2. DEFINITION
A nuclear and radiation accident is defined by the
International Atomic agency as an “event that has led to
significant consequences to people, the environment or the
facility”.
Examples include lethal effects to individuals, large
radioactivity release to the environment, or “reactor core
melt.”
3. Two of the major nuclear accidents
are as follows:
(i) Chernobyl Nuclear Disaster (ii) Fukushima Daiichi Nuclear Disaster
4. INDETAILABOUTTHEAccident-1
Chernobyl Nuclear Disaster:
26th of April 1986 witnessed one of the world’s worst Nuclear Disaster ever in
Chernobyl. Chernobyl is approximately 80 miles (which is 120 kilometers) north of the
capital city of the Ukraine, Kiev. The accident took lives of 30 people immediately and
vast evacuation of 135000 people within 20 mile radius of the power plant was carried
out after the accident.
5. Causes of the Accident:
A chain reaction occurred in the reactor and got out of control, causing explosions and a
huge fireball which blew off the heavy concrete and steel lid on the reactor.
These are the causes:
1. Design fault in RBMK reactor
2. A violation, of procedures
3. Breakdown of communication
4. Lack of a ‘Safety Culture’ in the power plant
6. Consequences of the Accident:
1. Environmental consequences:
Within 4 years of the accident nature began to restore itself, but genetically these plants may be scarred for life.
2. Health effects:
Firstly, there was a huge increase in Thyroid Cancer in Ukrainian children (from birth to 15 years old).
3. Psychological consequences:
There has been an increase in psychological disorders such as anxiety, depression, helplessness and other
disorders which lead to mental stress.
4. Economic, political and social consequences:
The worst contaminated areas were economically, socially and politically declining as the birth rate had
decreased and emigration numbers had substantially risen which had caused a shortage in labour force.
7. INDETAILABOUTTHEAccident-2
Fukushima Daiichi Nuclear Disaster:
The Fukushima Daiichi nuclear disaster was a series of equipment failures,
nuclear meltdowns, and releases of radioactive materials at the Fukushima
I Nuclear Power Plant, following the Tohoku earthquake and tsunami on 11
March, 2011. It is the largest nuclear disaster since the Chernobyl disaster
of 1986.
The plant comprises six separate boiling water reactors originally designed
by General Electric (GE), and maintained by the Tokyo Electric Power
Company (TEPCO). At the time of the quake, Reactor 4 had been de-fuelled
while 5 and 6 were in cold shutdown for planned maintenance.
8. The remaining reactors shut down automaticallyafter the earthquake, and emergency generators came
online to control electronics and coolant systems. The tsunami resulted in flooding of the rooms
containingthe emergency generators.
Consequently those generators ceasedworking, causing eventual powerloss to the pumps that circulate
coolant waterin the reactor. The pumpsthen stopped working, causingthe reactors to overheat due to
the high decayheat that normally continuesfor a short time, even aftera nuclear reactor shut down.
The flooding and earthquake damage hindered external assistance.In the hours and days that followed.
Reactors 1, 2 and 3 experienced full meltdown. As workers struggled to cool and shut down the reactors,
several hydrogen- air chemical explosionsoccurred.
The hydrogen gas was produced by high heat in the reactors causing a hydrogen-producingreaction
betweenthe nuclear fuel metal claddingand the watersurrounding them. The government ordered that
seawaterbe used to attempt to cool the reactors this had the effectof ruining the reactors entirely. As the
water levels in the fuel rods pools dropped, they began to overheat. Fears of radioactivity releases led to
a 20 km (12 mi)-radius evacuation around the plant.
During the early days of the accident workers were temporarily evacuated at various times for radiation
safety reasons. Electrical power was slowly restored for some of the reactors, allowing for automated
cooling.
9. DATA ANALYSIS OF NUCLEAR ACCIDENTS
III.
I. Benjamin K. Sovacool has reported that worldwide there have been 99
accidents at nuclear power plants. Fifty-seven accidents have occurred since
the Chernobyl disaster, and 57% (56 out of 99) of all nuclear-related
accidents have occurred in the USA.
II. Serious nuclear power plant accidents include the Fukushima Daiichi
nuclear disaster (2011), Chernobyl disaster (1986), Three Mile Island
accident (1979), and the SL-1 accident (1961). Stuart Arm states, “apart
from Chernobyl, no nuclear workers or members of the public have ever
died as a result of exposure to radiation due to a commercial nuclear
reactor incident.”
Nuclear-powered submarine mishaps include the K-19 reactor accident
(1961), the K-27 reactor accident (1968), and the K-431 reactor accident
(1985). Serious radiation accidents include the Kyshtym disaster, Wind
scale fire, radiotherapy accident in Costa Rica, radiotherapy, and radiation
accident in Morocco, Goiania accident, radiation accident in Mexico City,
radiotherapy unit accident in Thailand, and the Mayapuri radiological
accident in India.
