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Project A-92
Safety
Reliability
Nuclear fuel cycle
Radioactive waste
Protection
of the environment
The Belene NPP project includes construction of two units with a capacity of 1,000 MW each under the А-92 design of the third generation of the most commonly used nuclear reactors in the world - pressurized water reactors.
The technical design of Belene NPP was prepared by the Chief Designer FSUE Atomenergoproekt - Moscow, while Areva NP GmbH was a subcontractor for the electrical systems, control and protection, and other systems.
The technological process of the nuclear power plant in Belene is double-circuit and consists of a nuclear steam supply system (NSSS) based on new generation reactor V-466 design and a turbogenerator installation comprising of a condensing steam turbine and an alternating current generator driven by the steam turbine.
The technological process of the plant is analogous to the well-mastered technology used in the operating units of Kozloduy NPP.
The primary circuit is realized by the NSSS, which includes a pressurized water reactor with a nominal heat output of 3000 MW and four circulation loops.
The secondary circuit includes the steam generators, the main steam pipelines and the condensing steam turbine unit.
The safety strategy of the A-92 design is implemented in 2 levels:
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Improved preventive level of defence in depth by reducing the likelihood of severe accidents using a combination of active and passive safety systems.
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Effective management and reduction of the consequences of any accidents, including complete melting of the reactor core.
The safety strategy is implemented by systematic application of the defence in depth concept, based on implementation of:
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A system of physical barriers to prevent release of radioactive materials into the environment
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A system of technical and organizational measures to protect and to ensure the effectiveness of these barriers as well as for protection of the staff, public and the environment.
For the effective implementation of the concept, safety systems are provided to perform the following functions:
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Emergency reactor shutdown and maintaining of the reactor in a safe sub-critical state
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Emergency heat removal from the reactor and from the used fuel, located in the spent fuel pool
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Retention of radioactive materials within the specified boundaries.
The required high level of safety is ensured by applying the principle of building safety systems in such a way that all basic safety functions are performed by both active and passive safety systems.
In addition, passive systems do not replace, but complement active ones, ensuring the performance of safety functions independently of active safety systems.
In this way, the structure of the safety systems ensures that the safety for each individual function is ensured by at least two completely independent principles, which leads to a qualitatively new, higher level of reliability.
The hermetic protective structure (containment) of the A-92 project is designed as a double one: a primary one made of prestressed reinforced concrete with an inner metal cladding and a secondary one made of ordinary reinforced concrete covered with a spherical dome.
The hermetic protective structure performs the functions of a localizing safety system and represents the last barrier to the spread of radioactive releases into the environment in all operational states and emergency conditions.
As a specific feature of a third-generation reactor, the A-92 design also provides a special system with 100% capacity to deal with a severe accident, involving melting of the core and penetration of the molten core outside the reactor pressure vessel.
In the event of such an accident, the system protects the concrete base of the reactor shaft from erosion, thus preserving the integrity of the hermetic construction and preventing release of the radioactivity into the environment.
This function is performed by a special core catcher, which can be cooled with water from various sources, including from an external source. As a result, the melt stabilizes in the core catcher and solidifies within 3-5 days.
Design solutions for protection against natural phenomena and events are based on the criteria that, when considering the effects of natural phenomena in the design of safety important structures, systems and components (SSC), such as earthquakes, tornadoes, hurricanes, floods, tsunamis and more, the SSC ability to perform assigned safety functions shall be maintained.
In 2011, as a result of the accident at Fukushima NPP, the Belene NPP project was analyzed according to the methodology for safety reassessment of the conditions of extreme natural phenomena that could lead to severe accidents („stress tests“ of the design).
The general conclusions from the evaluations and assessments carried out, are that, in the design of Belene NPP, initiating events that go beyond the design basis are properly addressed by availability of both active and passive systems for severe accident management and major radioactive releases to the environment will be prevented:
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The design provides appropriate safety systems, the automatic operation of which maintains or restores the critical safety functions in case of accident conditions that go beyond the design basis.
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Severe accident management principles, incorporated in the design, are in conformity with the requirements towards last generation NPPs and respectively the design provides for the required technical measures to ensure implementation of the procedures for severe accident management.
Based on the completed analysis, proposals were made for some possible measures to further increase of the design reliability.
In December 2011, an international expert team of the IAEA carried out a peer review of the report on "stress tests" of the Belene NPP project.
According to the conclusions of the international experts, Belene NPP design ensures adequate technical provisions to cope with the entire spectrum of accidents, which should be considered by the design of the latest generation of NPPs (III +).
The design nuclear fuel cycle of Belene NPP foresees the following well defined activities:
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Supply of fresh nuclear fuel from the fuel supplier;
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Storage of the spent fuel in wet type storage;
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Storage of the spent nuclear fuel on the site in dual purpose containers – for storage and for transportation;
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Transportation of the spent fuel for reprocessing.
The project envisages the construction of a dry storage facility on the site, with an initial capacity for 10 years of operation of the two units and the possibility of expansion for the entire period of operation of the plant.
According to the requirements set up to the plant design, the annual amount of radioactive waste (RAW) generated during the operation of Belene NPP should not exceed 50 m3 / year.
To fulfill this requirement, the project envisages various technological systems for minimizing the quantities of RAW and bringing them in a form that meets the state-of-the-art requirements for storage of conditioned RAW.
The project envisages the construction of a repository, within the NPP site, for storage of RAW packaged in containers for a 10-year period, with the possibility of expanding it for the entire period of operation of the two units.
Nuclear power plants produce 86 million times less waste than fossil fuel power plants.
Like other nuclear power plants, Belene NPP will produce electricity without greenhouse gas and anthropogenic gas emissions.
For the 60 years of operation, Belene NPP will save humanity:
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1 billion and 52 million tons of carbon dioxide;
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7 million tons of sulfur oxides and almost 2 million tons of nitrogen oxides;
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762 thousand tons of dust.
The nuclear industry assumes full responsibility for all waste products from its activity, and from the first kilowatt-hour produced it includes in its production cost all costs for management of spent nuclear fuel and radioactive waste, as well as costs for decommissioning and reclamation of the site to a green field.