Jens Martensson
University Teaching Department,
Rajasthan Technical University, Kota
Practical Training Report:
Rajasthan Atomic Power Plant, Rawatbhata
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SUBMITTED BY -
MALAY JADIA
B. TECH IV YEAR
ELECTRONICS & COMMUNICATION ENGINEERING
UTD, RTU, KOTA
TRAINING PERIOD : JUNE 13, 2022 TO JULY 11, 2022
SUBMITTED TO :
Dr. MITHILESH KUMAR
Dr. M. L. MEENA
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Jens Martensson
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PREFACE
• As we know that an engineer has to serve an industry,
for that one must be aware of industrial environment,
their management, problems and the way of working
out their solutions at the industry.
• After the completion of the course an engineer must
have knowledge of interrelation between the theory
and the practical. For this, one must be familiar with
practical knowledge with theory aspects.
• I have been lucky enough to get a chance for
undergoing this training at RAJASTHAN ATOMIC
POWER STATION (RAWATBHATA). It is a
constituent of board of Nuclear Power Corporation of
India, Limited. This report has been prepared on the
basis of knowledge acquired by me during my training
period at the plant.
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ACKNOWLEDGEMENTS
It awards me abundant pleasure and aspiration in presenting my training report
consisting of various pages along with suitable drawings and references. As this is my
first effort to prepare a training report, I have tried my best to compile all necessary data
yet there may be possibility of error and omission.
I want to express my heartiest gratitude to Mr. N. K. Pushpkar, Site Director, RR Site ; Mr. A.
P. JAIN, Training Superintendent and my training coordinator Scientific Officer SO/F at
NTC RR SITE for providing me an opportunity to get a rigorous training at Rajasthan
Atomic Power Station, Rawatbhata.
I would like to convey my special thanks to my project-guide Mr. A. P. Jain, SO/F NTC RR
SITE for his guidance and supervision during my training period.
I would like to extend my thanks to all other field engineers, supervisors and technicians of
RAPS, those who directly and indirectly helped me during this training period with there
valuable guidance and help provided in understanding the task of this training.
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My training at RAPS covered gathering information about the
general working of the plant, safety features and various
technical aspects of the design. This gave way to general
classification of various systems of the plant, then covering the
information about the theory and working of Control Systems of
the plant. Further it included knowing about the maintenance
work carried in the NTC Control & Instrumentation Shop.
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•THREE STAGES OF INDIAN NUCLEAR POWER PROGRAMME
•Introduction
India figured on the nuclear power map of the world in 1969, when two Boiling Water Reactors (BWRs) were
commissioned at Tarapur (TAPS-1&2). M/s. General Electric Company (GEC) of USA built these reactors on
turnkey basis. The main objective of setting up these units was, largely to prove the techno-economic
viability of nuclear power and to obtain experience in operation & maintenance of nuclear power plants and to
demonstrate technical viability of operating the nuclear power stations with Indian regional grid system. For
Tarapur plant all the components and nuclear fuel were imported and the roles of Indian Industries were
limited to construction, erection and service contract.
However, as a long term strategy, the Nuclear Power Programme formulated embarked on the three stage
nuclear power programme, linking the fuel cycle of Pressurized Heavy Water Reactor (PHWR) and Fast
Breeder Reactor (FBR) for judicious utilization of our reserves of Uranium and Thorium. The emphasis of
the programme is self-reliance and thorium utilization as a long-term objective.
The three stages of our Nuclear Power Programme are:
•Stage-I envisages, construction of Natural Uranium, Heavy water moderated and Cooled Pressurized Heavy
Water Reactors (PHWR). Spent fuel from these reactors is reprocessed to obtain Plutonium.
•Stage-II envisages, construction of Fast Breeder Reactors (FBR) fueled by Plutonium and depleted U
produced in Stage-I. These reactors would also breed U233 from Thorium.
•Stage-III would comprise power reactors using U233 -Thorium as fuel, which is used as a blanket in these
types of reactors.
