Most feared accident at a nuclear plant is the LOCA (Loss of Coolant Accident) – it’s what happened at Three Mile Island, and at Fukushima.
New Chinese design tested in real life demonstration and passed – cooling down completely on its own, so we’re told, after shut down of cooling system.
Could this be the first “fool proof” reactor? Waiting for more trials with bigger fools.
A large-scale nuclear power station in China is the first in the world to be completely impervious to dangerous meltdowns, even during a full loss of external power. The design can’t be adapted to existing nuclear reactors around the world, but could be a blueprint for future ones.
All modern nuclear power plants rely on powered cooling mechanisms to take excess heat away from reactors or, in the event of an emergency, human intervention to shut the plant down. Water or liquid carbon dioxide are often used as coolants, but these typically rely on external power supplies to function.
If these systems fail, then the reactors can become too hot and lead to explosions or overheating, causing the plant to literally melt from the excess heat. This was one factor in the Fukushima nuclear accident in Japan in 2011, where a loss of both standard and emergency power systems led to a meltdown.
A relatively new kind of reactor design, called a pebble-bed reactor (PBR), has the advantage of being passively safe, which means that if power for cooling systems is lost, then the reactor can safely shut down by itself. Rather than use highly energy-dense fuel rods like many other reactor designs, PBRs use a large number of low-energy-density “pebbles” as fuel, which contain a small amount of uranium surrounded by graphite. This can help slow the nuclear reaction and withstand high temperatures.
This lower energy density means any excess heat will be spread out over all of the pebbles, and so will be easier to transport away using natural cooling processes like conduction and convection, says Zhe Dong at Tsinghua University in China.
Continue reading “First Fool-Proof Nuke? Chinese Reactor Demonstrates Loss-of-Coolant Safety”








