About nuclear power plants
It is not true that nuclear power plants are no longer being built. According to the statistics of the World Nuclear Association (WNA), there were 440 nuclear reactors, with a total installed capacity of 390,382 MWe, operating in the world on July 1, 2020. Another 56 are currently being built in 18 countries, and the construction of 108 reactors is planned. In total, another 329 reactors, with the power of approximately 359,682 MWe, are estimated to be built in the world.
The usage of nuclear energy also plays a significant role in the EU, where approximately one third of all energy generated comes from nuclear power plants. Nuclear power plants are being built in Belarus, Finland, France, Russia and Slovakia, with construction also being prepared in Bulgaria, the Czech Republic, Lithuania, Finland, Hungary, Poland, Romania, Russia, the United Kingdom, Turkey and Ukraine.
The countries with the highest number of nuclear sources are USA (95), France (57), China (47), Russia (38), Japan (33), South Korea (24), India (22), Canada (19) and Ukraine and the United Kingdom (both 15). Pressurised water reactors are usually used in the EU (65 %), in terms of frequency, boiling water reactors (BWR) are in the second place (22 %). Pressurised heavy water reactors, graphite-moderated reactors, gas-cooled reactors, fast reactors and other types of reactors are also used.
The pace of construction of new sources does not correspond with the consumption growth trend and there is therefore a risk of lack of production capacity. According to the predictions, the overall annual consumption of electricity in the EU and in the world may increase by 30 % over the next 15 years. Climate commitments and the resulting attenuation of lignite power plants and the transition to emission-free mobility will further increase this deficit. Neither renewable resources, nor any real energy savings, will solve this problem. The transformation of energetics will require the construction of new and stable sources of electrical energy.
Electrical production in nuclear power plants is not expensive. Nuclear power plants, like renewable energy sources, are characterised by higher initial costs but low operating costs. The low impact of fuel costs that represents a major financial burden in the operation of fossil fuel power plants (or power plants using renewable sources such as biomass combustion) is positively reflected here. Moreover, total specific costs of a nuclear power plant are highly resistant to fluctuations in fuel prices. To double the cost of electricity production, the price of uranium would have to rise tenfold, while production costs of fossil power plants are increasing almost in direct proportion to fuel costs. Nuclear power plants also benefit from sufficient raw materials, services for the production of nuclear fuel that are available on stable markets and ecologic operation, which does not produce CO2. Furthermore, compared to other sources, nuclear power plants include externalities in costs, i.e. influences on society and the environment connected to the generation of electricity, which are not a priori included in the costs and prices of electricity from other sources.
Key factors of Energy Well Project
The Energy Well reactor belongs to the so-called fourth generation of nuclear reactors. This generation is characterised by a high level of passive safety, uses physical properties of advanced cooling media and innovative kinds of nuclear fuel. That is, where conventional reactors rely on complex safety systems, the Energy Well reactor relies on features resulting from the essence of the design itself and the physical properties of the cooling medium. Another major difference is the size of the entire power plant, which is derived mainly from the chosen technology or the installed capacity. The capacity of the reactor is 20 MW thermal (approximately 150 times less than in today’s conventional reactors). However, the chosen technology of the system is important in terms of the size of the powerplant. Due to the absence of a necessity to have a vast number of active safety systems, the Energy Well is very compact. Due to the use of supercritical CO2 in the tertiary circuit, the turbine and generator are transportable in an ordinary transport container.
The biggest advantage of the Energy Well reactor is the contribution of pure nuclear energy to the energetics field, which has long been dominated by resources with high emissions of greenhouse gases. Specifically, it is the possibility of supplying not only electrical energy to small regions but also heat. The heating industry faces significant changes due to the requirements within low-carbon strategies, and the Energy Well reactor aims to be the one of the possible solutions.
The main advantage stems from the principle of nuclear energy – a continual operation regardless of external influences. The reactor is able to generate energy regardless of the wind or amount of sunlight. At the same time, it is a highly concentrated source of energy, which, due to its physical size, does not disturb the character of the landscape in any way. However, the Energy Well also brings advantages that are similar to renewable sources of energy, like the possibility to discretise energy sources. Unlike conventional nuclear sources, it can be constructed on a significantly wide portfolio of locations and so decentralises the production of electricity.
