By ALAN4DISCUSSION
Updated: Mon, 03 Oct 2011 11:37:07 UTC

I was having a look over the latest National Geographic mag, and saw this article on nuclear power generation, which could provide an interesting discussion.

It seems that the problems experienced in Japan could have been avoided with this sort of system.

The (individually linked) 2 page article gives concise information along with some clear diagrams:
KAITLIN M. YARNALL, NGM STAFF; ART: STEFAN FICHTEL; SOURCE: ANDREW KADAK, MIT

THE NEXT GENERATION of nuclear plants may be cooled by gas—helium gas. Such reactors were proposed in the 1960s but rarely pursued; only a few have ever been built. But that could change. Though issues such as fuel storage are a potential concern, gas reactors—which can’t melt down—may be a way forward in the wake of Japan’s nuclear disaster.

Using helium as a coolant has at least a couple of advantages. For one thing, it’s inert, so it can’t become radioactive like the water in water-cooled plants. For another, gas reactors are more efficient at generating electricity than water-cooled ones, because they run much hotter.

http://ngm.nationalgeographic.com/2011/10/visions-now-next#/next/1

How It Works

A pebble-bed reactor is made up of about 400,000 pebbles. Heat from the fuel spheres is picked up by helium and can then be used to generate electricity—or to drive industrial processes such as oil refining and desalination.

1. Blowers move helium gas through the reactor and over the pebbles, where nuclear fission releases large amounts of energy, heating up the helium.

2. About 5,000 spheres move through the reactor each day, like gum balls through a vending machine. The constant circulation means no refueling interruptions.

3. If a pebble taken from the bottom can produce more power, it goes back in the top. If it’s spent, it’s stored as waste, and a new pebble is added.

http://ngm.nationalgeographic.com/2011/10/visions-now-next#/next

TAGGED: ENVIRONMENT, PHYSICS, SCIENCE, TECHNOLOGY