First Reactor in Kudankulam sopped for fuel replacement

First Reactor in Kudankulam sopped for fuel replacement

Subject : Science & tech

Context :The first reactor of Kudankulam Nuclear Power Project (KKNPP) was stopped at 8.30 a.m. on Tuesday for the scheduled and mandatory annual fuel replacement.

Concept :

• The exercise, which was done last time from May 31, 2020, is expected to last 45 to 60 days for replacing 33% of the spent fuel with enriched uranium fuel bundles. The process is done by fully automated refuelling equipment.

Kudankulam Nuclear Power Plant

• KKNPP is the single largest nuclear power station in India.
• It is situated in Koodankulam in the Tirunelveli district of Tamil Nadu.
• It is scheduled to have six VVER-1000 reactors with an installed capacity of 6,000 MW of electricity.
• It has been built in collaboration with Atomstroyexport, the Russian state company and NPCIL.
• Unit 1 and 2 have started generating electricity
• Unit 3 and 4 are under construction.

PRESSURIZED HEAVY WATER REACTORS (PHWR)

• Natural Uranium is used as a fuel and heavy water as a coolant and moderator
• The 0.7% U-235 undergoes fission to release energy. As the remaining 99% U-238 is not fissionable, it undergoes transmutation and forms Plutonium-239(Pu-239).

Working of the reactor –

• The heat is removed from the reactor by water flowing in a closed pressurised loop
• The heat is transferred to a second water loop through a heat exchanger.
• The second loop is kept at a low pressure allowing the water to boil and create steam, that is used to turn the turbine-generator
• Then the steam is condensed into water and returned to the heat exchanger

VVER – Reactors

• The water-water energetic reactor (WWER) or VVER is a series of pressurized water reactor designs originally developed in the Soviet Union, and now Russia, by OKB Gidropress.
• Two Russian-built VVER-1000 reactors have been in commercial operation in Kudankulam, southern India, since 2014 and 2017 respectively.