Safety by design

Operators of current Generation II LWRs cope with loss of coolant (LOCA) accidents by active, often mechanical, means. Pebble beds, in contrast, are said to be "naturally" safe and cool on their own using only conduction, convection, and radiative heat transfer without the need for emergency core cooling systems to prevent core failure or meltdown. Best of all, pebble bed reactors experiencing LOCA reportedly will release little if any radioactivity to the environment to the extent that no offsite emergency plan would be required.
Besides being safer to operate, pebble bed reactors use fuel more efficiently and can achieve higher fuel utilization (higher burn up) than conventional nuclear plants. Because pebble bed reactors use more of the fuel, once discharged there is less fissile material left that can be extracted for weapons use. This, along with the protective silicon carbide armor surrounding the Triso fuel, makes the pebble bed design more proliferation resistant.

The near termIf the proposed test plant near Capetown, South Africa, passes technical review, Eskom will apply to the National Nuclear Regulator (NNR) of South Africa for an early site permit next year and construction and operating licenses later in 2002 or 2003.
MIT is collaborating with the Idaho National Engineering and Environmental Laboratory (INEEL). MIT plans (within the next five years or so) to build a full-scale research/demonstration reactor at the INEEL. The goal: Show that even with a maximum LOCA the reactor core won't melt. According to Dr. Kadak this so-called "License by Test" approach would help boost public confidence in the pebble bed technology and dramatically reduce licensing costs and accelerate commercialization.
This approach is unlike conventional NRC licensing that approves a plant design on paper before it's built. The INEEL has conducted many similar LOCA tests on small-scale reactors but the MIT MPBR would be the first full-scale reactor to under go such rigorous testing.