NUCLEAR REACTOR : RISKS &
ROLL NO. 46
T.E. AUTO (2013-2014)
• This is a presentation showing the real effects of Nuclear Power Plants how harmful it actually is
compared to other forms of energy.
• After this presentation we evaluate the risks and benefits of Nuclear Energy generation.
TYPES OF RADIATION
• What is radiation?
• Transmitted Energy
• Types of radiation
• Electromagnetic (radio, visible, x-rays, γ rays)
• Charged particles (electrons, protons, α particles)
• Other (neutrons, neutrinos, other exotic beasts)
• Categorized as either ionizing or non-ionizing
• Depending on whether they can ionize other particles
(i.e., rip off electrons from the atom)
• All 3 types of radiation can be ionizing depending on
their energies. Ionization Interaction
EFFECTS OF RADIATION
Dose delivered over an extended period of time.
Dose delivered over a short period of time.
An acute dose is generally more damaging than a chronic dose of the same size, because the body’s
repair mechanisms have less opportunity to act.
Immediate Effects (hours to days)
– Skin reddening, inflammation
– Immune suppression
– Blood chemistry changes
– Loss of hair
– Gastrointestinal syndromes
– Central nervous system syndromes
Long term effects (months to years)
– Cancer / leukemia
– Genetic defects
– Blood disorders
– Lifespan shortening
Natural uranium consists of mainly 3 isotopes :
Isotope % Abundance Half Life (years)
U-238 99.284 4.5billion
U-235* 0.711 704million
U-234 0.005 245thousand
*Must be enriched up to about 3-5% for commercial fuel
The good stuff!!
As we can see, from the total ore mined, only a small fraction is used for actual energy generation. Thus extraction and
enrichment of uranium ore is an expensive process and increases the cost of energy production.
The most commonly used fuel for production of energy by Nuclear Fission is Uranium.
• The reactor is where the energy is
• Neutrons produced in a chain reaction
split uranium-235 atoms into smaller
atoms, converting the mass difference
into pure energy as given by Einstein's
equation E = mc2. The reaction has to be
controlled and kept running continuously.
The reactor is a very complex generator
which is expensive to build and requires
Pressurized Water Reactor ( Light water Thermal Reactor)
• Nuclear waste is one of the major issues in
Nuclear power production today.
• Even though a very tiny amount of waste is
created in nuclear power production, the spent
fuel rods are hot and highly radioactive with half
life of billions of years.
• Nuclear waste cannot be disposed easily due to
the risk of radioactive contamination in organisms
which can cause mutations and last for
• There is currently no full proof method of dealing
with these spent fuel rods. Burial deep into the
earth (Deep Geological Repository) is the most
commonly employed method, but it suffers the
risk of earthquakes and natural calamities and
being unearthed by future generations.
REACTOR SAFETY FUNDAMENTALS
• What is the biggest risk to the public that is unique to nuclear power reactors?
– Release of radioactive materials.
• Release is prevented by Multiple-
– Reactor Primary Coolant System
– Containment / Safety Systems
MAJOR REACTOR ACCIDENTS
1. SL-1 (Idaho)
• Criticality Accident - Destroyed reactor and killed
three operators. Little release of contamination in
spite of the fact that SL-1 did not have containment.
• Fatalities - 3
2. Three Mile Island (Pennsylvania)
• 50-80% of fuel in core melted. Reactor core and
vessel were total losses. Containment held.
• Fatalities - 0
3. Chernobyl (Russia)
• Super Critical Power Excursion which created a steam
explosion and destroyed the plant. “Containment”
4. Fukushima (Japan)
• Natural disaster of tsunami overwhelmed emergency
systems. Suspect reactor core damage.
• No known fatalities.
• The main source of radiation for general public is the
background radiation which lies in the range of 1mSv to
• Studies have shown that low level radiation can be
beneficial to biological life forms.
• Public dose limits for exposure from uranium mining or
nuclear plants are usually set at 1mSv/yr above background.
• Radiation from Grand Central Station (NYC) is 5.25mSv/yr,
from St. Peter Square (Vatican) 8mSv/yr and from eating a
banana 0.1μSv/yr (Banana equivalent Dose).
• Anything below 0.25Sv (250mSv) has no observable effects.
Hormesis is a biological process where cells react
differently to small doses of otherwise harmful
• The stress of low dose exposure causes cell to
“learn” (or evolve) to efficiently repair
• Possible effects of Hormesis :
• Increased cell growth/fertility
• Reduction in cancer incidence
CASUALTIES COMPARISON TO OTHER
Deaths from Accidents from Generating Electricity per Billion Mwe-h
400-page study of 4,290 energy-related accidents:
• 15,000 deaths related to Oil
• 8,000 related to Coal
• 5,000 related to Gas
Paul Scherrer Institute , Switzerland. (2001)
• It is not possible to accurately estimate costs on a
• 0.453592kg (1 Lb.) of Uranium 235 produces energy
equivalent to 260,000,000 kilograms
• The capital cost for construction of a nuclear facility
and manufacturing of fuel rods is quite high, but once
running, the nuclear power plant produces more
energy pre dollar compared to other conventional
The major hurdle of Waste Disposal
and Accidents can be overcome in
the future through research and
better engineering. We must keep
an open mind and not be afraid of
"A day without sunlight is a day without radiation."
- Proffessor Larry Foulke
(Department of Mechanical Engineering and Materials Science)
(University of Pittsburgh)
Much fear and paranoid is observed
among the people towards newer
technologies like Nuclear
Power, Genetically Modified
Food, Artificial Intelligence, etc. This
irrational attitude towards new
technology is what Arthur Clarke
called “The Frankenstein Complex”.
With the world’s energy needs
growing, there is a dire need of
energy that is constantly
Nuclear energy can provide such
energy and fulfil most of our current