Nuclear Safety Lect1(Environmental studies.pdf

Specific objectives
INTRODUCTION Binding energy – fission process – radio activity – alpha, beta and gamma rays radioactive decay – decay schemes – effects of radiation – neutron interaction – cross section – reaction rate – neutron moderation – multiplication – scattering – collision – fast fission – resonance escape – thermal utilization – criticality.

1. National Ribat University
Nuclear Engineering and Safety Course
“Nuclear power is a hell of a way to boil water.”
- Albert Einstein
Dr Ahmed Hassan
July 2018

2. 2
Specific objectives
INTRODUCTION Binding energy – fission process – radio activity – alpha, beta and
gamma rays radioactive decay – decay schemes – effects of radiation – neutron
interaction – cross section – reaction rate – neutron moderation – multiplication –
scattering – collision – fast fission – resonance escape – thermal utilization – criticality.
REACTOR CONTROL Control requirements in design considerations – means of
control – control and shut down rods – their operation and operational problems –
control rod worth – control instrumentation and monitoring – online central data
processing system.
REACTOR TYPES Boiling water reactors – radioactivity of steam system – direct cycle
and dual cycle power plants-pressurized water reactors and pressurized heavy water
reactors – fast breeder reactors and their role in power generation in the Indian context –
conversion and breeding – doubling time – liquid metal coolants – nuclear power plants.
SAFETY OF NUCLEAR REACTORS Safety design principles – engineered safety
features – site related factors – safety related systems – heat transport systems – reactor
control and protection system – fire protection system – quality assurance in plant
components – operational safety – safety regulation process – public awareness and
emergency preparedness.
RADIATION CONTROL Radiation shielding – radiation dose – dose measurements –
units of exposure – exposure limits – barriers for control of radioactivity release – control
of radiation exposure to plant personnel – health physics surveillance – waste
management and disposal practices – environmental releases.

3. The 100 Ton Test
On May 7, 1945, 108 tons
of TNT stacked and
threaded with
radioactive material
was detonated in the
White Sands desert in
New Mexico.
This explosion was
meant to calibrate the
instruments that would
measure the actual
nuclear bombs to be
tested later.
3

4. Atomic Structure
Nuclear technology takes advantage of the power locked in
structure of atoms, the basic particle of matter.
The nucleus of an atom
contains all of its
positively-charged protons
and non-charged neutrons.
Negatively-charged electrons
orbit the nucleus.
Atoms always contain equal numbers of protons and electrons,
, making them electrically neutral.
4

5. Atoms can have different numbers of
neutrons in their nuclei.
Nuclei from the same element with
different numbers of neutrons are
called isotopes.
Most isotopes are stable, but some
can spontaneously break apart,
emitting energy and particles.
This is radiation.
5

6. Nuclear weapons harness a specific type of decay called
nuclear fission.
This is the splitting of the nucleus into two smaller fragments.
The fuel used by the first
nuclear weapons was
Uranium-235, a naturally
occurring isotope.
Uranium-235 has an
extremely large nucleus
that can be split when it
is hit with a high-speed
neutron.
6

7. In a nuclear bomb, a large amount of uranium-235 is clustered
together, so that when fission is initiated in one of the atoms, it
splits and released more neutrons, which then cause fission in
other atoms.
This creates a fission chain
reaction.
Each time a nucleus splits,
a large amount of energy is
released.
Multiplied across the entire
chain reaction…
7

8. World Distribution of Uranium

9. Trinity
The first nuclear test detonation used a device
that was an exact replica of “Fat Man”, which
would later be dropped on Nagasaki, Japan.
The heat of the explosion fused the desert sands
together, forming a layer of radioactive green
glass.
9

10. Two atomic bombs were dropped during World War II – Hiroshima
and Nagasaki, Japan.
Each had yields of 15-21 kilotons of TNT.
These blasts ended World War II.
10
Hiroshima, March 1946.

