The NuScale reactor would rest inside 10-million-gallon tanks of water, mostly below ground, which will lower the chance of meltdown to a thousandth of the risk of conventional reactors. Should all go wrong in one of his reactors and it boils over, the resulting steam would hit the cold outer wall that borders the pool and condense back into water to cool the core. The goal was simplicity.
The NuScale reactor has no pipes bigger than three inches. The NuScale reactor eliminates pumps and relies on thermodynamics.  The NuScale reactor is small enough to rely on the natural, cooling circulation that occurs because hot water rises and cold water sinks. NuScale also does not require emergency diesel generators.

The company has persuaded one important partner, Fluor, an engineering company that specializes in power plants, to invest in its technology. Fluor has invested $145 million in NuScale, on top of about $20 million raised elsewhere.    
The downside is that getting a new design licensed by the Nuclear Regulatory Commission, an essential precursor for sales in the United States, could cost $100 million or more.
In addition, the level of opposition, and the difficulty in getting approvals and permits, might not be much different for a small reactor than for a big one, some experts say, diminishing the logic of going small. For the economics to work, builders would have to convince regulators that the smaller plants can get by safely with less robust containment structures, smaller evacuation planning zones and smaller security forces. And, the industry has always calculated that with economies of scale, bigger means cheaper.
Babcock & Wilcox, a former builder of big reactors, is pushing a 180-megawatt design (four times the size of NuScale’s reactor) and has won support from the Department of Energy. The department is expected to issue a similar grant to another designer soon, a grant that NuScale is chasing.
Small reactors are considered potential export products.  NuScale is talking to a variety of potential customers, although mostly not in the United States, where the low cost of natural gas has made it hard for nuclear power to compete.  (NYT, 12/12/2013)