Nov
2
Burn that Nuclear Waste
November 2, 2009 | 4 Comments
The more energy pulled out of uranium fuels the less radioactive waste remains at the end. That fact has been on the minds of many in science and business for decades.
Nuclear experts say the proposed Advanced Recycling Center (ARC) could help to solve the biggest radioactive waste concerns as the world atomic power industry looks to build more than 100 nuclear reactors to curb greenhouse gas emissions while continuing to ensure reliable energy supply.
GE Hitachi says their ARC, called ‘PRIZM’ will cut radioactive waste while it can extract by up to 90 percent of the energy in uranium, instead of the 2 to 3 percent that widely used light water reactors yield. That’s better than some thirty times more power from the same fuel with less waste left behind. Some wonder why the U.S. government is so slow to get behind this caliber of technology.
Prizm Process Diagram. Click image for more info.
It’s not all roses, though. The drawbacks of the system by GE Hitachi Nuclear Energy are that the fast reactors involved are very costly and the reprocessing technology involves handling highly radioactive material practices yet to be proven on industrial scale.
The PRIZM ARC combines electrometallurgical processing and one or more sodium cooled fast burner reactors on a single site. This process produces power while alleviating the spent nuclear fuel burden from nuclear power generation.
The PRIZM plan starts with the separation of spent nuclear fuel into three components: 1) uranium that can be used in CANDU reactors or re-enriched for use in light water reactors; 2) fission products (with a shorter half life) that are stabilized in glass or metallic form for geologic disposal; and 3) actinides, the long lived radioactive material in spent nuclear fuel (SNF), which are used as fuel in the Advanced Recycling Reactor (ARR).
PRISM is a reactor that uses liquid sodium as the coolant. This coolant allows the neutrons in the reactor to have a higher energy (sometimes called fast-reactors) that drive fission of the actinides, converting them into shorter lived “fission products.” This reaction produces heat energy, which is converted into electrical energy in a conventional steam turbine. Sodium cooled reactors are well developed and have safely operated at many sites around the world.
Today, in the US there are approximately 100 nuclear power reactors in operation. Assuming that they each produce 20 tons of SNF a year for 60 years of operation, then the current fleet will produce 120,000 tons of SNF. 26 ARCs are capable of consuming the entire 120,000 tons of SNF. Additionally, they are capable of producing 50,000 MWe and could reduce the emission of 400,000,000 tons of CO2 every year.
That could be a whole lot of coal not getting burned and getting rid of a big pile of atomic waste, forever.
ARC technology could be of particular interest for countries like the United States, home to the world’s largest fleet of nuclear reactors but where the government has put a hold on the plan to build the Yucca Mountain repository.
Lisa Price, a senior executive of GE Hitachi unit Nuclear Fuel Cycle said the GE Hitachi ARC would have the additional advantage of not extracting plutonium, which can be used for nuclear weapons. Current reprocessing methods, deployed in countries like France, Britain or Japan, extract uranium, plutonium and fission products separately from spent fuel rods.
“Recycling does not need to separate plutonium at all. So it does not ever come out in a form that could be used for ill gain. And that’s a major advantage from a non-proliferation point of view,” Price said.
That’s from a major advantage of the PRIZM process in that it is a dry process (the processing materials are solids at room temperature). This significantly reduces the risk of inadvertent environmental releases. Additionally, unlike traditional aqueous MOX separations technology, electrometallurgical separations does not generate separated pure plutonium making the dry process separations more proliferation resistant.
The dry process is called electrometallurgical separation technology and is currently widely used in the aluminum industry. Electrometallurgical separation has been studied and demonstrated in US National Laboratories as well as other research institutes around the world.
In a report at Reuters Tim Abram, Professor of Nuclear Fuel Technology at Manchester University in Britain is quoted as saying, “A lot of the technology on which sodium fast reactors are based has already been demonstrated in the past. The big challenge is: can we make it economic? Today, the answer is no, so this remains one of the main goals of the Generation IV initiative.” Professor Abram added that a European study in the 1990s showed fast reactors would cost about 20 percent more than conventional reactors.
In contrast Ian Hore-Lacy of the World Nuclear Association said there was increasing interest in fast reactors because they could recycle elements that normally became high-level waste. Fuel reprocessing, like GE Hitachi’s electrometallurgical process, was the area of the technology that was least well proven.
Abram agreed, saying: “On a relatively small scale, the electrometallurgical reprocessing technology has been shown to work. It’s conceptually relatively easy to describe. But because the fuel is very radioactive, all of the fuel manufacturing operations would have to be done in very heavily shielded facilities, and remotely, using robotic manipulation. Nobody has demonstrated it at industrial scales yet.”
GE Hitachi says they can do it. The technology development has been underway for more than 15 years since the work began in the late 1980s. The effort has been partly funded by the U.S. government, so your money is in already.
GE Hitachi also figures it would be also economic; particularly if the disposal costs of nuclear waste from the existing technologies are taken into account. If the utilities and ratepayers wind up holding the bag on disposal, the view could get very positive on ARC reactors.
“If you factor in long term storage, then the economics support recycling, and even reprocessing,” GE Hitachi’s Price said. “The long term disposal is going to be very expensive.”
Thirty times the spent energy in ready to process fuel, believable costs, well worn technology and a whole lot of electrical power – the answer should be – go, get on and over with it.
Tip to Brian Wang at NextBigFuture.com for the trigger and some source leads.
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