Life in a nuclear era

8/14/2019 Life in a nuclear era

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LIFE IN A NUCLEAR ERA

Group members

Ashwin M. 04

Bento Fernandes 12

Ishan Gindra - 13

Rinat Mendon 30

Subramanyan R. 52

Nevil Thakkar - 53


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INTRODUCTION

When the first nuclear bomb was exploded on July 16, 1945 at Almogorodo

of New Mexico deserts in the USA, the great scientist and leader of the

Manhattan Project, Professor Robert Openheimer, described what he saw by

quoting two lines of famous stanza ofBhagavad Gita.

The shine of a thousand suns in the sky,

Shall nt match, my Lord, Thy brilliance.

For once the mankind at large came face to face with two faces of the atom,

one as the destroyer of humanity and the other as the provider of electrical

energy for development and prosperity. This dilemma has continued ever

since as the essence of the nuclear saga facing mankind.


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Nuclear Terror Days

When the two bombs, nicknamed Little Boy and Fat Man, were dropped by

the United States over the Japanese cities of Hiroshima and Nagasaki on

August 6 and 9, 1945, fortunately the only such cases so far, over 340,000

persons were killed barbarously. Near the centre of the explosion, people

were instantaneously vaporized by the searing heat, leaving only their

shadows scorched into the stonework of walls or roads. Thousands more

were killed by being blown to bits, more commonly being hurled against

solid objects, crushed beneath falling buildings or lacerated by the shrapnel

of flying glass. Others were simply cremated into charred corpses or

hideously burned with great patches of skin stripped from their bodies and

hanging grotesquely in flaps around them. In Hiroshima 13 sq.kms. of area

was devastated and 9.2% of all buildings destroyed. The destruction in

Nagasaki was relatively less due to its hilly terrain which shielded part of the

city from the heat and blast effects even though the bomb was more

powerful than the one dropped in Hiroshima. It is estimated that about 60%deaths were caused due to burns, 20% due to injuries and the rest due to

physical disorders caused by nuclear radiation. Hearing of those terror days,

Mahatmaji said I regard the employment of the atom bomb for the

wholesale destruction of men, women and children as the most diabolical

use of science.

Even though such horrible effects of the atom bomb became well known, the

nuclear powers went ahead with massive programmes of nuclear

weaponisation. They conducted 403 atmospheric tests between July 16,

1945 and August 5, 1963 216 by USA, 162 by USSR, 21 by UK and 4 by

France.


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THE CHERNOBYL DISASTER

Chernobyl nuclear plant is located at about 80 miles north at Kiev. On 26th

April, 1986 at this plant the worst reactor disaster took place. The accident

was a result of many small mistakes adding up to create a catastrophe.

Before the test, the power output pf the reactor was dropped in preparation

of the upcoming test. Unexpectedly the power output dropped almost to

zero. Because of this, some control rods were removed to bring the power

back up. The power output raised & all appeared normal.

Later 2 pumps were switched on in the cooling system. They increased the

water-flow out of the reactor & thus removed heat more quickly. They also

caused the water level to lower in the steam separator of the reactor. In the

hopes that the water level would rise, the operator increased the amount of

feed water coming into the steam operator. Also more control rods were

taken out of the reactor to raise the internal reactor temperature & pressure,

also hoping the water level to rise. The water level in the steam separatorbegan to rise, so the operator adjusted again the flow of feed water by

lowering it. This decreased the amount of heat being removed from the

reactor core.

As there wasnt enough coolant, the cores temperature kept rising. A valve

at the top of core automatically opened to vent some of the steam. But the

valve didnt close properly, because of which steam continued to vent from

the reactor, further reducing the coolant level. The operators didnt know

about it as the indicator in the control room was covered by a maintenance

tag. They thought that the situation was under control as the temperature

stopped rising. Because they didnt know the pump outlets were closed, they


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thought the coolant had been replaced. A few minutes later the temperature

began to rise again & the Emergency Core Cooling System automatically

switched on. But the operator deactivated thinking the situation was under

control.

Because of the coolant lost through the open valve, the core temperature

started to rise. At this point the fuel rods started to collapse from the intense

heat. The operators knew something was wrong but didnt understand what

it was. After 2 hrs. someone figured out that the valve at the top of the core

didnt close properly. During that time precious coolant was released from

the reactor. At around 6am an operator discovered it and closed the valve.

During the day, hydrogen gas began to accumulate inside the reactor &

caused an explosion later in the afternoon. The explosion did not damage the

containment systems. A group of nuclear experts were called to help as the

core was still not under operator control for past 2 days. They figured that lot

of hydrogen gas had accumulated at the top of the core, which could have

exploded or it could have displaced the reactor causing a complete nuclear

reactor meltdown. A hydrogen recombiner was used to remove some of the

hydrogen, but it was not very effective. However, hydrogen dissolves in

water, which is what the coolant was composed of. Thus, overtime the

hydrogen that had collected at the top of the core completely dissolved in the

coolant. Two weeks later the reactor was brought to a cold shutdown & the

accident was over.

