What does a nuclear reactor work on? Innovative nuclear systems and projects
Every day we use electricity and do not think about how it is produced and how it got to us. Nevertheless, it is one of the most important parts of modern civilization. Without electricity there would be nothing - no light, no heat, no movement.
Everyone knows that electricity is generated at power plants, including nuclear ones. The heart of every nuclear power plant is nuclear reactor. This is what we will be looking at in this article.
Nuclear reactor, a device in which a controlled nuclear chain reaction occurs with the release of heat. These devices are mainly used to generate electricity and to drive large ships. In order to imagine the power and efficiency of nuclear reactors, we can give an example. Where an average nuclear reactor will require 30 kilograms of uranium, an average thermal power plant will require 60 wagons of coal or 40 tanks of fuel oil.
Prototype nuclear reactor was built in December 1942 in the USA under the direction of E. Fermi. It was the so-called “Chicago stack”. Chicago Pile (later the word“Pile”, along with other meanings, has come to mean a nuclear reactor). It was given this name because it resembled a large stack of graphite blocks placed one on top of the other.
Between the blocks were placed spherical “working fluids” made of natural uranium and its dioxide.
In the USSR, the first reactor was built under the leadership of Academician I.V. Kurchatov. The F-1 reactor was operational on December 25, 1946. The reactor was spherical in shape and had a diameter of about 7.5 meters. It had no cooling system, so it operated at very low power levels.
Research continued and on June 27, 1954, the world's first nuclear power plant with a capacity of 5 MW came into operation in Obninsk.
The operating principle of a nuclear reactor.
During the decay of uranium U 235, heat is released, accompanied by the release of two or three neutrons. According to statistics - 2.5. These neutrons collide with other uranium atoms U235. During a collision, uranium U 235 turns into an unstable isotope U 236, which almost immediately decays into Kr 92 and Ba 141 + these same 2-3 neutrons. The decay is accompanied by the release of energy in the form of gamma radiation and heat.
This is called a chain reaction. Atoms divide, the number of decays increases exponentially, which ultimately leads to a lightning-fast, by our standards, release of a huge amount of energy - an atomic explosion occurs as a consequence of an uncontrollable chain reaction.
However, in nuclear reactor we are dealing with controlled nuclear reaction. How this becomes possible is described further.
The structure of a nuclear reactor.
Currently, there are two types of nuclear reactors: VVER (water-cooled power reactor) and RBMK (high-power channel reactor). The difference is that RBMK is a boiling reactor, and VVER uses water under pressure of 120 atmospheres.
VVER 1000 reactor. 1 - control system drive; 2 - reactor cover; 3 - reactor body; 4 - block of protective pipes (BZT); 5 - shaft; 6 - core enclosure; 7 - fuel assemblies (FA) and control rods;
Each industrial nuclear reactor is a boiler through which coolant flows. As a rule, this is ordinary water (about 75% in the world), liquid graphite (20%) and heavy water (5%). For experimental purposes, beryllium was used and was assumed to be a hydrocarbon.
TVEL- (fuel element). These are rods in a zirconium shell with niobium alloy, inside of which uranium dioxide tablets are located.
The fuel rods in the cassette are highlighted in green.
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Fuel cassette assembly.
The reactor core consists of hundreds of cassettes placed vertically and united together by a metal shell - a body, which also plays the role of a neutron reflector. Among the cassettes, control rods and reactor emergency protection rods are inserted at regular intervals, which are designed to shut down the reactor in case of overheating.
Let us give as an example data on the VVER-440 reactor:
The controllers can move up and down, plunging, or vice versa, leaving the active zone, where the reaction is most intense. This is ensured by powerful electric motors, in conjunction with a control system. The emergency protection rods are designed to shut down the reactor in the event of an emergency, falling into the core and absorbing more free neutrons.
Each reactor has a lid through which used and new cassettes are loaded and unloaded.
Thermal insulation is usually installed on top of the reactor vessel. The next barrier is biological protection. This is usually a reinforced concrete bunker, the entrance to which is closed by an airlock with sealed doors. Biological protection is designed to prevent the release of radioactive steam and pieces of the reactor into the atmosphere if an explosion does occur.
A nuclear explosion in modern reactors is extremely unlikely. Because the fuel is quite slightly enriched and divided into fuel elements. Even if the core melts, the fuel will not be able to react as actively. The worst that can happen is a thermal explosion like at Chernobyl, when the pressure in the reactor reached such values that the metal casing simply burst, and the reactor cover, weighing 5,000 tons, made an inverted jump, breaking through the roof of the reactor compartment and releasing steam outside. If the Chernobyl nuclear power plant had been equipped with proper biological protection, like today’s sarcophagus, then the disaster would have cost humanity much less.
Operation of a nuclear power plant.
In a nutshell, this is what raboboa looks like.
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Nuclear power plant. (Clickable)
After entering the reactor core using pumps, the water is heated from 250 to 300 degrees and exits from the “other side” of the reactor. This is called the first circuit. After which it is sent to the heat exchanger, where it meets the second circuit. After which the steam under pressure flows onto the turbine blades. Turbines generate electricity.
Design and principle of operation
Energy release mechanism
The transformation of a substance is accompanied by the release of free energy only if the substance has a reserve of energy. The latter means that microparticles of a substance are in a state with a rest energy greater than in another possible state to which a transition exists. A spontaneous transition is always prevented by an energy barrier, to overcome which the microparticle must receive a certain amount of energy from the outside - excitation energy. The exoenergetic reaction consists in the fact that in the transformation following excitation, more energy is released than is required to excite the process. There are two ways to overcome the energy barrier: either due to the kinetic energy of colliding particles, or due to the binding energy of the joining particle.
If we keep in mind the macroscopic scale of energy release, then all or initially at least some fraction of particles of the substance must have the kinetic energy necessary to excite reactions. This is achievable only by increasing the temperature of the medium to a value at which the energy of thermal motion approaches the energy threshold limiting the course of the process. In the case of molecular transformations, that is chemical reactions, such an increase is usually hundreds of kelvins, but in the case of nuclear reactions it is at least 10 7 due to the very high height of the Coulomb barriers of colliding nuclei. Thermal excitation of nuclear reactions is carried out in practice only during the synthesis of the lightest nuclei, in which the Coulomb barriers are minimal (thermonuclear fusion).
Excitation by joining particles does not require large kinetic energy, and, therefore, does not depend on the temperature of the medium, since it occurs due to unused bonds inherent in the attractive forces of particles. But to excite reactions, the particles themselves are necessary. And if we again mean not a separate act of reaction, but the production of energy on a macroscopic scale, then this is possible only when a chain reaction occurs. The latter occurs when the particles that excite the reaction reappear as products of an exoenergetic reaction.
Design
Any nuclear reactor consists of the following parts:
- Core with nuclear fuel and moderator;
- Neutron reflector surrounding the core;
- Chain reaction control system, including emergency protection;
- Radiation protection;
- Remote control system.
Physical principles of operation
See also the main articles:
The current state of a nuclear reactor can be characterized by the effective neutron multiplication factor k or reactivity ρ , which are related by the following relation:
The following values are typical for these quantities:
- k> 1 - the chain reaction increases over time, the reactor is in supercritical state, its reactivity ρ > 0;
- k < 1 - реакция затухает, реактор - subcritical, ρ < 0;
- k = 1, ρ = 0 - the number of nuclear fissions is constant, the reactor is in a stable critical condition.
