Nuclear Energy

About Nuclear Energy

Introduction
The peaceful use of nuclear energy is growing in various walks of life, including industrial, medical, agricultural and other fields. The generation of electricity from nuclear energy is one of the most important uses by generating clean and economically competitive energy. It is also a sustainable technology that guarantees the right of future generations to fossil resources as a result of the availability of their fuel for decades.

Power stations are spread in more than 30 countries with a global contribution estimated at 16% of the total electricity generated from all sources combined, through 449 nuclear reactors operating. Currently there are about 60 reactors under construction, and many countries have announced plans to develop nuclear power generation programs and consider them as a strategic energy option.

Since its inception, the technology of nuclear power reactors has undergone several developments from the first generation to the so-called advanced third generation ( III +) . The designs of this advanced generation are characterized by the adoption of standard and stereotypical techniques, which has reflected positively on the safety and cost factors of these reactors.

The Egyptian Nuclear Program (Key Events)

1955
Establishment of Atomic Energy commission.
1957
Establishment of Atomic energy institution.
1961
Operating the first research reactor at Inshas.
1963
Establishment of the Nuclear Engineering Dept at Alexandria University.
1964
Invitation for an international tender to construct a nuclear power plant for electricity generation and sea water desalination at Sidi-krer.
1966
Issuance of a Letter of Intent to the first company in the tender.
1967
War of June 1967,the project came to a halt.
1974
Invitation for a restricted tender among American companies to implement the project of constructing a nuclear power plant at Sidi-Krer.
1976
Establishment the Nuclear Power Plants Authority (NPPA).
1976
Establishment of the Supreme Council of Energy.
1977
Establishment of the Nuclear Materials Authority.
1979
The project stopped as a result of TMI accident in the United States.
1980
Selection of El-Dabaa site for the construction of the Egyptian nuclear power plant.
1981
Issurance of the presidential decree to allocate El-Dabaa site to establish the nuclear power project.
1981
Approval of the Supreme Council of Energy for the Egyptian nuclear program.
1981
Establishing a fund to support alternative energy projects.
1982
Invitation for an international tender for the construction of a nuclear power plant at El-Dabaa site.
1986
The project was interrupted as a result of Chernobyl accident in the former Soviet Union.
1998
Installation and operation of the second Egyptian experimental reactor at Inshas.
2006
Starting a national dialogue to study the use of nuclear power in electricity generation.
2006
Re-formation of the Supreme Council of Energy chaired by the Prime Minister.
2007
Declaration of Egypt`s strategic decision to build a number of reactors for electricity generation.
2007
Formation of the Supreme Council for the Peaceful use of nuclear energy headed by the President of the Republic.
2008
Invitation for an international tender to select a consultation firm for the construction of the nuclear power plant.
2011
Upgrading and finalizing the specifications of the first nuclear power plant in cooperation with the experts of the IAEA in the wake of Fukushima accident.
2013
Issuance of the decision of the Council of Ministers in its session held 10/10/2013 approving to NPPA to resume the consultant`s work to implement the phases with regard to the nuclear power plant project.
2014
Contracting with the Engineering Authority of the Armed Forces for the rehabilitation of El-Dabaa site with the basic facilities , protecting and securing it, Completion of environmental monitoring system at the site.
2015
Singning of an Inter-governmental agreement between Egypt and Russia on cooperation in the field of building and operating the first nuclear power plant in Egypt with the Russian technology.
2016
2017
Negotiations with the Russian side to build, operate , fuel supplying, storage of spent fuel for a nuclear power plant consisting of 4 units with VVER type reactors , 1200 MW each.
2019
Site Approval Permit (SAP) for El Dabaa site was issued by the Egyptian Nuclear Regulation and Radiological Authority (ENRRA).

