Friday, January 29, 2010

The interactive scale of the Universe

This article from Bad Astronomy (actually a very good website, its name came from Phil's desire debunk the bad astronomy found in hoax sites) links to a very useful interactive demonstration of the relative size of things in the Universe from far smaller than an atom, to the size of the known universe.

It will be very usefully in getting a handle on the relative size of things, plus get an understanding of modern physics and astronomy, with the size of biological things somewhere in the "middle" of the size scale.

Monday, January 4, 2010

Thorium is a much safer more efficient reactor fuel than Uranium

The main reason all current commercial and military nuclear reactors use Uranium, is because the US government wanted to produce lots of Plutonium for nuclear weapons. Now that the infrastructure and perceptions of many people are fixated on Uranium, and hence there is a huge commercial and political inertia against moving towards a Thorium energy program.

Thorium as a fuel is a lot less expensive to refine and manufacture for use in nuclear reactors than Uranium, by several orders of magnitude. Plus the Thorium reactors are intrinsically much safer, as there is no chance of a Chernobyl style incident using Thorium.

Using Thorium largely eliminates the problems of radioactive waste (compared to Uranium), and totally eliminates the worry that such reactors could lead to increased availability of weapons grade Plutonium.

I think that if nuclear reactors had been based on using Thorium, rather than Uranium and there had been less emphasis on Nuclear weaponry, then New Zealand would have been much less anti-nuclear.

The article itself goes into much more depth, and also gives some useful additional background:
When Sorensen and his pals began delving into this history, they discovered not only an alternative fuel but also the design for the alternative reactor. Using that template, the Energy From Thorium team helped produce a design for a new liquid fluoride thorium reactor, or LFTR (pronounced “lifter”), which, according to estimates by Sorensen and others, would be some 50 percent more efficient than today’s light-water uranium reactors. If the US reactor fleet could be converted to LFTRs overnight, existing thorium reserves would power the US for a thousand years.

Overseas, the nuclear power establishment is getting the message. In France, which already generates more than 75 percent of its electricity from nuclear power, the Laboratoire de Physique Subatomique et de Cosmologie has been building models of variations of Weinberg’s design for molten salt reactors to see if they can be made to work efficiently. The real action, though, is in India and China, both of which need to satisfy an immense and growing demand for electricity. The world’s largest source of thorium, India, doesn’t have any commercial thorium reactors yet. But it has announced plans to increase its nuclear power capacity: Nuclear energy now accounts for 9 percent of India’s total energy; the government expects that by 2050 it will be 25 percent, with thorium generating a large part of that. China plans to build dozens of nuclear reactors in the coming decade, and it hosted a major thorium conference last October. The People’s Republic recently ordered mineral refiners to reserve the thorium they produce so it can be used to generate nuclear power.

Saturday, January 2, 2010

Sailing the Seas of Titan

There are shades of Hal Clement's Science Fiction (SciFi) novel "Mission of Gravity", where aliens are employed by Earth's scientists to investigate a fast spinning super Jupiter type planet in sailing ships. However, this article about a nautical craft for Saturn's moon Titan, is a real proposed scientific project, although no aliens are involved as crew members!
The first interplanetary nautical craft may be a boat to explore the methane seas of Titan. A proposed mission to Titan would explore some of its largest seas, including Ligeia Mare (pictured) or the Kraken Mare, both of which are in the northern hemisphere of the foggy moon of Saturn. The concept has been studied for over two years by scientific team led by Ellen Stofan of Proxemy Research, Inc. in Washington DC, and has recently been submitted to NASA.