Criticality condition for a nuclear reactor:
, WhereReversing the multiplication factor to unity is achieved by balancing the multiplication of neutrons with their losses. There are actually two reasons for the losses: capture without fission and leakage of neutrons outside the breeding medium.
It is obvious that k< k 0 , поскольку в конечном объёме вследствие утечки потери нейтронов обязательно больше, чем в бесконечном. Поэтому, если в веществе данного состава k 0 < 1, то цепная самоподдерживающаяся реакция невозможна как в бесконечном, так и в любом конечном объёме. Таким образом, k 0 определяет принципиальную способность среды размножать нейтроны.
k 0 for thermal reactors can be determined by the so-called “formula of 4 factors”:
, Where- η is the neutron yield for two absorptions.
The volumes of modern power reactors can reach hundreds of m³ and are determined mainly not by criticality conditions, but by heat removal capabilities.
Critical volume nuclear reactor - the volume of the reactor core in a critical state. Critical mass- the mass of the fissile material of the reactor, which is in a critical state.
Reactors in which the fuel is aqueous solutions of salts of pure fissile isotopes with a water neutron reflector have the lowest critical mass. For 235 U this mass is 0.8 kg, for 239 Pu - 0.5 kg. It is widely known, however, that the critical mass for the LOPO reactor (the world's first enriched uranium reactor), which had a beryllium oxide reflector, was 0.565 kg, despite the fact that the degree of enrichment for isotope 235 was only slightly more than 14%. Theoretically, it has the smallest critical mass, for which this value is only 10 g.
In order to reduce neutron leakage, the core is given a spherical or close to spherical shape, for example, a short cylinder or cube, since these figures have the smallest surface area to volume ratio.
Despite the fact that the value (e - 1) is usually small, the role of fast neutron breeding is quite large, since for large nuclear reactors (K ∞ - 1)<< 1. Без этого процесса было бы невозможным создание первых графитовых реакторов на естественном уране.
To start a chain reaction, neutrons produced during the spontaneous fission of uranium nuclei are usually sufficient. It is also possible to use an external source of neutrons to start the reactor, for example, a mixture of and, or other substances.
Iodine pit
Main article: Iodine pitIodine pit is a state of a nuclear reactor after it is turned off, characterized by the accumulation of the short-lived isotope xenon. This process leads to the temporary appearance of significant negative reactivity, which, in turn, makes it impossible to bring the reactor to its design capacity within a certain period (about 1-2 days).
Classification
By purpose
According to the nature of their use, nuclear reactors are divided into:
- Power reactors designed to produce electrical and thermal energy used in the energy sector, as well as for desalination of sea water (desalination reactors are also classified as industrial). Such reactors are mainly used in nuclear power plants. The thermal power of modern power reactors reaches 5 GW. A separate group includes:
- Transport reactors, designed to supply energy to vehicle engines. The widest groups of applications are marine transport reactors used on submarines and various surface vessels, as well as reactors used in space technology.
- Experimental reactors, intended for the study of various physical quantities, the value of which is necessary for the design and operation of nuclear reactors; The power of such reactors does not exceed several kW.
- Research reactors, in which fluxes of neutrons and gamma quanta created in the core are used for research in the field of nuclear physics, solid state physics, radiation chemistry, biology, for testing materials intended to operate in intense neutron fluxes (including parts nuclear reactors) for the production of isotopes. The power of research reactors does not exceed 100 MW. The released energy is usually not used.
- Industrial (weapons, isotope) reactors, used to produce isotopes used in various areas. Most widely used to produce nuclear weapons materials, such as 239 Pu. Also classified as industrial are reactors used for desalination of sea water.
Often reactors are used to solve two or more different problems, in which case they are called multi-purpose. For example, some power reactors, especially in the early days of nuclear power, were designed primarily for experimentation. Fast neutron reactors can simultaneously produce energy and produce isotopes. Industrial reactors, in addition to their main task, often generate electrical and thermal energy.
According to the neutron spectrum
- Thermal (slow) neutron reactor (“thermal reactor”)
- Fast neutron reactor ("fast reactor")
By fuel placement
- Heterogeneous reactors, where fuel is placed discretely in the core in the form of blocks, between which there is a moderator;
- Homogeneous reactors, where the fuel and moderator are a homogeneous mixture (homogeneous system).
In a heterogeneous reactor, the fuel and moderator can be spatially separated, in particular, in a cavity reactor, the moderator-reflector surrounds a cavity with fuel that does not contain a moderator. From a nuclear physical point of view, the criterion for homogeneity/heterogeneity is not the design, but the placement of fuel blocks at a distance exceeding the neutron moderation length in a given moderator. Thus, reactors with the so-called “close lattice” are designed as homogeneous, although in them the fuel is usually separated from the moderator.
Nuclear fuel blocks in a heterogeneous reactor are called fuel assemblies (FA), which are located in the core at the nodes of a regular lattice, forming cells.
By fuel type
- uranium isotopes 235, 238, 233 (235 U, 238 U, 233 U)
- plutonium isotope 239 (239 Pu), also isotopes 239-242 Pu in the form of a mixture with 238 U (MOX fuel)
- thorium isotope 232 (232 Th) (via conversion to 233 U)
By degree of enrichment:
- natural uranium
- weakly enriched uranium
- highly enriched uranium
By chemical composition:
- metal U
- UC (uranium carbide), etc.
By type of coolant
- Gas, (see Graphite-gas reactor)
- D 2 O (heavy water, see Heavy water nuclear reactor, CANDU)
By type of moderator
- C (graphite, see Graphite-gas reactor, Graphite-water reactor)
- H2O (water, see Light water reactor, Water-cooled reactor, VVER)
- D 2 O (heavy water, see Heavy water nuclear reactor, CANDU)
- Metal hydrides
- Without moderator (see Fast reactor)
By design
By steam generation method
- Reactor with external steam generator (See Water-water reactor, VVER)
IAEA classification
- PWR (pressurized water reactors) - water-water reactor (pressurized water reactor);
- BWR (boiling water reactor) - boiling water reactor;
- FBR (fast breeder reactor) - fast breeder reactor;
- GCR (gas-cooled reactor) - gas-cooled reactor;
- LWGR (light water graphite reactor) - graphite-water reactor
- PHWR (pressurized heavy water reactor) - heavy water reactor
The most common in the world are pressurized water (about 62%) and boiling water (20%) reactors.
Reactor materials
The materials from which reactors are built operate at high temperatures in a field of neutrons, γ quanta and fission fragments. Therefore, not all materials used in other branches of technology are suitable for reactor construction. When choosing reactor materials, their radiation resistance, chemical inertness, absorption cross section and other properties are taken into account.
The radiation instability of materials has less effect at high temperatures. The mobility of atoms becomes so great that the probability of the return of atoms knocked out of the crystal lattice to their place or the recombination of hydrogen and oxygen into a water molecule increases markedly. Thus, the radiolysis of water is insignificant in energy non-boiling reactors (for example, VVER), while in powerful research reactors a significant amount of explosive mixture is released. Reactors have special systems for burning it.
Reactor materials are in contact with each other (fuel shell with coolant and nuclear fuel, fuel cassettes with coolant and moderator, etc.). Naturally, the contacting materials must be chemically inert (compatible). An example of incompatibility is uranium and hot water entering into a chemical reaction.
For most materials, the strength properties deteriorate sharply with increasing temperature. In power reactors, structural materials operate at high temperatures. This limits the choice of construction materials, especially for those parts of the power reactor that must withstand high pressure.
