Princeton - Department of Chemistry USC - Department of Physics Princeton - Department of Chemistry Nuclear Physics Lab – Oliver R. Gothe May 12, 2008 Nucular Reactors: Classification and Technology Oliver Gothe Nucular Physics Laboratory Professor Ralf Gothe May 12, 2008
Princeton - Department of Chemistry USC - Department of Physics Princeton - Department of Chemistry Nuclear Physics Lab – Oliver R. Gothe May 12, 2008.
Dec 18, 2015
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Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Nucular Reactors: Classification and Technology
Oliver GotheNucular Physics Laboratory
Professor Ralf Gothe
May 12, 2008
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Reaction Types
•Three main reaction types:•Radioactive Decay
•Atomic Batteries•Radioisotope thermoelectric generators
•passive•Nuclear Fusion
•Not suitable for power production yet•Nuclear Fission
•Used in most reactors including all commercial ones
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Reactors - Introduction
•Conventional thermal power plants•All have a fuel source to provide heat•Gas, coal, or oil•Nuclear fission•Uranium-235 or plutonium-239 •Produce steam•Drive a turbine that generates electricity (86%)•Enriched uranium is uranium in which the percent composition of uranium-235 has been increased from that of uranium found in nature
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Radioactive Decay (passive) - RTG
•Electric Generator•Obtains power from passive radioactive decays•Utilized in satellites and space probes•Seebeck effect
• Junction of two dissimilar metals at different temperatures create a current
•Fuel•Long half life, low shielding...•Plutonium 238 most common
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Advantages and Disadvantages
•Advantages:•Relatively constant power production•Useful for long time missions•Solar Panels not applicable
•Disadvantages: •Decays over time•May require shielding•Radioactive waste
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Nuclear Fusion
•Experimental Technology•Not yet in use•Generally utilizes Hydrogen as fuel•Contained with Magnetic fields•Farnsworth-Hirsch Fusor
•Not viable for power creation•Neutron Generator
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Nuclear Fission Reactors - Overview
•First Reactor:•Chicago Pile-1•Enrico Fermi in 1942•Inspired by the discovery that Uranium fissions after being bombarded with neutrons
•Fission process creates new neutrons•Creates chain reaction that needs to be moderated•Unmoderated reaction used for bombs
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Nuclear Fission - Process
• Fission is initialized in the reaction chamber
• Creates Chain reaction
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Nuclear Fission - Process
• Fission is initialized in the reaction chamber
• Creates Chain reaction• Moderators are used to
control the amount of neutrons in the reactor chamber
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Nuclear Fission - Process
• Fission is initialized in the reaction chamber
• Creates Chain reaction• Moderators are used to
control the amount of neutrons in the reactor chamber
• Heat released from fission is processed via heat exchangers or directly via steam turbines
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Nuclear Fission - Process
• Turbines create electricity and the coolant is recycled through the reactor
• The environmental problems with nuclear reactors is the heat that is released into the environment from the condensors.
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Nuclear Fission – Reactor Classification
•Two Types•Thermal vs. Fast Neutron speeds•Thermal Reactors (most common)
•Classified by Moderator Material•Absorption cross-section much smaller than fission cross-section•Natural Uranium
•Fast Reactors•No moderator•Requires Enriched Uranium
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Fast Neutron Reactor
•Fuel must be enriched•Produces fast neutrons•Can be used for transmutation•Fuel Production•Breeder Reactors•Fast Breeder Reactors
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Nuclear Fission - Moderators•Graphite moderate reactors
•Graphite has high neutron absorption cross section•Water moderated reactors
•Heavy water moderated reactors•can be fueled with unenriched uranium
•Light Water moderated reactors•Negative feedback stabilizes reaction (neutron absorption)
•Light element moderated reactors•are moderated by a light elements such as Li or Be
•Organically moderated reactors •Use biphenyl and terphenyl as moderator and coolant
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Nuclear Fission Reactors - Coolant
•Pressurized Water Cooling•specialized pressure vessel•A pressurizer is partially filled with water•steam bubble is maintained above it by heating the water with submerged heaters•Avoid film boiling
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Nuclear Fission Reactors - Coolant
•Pressurized Water Cooling•specialized pressure vessel•A pressurizer is partially filled with water•steam bubble is maintained above it by heating the water with submerged heaters•Avoid film boiling
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Nuclear Fission Reactors - Coolant
•Boiling water reactor•Simplification of designs for civilian purposes•Heat is generated directly in the reaction chamber•Chamber is still pressurized and boils at about 285 degrees Celsius
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Pool Type Reactors
•In pool type reactors the reactor core and control roads are immersed into a pool•Water is simultaneously:
•Cooling agent •Moderator •Shielding
•Used for:•Neutron generation•Training•Not for generating electricity
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Liquid Metal Cooled Reactors
•Liquid metal cooled nuclear reactor•primary coolant is a liquid metal•Used in nuclear submarine use•extensively studied for power generation applications•Fast Breeder Reactors•Lead•Sodium•Bismuth•Mercury
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Gas Cooled Reactors
• Gas cooled reactors• Use inert gases such as
Helium or Carbon dioxide to cool
• Some heat the gas enough to run turbines
• Older models run through heat exchangers to generate steam
• Can be refuelled while online• Higher thermal efficiency than
BWRs• Uses fuel less efficiently though
1. Charge tubes2. Control rods3. Graphite moderator4. Fuel assemblies5. Concrete pressure vessel and radiation shielding6. Gas circulator7. Water8. Water circulator9. Heat exchanger10. Steam
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Molten Salt Reactors
•Molten salt reactors•cooled by circulating a molten salt •mixture of fluoride salts, such as LiF and BeF2•Uranium is often dissolved in the matrix•Maintenance issues•Corrosion•Can use spent fuel•Immature Technology
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Generations of Nuclear Reactors
• Generation I reactors• Developed in 1950-60s • used natural uranium fuel • graphite as moderator
• Generation II reactors• use enriched uranium fuel • mostly cooled and moderated by water
• Generation III • advanced reactors• developments of the second generation with enhanced safety.
• Generation IV • drawing board • burn the long-lived actinides now forming part of spent fuel
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Examples – Pressurized Water Reactor
•Pressurized Water Reactors•high pressure liquid •majority of current reactors•considered the safest and most reliable
Diablo Canyon
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Examples – Boiling Water Reactor
•Boiling Water Reactors (BWR)•Cooled and moderated by water•Lower pressure•Water boils in reactor•Simpler•Potentially more stable•Substantial percentage of modern reactors Laguna Verde nuclear power plant
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Examples – Pressurized Heavy Water Reactor
•Pressurized Heavy Water Reactor (PHWR)
•Heavy water cooled and moderated •Hundreds of pressure tubes•Fueled with natural uranium•Thermal neutron reactor design•Can be refueled without shutdown
CANDU at Qinshan
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Examples – High Power Channel Reactor
•High Power Channel Reactor (RBMK)
•Produces plutonium as well as power•Graphite moderator•Too large to have containment buildings•Chernobyl accident•RBMK reactors are considered the most dangerous reactor designs in use
The Ignalina Nuclear Power Plant
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
Examples – Advanced Gas Cooled Reactor
•Advanced Gas Cooled Reactor (AGCR)
•Graphite moderated•CO2 cooled•High thermal efficiency compared with PWRs•Thermal neutron reactor design Torness nuclear power station
Princeton - Department of Chemistry
USC - Department of PhysicsPrinceton - Department of ChemistryNuclear Physics Lab – Oliver R. Gothe
May 12, 2008
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