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At the end of July, the loading of the floating power unit Akademik Lomonosov with nuclear fuel started in Murmansk. This is one of the key stages of the project, which as of today has no analogues in the world. In 2019, the power unit will begin to supply local population and industrial facilities in North-Eastern Siberia with heat and electricity. The project is expected to open up opportunities for the mass production of floating nuclear power plants – a number of countries have already voiced their interest.

On July 25, the Russian city of Murmansk, the largest non-freezing seaport in the world and the largest city above the Arctic Circle, saw the start of the loading of nuclear fuel into the reactors of the world’s only floating nuclear power unit (FPU) Akademik Lomonosov. The project, named after the outstanding Russian scientist and laid down back in 2006, is the first in a series of mobile transportable small-capacity power units. It is designed to operate as part of a floating nuclear thermal power plant (FNPP) and represents a new class of energy sources based on Russian technologies of nuclear shipbuilding.

The Akademik Lomonosov is intended for the regions in the High North and the Far East. Its main goal is to provide energy to remote industrial facilities, port cities, as well as gas and oil platforms located on the high seas. The permanent mooring site of the floating NPP will be the Siberian city of Pevek on the Chukchi Peninsula in the northeastern extremity of Eurasia. The new plant will replace there two technologically obsolete generation facilities: Bilibino NPP and Chaunskaya CHPP. After being brought into operation, the Akademik Lomonosov will become the northernmost nuclear power plant in the world.

In the spring of this year, the floating power unit was towed from the territory of the Baltic Shipyard, where its construction was carried out from 2009, to the base of Atomflot in Murmansk. During its transportation, the ship 144 meters long and 30 meters wide travelled the 4000 km route through the waters of four seas – the Baltic Sea, the North Sea, the Norwegian Sea and the Barents Sea – around the Scandinavian Peninsula and along the coasts of Estonia, Sweden, Denmark and Norway. On May 19, the Akademik Lomonosov was successfully moored in Murmansk, where it was presented to the public in a ceremonial atmosphere.

Vitaliy Trutnev, Head of Rosenergoatom’s Directorate for the Construction and Operation of FNPPs, commented on the current status of the project development: “Here in Murmansk, we finalize the remaining technological operations. Specialists have begun to implement one of the most important tasks – the stage-by-stage loading of nuclear fuel into the reactor plants. The next key stages that are planned to be implemented before the end of this year will be the physical launch of the reactors and the beginning of complex mooring tests - after obtaining the appropriate Rostekhnadzor permits (Federal Service for Environmental, Technological and Nuclear Supervision – author's note).

The FNPP project is based on the technology of small modular reactors (SMRs) – this category, according to IAEA classification, typically includes reactors with electrical power up to 300 MW. A characteristic feature of the majority of such designs is the integrated layout of the reactor plant, in which the active zone, the steam generator, the pressure compensator and a number of other types of equipment are assembled in a single unit – a factory-finished monoblock delivered ready-made to the site. This technology has been known since the 1960s: for instance, the U.S. floating nuclear power plant Sturgis was used for ten years to provide energy to the Panama Canal in case of a threat of an intentional failure of the ground-based power supply system, but it was decommissioned in 1976. To date, despite the existence of many similar developments in the world, the Akademik Lomonosov is the only floating power unit in the world, which gives uniqueness to the Russian project.

The FPU is equipped with two KLT-40S icebreaker-type reactors with a capacity of 35 MW each – together they are able to produce up to 70 MW of electricity and 50 Gcal/h of heat energy in the nominal operating mode, which is enough to support the life of a city with a population of about 100 thousand people. In addition to the floating power unit itself, the structure of the FNPP project 20870 includes hydrotechnical facilities that provide installation and detachment of the FPU and transfer of generated electricity and heat to the shore, as well as onshore facilities for transmitting this energy to external networks for distribution to consumers. Currently, specialists are working on the creation of this infrastructure in Pevek.

One of the main features of the project being implemented is the placement of two reactor units in a small hull of the vessel while preserving all the functional characteristics of the ground-based nuclear power plant with fewer maintenance personnel. At the same time, the highest reliability and safety of operation is provided with no environmental impact.

The floating power unit is supposed to have a lifespan of from 35 to 40 years. For its operation, low-enriched uranium will be used, and spent fuel will be accumulated on the platform itself. Once every three years, fuel will be reloaded, with the average annual duration of the reactor refuelling not exceeding 60 days. In addition, on an annual basis, scheduled shutdowns will be carried out at the plant for routine maintenance, the average annual duration of which will be no more than 20 days.

