Dwight L. Williams, Ph.D., P.E. Martin Luther King Visiting Professor Department of Nuclear Science and Engineering Massachusetts Institute of Technology
Overview Introduction Types of Plutonium
About the Speaker -- the “New Guy” Education and Registration (Nuclear Engineering) - B.S., North Carolina State University (NCSU)
- M.S., NCSU, Plasma Physics/Fusion
- Ph.D. University of Maryland, Radionuclide Detection
- P.E., Commonwealth of Virginia
Professional Experience - Nuclear Analyst, Prototype International Data Centre
- Senior Nuclear Engineer, Department of Defense (DoD)
- Chief Engineer/Principal Nuclear Physicist, DoD
Introduction Why knowledge of nuclear proliferation is useful within peaceful nuclear academic program - expands upon foundational knowledge
- fosters effective nonproliferation and counterproliferation efforts
- facilitates nuclear security planning
- enables better public relations and perceptions to be cultivated
Weapons Development Pathways
Weapons Development Pathways
Typical Reactor Isotopes of Interest Plutonium (Pu-239) - product of natural and depleted uranium irradiation
- one of many Pu isotopes generated
Uranium (U-235) - U-235 abundance customarily of 3 - 5% in reactors
Tritium (H-3) - product of heavy water irradiation
- product of Li-6 and Li-7 irradiation
- possible fission product
Relevant Plutonium Isotopes Pu-239: U-238 + n → U-239 → Np-239 → Pu-239 - most desirable for nuclear weapons use
Pu-240: Pu-239 + n → Pu-240 (if no fission) - neutron emitter/spontaneous fission
Pu-241: Pu-240 + n → Pu-241 Pu-238: U-235 or U-238 + n → → → Pu-238 - generates heat from rapid decay
Plutonium Isotope Properties Notes, - Pu-241 decays into Am-241, an intense emitter
- Most even Pu isotopes (238, 240, etc.) decay by SF
Production of Weapons Grade Pu At least 94% Pu-239 - frequent refueling required for optimum production
- separating isotopes is nontrivial effort
Typically affects power production
Comparison of Plutonium Grades In general, - Weapons Grade: < 7% Pu-240
- Reactor Grade: > 18% Pu-240
Pu Production in Various Reactors Pu in Fuel at 1000 MWd/MTU
Estimated Pu in Fuel at Discharge
Pu Production Rules of Thumb
Conclusions Roles exist for nuclear proliferation knowledge within peaceful nuclear program Pu-239 is most useful isotope for weapons, but generating weapons grade plutonium (>94% Pu-239) is nontrivial Typical power reactor operations are not conducive for weapons grade plutonium production
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