No one was directly injured as a result of the accident. However some

radioactive gas & water were vented to the environment around the reactor.

At one point, radioactive water was released into the Susquehanna River,

which is a source of drinking water for near by communities. No one is


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really sure what effects these radio active releases might have had on the

people living near the power plant.


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NUCLEAR POWER & SAFETY

As mentioned earlier, when a nucleus of U 235 absorbs a neutron, the

resultant compound nucleus fissions into two fragments roughly of equal

mass number in the case of symmetrical fission and a number of unequal

fragments in other cases. These fission fragments undergo radioactive decay

and ultimately end up as stable nuclei. In the case of U 235 there are formed

over 80 primary products which, as a result of further radioactive decay,

would end up as over 200 radio-isotopes of over 30 elements as fission

products. This is simultaneously followed also by evolution of large

amounts of energy. This symmetrical fission process is described in a

simplified way as below.

U 235 + n ..> X 95 + Y 139 + 2n + 200 MeV

The major public concerns on the safety of nuclear reactors arise from the

following:

a) Health hazards from nuclear radiations (both from the background

around the reactors and from exposures from accidents).

b) Long term effects from nuclear wasters.

Based on very elaborate and rigorous scientific studies appropriate strategies

have been worked out for managing these aspects of reactor


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Nuclear Waste

Although the benefits of nuclear power seem to make it the obviouschoice for the power source of the future, it still has many drawbacks.

Nuclear disasters can become of the most devastating incidents on the

planet, and though rare, the possibility of their occurrence must be taken into

consideration. Many safety features exist to prevent such catastrophes;

however, the environment does not have any safety features to protect it

from the harmful effects of nuclear waste.

Obviously, nuclear waste consists of the Uranium broken down

during the fission process that creates nuclear energy. However, many

people forget to take into account that nuclear waste also means the

machinery used in the process, and the architecture of the nuclear power

plant. During the fission process, anything that has come in contact with the

energy created becomes radioactive. Not only does the energy released

create radioactivity, but so do the by-products created by the fission process.

The elements cesium, strontium and plutonium are highly radioactive and

must also be disposed of. Since there is no long-term solution for nuclear

waste disposal, and because nuclear energy is a relatively new source for

energy, long-term environmental and health effects remain to be seen.

Mostly, nuclear waste is just dumped in low population areas all over the

globe, but with the population growing as fast as it is, it is only a matter of

time before we will have to find a new solution. Especially if nuclear wastebegins to destroy the environment we are trying so hard to protect (Reaching

Critical Will).

The effects of nuclear waste are much like the effects of nuclear

fallout; however, the former can be avoided. Contaminated soil and


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groundwater do not have to be a problem, but they are. Increased risk of

cancer, birth defects, and infertility are just a few of the harmful effects

caused by nuclear waste. Concerned citizens created the Not in My

Backyard organization in an effort to deter government attempts to dispose

of nuclear waste near populated areas. However, the United States is

currently dumping waste in an underground site only 26 miles from a city

called Carlsbad with a population of 30,000 (Military Nuclear Mess). Now,

these people live in constant fear of possible contamination from leaking

radioactive material. The effects of nuclear waste on the population arent

only physical, they are mental as well. In 1957, the specifications for a safe

underground storage facility were a site that is dry, geologically stable,

away from natural resources and water, and has a salt creep which would

slowly entomb the nuclear substance. In addition, the waste should be

retrievable (Military Nuclear Mess).

If humans become exposed to nuclear waste, their cells may become

damaged, and repair themselves incorrectly, resulting in biophysical damage

that more often than not results in cancer. Different types of cancer than

have resulted from radiation exposure from nuclear waste include

leukaemia, breast, bladder, lung, colon, liver, lung, oesophagus, ovarian, and

stomach cancers (Harmful Effects). Humans become exposed to nuclear

waste radiation when nuclear waste is disposed of improperly. One example

is when low-level waste that is not properly stored seeps through its

containment area and comes in contact with groundwater. The same goes

for the soil. In this manner however, plants become contaminated, and in

turn the organisms that feed on them, including humans (Harmful Effects).


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USED FUEL DISPOSAL

At the present time, there is no disposal facilities (as opposed to storage

facilities) in operation in which used fuel, not destined for reprocessing, and

the waste from reprocessing can be placed. Although technical issues related

to disposal have been addressed, there is currently no pressing technical

need to establish such facilities, as the total volume of such wastes is

relatively small. Further, the longer it is stored the easier it is to handle, due

to the progressive diminution of radioactivity. There is also a reluctance to

dispose of used fuel because it represents a significant energy resource

which could be reprocessed at a later date to allow recycling of the uranium

and plutonium.

