Finland takes to VVER reactors
Photo: A. Shaikmohideen
Ensuring safety: The Kudankulam reactors incorporate unique safety systems to take care of even beyond-design based accidents. —
Finland, the only European country, currently constructing a 1,600 MWe nuclear power reactor started its tryst with nuclear energy by adopting the Russian VVER technology.
Water-cooled, water-moderated reactors (VVERs) underwent up-gradations to ensure that they comply with the safety standards comparable to reactors designed by Western nations. The reactors at Kudankulam belong to the third generation VVER. Their desig
n employs many novel systems and engineered safety features.
Accident prevention
The reactors have both active and passive safety systems to prevent accidents and or to mitigate their consequences.
The safety system used for long-term recirculation of coolant during a loss-of-coolant accident and decay heat removal can carry out multiple functions. It removes core heat following reactor shut down, provides cooling of spent fuel pool water and performs low-pressure emergency core cooling during a loss-of-coolant accident.
The Kudankulam reactors incorporate unique safety systems such as core catchers to take care of even beyond-design based accidents.
AERB’s review included the design of the containment liner, the ultimate barrier against release of radioactivity to ascertain its integrity under normal and accident conditions.
The first VVER 440 plants in Finland, though built by Soviet Atomenergoeksport, were fitted with Western instrumentation and control (I&C) systems. Was there any concern about this development?
How did the regulatory body assure safety in this case? I asked Jukka Laaksonen, Director General of Nuclear and Radiation Safety Authority in Finland.
“The VVER-plants built in Loviisa were re-designed to meet Finnish safety requirements ...from the regulators point of view it did not make much difference who was the I&C supplier.” Laaksonen clarified. They assessed the capabilities of the supplier and reviewed the systems design as usual in their regulatory practice.
Laaksonen recently attended the International Conference on Topical Issues in Nuclear Installation Safety (Nov 17-21) at Mumbai.
Evaluation time
Russians have now acquired appropriate I&C technology. Indian reviewers spent considerable time in evaluating the different systems before approving them.
According to Laaksonen, the average capacity factor of the Finnish plants over a time span of 25 years until today has been about 92 per cent.
Though Finnish Parliament rejected nuclear power earlier, it permitted construction of the new plant after prolonged discussions. After listening to 85 experts, it voted 108-91 in favour.
Green signal
“Since then, the public and political views have turned still more positive, and it is expected that the next plant will be approved easily. The question is only how many new plants will get the green signal because there are three applications in and each of them by a different company”, Laaksonen noted.
Today Finland remains the new beacon for nuclear power in Europe!
K.S. PARTHASARATHY
Former Secretary, AERB
( ksparth@yahoo.co.uk
)
Corrections and Clarifications
With reference to an article "Finland takes to VVER reactors" ("Science &
Technology" page, December 4, 2008) the author Mr. K.S. Parthasarathy,
former Secretary, AERB, clarifies: "The title of my article gives the wrong
impression that the reactor now under construction in Finland is a VVER. The
1,600 MWe reactor now under construction is Framatome ANP's European
Pressurised water Reactor (EPR).This reactor was selected on the
consideration of cost. Finland has not chosen VVER technology for all its
reactors. Finland's first two reactors built in 1977 and 1981 were VVERs;
the other two reactors (1979 and 1982) are Boiling Water Reactors. For its
sixth reactor, it is interested in Russia's new 1,150 MWe version of the
well-proven VVER-1000 (AES-2006) along with Toshiba's ABWR and GE-Hitachi's
ESBWR."
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