Finnish Nuclear Society publishes a quarterly
magazine ATS Ydintekniikka. ATS Ydintekniikka has been issued
since 1972, and it is still the only regularly published magazine
in Scandinavia covering nuclear engineering. The theme of ATS
Ydintekniikka issue 3/2005, from which the following article has
been extracted, was Olkiluoto 3 construction. More information:
Chief Editor Kai Salminen, email: email@example.com.
The EPR Becomes Reality at Finland's Olkiluoto
Background to Decision
In 1998, the two Finnish nuclear plant operators
– TVO and Fortum Power and Heat Oy – came to the conclusion
that the growth in the demand for electricity of around 25% predicted
to take place in Finland by the year 2015 could best be met by
building a new nuclear power plant. This view was based on a number
of studies, including one of the economics of different power-generating
technologies which showed that a new nuclear pl
ant was the most cost-effective option. Another
factor favoring nuclear power was that it would reduce the Finnish
power market's dependence on power purchases, for the country
presently imports more than 70% of its electricity. Furthermore,
the use of nuclear energy – a carbon-dioxide-free energy
source – would make it easier for Finland to meet its commitments
under the Kyoto Protocol.
In November 2000, TVO applied to the
Finnish Ministry of Trade and Industry for a decision
in principle according to the Finnish Nuclear Energy Act.
This had been preceded by environmental impact assessments
prepared for the two candidate sites – Olkiluoto
in southwestern Finland and Loviisa on the south coast
– and reviewed by the Ministry. In January 2002,
after an extensive official consultation procedure, the
Finnish Government's Council of State reached its decision
in principle in favor of a new nuclear unit. The decision
was ratified by Parliament in May of that year.
Affordable climate protection:
the EPR (foreground) will become a reality at Olkiluoto
in Finland in 2009.
Power generating costs of new nuclear power plants
according to Professor Risto Tarjanne, Lappeenranta University
In October 2002, four months after ratification
by Parliament, TVO issued a request for proposals for Finland’s
fifth nuclear unit, which called for a PWR or a boiling water
reactor (BWR) with a rated capacity of between 1000 and 1600 MW.
On March 31, 2003, TVO received proposals from
various vendors, including Framatome ANP that had formed a consortium
with Siemens. After carefully evaluating these proposals and clarifying
further technical aspects with all of the bidders, TVO announced
on October 18, 2003 that the Framatome ANP/Siemens Consortium
was the preferred bidder. TVO had concluded that, in terms of
future power generating costs, the EPR represented the most cost-effective
solution. At the same time, it was announced that the new power
plant unit would be built at the Olkiluoto site.
On December 18, 2003, the contract was signed
in Helsinki. It officially came into effect on January 1, 2004.
In parallel with this, the documentation required for obtaining
a construction license under the Finnish Nuclear Energy Act was
submitted to the Finnish Radiation and Nuclear Safety Authority
(STUK) and initial preparation of the construction site was commenced.
After reviewing these documents, STUK concluded in its preliminary
safety assessment for the Finnish Ministry of Trade and Industry
that it did not see any safety-related issues opposing issuance
of the nuclear construction license. STUK emphasized that the
evolutionary design of the EPR had been further improved by AREVA
compared to the previous product lines. This led to the Finnish
Government granting the construction license on February 17, 2005.
Framatome ANP's scope of supply and services
encompasses the nuclear island, including the design, procurement
and delivery of all of its mechanical and electrical equipment,
installation and initial startup, the fuel assemblies for the
first core and an EPR simulator. Furthermore, the company is responsible
for overall project coordination as well as for functional and
technical integration of the overall plant, and is also head of
Siemens is responsible for supplying the conventional
island, including the design, procurement and supply of all of
its electrical and mechanical equipment, as well as the turbine
and generator protection and control systems, and installation
and initial startup of the turbine generator set.
A significant proportion of the engineering,
construction and erection work, as well as the supply of mechanical
and electrical equipment, will be placed with subcontractors after
an international bidding process. Of course, Finnish companies
will also be able to participate in this bidding. If their proposals
should prove to be competitive at an international level they
will likewise be given consideration during the proposal evaluation
phase so that a large portion of the supplies and services for
the project could be remaining in the country. Quite appreciable
work packages have already been contracted out to Finnish companies.
They are also profiting from the fact that orders awarded to companies
outside Finland lead, in turn, to work being placed with Finnish
subcontractors so that, in the end, a substantial portion of the
total project value will be remaining with Finnish industry. Further
requests for proposals are scheduled to be issued in the course
of this year as well as at the beginning of the next year.
