Rajasthan Atomic Power Station : The Rajasthan Atomic Power Station (RAPS, also Rajasthan Atomic Power Project - RAPP) is located at Rawatbhata in the state of Rajasthan.

Background :

India started building nuclear power plants in the 1960s and continued to add more units progressively to meet the growing demand for electricity. Today, India has 14 operating nuclear power units with a total installed capacity of 2770 MWe. Starting the first unit in Tarapur in 1969, to commissioning of four units at Kaiga and Rajasthan in the year 2000, India has made significant advancements in this arena.  The Rajasthan Atomic Power Station, or RAPS, is located in the Northern grid and has the country's largest nuclear power plant. It has six nuclear power reactors at present with the total installed capacity of 1,180 MW.  Located in Rawatbhata, a remote village in the Chittorgarh district, RAPS I and RAPS I are the first two Indian Pressurized Heavy Water Reactors (PHWR).

History :

The construction of the Douglas Point Nuclear Generating Station Canada began in 1961 with a CANDU (CANada Deuterium Uranium) pressurised heavy water reactor (PHWR) capable of producing 220 MW of electricity. Two years after construction of the Rajasthan Power Project (RAPP) commenced, with two similar reactors built in the state of Rajasthan. Ten years later, in 1973 RAPS-1 was put into service. In 1974 after India conducted Smiling Buddha, its first nuclear weapons test Canada stopped their support of the project, delaying the commissioning of RAPS-2 until 1981.

In the context of the Indian atomic program, two more PHWR with an output of 220 MW each were built. They cost around 570 million dollars. RAPS-3 became critical on 24 December 1999, RAPS-4 became critical on 3 November 2000. Commercial operations began on 1 June 2000 for unit 3, and on 23 December 2000 for unit 4.

Two more reactors (RAPS-5 and RAPS-6) with 220 MWe have also been built, with unit 5 beginning commercial operation on 4 February 2010, and unit 6 on 31 March 2010. Two of the new Indian-designed 700 MWe series of reactor (RAPP-7 and RAPP-8) are under construction at Rajasthan.

In November 2012, the International Atomic Energy Agency (IAEA) intensively audited over several weeks two reactors at the Rajasthan Atomic Power Station for safety. It has concluded that the reactors are among the best in the world, the indigenously made 220 MW atomic plants can withstand a Fukushima type of accident, even suggesting that the "safety culture is strong in India" and that India emerged a winner with a high global safety rank.

First concrete for unit 7 was poured on 18 July 2011, with commercial operation expected by 2016. The two reactors will cost an estimated Rs 123.2 billion (US$2.6 billion).

Safety Issues :

RAPS I and II PHWRs have had various safety issues. Turbine blade has been one common issue. In 1981, RAPS I was shut down twice because of oil leakage in the turbine building. This leakage led to high levels of sparking in the generator exciters; after the initial shut down, it was later found that large amounts of oil had leaked form the turbine governing system. Later after reopening, it was discovered that there were high vibrations of the turbine bearings and the blades were failing; the ensuing shutdown and repair of the plant took another five months. In 1983 it was discovered that the temperatures were too high in the turbine bearing, and two plates in the second stage of the high-pressure rotor had sheered off at the root. RAPS I was further shut down in 1985, 1989, and 1990. In May 1998, titriated heavy water with levels of tritium above levels set by the AERB ( Atomic Energy Regulatory Board ) was released from RAPS II into the Rana Pratap Sagar Lake; the release was due to a leak in the moderator heat exchanger. However, the public did not know about this occurrence until December 1999.

 Yet, some upgrades have occurred in recent years. As part of the replacement of the pressure tubes in RAPS II, significant upgrades were performed to bring the safety systems to current standards. These include changing the containment dousing system with a fixed dousing flow rate, an enhanced Emergency Core Cooling System, the addition of a supplementary control room, a modification to the air flow valve system to minimize instrument air in-leakage in containment, and improvements to the station electric power supplies with a third diesel generator