nuclear-news

EXPLOSIVE DRAWBACK    Liquid sodium is better than water at evacuating heat from the reactor core and its high boiling point of about 900 degrees Celsius allows SFRs to operate close to atmospheric pressure, negating the need for the thick, steel containment vessels at pressurised water reactors.But sodium has significant disadvantages, too. On contact with air, it burns; plunged into water, it explodes.Early SFRs built by France, Russia and Japan have suffered corrosion and sodium leaks. But these were not built to GIF standards and the CEA research facility amid the pine trees in Cadarache, southeast France, is working on how to tame sodium as the agency seeks to convince lawmakers to allow construction of its new Astrid reactor, a 600 megawatt SFR.

The Astrid project was granted a 652 million euro ($823 million) budget in 2010 and a decision on construction is expected around 2019.

The use of sodium, which occurs naturally only as a compound in other minerals, presents huge challenges, however.

Nitrogen-driven turbines are being designed to prevent sodium from mixing with water, while purpose-built electromagnetic pumps are seen as the solution to moving the superheated metal within reactors. Then there’s the headache of not being able to see through the liquid metal should something go wrong in a reactor core.

The other five concepts – including lead and helium-cooled fast neutron reactors and three very-high-temperature reactors – are less mature than the SFR and face similar technological hurdles.

But technology is not the only obstacle. Cost is key, as ever, and abundant U.S. shale gas and a renewables energy boom in Europe have undermined the viability of the nuclear industry, leading some GIF member states, including Japan, Canada and Switzerland, to scale back funding. …..http://www.businessinsider.com.au/r-the-key-to-nuclear-s-future-or-an-element-of-doubt-2014-10