Aplicación Práctica / Practical Issues

Recibido: 02-10-2018, Aprobado tras revisión: 16-01-2019

Forma sugerida de citación: Ayala, E. (2019). “Nuclear Fission Reactor Generations Safety Evolution Analysis”. Revista Técnica

“energía”. No. 15, Issue II, Pp. 22-29

ISSN On-line: 2602-8492 - ISSN Impreso: 1390-5074

Nuclear Fission Reactor Generations Safety Evolution Analysis

Análisis de la Evolución de las Generaciones de Reactores de Fisión Nuclear

E. L. Ayala

GIE Grupo de Investigación de Energías “Energy Research Group”, Universidad Politécnica Salesiana, Cuenca, Ecuador

E-mail: eayala@ups.edu.ec

Abstract

Nowadays, there is a debate about how reliable nuclear

power is in terms of safety. Some countries are banning

its proliferation while others support the construction of

new nuclear power plants. There are multiple risks of its

implementation not only for the environment but also for

public health. In this paper it is analyzed the evolution of

nuclear fission reactors safety features through

generations for security improvements. It is included

information about how nuclear power plants guaranty

safeness and what the real risks are when producing

nuclear power. Moreover, some accidents in the past are

described as well as radioactive waste management.

Finally, some standards and attributes for energy

production are also presented. The aim of this analysis is

to provide different perspectives from technical to social

implications of nuclear power to offer a clear

understanding of nuclear waste hazards. The focus is not

only on the role of international regulations but also on

past accidents that have led to develop nuclear fission

reactor generations. In this work, it is explained the

importance of supporting nuclear power nonproliferation

until real solutions are found for nuclear radioactivity

threat.

Index terms



Nuclear Fission Reactor, Nuclear

Generations, Safety, Radioactive Waste.

Resumen

Hoy en día, existe un debate sobre qué tan confiable es la

energía nuclear en términos de seguridad. Algunos países

están prohibiendo su proliferación, mientras que otros

apoyan la construcción de nuevas centrales nucleares.

Existen múltiples riesgos de su implementación no solo

para el medio ambiente sino también para la salud

pública. En este artículo se analiza la evolución de las

características de seguridad de los reactores de fisión

nuclear a través de generaciones para mejorar la

confiabilidad. Se incluye información sobre cómo las

plantas de energía nuclear garantizan la seguridad y

cuáles son los riesgos reales al producir energía nuclear.

Además, se describen algunos accidentes en el pasado, así

como la gestión de residuos radiactivos. Finalmente,

también se presentan algunos estándares y atributos para

la producción de energía. El objetivo de este análisis es

proporcionar diferentes perspectivas de las implicaciones

técnicas de la energía nuclear para ofrecer una

comprensión clara de los peligros de los desechos

nucleares. La atención se centra no solo en el papel de las

regulaciones internacionales, sino también en los

accidentes pasados que han llevado al desarrollo de

generaciones de reactores de fisión nuclear. En este

trabajo, se explica la importancia de apoyar la no

proliferación de la energía nuclear hasta que se

encuentren soluciones reales para la amenaza de la

radioactividad nuclear.

Palabras clave— Reactor de Fisión Nuclear, Generaciones

Nucleares, Seguridad, Residuos Radiactivos.

Revista Técnica “energía”, Edición No. 15, Issue II, Enero 2019

1. INTRODUCTION

Historically, nuclear energy career started after the first

nuclear weapon was development in United States in 1945

leading a new controversial strategy for energy production.

Scientists studied nuclear fission where heavy nucleus are

separated into lighter nucleus and fusion reactions where two

nucleus are combined into a heavier ones. They replicated

fission by using raw materials such as: Uranium-235,

Plutonium-239, Plutonium-241 and Uranium-233 [1]. The

first prototypes of Nuclear Power Plants (NPP) were

developed in USA. In 1951 the first nuclear reactor was used

to produce electricity in an isolated facility in Idaho. Soon

after, in 1954 the first NPP was connected to a Soviet Union

electric grid. As a result, the era of nuclear energy began [2]

[3].

NPPs usually consist of multiple stations with individual

reactors working in parallel. It allows continues energy

production while other stations can be shut off for

maintenance [4]. First of all, each station generates electricity

by fission reaction produced inside the reactor when an

incoming neutron is launched to a Uranium-235 atom which

releases two free more neutrons and the Uranium become in

Krypton-97 and Barium-137 fission fragments [5]. Fusion is

the opposite reaction that produces energy by adding different

atoms creating a new one. For example, when the atom of

Deuterium and Tritium are launched they form helium which

is very stable. This method is still being researched for energy

production since the scientific community is interested in

developing more efficient energy sources [6].