Burnout and reproduction of nuclear fuel
During the operation of a nuclear reactor, due to the accumulation of fission fragments in the fuel, its isotopic and chemical composition changes, and transuranic elements, mainly isotopes, are formed. The effect of fission fragments on the reactivity of a nuclear reactor is called poisoning(for radioactive fragments) and slagging(for stable isotopes).
The main reason for reactor poisoning is , which has the largest neutron absorption cross section (2.6·10 6 barn). Half-life of 135 Xe T 1/2 = 9.2 hours; The yield during division is 6-7%. The bulk of 135 Xe is formed as a result of the decay ( T 1/2 = 6.8 hours). In case of poisoning, Keff changes by 1-3%. The large absorption cross section of 135 Xe and the presence of the intermediate isotope 135 I lead to two important phenomena:
- To an increase in the concentration of 135 Xe and, consequently, to a decrease in the reactivity of the reactor after it is stopped or the power is reduced (“iodine pit”), which makes short-term stops and fluctuations in output power impossible. This effect is overcome by introducing a reactivity reserve in regulatory bodies. The depth and duration of the iodine well depend on the neutron flux Ф: at Ф = 5·10 18 neutron/(cm²·sec) the duration of the iodine well is ˜ 30 hours, and the depth is 2 times greater than the stationary change in Keff caused by 135 Xe poisoning.
- Due to poisoning, spatiotemporal fluctuations in the neutron flux F, and, consequently, in the reactor power, can occur. These oscillations occur at Ф > 10 18 neutrons/(cm² sec) and large sizes reactor. Oscillation periods ˜ 10 hours.
When nuclear fission occurs big number stable fragments that differ in absorption cross sections compared to the absorption cross section of the fissile isotope. Concentration of fragments with great value The absorption cross section reaches saturation within the first few days of reactor operation. These are mainly fuel rods of different “ages”.
When complete replacement fuel, the reactor has excess reactivity that needs to be compensated, whereas in the second case compensation is required only during the first start-up of the reactor. Continuous overloading makes it possible to increase the burnup depth, since the reactivity of the reactor is determined by the average concentrations of fissile isotopes.
The mass of loaded fuel exceeds the mass of unloaded fuel due to the “weight” of the released energy. After the reactor is shut down, first mainly due to fission by delayed neutrons, and then, after 1-2 minutes, due to β- and γ-radiation of fission fragments and transuranium elements, the release of energy in the fuel continues. If the reactor worked long enough before stopping, then 2 minutes after stopping, the energy release is about 3%, after 1 hour - 1%, after a day - 0.4%, after a year - 0.05% of the initial power.
The ratio of the number of fissile Pu isotopes formed in a nuclear reactor to the amount of burnt 235 U is called conversion rate K K . The value of K K increases with decreasing enrichment and burnup. For a heavy water reactor using natural uranium, with a burnup of 10 GW day/t K K = 0.55, and with small burnups (in this case K K is called initial plutonium coefficient) K K = 0.8. If a nuclear reactor burns and produces the same isotopes (breeder reactor), then the ratio of the reproduction rate to the burnup rate is called reproduction rate K V. In nuclear reactors using thermal neutrons K V< 1, а для реакторов на быстрых нейтронах К В может достигать 1,4-1,5. Рост К В для реакторов на быстрых нейтронах объясняется главным образом тем, что, особенно в случае 239 Pu, для быстрых нейтронов g grows and A falls.
Nuclear reactor control
Control of a nuclear reactor is possible only due to the fact that during fission, some of the neutrons fly out of the fragments with a delay, which can range from several milliseconds to several minutes.
To control the reactor, absorber rods are used, introduced into the core, made of materials that strongly absorb neutrons (mainly, and some others) and/or a solution of boric acid, added to the coolant in a certain concentration (boron control). The movement of the rods is controlled by special mechanisms, drives, operating according to signals from the operator or equipment for automatic control of the neutron flux.
In case of various emergency situations, each reactor is provided with an emergency termination of the chain reaction, carried out by dropping all absorbing rods into the core - an emergency protection system.
Residual Heat
An important issue directly related to nuclear safety is decay heat. This is a specific feature of nuclear fuel, which consists in the fact that, after the cessation of the fission chain reaction and the thermal inertia usual for any energy source, the release of heat in the reactor continues for a long time, which creates a number of technically complex problems.
Residual heat is a consequence of the β- and γ-decay of fission products that accumulated in the fuel during the operation of the reactor. Fission product nuclei, due to decay, transform into a more stable or completely stable state with the release of significant energy.
Although the decay heat release rate quickly decreases to values small compared to steady-state values, in powerful power reactors it is significant in absolute values. For this reason, residual heat generation necessitates long time ensure heat removal from the reactor core after shutdown. This task requires the design of the reactor installation to include cooling systems with a reliable power supply, and also necessitates long-term (3-4 years) storage of spent nuclear fuel in storage facilities with special temperature conditions- cooling pools, which are usually located in close proximity to the reactor.
see also
- List of nuclear reactors designed and built in the Soviet Union
Literature
- Levin V. E. Nuclear physics and nuclear reactors. 4th ed. - M.: Atomizdat, 1979.
- Shukolyukov A. Yu. “Uranium. Natural nuclear reactor." “Chemistry and Life” No. 6, 1980, p. 20-24
Notes
- "ZEEP - Canada's First Nuclear Reactor", Canada Science and Technology Museum.
- Greshilov A. A., Egupov N. D., Matushchenko A. M. Nuclear shield. - M.: Logos, 2008. - 438 p. -
Nuclear reactors have one job: to split atoms in a controlled reaction and use the released energy to generate electrical power. For many years, reactors were seen as both a miracle and a threat.
When the first commercial U.S. reactor came online at Shippingport, Pennsylvania, in 1956, the technology was hailed as the energy source of the future, and some believed the reactors would make generating electricity too cheap. Currently, 442 have been built worldwide. nuclear reactor, about a quarter of these reactors are in the United States. The world has become dependent on nuclear reactors, producing 14 percent of its electricity. Futurists even fantasized about nuclear cars.
When the Unit 2 reactor at the Three Mile Island Power Plant in Pennsylvania experienced a cooling system failure and partial meltdown of its radioactive fuel in 1979, the warm feelings about reactors changed radically. Even though the destroyed reactor was contained and no serious radiation emitted, many people began to view the reactors as too complex and vulnerable, with potentially catastrophic consequences. People were also concerned about radioactive waste from the reactors. As a result, construction of new nuclear power plants in the United States has stalled. When a more serious accident occurred on Chernobyl nuclear power plant in the Soviet Union in 1986, nuclear power seemed doomed.
But in the early 2000s, nuclear reactors began to make a comeback, thanks to rising energy demands and dwindling supplies of fossil fuels, as well as growing concerns about climate change resulting from carbon dioxide emissions.
But in March 2011, another crisis occurred - this time the Fukushima 1 nuclear power plant in Japan was badly damaged by an earthquake.
Usage nuclear reaction
Simply put, a nuclear reactor splits atoms and releases the energy that holds their parts together.
If you have forgotten physics high school, we will remind you how nuclear fission works. Atoms are like tiny solar systems, with a core like the Sun and electrons like planets in orbit around it. The nucleus is made up of particles called protons and neutrons, which are bound together. The force that binds the elements of the core is difficult to even imagine. It is many billions of times stronger than the force of gravity. Despite this enormous force, it is possible to split a nucleus—by shooting neutrons at it. When this is done, a lot of energy will be released. When atoms decay, their particles crash into nearby atoms, splitting them, and those, in turn, are next, and next, and next. There is a so-called chain reaction.
