Sunday, March 1, 2009

Fission-fusion hybrid mops up nuclear waste

fusion-fission hybridU.S. scientists have designed a new system that they say could rid the world of radioactive waste produced by nuclear power stations opening the door to faster cleaner and more efficient energy production.

"Many people will be willing to give nuclear power a chance if the waste could be destroyed " said Prashant Valanju a nuclear physicist from the University of Texas in Austin.

Valanju is part of a team whose "waste deconstruction" scheme reported last month in the journal Fusion Engineering and Design proposes the use of nuclear fusion to break down the waste from existing fission power plants.

Holy Grail Fission-based nuclear power stations generate electricity from the energy created when large atoms such as uranium are broken apart. This process creates large amounts of energy but also radioactive transuranic waste which is heavier than uranium and includes plutonium which can be used to create nuclear weapons. Nuclear fusion is the opposite process to fission and is the fusion of atoms of hydrogen to form helium in the same process that powers the Sun.

Functional nuclear fusion power plants are one of the Holy Grails of modern physics as these would not require uranium or create radioactive waste but the technology is still decades away....

"Existing nuclear fission reactors can be used to relatively cheaply destroy 75 per cent of the waste by using a known method that does not create any new transuranic waste " explained Valanju. However the nasty stuff that remains nicknamed nuclear sludge is nearly impossible to destroy with fission-only reactors and must be stored. These waste products continue to be highly radioactive as they break down in a process that can take millions of years so storing the sludge safely is a major headache.

... In the new design, a compact fusion reactor, known as a tokamak, is positioned next to the waste material in a doughnut formation. When combined with a fission reaction, enough neutrons can be produced to break down the nuclear sludge in a constant and steady process.

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It's not yet clear if the process would produce a net level of energy, or if the fusion reaction would use up all the power produced in the fission process. However, even if it doesn't produce power, it could be an effective solution for dealing with the most stubborn nuclear waste.

Swadesh Mahajan a University of Texas fusion scientist and another co-author of the study said the hybrid design is a way of utilising fusion technology to reduce fission waste until fusion technology becomes more widespread.

via Fission-fusion hybrid mops up nuclear waste | COSMOS magazine.

I read the reader comments posted with this COSMOS article and I think we should try this. Clean nuclear would be great. It is well worth the effort as long as we can avoid accidents that mutate everyone into giant roaches.

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