Inside the NPP, the Nuclear Fission Reactor (NFR) is the

core of nuclear power where fission occurs. When fission

starts, decomposition of matter releases considerable amounts

of heat that is usually captured by water (or another fluid) and

quickly transformed into steam. Consequently, the fluid

moves into a close loop passing through electric turbines

transforming the kinetic forces into electricity. Then, the fluid

is cooled using different coolants through a heat exchanger

systems and then the cold fluid is returned again into the cycle.

That is why most of NPPs have big cooling towers [5].

Inside the NFR there are multiple rods of Uranium or

another chosen active material forming an array [7]. Between

them are disposed rods named “poison” which are heavy

matter for fission control [8]. When the rods are introduced

very deeply the energy released is reduced. On the other hand,

when the poison is not located properly it could produce over

fission reaction. If this process fails, the result is called

“melting of the core” where fission destroys the container of

the NFR which is usually built using different concrete layers

plus thermic insulation materials in order to prevent the scape

of radioactive fluids. As a result, manipulation of high

temperatures, radioactive byproducts, kinetic forces and

electricity involves some hazards that are considered for a

proper NPP design and licensing [9].

Nowadays, many countries recognize the classification of

NPPs by generations. The purpose is to find the best method

for controlling nuclear power generation and preventing

catastrophes in case of accidents or attacks. The scientific

community is still reviewing the standards, however other

methods are been researched to provide the mechanisms for a

safe nuclear energy production [6] [7] [10]. At the moment

there are principally four generations of NPP referring to

security and operational standards [8]. They are implemented

in order to improve safety performance.

Even though multiple improvements have been developed

in nuclear stations, there is a controversial discussion about

how reliable fission reaction is since many disasters have

occurred in the past. The aim of this work is to analyze the

advantages and disadvantages of nuclear energy based on the

nuclear fission reactor generations safety evolution. In the

second section of this work it is presented the nuclear power

plants attributes that are usually considered for a new design.

In the third section it is described the nuclear fission reactor

generations and characteristics as well as the time line. The

fourth section presents the hazards of nuclear stations based

on historical events, present-day threats and future problems.

Finally, fifth section analyses the current and future scenario

for nuclear energy based on the presented information.

Radioactive waste management is also presented to

understand how nuclear stations are dealing with these

unavoidable by-products. Statistical data is analyzed in

contrast with political, economic, environmental and social

implications for supporting the non-proliferation of nuclear

energy.

2. NUCLEAR POWER PLANTS ATTRIBUTES

Over the last few decades there are multiple debates about

the proliferation of nuclear power. In Europe for instance

Germany has promoted shutting down their nuclear fission

reactor by the end of 2022 [11]. Some countries such as India

and China on the other hand seek for new NPPs

implementations [12]. Another important benefit is the

reduction of carbon emissions to the environment as the

Environmental Protection Agency (EPA) promotes [13].

There are economic implications that promote the

proliferation of nuclear power since its implementation and

operation is considerable low cost compared with other energy

sources. Because of this international interest, there are some

organizations that regulate and provide recommendations for

nuclear energy safety. For instance, the International Atomic

Energy Agency (IAEA) and the Nuclear Energy Agency

(NEA) seek for a peaceful use of nuclear energy [14]. This is

because the closeness between nuclear energy and nuclear

weapons. For this reason, many countries create their own

standards and regulations for NPP facilities leading political

implications. Moreover, because of the environmental threat,

some legislations also influence the law as well as the

engineering aspects for the design [15].

When planning a NPP construction, there are social,

economic and technical implications for the proposed design.

Those implications are usually described by authors from

different perspectives, for instance: social, environmental,

technical and economic considerations are usually discussed.

Governments often organize different commissions that are

required to apply guidelines in order to attain the best possible

design [9]. For instance, S. Goldberg and R. Rosner describe

some of the following attributes for a NPP design and

implementation [8]:

Ayala E. / Nuclear Fission Reactor Generations Safety Evolution Analysis

2.1. Cost Effectiveness

It refers to the capacity of replacing fossil fuels with

renewable energy as well as the methods involved. For

instance, investment, times and life-cost cycle of the plant are

important factors in order to guaranty competitive kilowatt

hour cost for consumers. Generally, nuclear energy is not

considered entirely renewable because it requires other

sources for fueling the reactor. Rokhshad Hejazi states that

nuclear energy is an important solution to reduce carbon

emissions besides that economic advantages over

governments and the environment [14]. Moreover, the energy

can be considered renewable if uranium extraction can be

also conceived unlimited. For instance, Claude Degueldre

states that uranium extraction using parsimony in sea water

could be carried indefinitely [7].