Uranium, an element with large atoms, is ideal for the fission process because the force that binds the particles of its nucleus is relatively weak compared to other elements. Nuclear reactors use a specific isotope called Uran-235 . Uranium-235 is rare in nature, with ore from uranium mines containing only about 0.7% Uranium-235. This is why reactors are used enrichedUwounds, which is created by separating and concentrating Uranium-235 through a gas diffusion process.
A chain reaction process can be created in an atomic bomb, similar to those dropped on the Japanese cities of Hiroshima and Nagasaki during World War II. But in a nuclear reactor, the chain reaction is controlled by inserting control rods made of materials such as cadmium, hafnium or boron that absorb some of the neutrons. This still allows the fission process to release enough energy to heat the water to about 270 degrees Celsius and turn it into steam, which is used to spin the power plant's turbines and generate electricity. Basically, in this case, a controlled nuclear bomb works instead of coal to create electricity, except that the energy to boil the water comes from splitting atoms instead of burning carbon.
Nuclear Reactor Components
There are a few various types nuclear reactors, but they all have some common characteristics. They all have a supply of radioactive fuel pellets - usually uranium oxide - which are arranged in tubes to form fuel rods in active zonesereactor.
The reactor also has the previously mentioned managerserodAnd- made of a neutron-absorbing material such as cadmium, hafnium or boron, which is inserted to control or stop a reaction.
The reactor also has moderator, a substance that slows down neutrons and helps control the fission process. Most reactors in the United States use ordinary water, but reactors in other countries sometimes use graphite, or heavywowwaterat, in which hydrogen is replaced by deuterium, an isotope of hydrogen with one proton and one neutron. Another important part of the system is coolingand Iliquidb, usually, plain water, which absorbs and transfers heat from the reactor to create steam to spin the turbine and cools the reactor area so that it does not reach the temperature at which the uranium will melt (about 3815 degrees Celsius).
Finally, the reactor is enclosed in shellsat, a large, heavy structure, usually several meters thick, made of steel and concrete that keeps radioactive gases and liquids inside where they can't harm anyone.
There are a number various designs reactors in use, but one of the most common is pressurized water power reactor (VVER). In such a reactor, water is forced into contact with the core and then remains there under such pressure that it cannot turn into steam. This water then comes into contact with unpressurized water in the steam generator, which turns into steam, which rotates the turbines. There is also a design high-power channel-type reactor (RBMK) with one water circuit and fast neutron reactor with two sodium and one water circuits.
How safe is a nuclear reactor?
Answering this question is quite difficult and depends on who you ask and how you define “safe”. Are you concerned about radiation or radioactive waste generated in reactors? Or are you more worried about the possibility of a catastrophic accident? What degree of risk do you consider an acceptable trade-off for the benefits of nuclear power? And to what extent do you trust the government and nuclear energy?
"Radiation" is a strong argument, mainly because we all know that large doses of radiation, such as from a nuclear bomb, can kill many thousands of people.
Proponents of nuclear power, however, point out that we are all regularly exposed to radiation from a variety of sources, including cosmic rays and natural radiation emitted by the Earth. The average annual radiation dose is about 6.2 millisieverts (mSv), half of it from natural sources and half from man-made sources ranging from chest X-rays, smoke detectors and luminous watch dials. How much radiation do we get from nuclear reactors? Only a tiny fraction of a percent of our typical annual exposure is 0.0001 mSv.
While all nuclear plants inevitably leak small amounts of radiation, regulatory commissions hold plant operators to stringent requirements. They cannot expose people living around the plant to more than 1 mSv of radiation per year, and workers at the plant have a threshold of 50 mSv per year. That may seem like a lot, but according to the Nuclear Regulatory Commission, there is no medical evidence that annual radiation doses below 100 mSv pose any risks to human health.
But it's important to note that not everyone agrees with this complacent assessment of radiation risks. For example, Physicians for Social Responsibility, a longtime critic of the nuclear industry, studied children living around German nuclear power plants. The study found that people living within 5 km of plants had double the risk of contracting leukemia compared to those living further from nuclear power plants.
Nuclear reactor waste
Nuclear power is touted by its proponents as "clean" energy because the reactor does not emit large amounts of greenhouse gases into the atmosphere compared to coal-fired power plants. But critics point to something else environmental problem— disposal of nuclear waste. Some of the spent fuel from the reactors still releases radioactivity. Other unnecessary material that should be saved is high level radioactive waste, a liquid residue from the reprocessing of spent fuel, in which some of the uranium remains. Right now, most of this waste is stored locally at nuclear power plants in ponds of water that absorb some of the remaining heat produced by the spent fuel and help shield workers from radiation exposure
One of the problems with spent nuclear fuel is that it has been altered by the fission process. When large uranium atoms are split, they create by-products- radioactive isotopes of several light elements such as Cesium-137 and Strontium-90, called fission products. They are hot and highly radioactive, but eventually, over a period of 30 years, they decay into less dangerous forms. This period is called for them Pperiodohmhalf-life. Other radioactive elements will have different half-lives. In addition, some uranium atoms also capture neutrons, forming heavier elements such as Plutonium. These transuranium elements do not create as much heat or penetrating radiation as fission products, but they take much longer to decay. Plutonium-239, for example, has a half-life of 24,000 years.
These radioactiveewastes high level of reactors are dangerous to humans and other life forms because they can release huge, lethal doses of radiation even from a short exposure. Ten years after removing the remaining fuel from the reactor, for example, they are emitting 200 times more radioactivity per hour than it would take to kill a person. And if the waste ends up in groundwater or rivers, they can enter the food chain and endanger large numbers of people.
Because waste is so dangerous, many people are in a difficult situation. 60,000 tons of waste are located at nuclear power plants close to major cities. But finding a safe place to store waste is not easy.
What can go wrong with a nuclear reactor?
With government regulators looking back on their experience, engineers have spent a lot of time over the years designing reactors for optimal safety. It's just that they don't break down, work properly, and have backup safety measures if something doesn't go according to plan. As a result, year after year, nuclear power plants appear to be fairly safe compared to, say, air travel, which regularly kills between 500 and 1,100 people a year worldwide.
However, nuclear reactors suffer major breakdowns. On the International Nuclear Event Scale, which rates reactor accidents from 1 to 7, there have been five accidents since 1957 that rate from 5 to 7.
The worst nightmare is a cooling system failure, which leads to overheating of the fuel. The fuel turns to liquid and then burns through the containment, releasing radioactive radiation. In 1979, Unit 2 at the Three Mile Island nuclear power plant (USA) was on the verge of this scenario. Fortunately, a well-designed containment system was strong enough to stop the radiation from escaping.
The USSR was less fortunate. A severe nuclear accident occurred in April 1986 at the 4th power unit at the Chernobyl nuclear power plant. This was caused by a combination of system failures, design flaws and poorly trained personnel. During a routine test, the reaction suddenly intensified and the control rods jammed, preventing an emergency shutdown. The sudden buildup of steam caused two thermal explosions, throwing the reactor's graphite moderator into the air. In the absence of anything to cool the reactor fuel rods, they began to overheat and completely collapse, as a result of which the fuel took on a liquid form. Many station workers and accident liquidators died. A large number of radiation spread over an area of 323,749 square kilometers. The number of deaths caused by radiation is still unclear, but the World Health Organization says it may have caused 9,000 cancer deaths.