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The PHWR was chosen due to the following:
1) It uses natural uranium as fuel. Use of natural uranium available in India, helps cut
heavy investment on enrichment, as uranium enrichment is capital intensive.
2) Uranium requirement is the lowest and plutonium production is highest.
3) The infrastructure available in country is suitable for undertaking manufacture of
equipment.
Now, let’s see some basic and important components in a Nuclear Power Plant.
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The pressurized water reactor (PWR) is a type of nuclear reactor used to the generate
electricity and propel nuclear submarines and naval vessels. They make use of light water or
heavy water as their coolant and neutron moderator.
As the name implies, the water in the reactor is pressurized. This is due to the fact that as the
pressure gets higher, the boiling point of water increases with it. This means that at high
pressures the water can operate at extremely high temperatures without boiling to steam. This is
important for the reactor as higher pressures allow for greater power output and higher thermal
efficiency. The pressure is maintained by the pressurizer, which acts to stabilize pressure
changes caused by changes in electrical load.
Water enters the reactor at 290°C, and by the time it exits it is at around 325°C. In order for it to
remain a liquid at these temperatures, the pressure must be 15 MPa, or about 150
times atmospheric pressure. By keeping the water in liquid form, the control rod system is
simplified as they are able to be placed in from the top. Therefore, if the power is lost in the
plant, the electromagnetic system holding the rods will give out, and gravity will cause the rods
to fall into the core, stopping the reaction.
The hot water flowing from the reactor flows through inverted U-tubes which acts as a heat
exchanger, heating up a secondary loop of water in what is called a "steam generator". This
secondary loop is at a lower pressure so it is able to boil to steam, which then passes
through turbines in order to generate electricity. Large reactors have up to 4 steam generators,
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each of which may be larger than the reactor itself.
A nuclear reactor is a system used to initiate and contain a nuclear chain reaction, and they
have many useful applications. These nuclear reactions produce thermal energy through
either nuclear fission (in practice) or nuclear fusion (in development). Nuclear reactors are
primarily used for the generation of electricity, however they can be used for propulsion in
vehicles such as submarines or naval vessels, for production of useful isotopes or neutrons,
and for research and training.
How do they work?
The basic operating principles of a nuclear reactor for the production of power are as
follows: Nuclear chain reactions within the reactor produce heat, which is transferred to a
coolant, the coolant either boils to steam directly or heats another loop of water into steam, it
then passes through a turbine which spins a generator, and produces electricity. Although
the basic principles appear simple, the process is fairly complex.
Economics
The building of nuclear reactors is economically intensive. The initial capital costs are high
compared to fossil fuel plants with similar output. Nuclear power requires a high amount of
additional safety, and is completely responsible for all possible nuclear waste. What makes
nuclear power economically feasible is the large amount of energy that comes from a
small volume of fuel. This relationship is known as energy density, and provides a cost
advantage to using nuclear fuels. The cost of fuel is relatively lower for a nuclear power
plant compared to fossil fuels. This is what makes nuclear reactors competitive despite high
initial capital costs.
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Moderators are used to slow down the neutrons produced from fission. This is necessary
because many nuclear fuels (uranium-235, for instance) require neutrons to be slow-moving in
order to absorb them. Nuclei with low mass numbers are most effective at doing so, therefore
materials like water or graphite are often used.
Most reactors use light water as a moderator, such as pressurized water reactors and boiling
water reactors. Carbon works similarly and is used in reactors such as the RBMK. A third type
of moderator used in CANDU reactors is heavy water, which is water composed of heavy
hydrogen, called deuterium, rather than normal hydrogen.
The graphic here should help in visualizing how a
moderator does its job: neutrons that are going too
fast are absorbed by uranium-238 and do not yield
fission (green) and the moderated neutrons are
absorbed by uranium-235 which splits into smaller
atoms and produces excess neutrons to continue the
reaction (red).