2.2. Safety

Nuclear Energy is considered a critical contaminant. On

one hand, the manipulation of active materials implies the

generation of radioactive waste. On the other hand, when an

accident occurs in a NPP, a lot of radiation can be released to

the environment.

2.2.1 Fission Reactor Accidents

During fission reaction, the core of the reactor can reach

high temperatures (480°C to 950°C) in order to generate

electricity [8]. Therefore, a cooling system must be

implemented for lowering the extreme temperature in the

reactor. However, if the cooling systems fails, the

temperatures can reach critical temperature similar to core of

the sun (where nuclear fusion of hydrogen nuclei produces

helium and huge amounts of energy). The extreme heat can

melt the structure of the reactor releasing radioactive

byproducts. This type of accident is one of the most

dangerous because environmental impact is irreversible and

can occur at any moment if safety protocols fail (usually

when cooling the reactor). That is one important reason for

some governments to prohibit nuclear energy proliferation

[9].

2.2.2 Radioactive Waste

Another problem that NPPs face is nuclear waste. When

it is not properly disposed, it may affect health of people and

damaging different ecosystems making the area inhabitable

for almost any live form.

2.2.3 Security and nonproliferation

This factor is related with the demand of NPP around the

world. Nowadays the scientific communities as well as

different organizations are promoting the nonproliferation of

nuclear energy because of the hazards of double use of this

technology for producing nuclear weapons since NPP is the

first step to reach nuclear weapons. In this context, potential

terrorist or military attracts represent a risk to be considered

in the design of the NPP.

2.2.4 Grid Appropriateness

NPPs must be connected to the grid which allows to

provide extra energy. However, it implies an investment

related with security, control and monitoring systems. The

purpose is to maintain the NPP connected to the grid and

generate as much power as possible and maintain the levels

of frequency and voltage stable. For instance, grid connection

can produce faults that affect entire countries representing

millions of dollars in losses [16].

2.2.5 Commercialization roadmap

This factor relates with roads availability for NPPs

construction and operation. That means the considerations for

the development of regions or cities have to be considered in

order to do not affect the expansion of territories preserving

the area where the NPP will be located.

2.2.6 The fuel cycle:

It is also important to consider that the fuel for a reactor

cycle is a critical element in determining the safety protocols

for a specific design. For example, the thermodynamics in

NPP is usually controlled by the reaction itself but also by

external systems. There are some different methods to

transmit the steam to the turbine.

3. NUCLEAR FISSION REACTOR GENERATIONS

In order to classify the existing NPP systems around the

world, it was necessary to standardize and categorize the NPP

into generations. Nowadays, there are four generations

running on around the world. Most of them are controlled by

organizations as The Academy’s Committee on International

Security Studies (CISS), the more recently, the Academy’s

Global Nuclear Future (GNF) Initiative—under the guidance

of CISS—is examining the safety, security, and non-

proliferation implications of global spread for nuclear energy

[8]. There are basically four generations that describe the NPP

evolution.

3.1 Generation I

Generation one is basically a prototype of NPP which was

conceived for experiments. For long time many different NPP

were built around the world. All of those are considered

Generation I because they basically do not follow any

international specifications. On the other hand, NPPs are the

result of nuclear weapons development. This is because the

prototypes are required in order to obtain the necessary

materials to experiment with fission and attain energy. The

first NPP generation one appears in United States in 1950 and

the last one operated in United Kingdom in 2010 [8].

The safety issues of this generation are related to the lack

of security protocols when fission is conducted. After the

fission heats up the water, the molecules vibrate very fast

producing steam. In Generation I and some Generation II

NPPs the steam was directly conducted to the turbine and then

to the generator. In this NPPs there were no heat exchanger

and the steam produced by fission was directly released to the

environment implying radioactive pollution dispersed by

wind. There is a debate about how much of this radioactivity

remains in water and soil, but it is understood that even if it

was dispersed it still exist active. For this reason, in new

designs the heat exchanger is incorporated in order to guaranty

the safety of the system.

Revista Técnica “energía”, Edición No. 15, Issue II, Enero 2019

Moreover, the system can be easily tested, monitored and

controlled. When the steam is cooled to be returned to the

cycle again, that prevents to overheat the materials and the

consequently destruction of the reactor core [17].

3.2 Generation II

These types of reactors were developed for commercial

purposes only. They were improved versions of previous

generation designed to obtain more power. They were

economically more reliable with a typical life time of 40 years.

Those Reactors include Pressurized Water Reactors (PWR),

Canada Deuterium Uranium reactors (CANDU), Boiling

Water Reactors (BWR) and Advanced Gas-cooled Reactors

(AGR). Those are the basic examples for this kind of

technology. Most of the NPP around the world are using this

technology because it was developed with commercial

purposes. Moreover, the lifetime of generation one is each

time finished and replaced by Generation two. However, for

new NPP there is a new option called Generation III [8].

