Boiling Water Reactors (BWRs)
The Boiling Water Reactor (BWR) is a type of light water nuclear reactor used for the generation of electrical power. It is the second most common type of electricity-generating nuclear reactor after the pressurized water reactor (PWR), also a type of light water nuclear reactor. The main difference between a BWR and PWR is that in a BWR, the reactor core heats water, which turns to steam and then drives a steam turbine. In a PWR, the reactor core heats water, which does not boil. This hot water then exchanges heat with a lower pressure water system, which turns to steam and drives the turbine. The BWR was developed by the Idaho National Laboratory and General Electric (GE) in the mid-1950s. The main present manufacturer is GE Hitachi Nuclear Energy, which specializes in the design and construction of this type of reactor
Fast Breed Reactors (FBRs)
The Prototype Fast Breeder Reactor (PFBR) is a 500 MWe fast breeder nuclear reactor presently being constructed at the Madras Atomic Power Station in Kalpakkam, India.The Indira Gandhi Centre for Atomic Research (IGCAR) is responsible for the design of this reactor. As of 2007 the reactor was expected to begin functioning in 2010 but now it is not expected to achieve first criticality before October 2017.The Kalpakkam PFBR is using uranium-238 not thorium, to breed new fissile material, in a sodium-cooled fast reactor design. The power island of this project is being engineered by Bharat Heavy Electricals Limited, largest power equipment utility of India.
The surplus plutonium (or uranium-233 for thorium reactors) from each fast reactor can be used to set up more such reactors and grow the nuclear capacity in tune with India's needs for power. The PFBR is part of the three-stage nuclear power program. India has the capability to use thorium cycle based processes to extract nuclear fuel. This is of special significance to the Indian nuclear power generation strategy as India has one of the world's largest reserves of thorium, which could provide power for more than 10,000 years,and perhaps as long as 60,000 years.
The design of this reactor was started in the 1980s, as a prototype for a 600 MW FBR. Construction of the first two FBR are planned at Kalpakkam, after a year of successful operation of the PFBR. Other four FBR are planned to follow beyond 2030, at sites to be defined.
Pressurized Heavy Water Reactors (PHWRs)
A pressurized heavy water reactor (PHWR) is a nuclear power reactor, commonly using unenriched natural uranium as its fuel, that uses heavy water (deuterium oxide D2O) as its coolant and moderator. The heavy water coolant is kept under pressure, allowing it to be heated to higher temperatures without boiling, much as in a typical pressurized water reactor. While heavy water is significantly more expensive than ordinary light water, it yields greatly enhanced neutron economy, allowing the reactor to operate without fuel enrichment facilities (mitigating the additional capital cost of the heavy water) and generally enhancing the ability of the reactor to efficiently make use of alternate fuel cycles.
All the nuclear reactor units of Rajasthan, Kaiga, Kakrapar, Madras and Narora are based on PHWRs. Two of the four units of Tarapur are also based on PHWRs. Also India is ready to sell Pressurised Heavy Water Reactors of 220 MWe or 540 MWe capacity to other countries. These reactors, which use natural uranium as fuel and heavy water as both moderator and coolant, offered a basket of options for countries looking for cost-competitive and proven technologies in the small- and medium-sized reactors.