Competitive Exams: Science and Technology Safety of Nuclear Power Plants in India

Safety of Nuclear Power Plants in India

  1. Nuclear, in light of the Japanese nuclear accident let us take a look at Indian nuclear power reactors.

  2. In India, the Nuclear Power Corporation of India Ltd (NPCIL) currently operates 20 nuclear power reactors with an installed capacity of 4780 MW. Of these reactors, two are BWRs (2 × 160 MW) at TAPs 1 & 2 and others are Pressurized Heavy Water Reactors (PHWRs). The safety of these BWR plants was reanalyzed a few years ago and reviewed by the Atomic Energy Regulatory Board (AERB). Following this, the two BWRs at TAPS 1 & 2 have been renovated, upgraded and additional safety features provide with latest state of art safety standards. The PHWRs are of different design than that of BWRs and have multiple, redundant and diverse shutdown systems and cooling water systems.

  3. The Indian plants have amply testified to their safety during the severe earthquake of Gujarat on 26 January 2001 when the Kakrapar Atomic Power Station continued to operate safety, supplying much needed power to the region. Similarly, during the tsunami event in Tamil Nadu on 26 December 2004, the Madras Atomic Power Station (MAPS) was safety shutdown without any radiological consequences. The plant was restarted in a matter of days after regulatory review. The KKNPP under construction also remained unaffected by the tsunami due to the higher level chosen in design for locating the plant.

  4. In-depth review of all such events has been done for all the plants and necessary reinforcement features based on the outcome of these reviews have been incorporated as a laid down procedure. However, the Japan nuclear accident is being reviewed as information becomes available. Resulting out of such a review, any reinforcements needed in Indian reactors will be implemented. Safety of Nuclear Power Plants in India:

  5. A study of geographic areas combined with an assessment of historical earthquakes allow geologists to determine seismic risk and to create seismic hazard maps, which show the likely Peak Ground Acceleration (PGA) values to be experienced in region during an earthquake, with a probability of exceedance (PE). Seismic engineers and government departments use these values to determine the appropriate earthquake loading for designing important buildings and structures (such as hospitals, bridges, nuclear power plants etc.) In these zones needing to survive the maximum considered event (MCE).

  6. The criteria for assessment of siting of a NPP are specified in the siting code AERB/SC/S and related safety guides published by the Atomic Energy Regulatory Board (AERB). The safety guides detail the acceptable procedures for meeting the requirements laid down by the siting code given above:

  7. To eliminate any risk, in addition to the acceptance criteria, rejection criteria with respect to various hazards for siting of NPPs are also stipulated by the AERB.

  8. After selection of a nuclear power plant sites as per the above stipulated codes and guides of AERB, design and engineering of all the building structures and equipment are carried out and reviewed by highly specialized engineers and scientists. The final designs are again verified by the AERB.

Kudankulam Nuclear Power Project (KKNPP)

  1. The Kudankulam Nuclear Power Project (KKNPP) is a twin unit (2 * 1000 MWe) nuclear power project being built in Kudankulam, Tirunelvelly District of Tamil Nadu (about 25 km from Kanyakumari). The project is being executed under the provisions of the Inter Governmental Agreement signed between the India and the Russian federation.

  2. These WER-1000 reactors belong to the family of Pressurized Water Research (PWRs), which are the predominant type in operation the world over. This type of reactor uses light water as coolant and moderator and enriched uranium (up to 4.4%) as fuel. Reactors have various stateof-art reactor protection and safety system to handle all design basis and beyond design basis events. Some of the very interesting safety features of these reactors are passive systems (that work without any electrical power) for decay heat removal, core cooling in case of loss of coolant, quick boron injection to shut down the reactor, hydrogen recombiners, and melt fuel catcher.

Courtesy: Science Reporter