3.3 Generation III

This generation was developed during the last two

decades. This technology implies the same commercial

purposes of Generation II but includes some advantages. The

portability is one of the main reasons for choosing this

technology. Any power plant in the world using a different

fuel than the nuclear can be easily replaced with Generation

III. The safety and reliability of those systems are very high

compared with the generation two NPP. That is why the new

NPP around the world are been built following this new

standard. The life time of these plants are around 60 years of

operation and could be easily increased with the correct

maintenance. Those new reactors are regulated by NRC. The

first-Generation III reactor were built in Westinghouse

producing 600 MW using an ABWR and being tested by

NRC. It was built and went outline in Japan in 1996. However,

today there are other Generation III power plants working

around the world. Only a total of five generation power plants

are in service around the world. No third-generation power

plants are working in United States [8].

3.4 Generation III +

Significant changes in the design were added later in

NPPs. In United States in 1990s the NRC was the responsible

to certify the design and construction of the first generation

III+. Some other countries also adopted this standard, but they

are not officially considered in this category. There are

significant changes in the protocols. The most relevant change

is the implementation of new passive safety features which

means that the reactor is not likely to suffer any problem due

to human mistakes. The Generation III+ NPPs are basically

working in Canada, United States, Europe, Japan and China

[8] [18].

Canada is an example of Generation III+ power plants

certificated; similarly, some countries have adapted new

politics about the use of NPP. In Canada there are some NPPs

operating in Quebec, Ontario and New Brunswick. The

Canadian Nuclear Safety Commission (CNSC) regulates their

operation. After the use of the fuel or active material, the

remaining waste is disposed in water pools used as a shield for

between 5 to 10 years. These pools are specially designed to

support earthquakes and terrorist attacks. Not only the

disposition of nuclear waste is regulated but also the security

in the generation itself is also reinforced. They focused mainly

in the contention of radiation, cooling the fuel and the control

of the reactor. The systems are monitored continuously. The

CNSC utilizes some of the following safety backups including

[19]:

 Shout-off rods that are inserted automatically between

the fuels or active material rods in the reactor to

prevent overheating.

 Cooling the reactor by introducing frozen liquid or

“poison” to immediately stop the nuclear reaction.

Those security back-ups are continuously tested by

operators and they can perform any activity with or without

human intervention. The systems also do not require external

power intervention to guaranty the protection.

The CNSC states that for controlling the cool system in the

NPP, it is also important to cool the fuel using different

mechanisms even if the plant is not operating. The CNSC also

states that heat transport systems bring the heat produced by

the reactor to the steam generators. This system is made up of

very robust pipes, filled with heavy water which is a rare type

of water found in nature. Pipes and other components are

maintained and inspected regularly and replaced if necessary.

Inspections include measuring pipe wear, tear and identifying

any microscopic cracks or changes to prevent lines collapse

[19].

United States is researching the possibility of using

spheres containing active component and poison to have a

more complex nuclear fission. These spheres will be also

covered by an extra layer of a special material that will contain

the radioactive components in case of accidents. Also, the

temperature achieved by these spheres will be much lower

compared with the traditional generation two and three core

reactors [18].

3.5 Generation IV

This technology is still under research. The objective of

this generation is to reduce cost, increase life time of the

reactor and also improve safety and sustainability. Sodium fast

reactor has become the principal founded project since it

employs liquid sodium coolant achieving higher power

density at lower pressure. This system promises to generate

from 1000 to 1500 MW with long core life up to 20 years

without refueling.

Many countries are founding this research including

Canada, USA, China, France, Japan, Russia, South Korea,

South Africa, Switzerland, and the EU. Non-active members

include Brazil, Argentina, Australia and United Kingdoms.

Generation IV

Generation III+

Generation III

Generation II

Generation I

50's

60's

70's

80's

90's

2000

2010

2020

2030

2040

Figure 1. Nuclear fission reactors evolution

Ayala E. / Nuclear Fission Reactor Generations Safety Evolution Analysis

Technologies under research such us: Molten salt reactor

(MSR), Sodium-cooled fast reactor (SFR), Supercritical

water-cooled reactor (SCWR), and Very high-temperature gas

reactor (VHTR) [20]. Fig. 1 shows the evolution of NFRs

generations along a timeline.

4. NUCLEAR POWER PLANT HAZARDS

In the past years most of NPPs accidents have occurred

when poisoning rods have been manipulated incorrectly

producing explosions or melting. Safety violations also have

been reported as well as structure failures due to natural

disasters. Deficient instrumentation also has been detected

allowing radiation to be released to the environment.

