Presentation on theme: "An Overview of the Nuclear Fuel Cycle and Radioactive Materials Industry Chuck Cain U.S. Nuclear Regulatory Commission, Region IV Arlington, Texas."— Presentation transcript:
An Overview of the Nuclear Fuel Cycle and Radioactive Materials Industry Chuck Cain U.S. Nuclear Regulatory Commission, Region IV Arlington, Texas
Implementing Legislation Atomic Energy Act of 1954 established the Atomic Energy Commission (AEC) Energy Reorganization Act of 1974 separated the peaceful uses regulatory function from the weapons function established the NRC weapons function eventually included in Department of Energy (DOE)
Energy Policy Act of 2005 Authorizes NRC to regulate naturally occurring material and accelerator- produced material
Agreement States These are States that have agreements with NRC to regulate radioactive materials within their borders (except reactors) All States in NRC Region IV are Agreement States except Montana, Wyoming, South Dakota, Idaho, Alaska, and Hawaii
Uranium Mining and Milling Mining by conventional methods or by In-situ leaching Ore is < 1% uranium Mill extracts uranium from ore; rest is tailings Mill product is uranium oxide (known as yellowcake) and is shipped in 55-gallon drums
Facts About Yellowcake Can be held in hands without harm. A drum of yellowcake weighs about 1,000 pounds. Natural uranium contains mostly uranium-238 (99.3%). We want the U-235 which is only 0.7% of natural uranium.
Enriched Uranium The next challenge is to enrich the uranium (increase the proportion of U-235) Enrichment plants usually work by gaseous diffusion; therefore, the uranium must be converted to a gas.
Conversion Plants Produce UF 6 Yellowcake can be converted to uranium hexafluoride which has a triple point of 147° F Honeywell, Metropolis, IL Sequoyah Fuels, Gore, OK (closed)
Enrichment Plants Since an atom of U-238 is larger than an atom of U-235, the atoms can be filtered at a gaseous diffusion enrichment plant. Uranium must be enriched to ~10% to make nuclear fuel for a reactor.
Depleted Uranium Depleted uranium is a waste product of the enrichment process. Depleted uranium is “depleted” in U-235 (less than 0.7% U-235). DU can be used for purposes where a heavy mass is needed, such as military projectiles.
Spent Fuel Eventually fuel elements become “poisoned” during the fission process and need to be replaced. This is considered “high-level” waste. There is still much good U-235 left in spent nuclear fuel. The “poisons” (byproduct material) produced during the fission process are high-energy gamma emitters.
What’s next for spent fuel? Several options store at reactor site in pool store at site in Independent Spent Fuel Storage Installation (ISFSI) burial at geological repository reprocess (recycle) to separate the remaining good uranium from the waste
Also, Low-Level Waste Contaminated or potentially contaminated items such as protective clothing, building materials, tools, etc. Burial at licensed disposal site such as EnergySolutions (UT or SC), U.S. Ecology (WA)
Categories of Nuclear Materials Source material – natural uranium and thorium Special Nuclear Material (SNM) – enriched uranium, plutonium Byproduct material – byproduct of the fission process in a reactor
Quantity of Radioactive Material Unit of measurement - curies or becquerels
Half-Life Time it takes for half of a radioactive material to decay Cobalt-60, 5 years Uranium, millions of years Some materials decay with a half-life in minutes or seconds, such as those for medical use.
Dose to Radiation Units of rems or sieverts Radiation worker limit is 5 rems Limit for a member of the public is 100 millirems
Day 24 – Blisters are breaking and dead skin is sloughing off, exposing raw tissue underneath.
Day 27 – Areas of obvious injury continue to grow larger, with no evidence of healing. Increasing pain in damaged areas.
Day 56 – Pain has increased until damaged tissues can no longer be exposed to air. Decision to perform skin grafts.
Day 102 – Extensive skin grafting complete. Deep tissue injury continues.
5 years – Loss of fingers; hands sensitive to heat and cold; additional amputations may be required.
Another Radiation Exposure Case Warehouse worker finds radiography source on floor after radiographer leaves Worker places source pigtail in back pocket and asks secretary to call radiography company to come pick it up