Nuclear reactor manufacturers provide guarantees based on probabilistic assessmente, in which they try to balance the potential harm of an event with the likelihood with which it actually occurs. But some critics say they should prepare instead for rare, unexpected but highly dangerous events. A case in point is the March 2011 accident at the Fukushima 1 nuclear power plant in Japan. The station was reportedly designed to withstand strong earthquake, but not as catastrophic as the 9.0 magnitude earthquake that raised a 14-meter tsunami wave over dikes designed to withstand a 5.4-meter wave. The onslaught of the tsunami destroyed the backup diesel generators that were intended to power the cooling system of the plant's six reactors in the event of a power outage. So even after the Fukushima reactors' control rods stopped fission, the still-hot fuel allowed temperatures to rise dangerously inside the destroyed ones. reactors.
Japanese officials resorted to a last resort - flooding the reactors with huge amounts of sea water with additive boric acid, which was able to prevent a disaster, but destroyed the reactor equipment. Eventually, with the help of fire engines and barges, the Japanese were able to pump fresh water into reactors. But by then, monitoring had already shown alarming levels of radiation in the surrounding land and water. In one village 40 km from the plant, the radioactive element Cesium-137 was found at levels much higher than after the Chernobyl disaster, raising doubts about the possibility of human habitation in the area.
A fission chain reaction is always accompanied by the release of enormous energy. Practical use This energy is the main task of a nuclear reactor.
A nuclear reactor is a device in which a controlled, or controlled, nuclear fission reaction occurs.
Based on the principle of operation, nuclear reactors are divided into two groups: thermal neutron reactors and fast neutron reactors.
How does a thermal neutron nuclear reactor work?
A typical nuclear reactor has:
- Core and moderator;
- Neutron reflector;
- Coolant;
- Chain reaction control system, emergency protection;
- Control and radiation protection system;
- Remote control system.
1 - active zone; 2 - reflector; 3 - protection; 4 - control rods; 5 - coolant; 6 - pumps; 7 - heat exchanger; 8 - turbine; 9 - generator; 10 - capacitor.
Core and moderator
It is in the core that a controlled fission chain reaction occurs.
Most nuclear reactors operate on heavy isotopes of uranium-235. But in natural samples of uranium ore its content is only 0.72%. This concentration is not enough for a chain reaction to develop. Therefore, the ore is artificially enriched, bringing the content of this isotope to 3%.
fissile substance, or nuclear fuel, in the form of tablets, is placed in hermetically sealed rods, which are called fuel rods (fuel elements). They permeate the entire active zone filled with moderator neutrons.
Why is a neutron moderator needed in a nuclear reactor?
The fact is that the neutrons born after the decay of uranium-235 nuclei have a very high speed. The probability of their capture by other uranium nuclei is hundreds of times less than the probability of capture of slow neutrons. And if their speed is not reduced, the nuclear reaction may die out over time. The moderator solves the problem of reducing the speed of neutrons. If water or graphite is placed in the path of fast neutrons, their speed can be artificially reduced and thus the number of particles captured by atoms can be increased. At the same time, a chain reaction in the reactor will require less nuclear fuel.
As a result of the slowdown process, thermal neutrons, the speed of which is almost equal to the speed of thermal movement of gas molecules at room temperature.
Water, heavy water (deuterium oxide D 2 O), beryllium, and graphite are used as a moderator in nuclear reactors. But the best moderator is heavy water D2O.
Neutron reflector
To avoid neutron leakage into the environment, the core of a nuclear reactor is surrounded by neutron reflector. The material used for reflectors is often the same as in moderators.
Coolant
The heat released during a nuclear reaction is removed using a coolant. Conventional water is often used as a coolant in nuclear reactors. natural water, previously purified from various impurities and gases. But since water boils already at a temperature of 100 0 C and a pressure of 1 atm, in order to increase the boiling point, the pressure in the primary coolant circuit is increased. The primary circuit water circulating through the reactor core washes the fuel rods, heating up to a temperature of 320 0 C. Then, inside the heat exchanger, it gives off heat to the secondary circuit water. The exchange takes place through heat exchange tubes, so there is no contact with the secondary circuit water. This prevents radioactive substances from entering the second circuit of the heat exchanger.
And then everything happens as at a thermal power plant. Water in the second circuit turns into steam. The steam rotates a turbine, which drives an electric generator, which produces electric current.
In heavy water reactors, the coolant is heavy water D2O, and in reactors with liquid metal coolants it is molten metal.
Chain reaction control system
The current state of the reactor is characterized by a quantity called reactivity.
ρ = ( k -1)/ k ,
k = n i / n i -1 ,
Where k – neutron multiplication factor,
n i - the number of neutrons of the next generation in the nuclear fission reaction,
n i -1 , - the number of neutrons of the previous generation in the same reaction.
If k ˃ 1 , the chain reaction grows, the system is called supercritical y. If k< 1 , the chain reaction dies out, and the system is called subcritical. At k = 1 the reactor is in stable critical condition, since the number of fissile nuclei does not change. In this state reactivity ρ = 0 .
The critical state of the reactor (the required neutron multiplication factor in a nuclear reactor) is maintained by moving control rods. The material from which they are made includes neutron absorbent substances. By extending or pushing these rods into the core, the rate of the nuclear fission reaction is controlled.
The control system provides control of the reactor during its startup, scheduled shutdown, operation at power, as well as emergency protection of the nuclear reactor. This is achieved by changing the position of the control rods.
If any of the reactor parameters (temperature, pressure, rate of power rise, fuel consumption, etc.) deviates from the norm, and this can lead to an accident, central part the core is reset special emergency rods and the nuclear reaction quickly stops.
Ensure that the reactor parameters comply with the standards control and radiation protection systems.
For guard environment to protect against radioactive radiation, the reactor is placed in a thick concrete casing.
Remote control systems
All signals about the state of the nuclear reactor (coolant temperature, radiation level in different parts reactor, etc.) arrive at the reactor control panel and are processed in computer systems. The operator receives all the necessary information and recommendations for eliminating certain deviations.
Fast reactors
The difference between reactors of this type and thermal neutron reactors is that fast neutrons arising after the decay of uranium-235 are not slowed down, but are absorbed by uranium-238 with its subsequent conversion into plutonium-239. Therefore, fast neutron reactors are used to produce weapons-grade plutonium-239 and thermal energy, which nuclear power plant generators convert into electrical energy.
The nuclear fuel in such reactors is uranium-238, and the raw material is uranium-235.
In natural uranium ore, 99.2745% is uranium-238. When a thermal neutron is absorbed, it does not fission, but becomes an isotope of uranium-239.
Some time after β-decay, uranium-239 turns into a neptunium-239 nucleus:
239 92 U → 239 93 Np + 0 -1 e
After the second β-decay, fissile plutonium-239 is formed:
239 9 3 Np → 239 94 Pu + 0 -1 e
And finally, after the alpha decay of the plutonium-239 nucleus, uranium-235 is obtained:
239 94 Pu → 235 92 U + 4 2 He
Fuel rods with raw materials (enriched uranium-235) are located in the reactor core. This zone is surrounded by a breeding zone, which consists of fuel rods with fuel (depleted uranium-238). Fast neutrons emitted from the core after the decay of uranium-235 are captured by uranium-238 nuclei. As a result, plutonium-239 is formed. Thus, new nuclear fuel is produced in fast neutron reactors.