11. Following World War 2, additional nuclear weapons testing was
moved to part of the Marshall Islands, called the Bikini Atoll
(11°N, 165°E).
This testing was codenamed “Operation Crossroads.”
11

12. Two nuclear devices were detonated at sea as part of Operation
Crossroads.
The purpose was to study the effects of a nuclear blast on an
armada of naval ships.
The first blast, called Shot Able, was dropped from a plane. The
second, Shot Baker, was detonated underwater, beneath the
ships.
Different species of lab
animals were placed
on several ships, to test
for radiation poisoning
following the blast.
12

13. Operation Crossroads
Fallout
Glenn Seaborg,
chairman of the
Atomic Energy
Commission, called
Baker “the world’s
first nuclear disaster.”
The target ships of Shot
Baker were all heavily
contaminated with
radioactive fallout.
Some were so “hot” that they could not be safely
decontaminated and had to be sunk.
13

14. Operation Castle
In 1954, six large nuclear tests were conducted.
The largest was code named Castle Bravo.
This tested a new design, called a hydrogen bomb.
14

15. Castle Bravo Fallout
Castle Bravo was a much more
powerful blast than expected.
Residents of nearby atolls were
exposed to toxic levels of
radioactive fallout.
A Japanese tuna fishing boat called
the Lucky Dragon 5 was also caught
in the blast radius.
1
5

16. Nuclear fallout is dust and ash propelled into the atmosphere
following a nuclear blast.
Radiation exposure from fallout is measured in rems.
100-200 rems causes mild symptoms, such as nausea and vomiting.
400-600 rems has about a 50% mortality rate.
600-1000 rems will usually cause death.
Over 1000 rems will cause death in a few hours or less.
Interior exposure of fallout, from breathing or ingesting the dust
and ash, would have even more severe effects.
An average person will be exposed to about 620 millirems of
radiation per year from natural and man-made sources.
16

17. Radioactive coral dust fell on the Lucky Dragon 5.
Fishermen touched the dust with their bare skin, inhaled it, and in
some cases, tasted it.
One crewmember died from exposure.
17

18. Atoms for Peace
As the Bikini nuclear testing continued, President Dwight
Eisenhower gave a famous speech to the United Nations:
“My country wants to be
constructive, not destructive.”

“…the United States pledges before you…
its determination to help solve the
fearful atomic dilemma--to devote its
entire heart and mind to find the way by
which the miraculous inventiveness of man
shall not be dedicated to his death, but
consecrated to his life."
18

19. Equipment and technology were provided to schools, hospitals,
and research institutions to help develop nuclear technology
towards more peaceful goals.
The primary goal: electricity generation.
Optimism for the new technology was very high.
Lewis Strauss, chairman of the Atomic Energy Commission,
predicted that,
“Our children will enjoy in
their homes electrical energy
too cheap to meter.”
19

20. Dr. Ahmed Hassan
Introduction of
Nuclear Power Plant

31. Summary: How Nuclear Energy Works

32. World Nuclear Power

42. NUCLEAR POWER PLANT
YES OR NO???????

56. Fukushima
The most recent meltdown occurred following a
massive earthquake and tidal wave off the coast
of Japan.
The generators powering the water pumps of
some of the Fukushima Daiichi reactors were
flooded.
Without cooling water, the core overheated and
experienced a meltdown.
56

57. Contaminated water from the plant leaked into the
Pacific.
Top predators, like bluefin tuna, caught in the Pacific
have positively tested for small amounts of radioactive
fallout.
A single serving of tuna has less than half of the exposure
from an arm x-ray.
57

58. 58
Radioactive Waste Management
About 100,000 tons of low-level
waste (clothing) and about 15,000
tons of high-level waste (spent-
fuel) waste is stored in the U.S.
from reactor usage.
Spent fuel rods are temporarily
placed in deep water pools while
they cool down and the fission
reaction slows.
Waste is then moved to large casks
of metal and concrete near the
reactor.

59. 59
The U.S. Department of Energy
announced plans to build a high-
level waste repository near Yucca
Mountain, Nevada in 1987.
The facility met three important
criteria for long-term waste
storage:
Low moisture.
Geologically stable.
Far away from major population
centers.
Plans to use Yucca have since
been halted, due to objections
from Nevada residents.
No long-term storage plan has
been accepted by the U.S.

60. 60

61. Some alternative methods of nuclear waste
disposal have been researched.
Transmutation uses the waste as fuel in a
different type of reactor, which converts it to a
less-dangerous waste.
Geologic disposal involves
depositing the waste
deep below the Earth’s
crust in stable rock
formations.
61

62. Nuclear energy makes up only a fraction of our
total energy generation.
Its use may increase in the future, as fossil fuels
become more scarce or are considered too
environmentally damaging.
62