Current Project Status
Following completion of the excavation work that
had been carried out by Finnish contractors employed by the customer,
the Framatome ANP/Siemens Consortium took over the site on February
Early in the summer of 2004, the consortium had
already placed several major orders with Finnish companies. These
orders covered the concrete mixing plant and the detailed design
of the base slab of the reactor building complex as well as construction
of the common raft foundation. In addition to this, supplies for
the site infrastructure (office building and canteen, etc.) were
also ordered from Finnish companies. The concrete mixing plant,
which was erected directly on site, will have supplied a total
of around 250,000 cubic meters of concrete via permanently installed
pipelines and concrete mixer trucks by the time construction is
finished. It was placed in operation in the spring of 2005 so
that work could be started on pouring the leveling concrete.
In 2004, an order was also placed for a heavy-lift
crane with a load-carrying capacity of 1600 metric tons required
for the construction and erection work.
The largest single orders for construction work
went to companies based in France and Germany. However, significant
portions of these volumes of work will be coming back again to
Summer 2005: Situation on site looking at
the basemat of the reactor building
On July 15, the first sections of metallic
liner for the inside of the reactor containment building
arrived by the sea at the Olkiluoto 3 construction site.
Birth of the EPR and its Development Goals
Framatome of France and Germany’s Siemens
began developing the EPR in 1992 on behalf of and with significant
support from the French national utility Electricité de
France (EDF) and leading German utilities. The project was closely
monitored and supported by licensing authorities and independent
inspection agencies in both countries to ensure the EPR's licensability
in France and Germany. Through the Olkiluoto 3 project, the EPR
is now being fully licensed for the first time by the Finnish
The EPR builds on proven technologies deployed
in the two countries' most recently built nuclear power plants
– the French N4-series units and the German Konvoi-series
plants – and constitutes an evolutionary concept based on
these designs. This enables full use to be made of all of the
reactor construction and operating experience gained not only
in France and Germany – with their total of 2070 reactor
operating hours – but also worldwide. Guiding principles
in the design process included the requirements elaborated by
European and US electric utilities for future nuclear power plants,
as well as joint recommendations of the French and German licensing
The key development goals were:
To further increase safety and, at the same time,
To further improve economic performance.
Even Greater Safety
Safety levels at nuclear power plants have been
constantly improved in the past. The EPR, a nuclear reactor of
the third generation, represents yet another step forward in terms
of safety technology, offering in particular the following features:
Improved accident prevention, to reduce
the probability of core damage even further,
Improved accident control, to ensure that
– in the extremely unlikely event of a core melt accident
– the radioactivity is retained inside the containment
and the consequences of such an accident remain restricted
to the plant itself,
Improved protection against aircraft crash,
including large commercial jetliners.
Measures providing superior accident prevention
capability include a larger water inventory in the reactor coolant
system and the steam generators, a lower core power density, and
high safety-system reliability thanks to quadruple redundancy
and strict physical separation of all four safety system trains.
The plant design also incorporates state-of-the-art digital instrumentation
& control (I&C) systems along with optimized man-machine
If a core melt accident should occur despite
all of the accident prevention measures deployed, the molten core
material (corium) will be collected and cooled in a specially
designed corium spreading area located underneath the reactor
pressure vessel but still inside the containment. The extremely
robust double-walled containment will reliably keep any radioactivity
confined inside the building.
Probabilistic safety analyses were incorporated
from the outset into the design process in order to determine
those accident sequences capable of leading to severe core damage
or significant releases of radioactivity, to evaluate their probability
of occurrence and to implement design features that would further
reduce their contribution to the overall risk.
The following factors contribute towards making
the EPR's power generating costs even lower than those of the
most recently built nuclear power plants currently in operation:
Larger net electric output of around 1600 MW: this leads
to lower specific construction costs
Higher secondary-side pressure of 78 bar:
this in conjunction with an optimized turbine design results
in an efficiency of more than 37% under Finnish conditions
– the highest efficiency of any light water reactor
plant in the world
Shorter construction period of 48 months
Extended design plant service life of 60 years
Higher fuel utilization with a discharge
burnup of more than 60 GWd/t: this means reduced uranium consumption
and lower spent fuel management costs
Greater ease of maintenance thanks to improved
accessibility and standardization, with preventive maintenance
being possible while the plant is on line
Shorter refueling outages leading to higher plant availability.
Factors aimed at ensuring the longest possible periods of uninterrupted
power operation with minimal downtime comprise:
Fuel operating cycles of up to 24 months
Short refueling outages, even when extensive maintenance
work is necessary
Plant availability ratings of more than 90%.
The EPR Design
The reactor building, two of the four adjacent
safeguard buildings and the fuel building will be of double-walled
design to enable them to withstand the loads induced by natural
and external man-made hazards (particularly aircraft crash).
The EPR has a slightly higher reactor thermal
output than other PWRs currently in operation. The deployment
of steam generators with economizer sections along with an advanced
steam turbine design will lead to higher efficiency. In addition,
core coolant flow has been maximized based on operating experience.
