Spent Nuclear Fuel Timothy Pairitz

Nuclear Power 101 Uranium-235 is enriched from 0.7% to 3-5%. Enriched fuel is converted to a uranium oxide powder and pressed into pellets. Pellets are placed in thin tubes known as fuel rods, and fuel rods are further bundled into larger assemblies.

Nuclear Power 101 Energy released by fission reactions is used to produce steam and drive turbines.

Nuclear Power 101 Fuel loses efficiency over time and is eventually unable to maintain desirable reactions. Power production is halted, spent fuel is replaced by new fuel assemblies.

Spent Fuel Rougly one third of the fuel assemblies in a reactor are removed during a refueling procedure Removed assemblies are no longer suitable for use in the reactor, but still produce large amounts of radiation and heat that must be contained United States produces about 2,000 tons of spent fuel each year Spent fuel is estimated to be harmfully radioactive for somewhere between 10,000 and 1,000,000 years

Why is it important? As of 2012, 104 nuclear power plants were operating within the United States Provided 19% of the nation’s electricity Average age of commercial reactors: 34 years old

Why is it important? Presents a potential danger to both the environment and the public Frequently cited as an issue that must be resolved before the United States can increase nuclear generating capacity

A brief history of spent fuel 1957 – National Academy of Science study determines that federal government should be responsible for constructing a permanent geological repository for nuclear waste – Federal government formally states that it is responsible for nuclear waste disposal.

A brief history of spent fuel 1977 – President Carter bans reprocessing of spent fuel by private companies – Nuclear Waste Policy Act requires Department of Energy to begin investigating potential storage sites and be capable accepting fuel by January 31 st, – Private power companies agree to pay 1/10 of a cent for every kW hour generated toward a nuclear waste disposal fund

A brief history of spent fuel 1987 – Amendment to Nuclear Waste Policy Act requires DOE to shift primary focus to Yucca Mountain as permanent repository site.

A brief history of spent fuel 1998 – Spent fuel deadline passes with Department of Energy and Yucca Mountain estimated to be at least 12 years away from accepting waste.

Storage Options Pool Storage Dry Casks Storage Permanent Repositories Reprocessing

Pool Storage Located inside plant protected area Large amount of water act as coolant and radiation shield Holding racks contain boron to further absorb neutrons

Dry Cask Storage Located inside plant protected area Viable alternative when plant storage pools have been filled Designed to resist floods, earthquakes, tornadoes, projectiles, and temperature extremes. Metal or steel-reinforced concrete outer shells, sealed inner metal cylinder contain spent fuel

Yucca Mountain Proposed repository site northwest of Las Vegas Operates under theory that natural and engineering barriers will prevent release of radiation Alternating layers of “welded” and “non-welded” tuff Funding halted in 2010 after $15.4 billion in federal spending on research and development

Reprocessing Not currently used in the United States – known as an “open” fuel cycle Plutonium and uranium (95% of waste fuel) are separated from rest of waste fuel. Fissile products of this separation are combined with fresh uranium resulting in mixed oxide fuel (MOX) Increases volume of radioactive waste due to increased contact with various materials Can be very costly

How not to store fuel

What about space? Sending large masses into space is expensive Accidents during launch or ascent could be disasterous

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