Nuclear Safety

Safety principles in nuclear plants

  • Nuclear safety is the protection of individuals, the environment and society against the harmful effects of ionizing radiation, including the safety of nuclear facilities and activities. A series of strict technical and administrative measures are taken according to international standards designed to prevent, control and, if so, Principle (defense in depth). Preventing the incident is the primary and ultimate objective of all those concerned with nuclear energy. The regulation of nuclear and radiological safety is a national responsibility, and it is the responsibility of the operator.
  • In the design of nuclear power plants, there is combination of a number of consecutive and independent five levels of protection that would have to fail before harmful effects could be caused to people or to the environment. If one level of protection or barrier were to fail, the subsequent level or barrier would be available. This concept in design is called “defence in depth”.The first four levels are oriented towards the protection of barriers and mitigation of releases; the last level relates to off-site emergency measures to protect the public in the event of a significant release.

Radiation Protection

Protection and safety of workers and the public from the effects of exposure to ionizing radiation is a binding requirement in the nuclear industry. The International Commission on Radio-logical Protection has identified three main principles for the achievement of radio-logical protection:

  • The principle of justification – that is, it is not permissible to authorize a radiological exercise unless this practice produces sufficient benefit for the persons exposed or the society to balance the radiation damage it causes.
  • Optimization optimization principle: It is intended to keep radiation exposure at the least feasible, which is called ALARA. It includes three factors (time – distance – shielding)
  • Dose Constraints – dosage restriction should not exceed the permissible dose limit determined by the state regulatory body (excluding medical exposure where this principle is not applied).

Nuclear Reactor Types

Introduction

Nuclear power reactors are divided into two main types depending on the interaction type. Fission reactors for power generation and fusion reactors for power generation. Nuclear fission reactors are also divided into two main types based on the velocity of particles (neutrons) that cause nuclear fission: thermal reactors and fast reactors.

Pressurized Water Reactor (PWR)

It is the most widespread in the world, with 290 reactors representing about 64% of the world’s nuclear reactors, 50 of which are under construction.These reactors use enriched uranium between 3-4% of uranium-235 as fuel, and normal water for cooling and moderation. The fuel is made in the form of small tablets with a height of 2 cm and less than 1 cm in diameter. These tablets are packed into long tubes called fuel rods, each of which is about 4 meters long.

The cladding of fuel rods is usually made of zirconium or stainless steel alloys because of the ability to conduct heat, high resistance to corrosion and rust, and also to their low absorption of neutrons. A number of fuel columns are assembled in a regular engineering arrangement using a metal mesh to be the so-called fuel Assemblies. The reactor’s capacity is linked to the number of fuel assemblies in it.

The fuel Assemblies are assembled into the so-called Reactor pressure vessel , a cylindrical bowl with a Hemispherical head, one of the most important components in the station that determines the lifetime of the reactor.

The cooling water is kept under high pressure of about 150 bar through the so-called Pressurizer. Because of the high pressure of the coolant, the coolant is not allowed to switch to steam inside the reactor core. Therefore, a secondary circuit is used to transfer the cooling water temperature and then to produce steam and generate electricity. The presence of the secondary circuit increases the safety of these reactors by separating the primary cooling cycle exposed to the radiation from the steam-generating cycle to the turbine.

Boiling Water Reactor (BWR)

Which is the most common of the most prevalent, where there are 78 reactors operating, representing about 17% of the number of nuclear reactors in the world, and there are four reactors under construction. Enriched uranium is used for about 3% of the uranium-235 equivalent of fuel and normal water for cooling and moderation.

The composition of the fuel rods are not different from that used in PWRs, except in the form of fuel assemblies consisting of a number of fuel rods, which are grouped together by a metal mesh and placed together to form the fuel assemblies.

The cooling water is kept under an average pressure of up to 70 bar, allowing it to boil inside the reactor core, forming the steam that goes directly to the turbine, which in turn runs generators.

The cooling water is kept under an average pressure of up to 70 air pressure, allowing it to boil inside the reactor core, forming the steam that goes directly to the turbine, which in turn runs generators.


