Indian engineers have designed a new type of nuclear reactor that will be safer, smaller, cleaner, cheaper and last longer than its disgraced predecessors.
The reactor being planned at the Bhabha Atomic Research Centre in Mumbai will be the first operational reactor powered by thorium instead of uranium, making it safer and cheaper than the current generation of uranium reactors. The project is still in the design and planning stages, but the Indian Department of Atomic Energy is adamant that a thorium reactor is a necessary first step toward energy independence.
Why it’s Better: The Nuclear Reactor of the Future
Using thorium as a fuel source fundamentally changes the nature of nuclear power. A thorium-powered reactor would generate about 1% of the waste produced by its uranium-powered counterpart. Thorium nuclear waste is not especially radioactive, and decays within a few hundred years. By comparison, nuclear waste from uranium-powered plants takes tens of thousands of years to stop emitting lethal levels of radiation. Thorium is also more abundant and easier to mine than uranium, with one quarter of the world’s thorium reserves found in India. Best of all, because thorium is much less reactive than uranium, the risk of a catastrophic meltdown is practically nil.
Preventing Disaster: Not Another Fukushima
Current reactors rely on a constant circulation of water to keep the uranium fuel rods from overheating and melting through the concrete walls of the reaction chamber. A uranium reactor “goes critical” when the water supply is disrupted or the arrangement of the fuel rods is disturbed, both of which happened at the Fukushima reactor complex in March 2011. When the pumps fail or the uranium fuel rods are out of alignment, fission inside the core speeds out of control and a meltdown begins.
Indian engineers are working hard on the design’s inherent safety to solve the “Not In My Back Yard” problem. They hope to design a reactor stable enough and safe enough to build within city limits. They have taken lessons from Three Mile Island, Chernobyl and Fukushima, emphasizing passive safety systems with multiple layers of redundancy. Coolant circulates through the core naturally, so there are no pumps to fail. A massive water reservoir above the reactor uses gravity to deliver water to the core in the event of coolant loss. The reactor itself has two independent shut-off systems that can be triggered either actively or passively: boron carbide rods inserted into the core manually will absorb radiation; if this can’t be done, the resulting overpressure passively pushes a “neutron poison” into the core, shutting down the reactor.
Designers boast that the new reactor will be able to withstand blackouts, earthquakes, loss of coolant, and run continuously without an operator for months at a time, if necessary. “It is designed to have a life of 100 years,” says the director of the Bhabha Atomic Research Centre, Sekhar Basu. Before heading up the research centre in Mumbai, Sekhar Basu designed the compact reactor at the heart of India’s new fleet of nuclear submarines.