They are used as coolants in fast neutron nuclear reactors. liquid metals or mixtures thereof.
Classification and application of nuclear reactors
Nuclear reactors are mainly used in nuclear power plants. With their help, electrical and thermal energy is obtained in industrial scale. Such reactors are called energy .
Nuclear reactors are widely used in propulsion systems modern nuclear submarines, surface ships, in space technology. They supply electrical energy engines are called transport reactors .
For scientific research in the field of nuclear physics and radiation chemistry, fluxes of neutrons and gamma quanta are used, which are obtained in the core research reactors. The energy generated by them does not exceed 100 MW and is not used for industrial purposes.
Power experimental reactors even less. It reaches a value of only a few kW. These reactors are used to study various physical quantities, the significance of which is important in the design of nuclear reactions.
TO industrial reactors include reactors for the production of radioactive isotopes used for medical purposes, as well as in various fields of industry and technology. Seawater desalination reactors are also classified as industrial reactors.
Also, if necessary, quickly cool the reactor, they are used a bucket of water And ice.
| Element | Heat capacity |
|---|---|
| Cooling rod 10k(eng. 10k Coolant Cell) | |
| 10 000 | |
| Cooling rod 30k(eng. 30K Coolant Cell) | |
| 30 000 | |
| Cooling rod 60k(eng. 60K Coolant Cell) | |
| 60 000 | |
| Red capacitor(eng. RSH-Condenser) | |
| 19 999 | |
| By placing an overheated capacitor in a crafting grid along with redstone dust, you can replenish its heat reserve by 10,000 eT. Thus for full recovery The capacitor needs two dusts. |
|
| Lapis lazuli capacitor(eng. LZH-Condenser) | |
| 99 999 | |
| It is replenished not only with redstone (5000 eT), but also with lapis lazuli for 40,000 eT. |
Nuclear reactor cooling (up to version 1.106)
- The cooling rod can store 10,000 eT and cools by 1 eT every second.
- The reactor cladding also stores 10,000 eT, cooling every second with a 10% chance of 1 eT (on average 0.1 eT). Through thermoplates, fuel elements and heat spreaders can distribute heat to a larger number of cooling elements.
- The heat spreader stores 10,000 eT, and also balances the heat level of nearby elements, but redistributing no more than 6 eT/s to each. It also redistributes heat to the body, up to 25 eT/s.
- Passive cooling.
- Each block of air surrounding the reactor in a 3x3x3 area around the nuclear reactor cools the vessel by 0.25 eT/s, and each block of water cools by 1 eT/s.
- In addition, the reactor itself is cooled by 1 eT/s, thanks to internal system ventilation.
- Each additional reactor chamber is also ventilated and cools the housing by another 2 eT/s.
- But if there are lava blocks (sources or flows) in the 3x3x3 zone, then they reduce the cooling of the hull by 3 eT/s. And a burning fire in the same area reduces cooling by 0.5 eT/s.
- Emergency cooling (up to version 1.106).
- A bucket of water placed in the core cools the nuclear reactor vessel by 250 eT if it is heated by at least 4,000 eT.
- Ice cools the body by 300 eT if it is heated by at least 300 eT.
Classification of nuclear reactors
Nuclear reactors have their own classification: MK1, MK2, MK3, MK4 and MK5. Types are determined by the release of heat and energy, as well as some other aspects. MK1 is the safest, but produces the least amount of energy. The MK5 produces the most energy with the greatest chance of explosion.
MK1
The safest type of reactor, which does not heat up at all, and at the same time produces the least amount of energy. Divided into two subtypes: MK1A - one that meets class conditions regardless of the environment and MK1B - one that requires passive cooling to comply with class 1 standards.
MK2
The most optimal type of reactor, which, when operating at full power, does not heat up by more than 8500 eT per cycle (the time during which the fuel rod manages to completely discharge or 10,000 seconds). Thus, this is the optimal heat/energy compromise. For these types of reactors there is also a separate classification MK2x, where x is the number of cycles that the reactor will operate without critical overheating. The number can be from 1 (one cycle) to E (16 cycles or more). MK2-E is the standard among all nuclear reactors, since it is practically eternal. (That is, before the end of the 16th cycle the reactor will have time to cool to 0 eT)
MK3
A reactor that can run at least 1/10 full cycle without evaporating water/melting blocks. More powerful than MK1 and MK2, but requires additional supervision, because after some time the temperature can reach a critical level.
MK4
A reactor that can operate at least 1/10 of a full cycle without explosions. The most powerful of the operational types of Nuclear Reactors, which requires the most attention. Requires constant supervision. For the first time it emits approximately 200,000 to 1,000,000 eE.
MK5
Class 5 nuclear reactors are inoperable, mainly used to prove the fact that they explode. Although it is possible to make a functional reactor of this class, there is no point in doing so.
Additional classification
Even though reactors already have as many as 5 classes, reactors are sometimes divided into several more minor, but important subclasses of cooling type, efficiency and performance.
Cooling
-SUC(single use coolants - one-time use of cooling elements)
- Before version 1.106, this marking indicated emergency cooling of the reactor (using buckets of water or ice). Typically, such reactors are rarely used or not used at all due to the fact that the reactor may not operate for very long without supervision. This was usually used for the Mk3 or Mk4.
- After version 1.106 thermal capacitors appeared. The -SUC subclass now denotes the presence of thermal capacitors in the circuit. Their heat capacity can be quickly restored, but this will require spending red dust or lapis lazuli.
Efficiency
Efficiency is the average number of pulses produced by the fuel rods. Roughly speaking, this is the number of millions of energy obtained as a result of the operation of the reactor, divided by the number of fuel rods. But in the case of enrichment circuits, part of the pulses is spent on enrichment, and in this case the efficiency does not quite correspond to the energy received and will be higher.
Twin and quadruple fuel rods have higher basic efficiency compared to single ones. By themselves, single fuel elements produce one pulse, double ones - two, quadruple ones - three. If one of the four neighboring cells contains another fuel element, a depleted fuel element or a neutron reflector, then the number of pulses increases by one, that is, by a maximum of 4 more. From the above it becomes clear that the efficiency cannot be less than 1 or more than 7.
| Marking | Meaning efficiency |
|---|---|
| E.E. | =1 |
| ED | >1 and<2 |
| E.C. | ≥2 and<3 |
| E.B. | ≥3 and<4 |
| E.A. | ≥4 and<5 |
| EA+ | ≥5 and<6 |
| EA++ | ≥6 and<7 |
| EA* | =7 |
Other subclasses
You may sometimes see additional letters, abbreviations, or other symbols on reactor diagrams. Although these symbols are used (for example, the subclass -SUC was not officially registered before), they are not very popular. Therefore, you can call your reactor even Mk9000-2 EA^ dzhigurda, but this type of reactor simply will not be understood and will be considered a joke.
Construction of the reactor
We all know that the reactor heats up and an explosion can suddenly occur. And we have to turn it off and on. The following describes how you can protect your home, as well as how to make the most of a reactor that will never explode. In this case, you should already have 6 reactor chambers installed.
View of the reactor with chambers. Nuclear reactor inside.
- Cover the reactor with reinforced stone (5x5x5)
- Perform passive cooling, that is, fill the entire reactor with water. Fill it from the top as the water will flow down. Using this scheme, the reactor will be cooled by 33 eT per second.