Water Cooled Graphite-Moderated Reactor (RBMK)

The heart of the reactor consists of clusters of graphite blocks interspersed with pipes called pressure tubes containing inside the columns of nuclear fuel passing through it and inside these pipes the cooling water, which turns into steam, which comes out directly to the turbines.

Graphite is used in this type of reactor as a moderator of neutrons, and normal water is used as a coolant. It is worth mentioning that the first nuclear power plant in the world of this type was the “Obenisk” plant, which began operation in July 1954 in the former Soviet Union with a capacity of 5 megawatts electric and was shut down from operation in 2002. It is noteworthy that the Chernobyl-4 reactor which The nuclear incident occurred on April 26, 1986, resulting in a radiation leak of this type of reactor. There are no reactors of this kind in the world except within what was known as the former Soviet Union. This type of reactor differs from ordinary compressed water reactors and boiling water reactors in the absence of a concrete containment container surrounding it and the components of the cooling cycle to withstand the pressure and temperatures produced in the case of severe accidents, which prevents the leakage of radiation to humans and the environment.

Pressurized Heavy Water Reactor (PHWR)

49 Of these reactors are operating reactors, representing 10% of the world’s nuclear reactors. Four of the reactors are under construction and are of medium electric capacity and have been developed mainly in Canada. Natural uranium (which contains 0.7% of the uranium-235 ) is used as fuel and heavy water (where deuterium replaces hydrogen in water) for cooling and moderating purposes. Heavy water is characterized by low neutron absorption, which helps to increase the number of neutrons available to cause fission, thus allowing the use of natural uranium directly and without the need for enrichment.The coolant water of the reactor is kept under pressure and inside tubes containing fuel assemblies and a secondary circuit is used to generate steam. The reactor can be refueled online during operation.

Gas Cooled Reactor (GCR)

The gas-cooled nuclear reactors were the first reactors to control serial nuclear fission processes. The first nuclear reactor was built and operated in 1942, known as the “Fermi” reactor. The actual use of these reactors began in the generation of electric power since the mid-1950s. Where many countries, led by Britain, began building the first generations of these reactors. The most important known types of gas cooled reactors are:

– Magnox reactors

– Advanced gas cooled reactors

– High temperature gas cooled reactors

1 – MAGNOX reactors
The Majnox reactors use nuclear fuel in the form of metal uranium, the uranium-235 equivalent of about 7%, which is the ratio found in natural uranium. The use of natural uranium metal as fuel to maintain operational conditions in the  reactor core to avoid damage to fuel and packaged at temperatures or high combustion rates and therefore designed to operate at temperatures up to 350 m.

The core of the reactor contains a number of graphite blocks with vertical channels of fuel. The fuel rods are made of natural uranium metal coated with a thin layer of Magnox (Magnesium – Aluminum – Brillium – Copper). These reactors are therefore called Magnox.

Carbon dioxide is used as a refrigerant under pressure of up to 13 air pressure. The heat of the reactor passes through the coolant to six steam generators on both sides of the reactor’s core, where the steam is generated, which in turn turns to the turbine generating the electricity and the coolant returns to the core of the reactor. Graphite is used as a moderator, and in the form of blocks with channels through which fuel columns and control shafts enter.

2 – Advanced gas cooled reactors AGR
Despite the safe operation of the Magenox reactors, the desire to improve operating parameters led to some development of modern generations of gas cooled reactors, known as advanced gas cooled reactors.

Uranium dioxide is slightly used (1.4 – 2.6% of uranium – 235) as fuel. The fuel is made in the form of short, hollow capsules of income. These tablets are assembled in stainless steel casing with a ratio of chromium and niobium made up of fuel columns.

Carbon dioxide is used under pressure of up to 39 air pressure as a refrigerant. The heat of the reactor’s heart is transferred by the radiator to the steam generators where the steam is generated, which in turn turns to the turbine generating electricity, and the coolant returns to the reactor core. Graphite is used as a sedative where the heart of the reactor contains a number of graphite blocks that have channels containing fuel aggregates.

