Christian Science Monitor: New nuclear plants may have withstood the Japan earthquake
The 9.0 Japan earthquake was dire but the current meltdown might have been avoided by new advances in nuclear plant technology.
The latest nuclear reactor designs could help avoid the overheating and explosions that have occurred at the Fukushima Daiichi nuclear plant in Japan following the powerful earthquake and tsunami that struck on Friday. Newer reactor designs propose the use of passive cooling systems that would not fail after a power outage, as happened in Japan, as well as other novel approaches to managing reactor heat. ...
... The reactors at the nuclear plant, built in the early 1970s, rely on active cooling systems that require electricity. Newer plant designs would lessen or eliminate the need for active cooling, making use of natural convection or a "gravity feed" system to cool reactors in the event of an emergency.
In one design, for example, the relatively new Westinghouse AP1000, water is suspended over the reactor housing. If pressure within the system drops, this allows the water to fall into the reactor area, submerging it in enough water to keep it cool.
While passive systems could be better in the event of electrical failures, they might not always be the safest systems. Kadak says that in an active system, it's easier to ensure that coolant gets exactly where it needs to be—it's simply pumped to the right location. Designing passive systems, on the other hand, requires complex models of how fluids will behave in a system that could be rendered incorrect if the system is damaged.
Kadak says that even more advanced reactor designs could overcome these issues. ...