4.1. Nuclear Power Plant Accidents

According to Jakub Sierchuła there are about 449 nuclear

reactors for electricity generation around the world and more

than 60% of these are PWRs [21]. Even though they follow

safe standards, the risk of accidents is always present since

they have occurred in the past causing significant

humanitarian, environmental and economic disasters around

the world. As a result, some countries are banning nuclear

energy completely or at least the non-proliferation [11].

Scientists are researching for options that imply nuclear

energy safe generation by improving the current standards and

protocols. In order to attain safe technology, different

accidents around the world have studied in order to manage a

more precise fission control.

When measuring the balance of a nuclear disaster, the

IAEA introduced a seven-level scale. For instance, there have

been registered only two level seven events in history. One

occurred in 1986 in northern Ukrainian Soviet Socialist

Republic, Soviet Union and the other one was in 2011 in

Fukushima Daiichi, Japan. In both cases, information was not

clear about the incidents. Hence, some authors state that there

are governments hiding the information related to the real

implications of nuclear energy production [22].

Other minor disasters have been reported around the

World including United States where at least one incident per

year has been detected. The most significant disaster was in

Pennsylvania in 1979 when a meltdown occurred in a NFR

releasing radioactivity to the atmosphere and the nearby rivers

[15]. People exposed to radiation presented chromosomes

anomalies after some time. However, some governments are

encouraging still people to believe that this information is not

scientifically proved. This problem is still under investigation

because of the number of cases of cancer reported due to

radioactivity. However, it seems that some governments

promote the proliferation of Nuclear Power Plants while

others ban them completely.

The issue is because this NPP was working without the

respectively permissions and using falsification as a method

to pass the inspections. Moreover, the NPP in Japan was

designed to support earthquakes and more accidents.

However, when the tsunami hit the shore of Japan, all the

backup safety systems failed at the same time. That means that

not even the lack of a correct design but also the risk was well

know before the accident many investigations revealed. In

addition, third generation power plants are designed to work

for at least 40 years [8]. But this was not the case in Japan. All

this controversy reaffirms the idea that Nuclear Power is not

only a technical issue but also it implies the appropriate

regulation, the government control and intervention, the

international certification and control, but more than that the

Nuclear Power should be considered as the last resource to

generate energy in a country until the completely safety of the

system is assumed.

It is important to note that in the catastrophe in Japan in

Kashiwazaki, the radioactivity released to the ocean was about

0.6 liters - 280 Becquerel which is very dangerous and was

transferred to different places [23]. On Wednesday, 18 July

2007, at Unit 7, radioactive iodine was detected and at that

time some workers of the company were already exposed to

high levels of radioactivity. The leakages in the reactor

number two were about 0.9 liters - 16,000 Bq. For those

reasons, the Committee of Nuclear Security in Japan then

decided that the NPP will be closed and a deep investigation

was opened after finding that the reasons for the fault in the

reactor was due to problems in the backup design. Although

the facilities are more secure now, the future impact as well as

the implications in the present of the habitants of the near

communities is still unknown. The total impact of this disaster

is still under investigation [24].

Fukushima is a very important item in the nuclear history

because after this accident, many countries as Germany, Italy,

and Switzerland announced the prohibition of Nuclear Energy

production within their territories. Those countries allege that

this is not a question of technical issues but is also a question

of guaranty the health of the people and the environment [10].

4.2. Nuclear Waste Environmental Implications

Nuclear waste is all residual components that contains

radioactivity. It could be produced by: decomposition of

active materials such as Plutonium or Uranium, materials used

for their manipulation or active mineral extraction. The

production of these by-products usually is regulated by

government agencies. There are many issues about the

disposition of nuclear waste around the world. For instance,

environmental protection organizations have found some

companies discarding barrels with radioactive waste into the

ocean with low protection. This practice was justified because

it was considered that sea water will dilute the radioactive

components. However, this affirmation is not proved to be

safe for humans and the marine environment.

When nuclear waste is confined appropriately, the risk of

contamination is very low. However, control agencies have to

periodically verify these disposals and their radiation levels.

On the other hand, when an accident occurs in a NPP, the

radiation levels and propagation depend on many different

factors such as the presence of wind, rivers, sea, pressure,

temperature and even the magnitude of the accident. Some

companies provide information about radioactive levels close

to the NPPs. For instance, in Japan the government require the

NPPs to measure radioactivity exposition levels and inform it

to the citizens.

Revista Técnica “energía”, Edición No. 15, Issue II, Enero 2019

However, in the case of Pennsylvania NPP accident, they

were also required to measure these levels but when the

accident occurred, the measured level was considered normal

meaning those devices or the information presented where

manipulated somehow.