3 – HTGR gas heating reactors
This type of reactor uses uranium with a high proportion of uranium-235 mixed with the thorium-232 as fuel. The use of the thorium-232 in the fuel industry is due to the fact that it turns into a uranium-233 equivalent when absorbed into neutrons. Because the uranium-233 is fissionable, it is considered an addition to the original fuel. The fuel is made in the form of short capsules of “Uranium carbide and thorium” encased in graphite and placed in the cavities of graphite blocks used as a sedative.

Helium gas is used as a coolant and is characterized as an inert gas that does not interact with graphite, which is used as a moderator, no matter how high it is, and it does not absorb neutrons and therefore does not turn into radioactive gas.

Nuclear Fuel

Is the source of power generation of fissionable nuclear reactors, producing a huge amount of thermal energy from the fission process, and the specifications of these materials are related to the selection of technology used for the reactor and its design and operation methods. There are two types of nuclear material used as fuel:

1. Materials that undergo fission by thermal neutrons and are called fissile materials, of which the natural origin is uranium-235 and its presence in crude is 0.7% or substances that are not naturally formed and are manufactured, namely uranium-233 and plutonium-239.

Uranium-235 is used as a fuel either as a natural Uranium in heavy water reactors, or with about 3-4% enrichment in light water reactors. The process of increasing the counterpart ratio 235 in uranium is called the normal ratio of the enrichment process.

2. The so-called fertile materials, uranium-238 (up to 99.3% uranium ore) and thorium-232, are called fertile materials because they are converted into fissile material when collided by neutrons. The former converts into plutonium 239 and the latter converts into uranium 233. Plutonium is used as a main fuel in fast reactors and is used as fuel in thermal reactors in the form of a mixture with MOX fuel.

Advantages of using nuclear fuel:

  • It is very high energy compared to other types used in generating electricity, and a few Pellets of nuclear fuel can be placed by the individual in the palm of his hand to meet the needs of a whole family for a year.
  • Nuclear reactors need to generate electricity only for a limited amount of nuclear fuel per year, so it is easy to transport and store as a strategic stock and in quantities sufficient to operate the plants for many years.
  • The resulting waste is small in size, and therefore can be stored for long periods in a small space.
  • The contribution of nuclear fuel to electricity production costs is lower than that of other types, so electricity prices remain almost constant in case of fluctuation and price increases.
  • Maintains a clean environment where its use does not result in environmentally destructive gases such as carbon oxides, sulfur and nitrogen.
  • Available in abundant quantities and reliable as fuel for hundreds of years.

Nuclear Waste

Like all other energy sources, nuclear energy produces waste (appropriate disposal methods should be followed to protect both human and the environment from its negative effects).

The waste resulting from the use of certain energy sources varies in its size, characteristics and the disposal method.
The volume of waste generated by a coal fired power station of 1000 MW requires 1000 tons of coal.
These results in the release 300 tons of Sulphur dioxide, 5 tons of ash containing other elements such as: Chlorine, Cadmium , Arsenic, Mercury, Lead in addition to some radioactive substances.
In turn , the same energy generated from nuclear power results in 500 cubic meters of waste yearly .

Sources of radioactive waste

The radioactive waste is produced from the following manufacturing activities:

  • Burning of nuclear fuel in NPP to result in what is known as spent fuel.
  • All processes and stages of nuclear fuel cycle.
  • Using radioactive isotopes in scientific research, industry, mining and agriculture.
  • Nuclear medicine including diagnosis, treatment, production of drugs and radioactive sources.

Classification of radioactive waste

There is no international classification of radioactive waste; factors involved in the classification of radioactive waste are as follows:

  • Type and concentration of radioactive substances in waste.
  • Period of half-life of radioactive substance (Time required for half the radioactive nuclei in a substance to decay by half , and it is a natural characteristic that varies from one substance to another).
  • The physical state of the waste in terms of solid, liquid and gaseous state.
  • Treatment and storage methods.
  • Potential release to the adjacent environment.
  • Sources of waste.