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THE FUEL
Nuclear reactors require the use of nuclear fuels, elements that can be readily altered and will
release thermal energy. Uranium is the most common element used as a nuclear fuel,
although thorium is also possible. The naturally occurring isotopes are found in countries such
as Kazakhstan, Canada and Australia.
The uranium fuel is manufactured into small fuel pellets and are packed into fuel rods and
surrounded by cladding to avoid leaking into the coolant. These fuel rods are assembled into
a fuel bundle, as seen below. There can be hundreds of fuel bundles in a nuclear reactor,
meaning there can be tens of thousands of fuel rods.
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Coolant
The coolant, as its name implies, is used to remove heat from the core and move it to
somewhere that it is useful. This keeps the fuel from overheating and melting down, at the
same time as transferring the heat to water to make steam. Light water, heavy water, and
various gases are the most common coolants for nuclear reactors. Coolants may also serve
as the moderator, as is the case in many water-moderated reactors.
CONTROL RODS
Control rods can be inserted into the reactor core to reduce the amount of fuel which
undergoes fission reactions. The rods contain neutron absorbing atoms such as cadmium. By
absorbing neutrons within the core, it prevents those neutrons from reacting with the fuel.
Control rod movement can be used to adjust the number of reactions occurring at the core, or
fully inserted to shut down the reactor completely.
Safety systems
Safety systems are those in place to shut down the reactor and prevent radioactive material
from being released. Some systems are passive, such as the dropping the control rods into
the reactor core in CANDU reactors. The control rods are suspended above the core and held
there by an electromagnet. In the event that a loss of power occurs, the control rods work to
stop the reactions in the core. Strong containment buildings must also surround the reactor to
prevent any radioactive leaks or external damage to the reactor.
Other safety systems require activation. An example of such a system is the release of large
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quantities of water to surround the reactor core. This provides cooling for the core to disperse
the thermal energy and avoid a melt down.
•INTRODUCTION TO POWER PLANTS
•Power plays a very important role in the development of the country.
• The industrial and economic growth of a developing country largely depends upon quality and quantity of power production.
• In a developing country like India generation of power should be sufficient to satisfy industrial, agricultural,
household and other needs.
• An important factor related to the generation of power is the cost of production, i.e., the cost of production
should be minimized.
• Among the various ways of power production (power generation by coal, hydroelectric power, nuclear power,
power generation by natural gas, etc.) nuclear power is most economical and provides minimum cost of production.
•In India, generation of power is by three ways: •Thermal power plants
•Hydro power plants
•Nuclear power plants
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In thermal power plants, the heat energy generated by burning of coal is
utilized to generate steam at high pressure, which is impinged on the blades
of a rotor (steam turbine) this steam turbine is coupled to a generator, which
produces power. Thus heat energy produced by burning of coal is used to
generate electricity.
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In hydro power plants, the pressure head of a jet of water impinges on the
blades of a hydraulic turbine that is coupled to a generator. Hence the
potential energy of water is used to generate electricity.
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In nuclear power plants, the heat produced during the
nuclear fission of a heavy radioactive nucleus is efficiently
utilized to produce steam at high pressure. This steam is
made to impinge on the blades of a steam turbine that is
coupled to a generator.
Among the above mentioned ways of generating power, India meets its
most of the power demands by thermal and hydro power plants, and
nearly 3% of total power generation is by nuclear power plants and that’s
why power generation from nuclear means needs more attention.
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Rawatbhata Rajasthan Site
Rawatbhata Rajasthan site is situated at Rawatbhata, District Chittrogarh, via Kota,
Rajasthan. Rawatbhata Site consists of 6 units of PHWR under operation and two unit
of PHWR under construction.