According to the IAEA in the published: Radioactive

Waste Safety Standards (RADWASS) radioactive waste is

classified into five principal categories [25]:

4.2.1 Uranium tailings

heavy metals left over during mining process. This is not

considered as radioactive hazard.

4.2.2 Low Level Waste

Also known as Low Level Radioactive Waste (LLW)

includes all elements used for radioactive components

manipulation as well as nuclear fuel cycle of energy

generation. Requires shielding during transportation and is

usually buried.

4.2.3 Intermediate Level Waste

Also known as Intermediate-level radioactive waste (ILW)

includes all elements used for energy production and

chemical processes where the radioactive components are

solidified in concrete or bitumen before disposed properly.

Cooling is not required however proper area designation is

required.

4.2.3 High Level Waste

Also known as high-level radioactive waste (HLW) usually

once the fuel rods that have been used for a fission cycle into

a nuclear reactor finishes the process, it is removed and

disposed. This is the most radioactive element after fission

occurs and accounts 95% of all the radioactive byproducts of

nuclear energy generation around the world.

4.2.4 Transuranic Waste

It refeers to all transuranic components usually used for

nuclear weapons manufature. They are usually disposed into

confinated military facilities. Governments have been

investigating about the best possible scenarios for high level

waste considered long-term nuclear waste. However, because

of the risks all of those ideas represent only few have been

implemented. These options can be seen in Table I.

International agreements have made important progresses in

banning some hazardous disposals options. Not only for the

environmental treat but also for people health compromise.

For instance, Tc-99 long-lived fission products could remain

radioactive for 220,000 years and I-129 about 15.7 million

years [25].

When humans are exposed to ionizing radiation, it is able

to penetrate very deep in the body producing destruction of the

gens and chromosomes. The symptoms are fever, diarrhea and

headache very similar to the consumption of poisonous food.

Then, depending of the amount of exposition the symptoms

could last for few days before the person dies. However, in

small quantities the mutation of the genes produces

modification of the DNA structure in long term. This mutation

is even transmitted to the following generations and

irreversible [10]. It is also important to note that people are

constantly exposed to radioactivity, a very common example

is the isotope of radon 222Rn that induces cancer in people

and is present in some building materials [26].

Table 1. Waste disposal options

Waste

Disposal

Option

Description

Countries Involved

Near-

surface

disposal

Currently in use. LLW disposed

at ground levels or inside

caverns deep below the surface

Czech Republic,

Finland, France, Japan,

Netherlands, Spain,

Sweden, UK, and USA.

Deep

geological

disposal

Currently in use from 250 m to

5000 m depths.

France, Sweden,

Finland, and the USA,

UK and Canada

Long-term

on ground

storage

Project currently conceived

only as interim measure

France, Netherlands,

Switzerland, UK, and

USA

Disposal in

outer space

Abandoned project because

high cost which consisted

launching HLW to the deep

space.

USA

Rock-

melting

Banned project because

international agreements. For

heat generated HLW to be

injected as a fluid in solid

isolated massive rocks.

Russia, UK, and USA

Disposal at

subduction

zones

Banned project because

international agreements. HLW

to be located in subduction

(places where a section of Earth

descends beneath another one )

USA

Sea

disposal

Banned project because

international agreements.

Some countries implemented

this method in the past dropping

LLW and ILW.

Belgium, France,

Germany, Italy, Japan,

Netherlands, Russia,

South Korea,

Switzerland, UK, and

USA

Sub seabed

disposal

Banned project because

international agreements.

LLW, ILW and HLW to be set

beneath deep ocean floor.

Sweden and UK

Disposal in

ice sheets

Banned project because

international agreements.

For HLW mainly where it is

disposed in extreme cold

isolated places and buried in ice

USA

Deep well

injection

Implemented in Russia injecting

LLW and ILW in liquid form

deep wells where the waste gets

trapped underground.

Russia and USA

5. NUCLEAR ENERGY GENERATIONS

EVOLUTION ANALISYS

Nuclear energy generations evolution responds different

factors that has lead the development of safer and more

reliable production. According to the World Nuclear

Association, about 11% of the world´s electricity is produce

in NPPs [27]. This is a significant amount of energy

considering the rapid growth of renewable energies. Nuclear

stations fife time is another important consideration for new

generation development. The embrittlement of reactor

materials forces to decommission NPPs every 40 to 60 years

[28].

Ayala E. / Nuclear Fission Reactor Generations Safety Evolution Analysis

For this reason, the implementation of more reactors

around the world implies a nuclear waste over production.

Environmentally this is an issue that has not faced a permanent

solution nowadays. The proliferation of nuclear stations

increases risks of spreading radioactivity worldwide in case of

emergencies. That is why the nuclear scientific community

renews the safety standards continuously.