For example,

In the classification of radioactive waste, the United States relies on the concentration of the radioactive equivalent of a given volume of air or water as follows:

  • A: High-level radioactive waste, including some nuclear weapons production products, all nuclear fuel cycle products, and nuclear power plant residues such as spent nuclear fuel
  • B: Medium-level radioactive waste, which includes the nuclei of alpha-emitting radioactive elements with an atomic mass of 92 and a half-life of more than five years, with a concentration of more than 7.3 x 610 Becker-kg. This type of waste is produced mainly during production processes nuclear weapons
  • C: Low-level radioactive waste, including almost all other types of waste not included in the previous two categories, constitute the bulk of radioactive waste, sometimes reaching more than 70% of the total waste, and is produced primarily from the use of isotopes and radioactive sources In medicine, scientific research and industrial applications, as well as all materials and tools used in any operation involving a radioactive source, such as: clothing, gloves, injections, cleaning tools, liquids containing radioactive materials

Radioactive waste management

A radioactive waste management program aims at reaching a situation that ensures the protection of humans and the environment from the harmful effects of such wastes. This means that they are processed or saved, or both, so that their radiation levels fall below their natural radiation levels in the environment. A few hours may extend to days, even hundreds or thousands of years, and this is especially evident in the case of high-level waste.

Radioactive waste can be disposed of according to its radioactive level as follows:

    • 1. High-level radioactive waste, stored in concrete drums buried in permanent landfills at certain depths and in stable geological formations, carefully selected taking into account several factors such as rock quality, seismic activity, and water formations in or near the area , In addition to psychological factors and public opinion accept the existence of such graves.
    • 2. Wastes of medium and low radiation level, and can be disposed of their radioactive impact according to their physical condition, whether liquid or solid as follows:
      • A: Liquid radioactive waste:
        The process of liquid radioactive waste management goes through the following steps and stages:

        • Collection: Liquid radioactive waste is collected in plastic containers of different sizes or glass containers in the case of suspended organic matter. Periodic measurement of the radiation level is then carried out. Upon reaching the allowable level, waste is discharged through the sewerage system.
        • Treatment: If effluent contains the nuclei of elements with a long half life, this requires treatment before disposal, and chemical treatment is the most common and used in water treatment, such as sedimentation, evaporation and ion exchange. These methods are characterized by their low cost and the possibility of processing a large number of Radioactive nuclei.
      • B: Solid radioactive waste:
        With regard to solid radioactive wastes, they go through the following stages:

        • Collection and separation: A center for the collection, sorting and classification of solid waste is determined in terms of their incineration or not, and in terms of their ability to reduce volume, to facilitate treatment and disposal, and those that are still radioactive from others.
        • Treatment: includes temporary preservation in the case of wastes that include the nuclei of radioactive elements with a short half life, burning or burial, and is the most common method for solids that are hard to be considered or converted into ordinary waste, buried in closed landfills close to the surface.

Nuclear Energy Usage

1- Desalination of sea water

Fresh water represents 1.7% of the amount of water available on the planet appeared the rest of the amount consists of water seas and oceans, salt, and contain snow north and south poles at about 97% of the amount of fresh water. Thus, fresh water in rivers and lakes that can be used by humans, animals and plants does not exceed 0.05% of the amount of water on the ground.

In Egypt, the river Nile 55.5 billion cubic meters per year, and as a result of increasing population and the stability of fresh water sources, annual per capita in Egypt of fresh water decreased from 2560 cubic meters in 1955 to less than 800 cubic meters in 2005 so that Egypt became according to the global rating among Water-poor countries. In view of the continued decline in freshwater per capita and the scarcity of fresh water in the desert governorates, Egypt has resorted to the use of desalination technology to provide fresh water for domestic, industrial and tourism uses. According to the latest versions of the published capacities composite compound rose to remove water wells and sea water salinity in Egypt from about 14 thousand cubic meters per day in 1970 to more than 206 thousand cubic meters per day in 2000.