The main element of its uniqueness is the management of spent nuclear fuel. Due to the intended use of the reactor within residential areas, it is crucial to ensure the maximum safety of the population. This includes the Energy Well philosophy for management of spent fuel, which will not be in an open space at any time of operation, but always in a protective container. The fuel change itself will be centralised outside the area of operation.
TRISO is an abbreviation of TRI-structural ISOtropic particle fuel. Each TRISO particle consists of uranium, carbon and oxygen core. The core is encapsulated by three layers of materials based on carbon and ceramics, which prevents the leaking of radioactive fission products. The particles are unbelievably small (like poppy seeds) and very robust. It is possible to produce them in the shape of cylindrical pellets or billiard balls called ‘pebbles’ for use in high-temperature reactors cooled by gas or molten salts. TRISO fuels are structurally more resistant to neutron radiation, corrosion, oxidation and high temperatures (factors that affect the fuel power the most) than ordinary reactor fuels. Each particle acts as its own protective system due to its own triple-coated layers. Simply put, the TRISO particle does not melt in a reactor and can withstand extreme temperatures, which are far beyond the threshold of current nuclear fuels. In the Energy Well reactor, the total weight of uranium is comparable to one fuel cassette of the VVER-1000 reactor (Temelín nuclear power plant).
Safety of the Energy Well reactor
Nuclear power plants are generally considered very safe sources of energy. However, the Energy Well does not require any active systems to reach such a high level of safety, and this reduces the risk of a functionality failure. Currently, a main project event in conventional power plants is a rupture of the primary circuit and subsequent rapid leakage of coolant due to the high inner pressure. The Energy Well reactor works at an atmospheric pressure level, which results in a significantly lower pressure effect on the entire system. Thus, a main project accident of an Energy Well reactor is a loss of forced convection due to the internal and external power outage. In such a case, the system thermally stabilises at temperatures that are several hundred degrees below the limit safety criterion. The reactor is then completely cooled by the natural circulation of a coolant.
The Energy Well is a so-called fourth generation reactor, which is characterised mainly by the high level of passive safety. Due to the low pressure in the system in combination with a coolant, molten salt and exceptional thermohydraulic properties, the possibility of an accident causing radiation leakage into the environment is virtually ruled out.
Similar to conventional power plants, the Energy Well reactor will be subjected to the legislative requirements for safety and resistance to all kinds of natural disasters, including floods, conflagrations, tornados and earthquakes. However, in contrast to conventional nuclear power plants, due to the low installed power, it is possible to set aside the reactor and cool it down much faster without the need for supplies of internal or external electrical energy.
The Energy Well reactor uses an advanced kind of nuclear fuel called TRISO, which is designed to prevent abuse in the form of reprocessing. Because there is no manipulation of the nuclear fuel within the location itself, the fuel will be hermetically closed without the possibility of access. The Energy Well reactor will also be subjected to the same level of security as any other nuclear devices.
Use of the Energy Well reactor
The modularity of the Energy Well reactor does not only apply to a technological solution but is also reflected in the method of use. The Energy Well is designed for both inhabited and very remote regions and is able to supply electrical energy as well as heat. It can be used for desalination of water in the deserts, as a source of energy for mass production or as a heating plant for towns and cities. The variability and simplicity of the system allow a broad local usage.
As with all thermonuclear reactors, the Energy Well initially generates energy in the form of heat. This heat can then be transformed to electrical energy or used for hydrogen production, and the heat itself can also be used by the heating industry.
The three main circuits of the reactor occupy an area of approximately 120 square metres. It is also necessary to include other support systems, components and structures. The overall dimensions range within the lower hundreds of square metres.
The Energy Well reactor generates 20 MW of thermal power, which equates to 8.5 MW of electrical energy. This corresponds to 16,000 households.
The reactor is designed for binary operation. This means that it works at 100 % or 0 %. Due to the fact that the total power is 20 MWt, it is not necessary to use the same regulation systems as with 3,000 MWt reactors.
Most of the systems and components of the Energy Well reactor are designed to be reusable. The total waste rate, whether nuclear or non-nuclear, will be significantly lower than that of conventional power plants. The system of the reactor’s operation is designed to allow the maximal reuse of individual components in the future.
Nuclear power plants are less harmful to the environment than other significant sources of electricity production: they do not produce greenhouse gases, their (radioactive) waste and drains are completely under control and they do not use primary resources that can be used elsewhere. Current nuclear energy saves the environment by eliminating roughly 2.4 Gt CO2/year. Of course, nuclear power plants are not meant to save the world from CO2, but they are one of the reasonable ways to prevent an increase in the concentration of greenhouse gases.