Safety systems directly connected to the reactor
coolant system which serve to inject coolant into the system in
the event of a loss-of-coolant accident (LOCA) are designed with
The emergency core cooling systems comprise
four passive accumulators as well as four low- and intermediate-pressure
safety injection systems.
In addition to the systems for residual heat
removal that are connected directly to the reactor coolant system,
a further system designed to assure heat removal in the event
of loss of normal feedwater supply is connected to the secondary
system. This consists of a four-train emergency feedwater system
that supplies water to each steam generator. The emergency feedwater
system on the secondary side is equipped with electric-motor-driven
pumps that can be powered, if necessary, by the unit's four large
emergency diesel generators. In addition, the plant is also equipped
with small, separate diesel generators to ensure that feedwater
supply to the steam generators is guaranteed even in the event
of simultaneous failure of all four of the large emergency diesels.
In the steam generators, the heat generated
in the reactor is used to produce steam for driving the turbine.
This steam is then condensed in the turbine condenser. If the
condenser should be unavailable due to loss of the main heat sink,
the excess steam can be directly discharged to the atmosphere
from the steam generators.
The in-containment refueling water storage tank
serves to store water for emergency core cooling and accommodates
any leakage water discharged via a pipe break in the reactor coolant
Major safety features of the EPR.
Reactor thermal output:
Net electric output:
approx. 1600 MW
Main steam pressure:
Main steam temperature:
Reactor pressure vessel height:
Reactor core height:
Number of fuel assemblies:
Uranium inventory in reactor:
Number of control rods:
Containment inside width:
Outer Containment wall thickness:
To meet the requirements of the nuclear safety
authorities, additional provisions for preventing beyond-design
events were incorporated right from the start into the EPR design.
These comprise, in particular, backup functions deployed on a
systematic basis to further enhance safeguards for accident prevention.
If an entire accident control function should fail, diverse actions
will be implemented to achieve the same safety objective. What
does this mean in concrete terms? For example, if all four redundant
intermediate-pressure safety injection trains should be lost after
a small-break LOCA, the residual heat from the reactor core can
alternatively be removed via the secondary system, and the pressure
reduced to a level at which the passive accumulators and low-pressure
safety injection pumps can feed emergency coolant into the reactor.
Hence, even in the extremely unlikely event of complete loss of
all four redundant subsystems, the accident can still be controlled
in such a way that destruction of the core is ruled out.
The safety authorities require that, despite
all enhancements incorporated into the EPR design for accident
prevention, provisions nevertheless be made to control all events
that could possibly lead to melting of the core following a postulated
loss of all safety systems, the aim of this being to prevent catastrophic
impacts on the environment. In the case of the EPR this primarily
meant providing engineered safeguards that would prevent destruction
of the containment in the event of a postulated (hypothetical)
core melt accident. These safeguards comprise, in particular,
reactor coolant system depressurization, a special reactor pit
design, core melt stabilization, the design of the containment,
containment heat removal and hydrogen reduction.
Better Radiation Protection for Personnel
In the course of designing the EPR, improvements
were also made to the protection of operating and maintenance
personnel against radiation. The target is a collective radiation
dose of less than 0.4 person-Sieverts (pSv) per reactor unit and
year (by way of comparison: up until now the limit in the West
has been 1 pSv).
Nuclear Power Has a Future
The construction of Olkiluoto 3 in Finland has
sparked off discussions about new construction projects in other
European countries as well. The decision made by the private investor
TVO to build a new nuclear power plant underscores the fact that
nuclear technology plays an important role in liberalized power
markets as an economical solution for CO2-free base-load power
generation. The French utility Electricité de France (EDF)
likewise decided – in October 2004 – to construct
an EPR at Flamanville in Normandy. The key concern in France is
to ensure the availability of a reliable energy technology in
the long term: the project at Flamanville is to serve as a basis
for a new series of nuclear units to replace French plants reaching
the ends of their service lives from 2020 onwards.
The USA is following a similar strategy and
has made a long-term commitment to nuclear energy. The service
lives of many of its nuclear power plants are currently being
extended and in addition the Bush Administration, together with
the US utilities, is actively pursuing plans to launch the construction
of a new nuclear unit before the end of this decade. In Asia,
too, nuclear energy's share of the power-generating market is
being deliberately expanded: China alone is planning to construct
more than 30 GW of additional nuclear-based power-generating capacity
by the year 2020, which means around 20 new state-of-the-art reactors.
Energy experts predict that the demand for new
and replacement generating capacity in the Central and Western
European power plant market will reach 400,000 MW by 2020, with
the demand for new capacity set to reach similar levels in Eastern
Europe. A significant proportion of this additional capacity will
be needed for base-load service. Thanks to its economic efficiency,
climate-friendliness and long-term reliability, nuclear power
will continue to play a crucial role in the energy mix.
With the EPR, AREVA is in an excellent position
to meet the needs of this large market, just as the Finnish contract
– won in the face of stiff international competition –
Framatome ANP GmbH,