Desalination technology is the technological alternative currently available for freshwater production. Local and international studies have shown that there are no technical barriers to the use of nuclear plants in seawater desalination, and that the economics of producing drinking water using nuclear energy are competitive with conventional thermal stations and are environmentally superior.

Currently available several technologies for seawater desalination using nuclear energy, and proven nuclear reactors to generate electricity, which uses part of its capacity for this purpose, the effectiveness of large and reliable in operation, and the experiences of a number of countries stressed that it could use nuclear power in electricity generation and water desalination safe and economical manner The cost of production per cubic meter in freshwater is between $ 0.6 and $ 1.82.

It is worth mentioning that India has in the recent establishment of a desalination pilot plant using nuclear power production capacity of about 6300 m 3 / day to get high-quality fresh water and style economic and safe, and is currently Pakistan is building a desalination unit nuclear experimental production of about 4500 m3 of water per day Sweetened.

2- Consumer Products

Low amounts of radiation are used in many consumer products, including:

  • Smoke detectors with fire protection devices that rely on the use of a very small radioactive source in their work.
  • Some wristwatches and luminous clocks in total darkness use radioactive isotopes as a source of light.
  • Radioisotopes are used for some hard and flexible data recording disks related to computers.
  • Treatment of stickers by radiation to make them more relevant to different surfaces.
  • Use of small amounts of radiation photogravure machines to remove the electrostatic charges causing the adhesion of papers to each other and the spread of these machines.
  • Sterilization of cosmetics, hairdressing creams and contact lens solutions.
  • Sterilization of medical dressings and personal belongings for health and hygiene.

3- Food and agriculture

Radiation is used in foods such as grains, fruits, vegetables, fruit, meat and poultry to kill bacteria, insects and pathogenic parasites, increase productivity of different crops and improve different crop strains, which are more resistant to parasites, insects and unusual climatic changes and are more nutritious and productive.

4- Industrial uses

Radiation is widely used in industrial applications. Manufacturers use radioisotopes to improve the quality of their products, including their use as a high-sensitivity measure to measure the thickness and density of many materials and to conduct non-destructive testing of various goods and products.

It can be used to determine the rate of depreciation or corrosion of engine parts, gearboxes and other engineering applications. The most important uses are the detection of the quality of welds and potential cracks inside or surfaces of different materials And measure its purity and quality by detecting the percentage or amount of potential impurities involved in its composition.

5- Medicine and scientific research

Radioisotopes are used in medical cameras to detect human organs, blood circulation, renal detection, bone scans, bone injuries, tumor detection, diagnosis and treatment. X-ray is one of the most widely used medical diagnostic tools. It relies on radiation, and gamma rays are used to sterilize medical equipment safely and inexpensively, such as injection, burn dressings, surgical gloves and heart valves.

Radioisotopes are used in medical scientific research on the treatment of many diseases such as AIDS, Alzheimer’s and cancer, and are used in metabolic studies, gene engineering and environmental protection studies.

Radioisotopes are used to determine the chronological age of biological residues and residues, whether plants, animals or parasites, as in excavations, monuments and archaeological artifacts made of plant and animal components such as wood, leather, bones, etc.

6- Heating homes

Nuclear energy is used to produce heat energy that is used for heating and thermal energy generation. The technology is used in many countries, including Sweden, which is the first to take advantage of nuclear reactors to supply some 50 of its cities with heating and hot water in summer and winter.

7- Operation of ships, submarines and exploration of space

The use of nuclear power in ship engines and submarines with nuclear propulsion engines. The United States established the first military atomic submarine in 1954, followed by ships, submarines and icebreaker operated by this type of engine. It has been manufactured in many countries such as the United States, Russia, Britain, France, Germany and Japan.

Spacecraft relys on nuclear power as a sustainable resource that lasts for long periods of time and for decades to explore the vast space where the energy saving required for the operation of cameras, sensors, communications, etc.