•Rajasthan Atomic Power Station (RAPS 1) (100 MWe) PHWR completely defueled
and maintained under dry preservation
•Rajasthan Atomic Power Station (RAPS 2) (200 MWe) under operation
•Rajasthan Atomic Power Station (RAPS 3 & 4) (2 x 220 MWe PHWR)
•Rajasthan Atomic Power Station (RAPS 5 & 6) (2 x 220 MWe PHWR)
•Rajasthan Atomic Power Project (RAPP 7 & 8) (2 x 700 MWe PHWR)
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
Introduction to Nuclear Energy: Nuclear Fission
A neutron splits into two big parts hits when a heavy nucleus likes that of uranium – 235 & in
addition 2 or 3 neutrons are released. However, the mass of the parts is slightly less than the
mass of the uranium nucleus. The mass that is destroyed is converted into energy (200Mev/
fission). This process is called nuclear fission reaction.
It is much more likely if neutrons are slow, in a reactor, some of the neutrons produced are
absorbed so that for every neutron causing fission, only one is left. This neutron in turn collides
with another U235 nucleus & causes fission. A chain reaction is thus set up. Also, the neutrons
have to be slowed down. The fuel in a nuclear reactor consists of Uranium that may be natural or
enriched in which proportion of U235 is increased. Either light water (for enriched uranium) or
heavy water (for natural uranium) may be used as a moderator, for slowing down the neutrons.
The water (either light or heavy) absorbs the energy released. This coolant in turn transfers its
energy to the light water. Ultimately water is turned into steam at high pressure that is used to
derive turbines as in any conventional power plant.
Some Important Nuclear Reactions:
1) 92U238+0n1→92U239→93Np239→94PU239
Typical fission reaction:
2)92U235+0n1→38Sr90+54Xe144+20n1+ γ +200MeV
Reactor poisoning reaction:
3)52Te 135→53I135→54Xe135→55Cs135→56Ba135
(Stable)
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•PLANT LAYOUT
In RAPS 3&4 plant layout has been developed on the basis of two unit modules of 220MWe and takes care of current international
safety standards.
The two unit modules have the following principle features:
•The layout is basically dependent on a unitized concept except that in some of the no safety related areas,
sharing of common facilities has been allowed on module basis.
• In some cases such as control building where safety/safety support systems of both reactors of a module are located,
the principle on physical separation between the two is adhered to.
•The turbine building is located radial to the reactor building. The safety related structure such as Reactor Building,
Reactor Auxiliary Building, Control Building, Diesel Generator Building etc., are also located as to provide safety against
the low trajectory turbine disintegration missile.
•The seismic class of structure is commensurate with the seismic class of equipment to be housed in them.
• From this consideration a separate building called Control Building designed for SSE intensities has been provided which
will house various safety and safety support systems.
•Three diesel generators provided for class III emergency power requirements of each unit are distributed and housed in two separate
safety related diesel generator buildings located one on the north side and the other on the south side of the control building.
•Reactor auxiliary building which houses mainly the heavy water systems and other safety related systems are located
adjacent to the reactor building. This location is mainly selected from the consideration of reducing the locked up
heavy water inventory in the pipe lines running between the two buildings and to shorten the length of the piping carrying active fluids.
•A common spent fuel building is provided centrally between the two reactors building on the west side.
•The orientation and location of the building is so decided as to reduce the total number of bends traversed by the shuttle
carrying spent fuel from each reactor building to the respective inspection bay.
• This building is safety related and designed as class III. The common exhaust ventilation system for Reactor Building, Reactor Auxiliary
Building, Spent Fuel Building, Service building etc. is located on the first floor of SFB at 106 m elevation.
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 Main function and objectives
 To transport 756 MW of thermal power from reactor core to steam generators (four in
number) during normal operation.
 To maintain acceptable integrity of reactor coolant pressure boundary.
 To maintain acceptable integrity of the cladding of the fuel in the reactor core.
 To remove heat from the core, after a failure of the reactor coolant pressure boundary, in
order to limit fuel damage within acceptable limits.
 To prevent the failure or to limit the consequence of failure of a component or a structure
whose failure would cause the impairment of a safety function.
