|
Mixed Lots
Mixed oxide, or MOX fuel, is a blend of plutonium and natural uranium, reprocessed uranium, or depleted uranium which behaves similarly (though not identically) to the low enriched uranium feed for which most nuclear reactors were designed. more...
Home
Cultures, Ethnicities
Decorative Collectibles
All God's Children
Andrea by Sadek
ANRI
Armani
Avon
Bing & Grondahl Coll Plates
Blue Sky Clayworks
Boyds
Bradford Exchange
Byers Choice
Cat's Meow Village
Charming Tails
Christopher Radko
Danbury Mint
David Winter
Dept 56
Dreamsicles
Duncan Royale
Enesco
Faberge
Fitz & Floyd
Flambro
Franklin Mint
Halcyon Days
Hallmark
Hamilton Collector Plates
Harbour Lights
Harmony Kingdom
HOMCO
Hummel, Goebel
Josef
Knowles Collector Plates
Lefton Figurines
Lenox
Liberty Falls
Lilliput Lane
Limoges
Lladro
Longaberger
Baskets
1990-94
1995-99
2000
2001
2002
2003
2004
2005
Mixed Lots
Pre-1990
Unknown
Candle Holders, Votives
Candles
Coasters
Combos
Dinnerware, Serving, Pottery
Fabric
Garters
Handle Grippers
Handle Ties
Lids
Liners
Magnets
Metalworks
Napkins, Placemats
Ornaments
Other Longaberger Items
Pens, Pencils, Pads
Pins
Prints, Wall Hangings
Protectors
Tie-ons
Totes, Wallets, Cases
Cases, Accessories
Other
Totes, Bags
Wallets, Coin Purses
Towels
Madame Alexander
Margaret Furlong
Mary Engelbreit
Midwest of Cannon Falls
Norman Rockwell
Old World
Other Brands
PartyLite
Patricia Breen
Pendelfin
Polonaise
Precious Moments
Rein Poortvliet
Roman
Royal Copenhagen Coll Plates
Royal Doulton
San Francisco Music Box
Sarah's Attic
Schmid
Sebastian Miniatures
Shelia's
Slavic Treasures
Swarovski
Thomas Kinkade
Tom Clark
Unbranded
Wade Figurines
Wedgwood
Willitts
Willow Tree
Holiday, Seasonal
Religions, Spirituality
MOX fuel is an alternative to low enriched uranium (LEU) fuel used in the light water reactors that predominate nuclear power generation.
An attraction of MOX fuel is that it is a way of disposing of surplus weapons-grade plutonium, which otherwise would have to be handled as a difficult-to-store nuclear waste product, and a nuclear proliferation risk.
Overview
In every uranium-based nuclear reactor core there is both fission of isotopes such as uranium-235 (U-235), and the formation of new, heavier isotopes due to neutron capture, primarily by uranium-238 (U-238). Most of the fuel mass in a reactor is U-238. This can become plutonium-239 (Pu-239) and by successive neutron capture plutonium-240 (Pu-240), plutonium-241 (Pu-241) and plutonium-242 (Pu-242) as well as other transuranic or actinide isotopes. Pu-239 is fissile, like U-235. Small quantities of uranium-236 (U-236) and plutonium-238 (Pu-238) are formed similarly from U-235.
Normally, with the fuel being changed every three years or so, most of the Pu-239 is "burned" in the reactor. It behaves like U-235 and its fission releases a similar amount of energy. The higher the burn-up, the less plutonium remains in the spent fuel, but typically about one percent of the spent fuel discharged from a reactor is plutonium, and some two thirds of the plutonium is Pu-239. Worldwide, almost 100 tonnes of plutonium in spent fuel arises each year. A single recycling of plutonium increases the energy derived from the original uranium by some 17%, and if the uranium is also recycled this becomes about 30%. With additional recycling the percentage of fissile plutonium in the mix decreases requiring the total plutonium percentage to be increased.
Re-licensing precedes the introduction of MOX fuel into existing nuclear reactors. Often only a third to half of the fuel load is switched to MOX. The use of MOX does change the operating characteristics of a reactor, and the plant must be designed or adapted slightly to take it. More control rods are needed. For more than 50% MOX loading, significant changes are necessary and a reactor needs to be designed accordingly. The Palo Verde Nuclear Generating Station near Phoenix, Arizona was designed for 100% MOX core compatibility but has so far always operated on fresh slightly enriched uranium.
According to the AECL, CANDU reactors could use 100% MOX cores without physical modification. Atomic Energy of Canada Limited (AECL), reported to the United States National Academy of Sciences committee on plutonium disposition that it has extensive experience in testing the use of MOX fuel containing from 0.5 to 3% plutonium.
Read more at Wikipedia.org
|
|