In designing the Akademik Lomonosov, priority was given to such aspect as the safety of its operation. The technological solution for the design components of the FNPP is based on the tried and tested reference technology used on nuclear icebreakers since 1988. The icebreakers Taimyr and Vaigach were used as prototypes – their reactor units have operated without fail for several decades in the most difficult conditions of the Arctic. At the same time, it should be noted that the technologies of the reactor facilities for the icebreaking fleet are constantly being improved and have made a qualitative step forward since. This development is taking into account the fact that increasingly high demands are being placed on nuclear safety in the world.

Thanks to the use of this experience, the Akademik Lomonosov is today equipped with advanced icebreaker reactors, and the FPU vessel is designed to withstand a collision with an iceberg, the pressure exerted by a tsunami wave as well as hurricanes – this safety margin makes the ship virtually unsinkable and invulnerable to natural disasters. From the outside environment, the FPU premises are insulated with a double hull of the vessel, and reactor facilities are equipped with special biological barriers that do not allow radiation to spread beyond the compartments where these facilities are located.

The FPU vessel design has also taken into account the climatic conditions in which the FNPP will be operated. The main body and load-bearing structures are made of steel, resistant to brittle fracture under low temperature conditions. In addition, the FPU is equipped with ice strengthening – additional structural elements that ensure the vessel’s strength during navigation in ice-covered waters, as well as all the means necessary for towing with the help of an icebreaker.

The primary importance of safety in the operation of small modular reactors is emphasized by Professor Marco K. Koch, head of the working group Plant Simulation and Safety at the Ruhr University Bochum, who is also a board member of the German Nuclear Society (KTG): “Compliance with all safety standards, including safe nuclear fuel management, is absolutely imperative”. The expert also highlighted the advantages of SMRs in this aspect: “Depending on the design chosen, it is possible to increase the safety of small modular reactors by combining active and passive safety systems. Due to the smaller size and thus the lower capacity compared to today's power reactors, in the event of a hypothetical accident, SMRs have greater capabilities in terms of external cooling, as well as a higher dynamics of reactor start-up and shutdown. In addition, due to the lower inventory, absolutely less fission products are produced”.

Another important feature of the FPU, which determines the critical importance of technology for energy supply to hard-to-reach areas, is its environmental friendliness. Every day of the FPU operation, either directly or indirectly due to gas savings, reduces annual consumption to 200,000 tons of coal and 120,000 tons of fuel oil. This seems particularly relevant in the light of the global goals of the Paris Climate Agreement. As part of the fight against climate change, the Russian side plans to reduce greenhouse gas emissions by 2030 to 70 percent of the 1990 baseline. At the same time, the only way to achieve these goals, in terms of the energy sector, is to implement a program for the development of carbon-free energy. “Provided safety aspects are taken into account, small modular reactor technologies are an environmentally friendly alternative to energy supply due to the use of smaller areas and the absence of CO2 emissions”, agrees Prof. Marco K. Koch.

The floating power unit Akademik Lomonosov is the first representative in a series of plants, whose production is planned to be established in the future, not least for exports to other countries. “SMR concepts can really be of interest for countries with decentralized energy supply”, says Prof. Thomas Schulenberg, director of the Institute of Nuclear and Energy Technologies at the Karlsruhe Institute of Technology. “Decentralized energy supply should be understood as an energy grid that is not interconnected, as in Europe, but limited to small areas – for example, in island regions such as Indonesia, or in sparsely populated regions on land”, the professor explained.

The expert's words have been confirmed by real experience: Director General of Rosatom Alexei Likhachev noted interest in the new Russian development coming from island states, including in South-East Asia. “In the near future, we plan to move to negotiations on specific deliveries, and if the result is achieved, sufficiently large capacities of Russian shipbuilding will be loaded with orders”, he added.

Prof. Marco K. Koch notes that small modular reactors can be used both in countries that already have nuclear infrastructure on their territory and in the countries that are new to the industry. Another significant argument in favor of the development of these technologies is significantly lower financial costs compared to large energy facilities. In Prof. Schulenberg’s view, a developing country is very difficult to find an amount of 10 billion euros for the construction of a large nuclear power plant – it is much easier to get a loan for the amount of an order of magnitude less. These circumstances lead to the conclusion that the use of small modular reactors in floating power plants is able to open a wide potential not only for energy supply to remote regions, but also for expanding the club of states using atomic energy for peaceful purposes.

Source: print edition
Source: ATW