 To maintain cool able geometry of the core during all operational states and postulated
accident conditions.
 It also acts as a barrier against the release of radioactivity from the core.
 To ensure that the fuel is cooled in the core by appropriate amount and proper quality of
coolant during all operation states and following accident conditions.
 A feed and bleed system is provided to maintain PHT system pressure and also to provide
flow to purification system. A relief system is provided to limit the PHT system pressure.
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Reactor Safety System
Other advanced design features include safety against low trajectory internal missiles. The
philosophy behind the design of safety systems is “fail safe design philosophy”. Components are so
engineered that their functional failure does not affect the safety of the reactor and other
engineered safety systems.
Shutdown System
The design objective for shutdown system of a reactor is to make and hold the reactor sub-critical
for all anticipated operational occurrences and postulated accident conditions even for the most
reactive core.
This objective is achieved with the help of following systems:
Primary Shutdown System – also referred to as Mechanical Shut off system.
Secondary Shutdown System – also referred to as Liquid Shut off system.
Liquid Poison Injection System (LPIS).
The first two systems are capable of making the reactor sub-critical, under all anticipated
operational occurrences and postulated accidental conditions. Liquid Poison Injection System helps to
hold the reactor sub-critical for prolonged period of shutdown, including under station black out
conditions.
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Containment
Double containment philosophy has been followed. The containment system consists of
an inner (primary) containment enveloped by an outer (secondary) containment. The
annulus between the inner and outer containments is kept at a slightly negative pressure
with respect to the atmosphere so as to minimize ground level activity release to the
environment during an accident condition.
Emergency Core Cooling System (ECCS)
ECCS is provided to cool the core and thereby limit the core damage in the event of postulated
loss of coolant accidents.
The design requirement of the emergency core cooling system is to provide sufficient cooling of
the core following a LOCA, so as to limit the release of fission products from the fuel and to
ensure integrity of fuel channels.
The emergency core cooling system incorporates the following:
High-pressure heavy water injection.
Intermediate pressure light water injection.
Low-pressure long-term recirculation.
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Reactor
In concept, the Indian pressurized heavy water reactor is a pressure tube type reactor using
heavy water moderator, heavy water coolant & natural uranium dioxide fuel. The reactor
consists primarily of calandria a horizontal cylindrical vessel. It is penetrated by a large
number of Zircaloy pressure tubes (306 for 235MWe reactor), arranged in a square lattice.
These pressure tubes also refer as coolant channels; contain the fuel & hot high – pressure
heavy water coolant. The pressure tubes are attached to the alloy steel and fitting assemblies
at either end by special role expended joints. End – shields are the integral parts of the
calandria and are provided at each end of the calandria to attenuate the radiation emerging
from the reactor, permitting access to the fueling machine vaults when the reactor is
shutdown. The end fittings are supported in the end shield lattice tubes through bearing, which
permit their sliding. The calandria is housed in a concrete vault, which is lined with zinc
metallized carbon steel & filled with chemically treated demineralized light water for shielding
purposes. The end shields are supported in openings vault wall, and form part of the vault
enclosure at these openings. Removable shield plugs fitted in the end fittings provide axial
shielding to individual coolant channels.
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Radiation Monitoring
The evaluation of external radiation hazard is usually done by:
a) Area monitoring.
b) Personnel monitoring.
a) Area Monitoring
Monitoring the radiation field with a suitable radiation survey meter so as to
confirm that the radiation levels around the location of use of the radiation
source are well in specified limit for example: not to exceed 1 mSv/wk. (100
mrem/wk.) in the area occupied by radiation workers the radiation level must not
exceed 0.1msv/wk (10mrem/wk) e.g.: in the workshop, office rooms etc.
b) Personal Monitoring
Using film or TLD badges & pocket dosimeters (DRD) does it. Every radiation
worker must wear personnel monitoring badges, while handling radiation sources.
