Kakrapar Atomic Plant Achieves Criticality

• 23 Jul 2020

Why in News

Recently, the third unit of the Kakrapar Atomic Power Project (KAPP-3) in Tapi district of Gujarat achieved its first criticality.

Key Points

• Criticality:
  
  • Criticality is the first step towards power production. A nuclear reactor is said to be critical when the nuclear fuel inside a reactor sustains a fission chain reaction.
  • Each fission reaction releases a sufficient number of neutrons to sustain a series of reactions. Heat is produced in the event, which is used to generate steam that spins a turbine to create electricity.
    
    • Fission is a process in which the nucleus of an atom splits into two or more smaller nuclei, and some byproduct.
    • When the nucleus splits, the kinetic energy of the fission fragments (primary nuclei) is transferred to other atoms in the fuel as heat energy, which is eventually used to produce steam to drive the turbines.
• KAPP-3:
  
  • KAPP-3 is the country’s first 700 MWe (megawatt electric) unit, and the biggest indigenously developed variant of the Pressurised Heavy Water Reactor (PHWR).
    
    • Until now, the biggest reactor size of indigenous design was the 540 MWe, two of which have been deployed in Tarapur, Maharashtra.
    • A 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.
    • PHWR technology was started in India in the late 1960s with the construction of the first 220 MWe reactor, Rajasthan Atomic Power Station (RAPS-1).
  • State-owned Nuclear Power Corporation of India Ltd (NPCIL) had awarded the reactor-building contract for both KAPP-3 and 4 in 2010.
• Safety Features:
  
  • The 700 MWe PHWRs have advanced safety features like steel lined inner containment, passive decay heat removal system, containment spray system, hydrogen management system, among others.
    
    • The ‘passive decay heat removal system’ can remove decay heat (released as a result of radioactive decay) from the reactor core without requiring any operator actions.
    • This is on the lines of similar technology adopted for Generation III+ plants to negate the possibility of a Fukushima-type accident that happened in Japan in 2011.
• Significance:
  
  • KAPP-3 addresses the issue of excess thermal margins.
    
    • Thermal margin refers to the extent to which the operating temperature of the reactor is below its maximum operating temperature.
  • KAPP-3 would constitute the biggest component in the nuclear power capacity expansion plan.
    
    • India is working to ramp up its existing nuclear power capacity of 6,780 MWe to 22,480 MWe by 2031.
    • Currently, nuclear power capacity constitutes less than 2% of the total installed capacity of 3,68,690 MW (end-January 2020).
  • It will also help for the future construction for the PHWRs.

Nuclear Power Corporation of India Limited

• The Nuclear Power Corporation of India Limited (NPCIL) is an Indian public sector undertaking, Headquartered at Mumbai.
• It is wholly owned by the Government of India and is responsible for the generation of nuclear power for electricity.
• NPCIL is administered by the Department of Atomic Energy (DAE).

Source: IE