Due to the low power of the rector (8.5 MWe), its connection into the network is not a major problem.
Due to the possibility of decentralising the sources of electricity production, the Energy Well reactor has a positive influence on the electrical distribution system. There is no negative influence.
Construction of the Energy Well reactor
It is too early for a specific price at this time. It will depend not only on the finalisation of the whole design, but also on the location within which the reactor will operate. A major financial advantage of modular reactors such as the Energy Well is the investment predictability. Due to their unit uniqueness, conventional reactors face long-term problems related to the meeting of a construction schedule. This results in not only high investment costs but also in high interest on financial resources. The modularity and simplicity of the Energy Well reactor provide significantly higher investment security.
In the case of conventional reactors, individual systems and components are unique and discrete devices. The Energy Well’s systems are maximally integrated into large units. This allows faster production, transportation and construction of individual parts of the Energy Well. The modularity significantly reduces risks related to delays in construction, which fundamentally reduces investment risks.
Access to water resources is mainly required for heat dissipation from the tertiary circuit of the system. Due to the fact that the Energy Well reactor works at a relatively low power compared to conventional reactors, access to water is not necessary.
Due to the modularity of the system, the design itself is significantly simpler than with conventional thermonuclear reactors, because the internal systems of the power plant will be transported to the site almost at once. The total length of construction then depends on the preparedness of the buildings themselves.
The Energy Well reactor must meet all legislative site requirements. However, due to the high level of passive safety, which practically eliminates accidents associated with the release of radioactivity into the environment, a significantly reduced emergency planning zone is expected. This means that the Energy Well reactor will be able to operate similarly to research reactors, thus close to populated areas.
The distance itself depends on the specific location and is a matter for consideration by the State Office for Nuclear Safety. However, experimental reactors with power similar to the Energy Well are operated in the immediate proximity of residential areas in the Czech Republic. The high and advanced safety level of the Energy Well reactor allows it to meet the same stringent location requirements as experimental reactors.
Operation of the Energy Well reactor
The Energy Well reactor is designed in such a way to require minimal presence of operators during the seven-year operation period itself. Thus, in the case of a higher number of units, it is possible to centralise the administration and control of reactors and so significantly reduce human resources.
The total length of operation is planned for seven years, after which a unit will cool down for three years until it is possible to transport it for fuel change and maintenance. After the seven years of operation, a second module will be brought to maintain continuous energy production.
The change itself is very simple. Prior to the termination of operation of the first unit, a new unit will be transported to the location, which will be prepared for its implementation. At the end of operation of the first unit, the simple reconnection and the continuation in the operation will take place. After three years of cooling down, it will be possible to transport the original unit for recycling.
The spent fuel from the first campaign will be used to supplement other new modules. Fuel that is not reusable will be subjected to advanced processes for maximal reduction of its volume so the minimum amount of waste will remain.
Unlike fossil fuels, there is enough raw material for nuclear fuel with reserves that will cover the increasing demand and ensure the operation of new nuclear power plants. Due to the Uranium 2011 – Resources, Production and Demand report by the Organisation for Economic Co-operation and Development associating the most developed countries in the world, the uranium reserves identified so far are 5.3 million tonnes and they can suffice for another 85 years. So-called predicted and speculative reserves are estimated to have a horizon of 270 years. Furthermore, due to today's high demand for uranium, many countries are developing geological research that has led to the discovery of new, large reserves. It is estimated that the world’s geological research will reveal at least ten times the current amount of uranium in new deposits. Great deposits of uranium are bond in natural phosphates or in salt water (approximately 160 million tonnes). In addition to uranium, some nuclear reactors can use thorium, of which there is thrice the amount of uranium on Earth. Some countries (like India) are already implementing the thorium fuel cycle. In the case of fast reactors and when using recycling, the uranium reserves should suffice for 2,570 years and the so-called predicted and speculative reserves for 8,015 years.
For conventional power plants, the service life is defined by a reactor vessel and its aging in the neutron field. Due to the fact that the Energy Well reactor is designed to enable the reactor vessel to be changed and treated during the change of fuel and in combination with low neutron fluences, the service life of the whole device is not technically limited.