From Generation I to Generation IV, there are important

progresses in safety measurements. These improvements

respond to international and politic influences for supporting

nuclear energy proliferation. Moreover, there are countries

that have low natural resources such as Belgium where about

50% of the total energy is generated by nuclear stations [27].

Generally, these countries rely on their work force and that

implies high energy consumption. This reality demands more

technological improvements for new nuclear energy

implementations since the population energy demand

increases every year [29]. In other words, nuclear energy

generations evolution responds not only to necessity of

improving methods for energy production but also responds to

the global energy demand. Considering this form of energy is

relatively inexpensive compared with other sources, many

countries have decided to improve the conditions for its

implementation.

On the other hand, countries such as Germany have

proposed to change their energy production policy. They are

transitioning from nuclear to more reliable renewable

energies. In the case of Germany this is part of a program

named Energiewende (energy transition) [27]. Other countries

have signed an agreement for the peaceful use of nuclear

energy. However, most of the developed countries have

refused to sign that treaty since some possess nuclear weapons

[30].

The more nuclear stations around the world, the more

nuclear waste is produce and the more risks for nuclear

weapons development. Moreover, nuclear power plant

facilities represent a permanent treat of accidents or terrorist

attacks. These evidences probe that even though nuclear

energy is supporting the development of nations, the real cost

and its permanent dangers should be considered to decide

which source of energy must be selected worldwide. Until

now, nuclear energy generations evolution is still attempting

to find temporary solutions to the mentioned problems.

CONCLUSIONS

Even though nuclear power has proved to be an efficient

mechanism for energy production, radioactive waste

generation and military double use of nuclear power facilities

are international concerns. These issues have encouraged

some governments to ban its proliferation. Low, medium and

high-level waste management are not able to offer a

permanent solution for present civilization and future

generations. Moreover, some accidents have revealed the

vulnerability of nuclear power plant facilities. Radioactive

waste generation cannot be avoided for nuclear energy

production. Most of international organizations establish

environmental priority and some governments prioritize the

economic benefits of low costed energy production.

After some nuclear accidents and findings of the effects of

radiation on living organism have led in many improvements’

requirements for future facilities, these progresses are mainly

focused in reinforcing safety protocols leading the evolution

of nuclear power plants from generation I to IV. However, in

generation III+ and IV. there is still a risk of accidents caused

for extreme circumstances where facilities are not able to

manage emergencies such as natural disasters or terrorist

attacks.

There have been some important progresses in nuclear

waste management. For instance, governments have

prohibited damping any type of nuclear waste into the oceans,

the Antarctic or any other geological formations. Even though

these efforts have shown some results, it has not been

developed an efficient method to manage nuclear waste and

the 449 fission reactors around the world continue producing

dangerous by-products. It must be clear for future

implementations that it is urgent to find a permanent solution

for nuclear waste. Meanwhile, it must be granted the non-

proliferation of nuclear energy worldwide.

ACKNOWLEDGMENTS

I would like to take the opportunity to thank Professor

Jagdish Patra for inspiring me to follow the research path

during my master´s studies in Australia.

REFERENCES

[1]

B. Viswanathan, Energy sources : fundamentals of

chemical conversion processes and applications., Saint

Louis: Elsevier Science, 2016.

[2]

R. L. Murray and K. E. Holbert, "Chapter 8 - The history

of nuclear energy," in Nuclear Energy, Boston,

Butterworth-Heinemann, 2015, pp. 109-121.

[3]

S. Şahin and H. M. Şahin, "1.20 Nuclear energy," in

Comprehensive Energy Systems, I. Dincer, Ed., Elsevier,

2018, pp. 795-849.

[4]

M. Modarres, T. Zhou and M. Massoud, "Advances in

multi-unit nuclear power plant probabilistic risk

assessment," in Reliability Engineering & System Safety,

vol. 157, 2017, pp. 87-100.

[5]

S. Şahin and Y. Wu, "3.14 Fission energy production," in

Comprehensive Energy Systems, Elsevier, 2018, pp. 590-

637.

[6]

T. Koyanagi et al, "Recent progress in the development

of SiC composites for nuclear fusion applications,"

Journal of Nuclear Materials, 2018.

[7]

D. Claude, "Uranium as a renewable for nuclear energy,"

Progress in Nuclear Energy, vol. Volume 94, pp. 174-

186, 2017.

[8]

S. Golberg and R. Rosner, "Nuclear reactors: generation

to generation," Cambridge, MA: American Academy of

Arts and Sciences, vol. 2, pp. 1-3, 2011.

[9]

D. P. Amber, "Extending life by half [nuclear power plant

relicensing]," IEEE Spectrum, vol. 38, no. 11, pp. 48-51,

2001.

