Nuclear Energy: Fusion Power A Step Closer

The UK’s newest fusion reactor, ST40, was switched on last week, and has already managed to achieve ‘first plasma‘ – successfully generating a scorching blob of electrically-charged gas (or plasma) within its core.

The aim is for the tokamak reactor to heat plasma up to 100 million degrees Celsius (180 million degrees Fahrenheit) by 2018 – seven times hotter than the centre of the Sun. That’s the ‘fusion’ threshold, at which hydrogen atoms can begin to fuse into helium, unleashing limitless, clean energy in the process.

Nuclear fusion is the process that fuels our Sun, and if we can figure out a way to achieve the same thing here on Earth, it would allow us to tap into an unlimited supply of clean energy that produces next to no carbon emissions.Unlike nuclear fission, which is achieved in today’s nuclear reactors, nuclear fusion involves fusing atoms together, not splitting them apart, and it requires little more than salt and water, and primarily produces helium as a waste product.

 

Today is an important day for fusion energy development in the UK, and the world,” said David Kingham, CEO of Tokamak Energy, the company behind ST40. “We are unveiling the first world-class controlled fusion device to have been designed, built and operated by a private venture. The ST40 is a machine that will show fusion temperatures – 100 million degrees – are possible in compact, cost-effective reactors. This will allow fusion power to be achieved in years, not decades.

The next step is for a full set of those magnetic coils to be installed and tested within ST40, and later this year, Tokamak Energy will use them to aim to generate plasma at temperatures of 15 million degrees Celsius (27 million degrees Fahrenheit).

In 2018, the team hopes to achieve the fusion threshold of 100 million degrees Celsius (180 million degrees Fahrenheit), and the ultimate goal is to provide clean fusion power to the UK grid by 2030.

Source: http://www.tokamakenergy.co.uk/

How To Improve Efficency Of Power Plants

Most of the world’s electricity-producing power plants — whether powered by coal, natural gas, or nuclear fission — make electricity by generating steam that turns a turbine. That steam then is condensed back to water, and the cycle begins again.
But the condensers that collect the steam are quite inefficient, and improving them could make a big difference in overall power plant efficiency.
Now, a team of researchers at MIT has developed a way of coating these condenser surfaces with a layer of graphene, just one atom thick, and found that this can improve the rate of heat transfer by a factor of four — and potentially even more than that, with further work. And unlike polymer coatings, the graphene coatings have proven to be highly durable in laboratory tests.
The findings are reported in the journal Nano Letters by MIT graduate student Daniel Preston, professors Evelyn Wang and Jing Kong, and two others. The improvement in condenser heat transfer, which is just one step in the power-production cycle, could lead to an overall improvement in power plant efficiency of 2 to 3 percent based on figures from the Electric Power Research Institute, Preston says — enough to make a significant dent in global carbon emissions, since such plants represent the vast majority of the world’s electricity generation. “That translates into millions of dollars per power plant per year,” he explains.
MIT-Graphene-Coating
An uncoated copper condenser tube (top left) is shown next to a similar tube coated with graphene (top right). When exposed to water vapor at 100 degrees Celsius, the uncoated tube produces an inefficient water film (bottom left), while the coated shows the more desirable dropwise condensation (bottom right)
We thought graphene could be useful,” Preston says, “since we know it is hydrophobic by nature.”
They found that the single-atom-thick coating of graphene did indeed improve heat transfer fourfold compared with surfaces where the condensate forms sheets of water, such as bare metals. Further calculations showed that optimizing temperature differences could boost this improvement to 5 to 7 times. The researchers also showed that after two full weeks under such conditions, there was no measurable degradation in the graphene’s performance.

Source: http://newsoffice.mit.edu/