 140,000 Fissioned approximately 2 lbs

Conclusion Caused massive devastation in Japan Allied forces victorious Changed weaponry for warfare Hydrogen bomb Requires responsible development in future Nuclear non-proliferation Updating weapon supplies

References Settle, Frank. "Nuclear Chemistry." General Chemistry Case Studies. 2005. Kennesaw State University. 20 Nov 2008 <http://www.chemcases.com/nuclear/nc-01.htm#../nuclear/index2.htm#concept>. "Irène Curie, Frederic Joliot and Artificial Radioactivity." 2006. 20 Nov 2008 <http://www.dartmouth.edu/~phys1/labs/lab4.pdf>. "Why Uranium and Plutonium?" atomicarchive.com. 2008. AJ Software & Multimedia. 20 Nov 2008 <http://www.atomicarchive.com/Fission/Fission5.shtml>. Pike, John. "Plutonium Production." Federation of American Scientists. 2000. 20 Nov 2008 <http://www.fas.org/nuke/intro/nuke/plutonium.htm>. "Production Reactor (Pile) Design." Manhattan Project: An Interactive History. Department of Energy: Office of History & Heritage Resources. 20 Nov 2008 <http://www.mbe.doe.gov/me70/manhattan/reactor_design.htm>. “Manhattan Project.” Nuclear Age Peace Foundation. 2008. 18 Nov 2008 <http://www.nuclearfiles.org/menu/key-issues/nuclear-weapons/history/pre-cold-war/manhattan-project/index.htm>. Sublette, C. “The Manhattan Project.” 1999. 18 Nov 2008 <http://nuclearweaponarchive.org>. Bethe, H. A. “The German Uranium Project.” Physics Today. 2000. 18 Nov 2008 <http://www.wcpeace.org/History/A%20&%20H%20Bombs/german_u.html>. daryl2007. “World War II: Nazi Nuclear Weapons.” 18 Nov 2008. <http://hubpages.com/hub/World-War-II-Nazi-Nuclear-Weapons-Project>. Sublette, C. “Nuclear Weapons Frequently Asked Questions.” Version 2.18: 3. 2007. 18 Nov 2008. <http://nuclearweaponarchive.org>. Settle, F. “Nuclear Chemistry First Atomic Bombs.” 18 Nov 2008. <http://www.chemcases.com/nuclear/nc-09.htm>.

Questions http://www.isu.edu/departments/inse/images/atr.jpg

Backup Slides

Gaseous Diffusion Saturated uranium hexafluoride (UF6) gas enters chamber Vacuum applied on outer side of porous material Nickel or aluminum oxide Gas flows from high to low pressure 235U passes through porous material at greater rate than 238U Lower molecular weight http://www.chemcases.com/nuclear/nc-07.htm

Electromagnetic Separation Operated on basis of mass spectrometer 235U & 238U ions will have different paths passing through uniform magnetic field Same charge & kinetic energy Different mass & velocity http://www.chemcases.com/nuclear/nc-07.htm

Liquid Thermal Diffusion Utilizes temperature difference create thermal diffusion Convection current occurs Heavier 238U accumulates towards bottom Lighter 235U accumulates towards top http://www.chemcases.com/nuclear/nc-07.htm