Why the Bulgarian Nuclear Society insist that
the “small units” at Kozloduy NPP remain operational.
By Ruscho Yankov, Deputy Chairman of the Bulgarian
The Kyoto Protocol, which was signed in December
1997 in Kyoto, Japan, under the auspices of the United Nations,
was the political beginning of the process for limiting and reducing
the emitting of greenhouse gasses into the atmosphere. For the
first time in the world the Clean Development Mechanism is being
implemented with the objective of investing in environmental
projects that reduce greenhouse gas emissions in developing countries.
The financing of these projects is provided through the punitive
sanctions imposed on industrialized countries and countries
in transition, including Bulgaria, which are in breach of their
With regards to the process of Bulgaria’s
accession to the European Union, the World Bank has estimated
that the environmental protection costs to be paid by our country,
by the year 2015, will amount to 6,1 - 8,6 billion €. Part
of these costs result from the country's commitment to reducing
its greenhouse gas emissions, the main source of which are conventional
fossil-fired plants and vehicles that run off organic fuels.
One of the fundamental components of Bulgaria’s economic
competitiveness is the development of cheap and clean electricity.
Today, this is impossible without nuclear power’s environmentally
friendly profile and virtual inexhaustibility. The shutting down
of the first four units at Kozloduy NPP, with the environmental
consequences that this decision provoked in different regions
of our country, underlined the truth of this statement.
Our NPP, the only one in operation for the time being, employs
a WWER (Water – Water Energetic Reactor) first and second
generation reactor type that is analogous to a PWR type (pressurized
water reactors) reactor that is widely used in Western countries.
Its units have been operating for more than 100 reactor years
and over that period they have proven their operational reliability
and safety as a source of cheap electricity providing the main
base load for the country’s electricity grid.
Nevertheless, at an early stage of reactor design the “small” units
(WWER-440/ V230) demonstrated a number of innovative solutions,
which provided a basis for the design of the next generation
of reactor units.
The design of the reactor unit incorporated a number of design
and engineering solutions that ensured its "interior self-protection" and
provided a high level of plant safety and reliability. These
were as follows:
a high level (to maximum design safety
margins) of reactor core thermal reliability
high reliability of the reactor with regards to possible deviations
from basic operational parameters (self-regulation)
stable natural circulation of primary coolant, allowing removal
of up to 9% of the reactor thermal power in emergency modes
a high level of redundancy of heat removal system – 6
a large water reserve in the steam generators, allowing
long-term residual energy removal without feed/after reactor
use of high-strength steel for the reactor pressure vessels
use of high plastic-stainless steel for the primary equipment
and pipes, which allows the application of the “Leak- Before
two turbine generators, which allow continuous operation at power
rate different from the nominal rate
The advantages of the Kozloduy reactors are best described by
Western European Nuclear Regulator’s Association (WENRA)
in its report of 1999. “…When
assessing the safety of a WWER-440/230 nuclear power plant it
be pointed out that these reactors similar to all WWER 440 reactors
intrinsic safety parameters surpassing those of the modern western
…The amount of coolant per
megawatt is two times than the amount of coolant in any western
… These safety parameters provide
efficient protection against potential deteriorating of the
most transients into more severe accidents.”
The NPP is a capital-intensive installation – approximately
2000€/megawatt generating capacity. Experience in the developed
nuclear countries has shown that the continuous operation of
reactors, under guaranteed safety conditions, is cost-efficient
- costing approximately one tenth of the initial investment.
The WWER – 440 Model 230 reactors, which have been installed
in Russia, have already been granted a license for the extension
their operational life time for a further 15 years after modernization.
In 2002 the International Atomic Energy Agency (IAEA) visited
Bulgaria in order to review the implementation of recommendations
for the design of “small" units. Based on its review
of the results the IAEA team declared that the operational and
design safety of Units 3&4 at Kozloduy NPP were in compliance
with the safety standards achieved by the plants of the same
generation. They also reported that most of the measurements
carried out exceeded the scope of recommendations made for the
plant design, operation and seismic performance, and that the
plant personnel was highly qualified and personally committed
to the improvement of operational safety. This constituted a
guarantee for the continuation of this trend. This disproved
the claim made by the experts from G-group that such units “can
not be modernized” at a reasonable cost.
Bulgaria, with its well established traditions and culture,
human potential, natural resources and production capacities,
is already a full member of the European Union. Kozloduy NPP
is the pearl of our power sector, thus our country ranks deservedly
with developed nuclear countries that ave advanced electricity
generation technologies. The plant’s long-term operational
safety gives good grounds for the construction of new nuclear
This is why the Bulgaria Nuclear Society, since it was established,
has defended the ''small units" at Kozloduy NPP and has
voiced its conviction that it is the duty of every Bulgarian
citizen to protect the country's national wealth. There are no
sound arguments for the “Mercedes” of our national
power sector to be being “kept in the garage” while “Trabants” continue
to emit ash and poisonous gases onto the nation’s roads.
All experts in this field, most Bulgarian citizens and most
European citizens have been convinced of this for a long time.
The time has come to convince European Union politicians as well.