The pocket dosimeter should be used as an additional device in special cases,
which may be specified by the RSO/competent authority. Operators of Tele flex
cameras must wear wrist badges or TLDs in addition to the personnel monitoring
badges at the chest.
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Radiation Detection Devices
DRD: A DRD is nothing but a pen – type radiation level reader. It is abbreviated as DIRECT
READING DOSIMETER. It shows the amount of radiation present in the atmosphere & also
the dose taken by the radiation worker while handling some radioactive job or doing any
work in third or fourth zone.
This dosimeter gives the reading in the form of a graph. There is a number line inside the
DRD on which a hairline movable marker in mounted which moves on the number line and
gives the reading according to the radiation present in the atmosphere.
TLD: TLD (THERMO LUMINISCENT DOSIMETER) is consisting of a thermo luminescent
material which when exposed to ionizing radiation absorbs energy, when such a material is
heated it emits light. The intensity of emitted light is proportional to the dose.
Advantages of using TLD
Dose measurements over very wide range are possible (5mrem to 105 mrem).
Long-term use is possible since they respond only to radiation.
A light which is emitted out varies directly with the dose, received simplifies calibration
which is a straight line so only two points are needed to draw it.
TLD response to radiation is the same as human tissue.
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ONE BIG QUESTION
Can the atomic reactor explode like an atom bomb?
Atomic bomb uses 100% U235 or Pu239, where as in the
reactors either it is natural uranium or enriched uranium of
1.5% to 4.5% enrichment. The effort in the bomb is to
generate maximum energy in the smallest possible time there
by resulting in the explosion, where as in the reactor the
effort is to generate rated power on a continuing basis. So,
various controls are put to ensure that the power generated
is within its capacity at all the times. Thus, design of Nuclear
reactor does not permit such explosions.
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Plant Safety Measures
Programmable Logic Control (PLC)
The logic system is an essential system for the various instrumentation and control system of the plant.
Based in the importance of nuclear safety the station logic system has been sub-divided into two
independent systems. The relay logic system and PLC systems. Relay logic system is used for all safety
related systems including engineered safety features. Based on the field proven ness of hardwired relay
logic and the experience gained from the previous projects, the relay based system for the critical
application mentioned above is used. The PLC system is technological advancement over relay based
systems.
Programmable Digital Comparator System (PDCS)
It is a micro-processor based alarm system, generating voltage free contacts for external use in trip, set
back, system logic and for alarm annunciations. This is envisaged to replace all the hardwired indicating
alarm meters of earlier plants and will provide higher reliability. For trip applications, PDCS is confined to
primary system only to provide diversity from secondary shut down system.
Channel Temperature Monitoring System (CTM)
The system consists of two computer installations for set back and flux tilt control signal generation, alarm
generation and data logging. No. of cabinets required for the system has to be reduced to four. It helps in
making the system more compact.
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Beetle Monitoring System
Beetle is a two-electrode device used for the detection of Heavy Water Spillage in various selected areas.
The change in the resistance of the Beetle, when immersed in water is the parameter, which is measured to
indicate the presence of water.
Sensor for Reactor Power
The signal used in the control and protection system to represent the reactor power is derived primarily
from the neutron flux.
Cooling Water Systems
The main objective is to remove heat from various equipments and heat exchangers in Reactor Building,
Reactor Auxiliary Building, Spent Fuel Building, Service Building, D2O Upgrading Plant and Waste
Management Plant handling radioactive fluid.
VENTILATION SYSTEMS
The plant ventilation system is classified into the following three categories:
Contaminated air ventilation system.
Clean air ventilation system.
Survival ventilation system
FIRE PROTECTION SYSTEM
Designed Objectives
To minimize potential fire loads with the view to prevent fire.
To identify fire loads for various areas.
To provide appropriate fire protection, fire detection and firefighting systems based on fire loads in the
plants.
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Thank
You
MALAY JADIA
ECE
19/394
19EUCEC032
UTD RTU KOTA
m.jadia07@gmail.com