- Make the maximum amount of energy generated with cooling rods, etc. Be careful, because if even 1 heat spreader is placed incorrectly, disaster can occur! (the diagram is shown for versions up to 1.106)
- To prevent our MFE from exploding from high voltage, we install a transformer as in the picture.
Mk-V EB reactor
Many people know that updates bring changes. One of these updates included new fuel rods - dual and quadruple. The diagram above does not fit these fuel rods. Below is a detailed description of the manufacture of a rather dangerous but effective reactor. To do this, IndustrialCraft 2 requires Nuclear Control. This reactor filled the MFSU and MFE in approximately 30 minutes of real time. Unfortunately, this is an MK4 class reactor. But it completed its task by heating up to 6500 eT. It is recommended to install 6500 on the temperature sensor and connect an alarm and emergency shutdown system to the sensor. If the alarm screams for more than two minutes, then it is better to turn off the reactor manually. The construction is the same as above. Only the location of the components has been changed.
Output power: 360 EU/t
Total EE: 72,000,000 EE
Generation time: 10 min. 26 sec.
Reload Time: Impossible
Maximum cycles: 6.26% cycle
Total time: Never
The most important thing in such a reactor is not to let it explode!
Mk-II-E-SUC Breeder EA+ reactor with the ability to enrich depleted fuel elements
A fairly effective but expensive type of reactor. It produces 720,000 eT per minute and the capacitors heat up by 27/100, therefore, without cooling the capacitors, the reactor will withstand 3 minute cycles, and the 4th will almost certainly explode it. It is possible to install depleted fuel elements for enrichment. It is recommended to connect the reactor to a timer and enclose the reactor in a “sarcophagus” made of reinforced stone. Due to the high output voltage (600 EU/t), high-voltage wires and a HV transformer are required.
Output power: 600 EU/t
Total eE: 120,000,000 eE
Generation time: Full cycle
Mk-I EB reactor
The elements do not heat up at all, 6 quadruple fuel rods work.
Output power: 360 EU/t
Total EE: 72,000,000 EE
Generation time: Full cycle
Recharge Time: Not Required
Maximum cycles: Infinite number
Total time: 2 hours 46 minutes 40 sec.
Mk-I EA++ reactor
Low-power, but economical in terms of raw materials and cheap to build. Requires neutron reflectors.
Output power: 60 EU/t
Total eE: 12,000,000 eE
Generation time: Full cycle
Recharge Time: Not Required
Maximum cycles: Infinite number
Total time: 2 hours 46 minutes 40 sec.
Reactor Mk-I EA*
Medium power but relatively cheap and extremely efficient. Requires neutron reflectors.
Output power: 140 EU/t
Total EE: 28,000,000 EE
Generation time: Full cycle
Recharge Time: Not Required
Maximum cycles: Infinite number
Total time: 2 hours 46 minutes 40 sec.
Mk-II-E-SUC Breeder EA+ reactor, uranium enrichment
Compact and cheap to build uranium enricher. The safe operation time is 2 minutes 20 seconds, after which it is recommended to repair lapis lazuli capacitors (repairing one - 2 lapis lazuli + 1 redstone), which will require constant monitoring of the reactor. Also, due to uneven enrichment, it is recommended to swap highly enriched rods with weakly enriched ones. At the same time, it can produce 48,000,000 eE per cycle.
Output power: 240 EU/t
Total EE: 48,000,000 EE
Generation time: Full cycle
Recharge Time: Not Required
Maximum cycles: Infinite number
Total time: 2 hours 46 minutes 40 sec.
Mk-I EC reactor
"Room" reactor. It has low power, but it is very cheap and absolutely safe - all supervision of the reactor comes down to replacing the rods, since cooling by ventilation exceeds heat generation by 2 times. It is best to place it close to the MFE/MFSU and configure them to emit a redstone signal when partially charged (Emit if partially filled), so the reactor will automatically fill the energy store and turn off when it is full. To craft all components you will need 292 copper, 102 iron, 24 gold, 8 redstone, 7 rubber, 7 tin, 2 units of light dust and lapis lazuli, as well as 6 units of uranium ore. It produces 16 million eU per cycle.
Output power: 80 EU/t
Total EE: 32,000,000 EE
Generation time: Full cycle
Recharge Time: Not Required
Maximum cycles: Infinite number
Total time: about 5 hours 33 minutes. 00 sec.
Reactor Timer
MK3 and MK4 class reactors do produce a lot of energy in a short time, but they tend to explode unattended. But with the help of a timer, you can make even these capricious reactors work without critical overheating and allow you to go away, for example, to dig up sand for your cactus farm. Here are three examples of timers:
- Timer made from a dispenser, a wooden button and arrows (Fig. 1). A fired arrow is an essence, its lifespan is 1 minute. When connecting a wooden button with an arrow stuck in it to the reactor, it will work for ~ 1 minute. 1.5 sec. It would be best to open access to a wooden button, then it will be possible to urgently stop the reactor. At the same time, the consumption of arrows is reduced, since when the dispenser is connected to another button other than a wooden one, after pressing, the dispenser releases 3 arrows at once due to the multiple signal.
- Wooden pressure plate timer (Fig. 2). The wooden pressure plate reacts if an object falls on it. Dropped items have a “lifespan” of 5 minutes (in SMP there may be deviations due to ping), and if you connect the plate to the reactor, it will work for ~5 minutes. 1 sec. When creating many timers, you can put this timer first in the chain, so as not to install a distributor. Then the entire chain of timers will be triggered by the player throwing an item onto the pressure plate.
- Repeater timer (Fig. 3). A repeater timer can be used to fine-tune the delay of a reactor, but it is very cumbersome and requires a large amount of resources to create even a small delay. The timer itself is a signal support line (10.6). As you can see, it takes up a lot of space, and the signal delay is 1.2 seconds. as many as 7 repeaters are required (21
Passive cooling (up to version 1.106)
The base cooling of the reactor itself is 1. Next, the 3x3x3 area around the reactor is checked. Each reactor chamber adds 2 to the cooling. A block with water (source or current) adds 1. A block with lava (source or current) decreases by 3. Blocks with air and fire are counted separately. They add to the cooling (number of air blocks-2×number of fire blocks)/4(if the result of division is not an integer, then the fractional part is discarded). If the total cooling is less than 0, then it is considered equal to 0.
That is, the reactor vessel cannot heat up due to external factors. In the worst case, it simply will not cool due to passive cooling.Temperature
At high temperatures, the reactor begins to have a negative impact on the environment. This effect depends on the heating coefficient. Heating factor=Current reactor vessel temperature/Maximum temperature, Where Maximum reactor temperature=10000+1000*number of reactor chambers+100*number of thermoplates inside the reactor.
If the heating coefficient:- <0,4 - никаких последствий нет.
- >=0.4 - there is a chance 1.5×(heating coefficient -0.4) that a random block in the zone will be selected 5x5x5, and if it happens to be a flammable block, such as leaves, some wood block, wool or a bed, then it will burn.
- if it is a central block (the reactor itself) or a bedrock block, then there will be no effect.
- stone blocks (including steps and ore), iron blocks (including reactor blocks), lava, earth, clay will be turned into a lava flow.
- if it is an air block, then there will be an attempt to light a fire in its place (if there are no solid blocks nearby, the fire will not appear).
- the remaining blocks (including water) will evaporate, and in their place there will also be an attempt to light a fire.