Revista Técnica “energía”, Edición No. 15, Issue II, Enero 2019

[10]

J. Deutch et al, "The future of nuclear power,"

Massachusetts Institute of Technology Report of Nuclear

Power, 2003.

[11]

K. Bruninx, D. Madzharov, E. Delarue and W.

D'haeseleer, "Impact of the german nuclear phase-out on

europe's electricity generation," 2012 9th International

Conference on the European Energy Market, pp. 1-10,

2012.

[12]

S. Jain, "Inevitability of nuclear power in the asian

region," Energy Procedia, vol. 7, pp. 5-20, 2011.

[13]

S. William, "EPA's clean power plan: what to do about

nuclear power?," The Electricity Journal, vol. 28, no. 2,

pp. 10-16, 2015.

[14]

H. Rokhshad, "Nuclear energy: sense or nonsense for

environmental challenges," International Journal of

Sustainable Built Environment, vol. 9, no. 2, pp. 693-700,

2017.

[15]

R. P, "Engineering development and environmental law,"

Engineering Management Journal, vol. 10, no. 2, pp. 85-

87, 2000.

[16]

D. C. Smith, "Power cuts: risks and alternatives to the

current transmission system,," Refocus, vol. 4, no. 6, pp.

22-25, 2003.

[17]

D. A. Berkowitz and A. M. Squires,, "Nuclear power and

radionuclides in the environment," Power Generation

and Environmental Change, pp. 21-21, 2003.

[18]

M. J, "Evolution of nuclear fission reactors: third

generation and beyond," Energy Conversion and

Management, vol. 51, no. 9, pp. 1774-1780, 2010.

[19]

C. N. S. Commission, "Nuclear power plant safety

systems," 2018. [Online]. [Accessed 25 June 2018].

[20]

W. N. Association, "Generation IV nuclear reactors,"

2018. [Online]. Available: http://www.world-

nuclear.org/information-library/nuclear-fuel-

cycle/nuclear-power-reactors/generation-iv-nuclear-

reactors.aspx. [Accessed 2 June 2018].

[21]

S. J, "Analysis of reactivity changes during the operation

of a nuclear power plant," 2018 International

Interdisciplinary PhD Workshop (IIPhDW), pp. 61-66,

2018.

[22]

S. Ho, J. Looi, A. Chuah, A. Leong and N. Pang, "“I can

live with nuclear energy if…”: exploring public

perceptions of nuclear energy in Singapore," vol. 120,

Singapore, 2018, pp. 436-447.

[23]

A. Hasegawa et al, "Health effects of radiation and other

health problems in the aftermath of nuclear accidents,

with an emphasis on Fukushima," The Lancet, vol. 386,

no. 9992, pp. 479-488, 2015.

[24]

M. Nishikawa, T. Kato, T. Homma and S. Takahara,

"Changes in risk perceptions before and after nuclear

accidents: Evidence from Japan," Environmental Science

& Policy, vol. 55, no. Part 1, pp. 11-19, 2016.

[25]

I. A. E. Agency, "IAEA Regulatory control of nuclear

power plants," October 2000. [Online]. Available:

https://www.iaea.org/ns/tutorials/regcontrol/legis/legis1

121.htm?w=1radioactive+waste+safety+standards.

[Accessed 23 June 2018].

[26]

F. Del Claro, S. Paschuk, J. Corrêa, V. Denyak, J.

Kappke, A. Perna, M. Martins, T. Santos, Z. Rocha and

S. H.R, "Radioisotopes present in building materials of

workplaces," Radiation Physics and Chemistry, vol. 140,

pp. 141-145, 2017.

[27]

W. N. Association, "Nuclear Power in the World Today,"

[Online]. Available: http://www.world-

nuclear.org/information-library/current-and-future-

generation/nuclear-power-in-the-world-today.aspx.

[Accessed 7 January 2019].

[28]

D. Abbott, "Is Nuclear Power Globally Scalable? [Point

of View]," Proceedings of the IEEE, vol. 99, no. 10, pp.

1611-1617, 2011.

[29]

Energy Information Administration, “eia Beta

International,” [Online]. Available:

https://www.eia.gov/beta/international/. [Accessed 8

January 2019].

[30]

R. Gladstone, “"A Treaty Is Reached to Ban Nuclear

Arms. Now Comes the Hard Part",” New York Times, p.

2017, 9 August 2017.

Edy Leonardo Ayala Cruz.- He was

born in Cuenca, Ecuador in 1987. He

obtained his Bachelor degree of

Electronic Engineer from Universidad

Politécnica Salesiana, Ecuador in 2011;

his Master degree of Electrical and

Electronics Engineering Science from

Swinburne University of Technology,

Australia in 2015. His field research involves electronic

sensors, electrical safety, renewable energies and intelligent

systems.