A number of countries are carrying out studies to determine the optimum

approach to the disposal of spent fuel and wastes from reprocessing. The

general consensus favours its placement into deep geological repositories,

initially recoverable.


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INTERNATIONAL DATA FILE

Nuclear Power Status around the WorldIn Operation Under Construction

Countries No. of

Units

Total net

MWe

No. of Units Total net

MWe

Argentina 2 935 1 692

Armenia 1 376 - -

Belgium 7 5,631 - -

Brazil 1 626 1 1,245

Bulgaria 6 3,538 - -

Canada 21 14,907 - -

China 3 2,167 - -Czech

Republic

4 1,648 2 1,824

Finland 4 2,310 - -

France 56 58,493 4 5,810

Germany 20 22,017 - -

* This total includes Taiwan, Chine where six reactors totaling 4884 MWe

are in operation.

Notes to table: During 1995, two reactors were shut down (including Bruce-2in Canada which could restart in the future).


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THE INDIAN SCENARIO

Indian Nuclear Energy Programme was initiated with great farsight by its

great pioneer Homi Jehangir Bhabha in March 1944 (barely sixteen months

after the Fermis demonstration of the nuclear chain reaction) through his

letter addressed to the Tata Trust soliciting support to establish an advanced

research centre in Bombay so that when nuclear energy has been

successfully applied for power production in, say a couple of decades from

now, India will not have to look abroad for the experts but will find them

ready at hand. Subsequently developments are as given below:

1945 Tata Institute of Fundamental Research, Bombay,

with Bhabha as Director

1948 April Atomic Energy Act

1948

August

Atomic Energy Commission under Ministry of

Natural Resources & Scientific Research

1954

January

Atomic Energy Establishment, Trombay

1954

August

Department of Atomic Energy with Bhabha as its

Secretary

The Department underwent steady expansion over the decades


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NUCLEAR RESEARCH CENTRE

Bhabha Atomic Research Centre, Trombay*

Indira Gandhi Centre for Atomic Research, Kalpakkam*

Centre for Advanced Technology, Indoor*

Atomic Minerals Research & Directorate, Hyderabad*

Tata Institute of Fundamental Research, Bombay*

NUCLEAR INDUSTRIAL UNITS

Nuclear Fuel Complex, Hyderabad

Heavy Water Plants, Udaypur, Baroda, Hazira, Tuticorin, Manuguru, Nangal

and Talchar

Uranium/Thorium Mills, Jadaguda, Chatrapur, Manawalakurichi and

Alwaye ECIL, Hyderabad.

NUCLEAR POWER REACTORS

Tarapur, Kota, Narora, Kalpakkam, Kaiga, Kakrappara.

Total Capacity 1820 MWe

The activities of the DAE are centered around the above units and

interestingly enough they cover all established major uses of nuclear energy .


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APPLICATIONS OF NUCLEAR ENERGY

Protector of Green House Effect

Fossil fuels including coal form the major source of energy, thereby also

contributing significantly for increase in CO2 concentration in the

atmosphere. It is estimated that unless corrective action is taken, the present

value of around 280 ppm in air by volume would double between the middle

and the next century, leading probably to a rise in global mean temperatures

greater than any in mans history, between 1.5 to 4.50C. (These values are

only typical. According to the reports of the US Oak Ridge National

Laboratory, the CO2 values were 285 ppm in 1850 increasing to 312 ppm in

1953 and 360 ppm in 1993). This Green House Effect described by some

as the granddaddy of all environmental issues, trapping an extra 2W/m2

energy on the earths surface, can be combated to a good extent through

nuclear energy which generates only one hundredth of green house gases

compared to coal. It is already eliminating 40 million tones CO2 annually in

UK, with France reducing her contribution by as high as 50% through

generation of nuclear electricity; UK Atomic Energy Authority estimates that

if the world generates 50% electricity through nuclear sources, the Green

House Effect would perhaps be eliminated altogether.

THE NUCLEAR POWER PLANT INSTALLED IN FRANCE IN 1980s ANDWITH THE HELP OF THIS PLANT IT REDUCED ITS POLLUTION BY 90%.


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Summary & Conclusions

Ever since the phenomenon of nuclear fission was discovered in 1938 by

Hahn and Strassmann and the chain reaction demonstrated in 1942 in the

Chikago Pile by Enrico Fermi, humanity have never looked back to utilize

the power of the atom. The nuclear bombs have made the humanity quite

gullible. Nuclear (electric) power on the other hand has provided a Faustian

Alternative for uninterrupted development and progress. As the well-known

Buddhist saying goes, to quote the Nobel Laureate Richard Feynman from

his The Value of Science.

To every man is given the key to the gates of

heaven. The same key opens the gates of

Hell. The value-neutral science looks as always to Man, its master, for

instructions!

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Life in a nuclear era