- >=1 - Explosion! The base explosion power is 10. Each fuel element in the reactor increases the explosion power by 3 units, and each reactor cladding reduces it by one. Also, the explosion power is limited to a maximum of 45 units. In terms of the number of blocks dropped, this explosion is similar to a nuclear bomb; 99% of the blocks after the explosion will be destroyed, and the drop will be only 1%.
Calculation of heating or low-enriched fuel elements, then the reactor vessel heats up by 1 eT.
- If this is a bucket of water, and the temperature of the reactor vessel is more than 4000 eT, then the vessel is cooled by 250 eT, and the bucket of water is replaced with an empty bucket.
- If this is a lava bucket, then the reactor vessel is heated by 2000 eT, and the lava bucket is replaced with an empty bucket.
- If this is a block of ice, and the temperature of the case is more than 300 eT, then the case is cooled by 300 eT, and the amount of ice is reduced by 1. That is, the entire stack of ice will not evaporate at once.
- If this is a heat spreader, then the following calculation is carried out:
- 4 adjacent cells are checked, in the following order: left, right, top and bottom.
- If the balance is greater than 6, it is equal to 6.
- If the adjacent element is a cooling capsule, then it heats up to the calculated balance value.
- If this is the reactor cladding, then an additional calculation of heat transfer is performed.
- If there are no cooling capsules near this plate, then the plate will heat up to the value of the calculated balance (heat from the heat spreader does not flow to other elements through the thermal plate).
- If there are cooling capsules, then it is checked whether the heat balance is divisible by their number without a remainder. If it does not divide, then the heat balance increases by 1 eT, and the plate is cooled by 1 eT until it divides completely. But if the reactor cladding has cooled down and the balance is not divided completely, then it heats up, and the balance decreases until it begins to divide completely.
- And, accordingly, these elements are heated to a temperature equal to Balance/quantity.
- It is taken modulo, and if it is greater than 6, then it is equal to 6.
- The heat spreader heats up to the balance value.
- The adjacent element is cooled by the balance value.
- The heat balance between the heat spreader and the housing is calculated.
- If the balance is positive, then:
- If the balance is more than 25, it is equal to 25.
- The heat spreader is cooled by the calculated balance value.
- The reactor vessel is heated to the calculated balance value.
- If the balance is negative, then:
- It is taken modulo and if it turns out to be more than 25, then it is equal to 25.
- The heat spreader heats up to the calculated balance value.
- The reactor vessel is cooled to the calculated balance value.
- If this is a fuel rod, and the reactor is not drowned out by the red dust signal, then the following calculations are carried out:
- less than 3000 - chance 1/8 (12.5%);
- from 3000 and less than 6000 - 1/4 (25%);
- from 6000 and less than 9000 - 1/2 (50%);
- 9000 or higher - 1 (100%).
- 0? the reactor vessel heats up by 10 eT.
- 1: The cooling element heats up by 10 eT.
- 2: the cooling elements heat up by 4 eT each.
- 3: each is heated by 2 eT.
- 4: each one is heated by 1 eT.
Calculation example
There are programs that calculate these circuits. For more reliable calculations and a better understanding of the process, it is worth using them.
Let's take for example this scheme with three uranium rods. 
The numbers indicate the order of calculation of the elements in this scheme, and we will use the same numbers to denote the elements so as not to get confused.
For example, let's calculate the heat distribution in the first and second seconds. We will assume that at first there is no heating of the elements, passive cooling is maximum (33 eT), and we will not take into account the cooling of the thermoplates.
First step.
- The reactor vessel temperature is 0 eT.
- 1 - The reactor casing (RP) is not yet heated.
- 2 - The cooling capsule (OxC) is not yet heated, and will no longer cool at this step (0 eT).
- 3 - TVEL will allocate 8 eT (2 cycles of 4 eT each) to the 1st TP (0 eT), which will heat it to 8 eT, and to the 2nd OxC (0 eT), which will heat it to 8 eT.
- 4 - OxC is not yet heated, and there will be no cooling at this step (0 eT).
- 5 - The heat spreader (HR), not yet heated, will balance the temperature with 2m OxC (8 eT). It will cool it down to 4 eT and heat up to 4 eT.
- 6 - TVEL will allocate 12 eT (3 cycles of 4 eT each) to the 5th TP (1 eT), which will heat it to 13 eT, and to the 7th TP (0 eT), which will heat it to 12 eT.
- 7 - TP is already heated to 12 eT and can cool down with a 10% chance, but we do not take into account the chance of cooling here.
- 8 - TP (0 eT) will balance the temperature of the 7th TP (12 eT), and take 6 eT from it. The 7th TP will cool to 6 eT, and the 8th TP will heat up to 6 eT.
- 9 - OxC (3 eT) will cool to 2 eT.
- 10 - OxC (2 eT) will cool to 1 eT.
- 11 - TVEL will allocate 8 eT (2 cycles of 4 eT each) to the 10th OxC (1 eT), which will heat it to 9 eT, and to the 13th TP (0 eT), which will heat it to 8 eT.
In the figure, red arrows show heating from uranium rods, blue arrows show heat balancing by heat distributors, yellow arrows show energy distribution to the reactor vessel, brown arrows show the final heating of the elements at this step, blue arrows show cooling for cooling capsules. The numbers in the upper right corner show the final heating, and for uranium rods, the operating time.
Final heating after the first step:
- reactor vessel - 1 eT
- 1TP - 8 eT
- 2ОхС - 4еТ
- 4ОхС - 1еТ
- 5TP - 13 eT
- 7TP - 6 eT
- 8TP - 1 eT
- 9ОхС - 2еТ
- 10ОхС - 9еТ
- 12ОхС - 0еТ
- 13TP - 8 eT
Second step.
- The reactor vessel will cool to 0 eT.
- 1 - TP, do not take into account cooling.
- 2 - OxC (4 eT) will cool to 3 eT.
- 3 - TVEL will allocate 8 eT (2 cycles of 4 eT each) to the 1st TP (8 eT), which will heat it to 16 eT, and to the 2nd OxC (3 eT), which will heat it to 11 eT.
- 4 - OxC (1 eT) will cool to 0 eT.
- 5 - TP (13 eT) will balance the temperature with 2m OxC (11 eT). It will heat it up to 12 eT, and it will cool down to 12 eT.
- 6 - TVEL will allocate 12 eT (3 cycles of 4 eT each) to the 5th TP (5 eT), which will heat it to 17 eT, and to the 7th TP (6 eT), which will heat it to 18 eT.
- 7 - TP (18 eT), do not take into account cooling.
- 8 - TP (1 eT) will balance the temperature of the 7th TP (18 eT) and take 6 eT from it. The 7th TP will cool to 12 eT, and the 8th TP will heat up to 7 eT.
- 9 - OxC (4 eT) will cool to 3 eT.
- 10 - OxC (10 eT) will cool to 9 eT.
- 11 - TVEL will allocate 8 eT (2 cycles of 4 eT each) to the 10th OxC (9 eT), which will heat it to 17 eT, and to the 13th TP (8 eT), which will heat it to 16 eT.
- 12 - OxC (1 eT) will cool to 0 eT.
- 13 - TP (8 eT), do not take into account cooling.
Final heating after the second step:
- reactor vessel - 4 eT
- 1TP - 16 eT
- 2ОхС - 12 eT
- 4ОхС - 2еТ
- 5TP - 17 eT
- 7TP - 12 eT
- 8TP - 4 eT
- 9ОхС - 3еТ
- 10ОхС - 17еТ
- 12ОхС - 0еТ
- 13TP - 16 eT