NUCLEAR WEAPONS-HOW DO THEY WORK?

 

With the current battle between Israel and Iran and the US involvement in the war day before yesterday, the news about Iran’s nuclear facilities and enriched Uranium have come to the fore.

What is the process through which Nuclear Weapons work?

For knowing this we have to go to the atomic structure of the atoms. Now there are two varieties of nuclear devices; Fission and Fusion. Both of them depend on the principle of release of energy from the atoms. Fission involves the energy released when an atom is split into different smaller atoms while fusion involves the energy released when two atoms fuse together to produce another bigger atom. In both cases there is release of energy. The latter process takes place in our Sun and it loses 42 lac tons of matter each second on account of fusion which is turned into energy and the Sun shines with that radiation.  

But why does an atom split in the first place? An atom consists of particles called protons (positive charge) and neutrons (neutral) in the nucleus with the electrons (negative charge) going round  them in different orbits.

The Periodic table starts with the Hydrogen atom.  A Hydrogen atom has 1 proton and no neutrons. It has one electron orbiting the nucleus.

The next element Helium has 2 protons and 2 neutrons in the nucleus. Now how can that be?,  because 2 protons mean 2 positive charges staying close together in the nucleus while like charges repel each other? Moreover, there are 2 neutrons in the nucleus as well. Why are all these 4 particles, 2 protons and 2 neutrons stay together in the nucleus? What is the force holding them? On top of that, the nucleus of an atom is highly dense, and has a density that is a few lakh crore times that of water. All the 4 particles 2 of whom have the same charge packed like that in the nucleus? Scientists call the force holding them together cohesive force or nuclear force.   

On the periodic table the elements from Hydrogen and Helium onwards which has 2 protons and 2 neutrons to Silver which has 47 protons and 61 neutrons, the cohesive force is greater than the repealing force between the protons in the nucleus. However, after Silver in the higher elements the repulsive forces slowly strengthen while the cohesive force starts decreasing. Therefore there is a tendency for the protons and neutrons in the nucleus to try and free themselves from the nucleus. But this tendency strengthens only very gradually

For example in Gold which has 79 protons and 197 neutrons and Mercury 80 protons and 200 neutrons, this process is so slow that in a few centuries only one atom splits. The same thing continues till the element Lead which has 82 protons and 207 neutrons. But the elements that come after that are more unstable and the repulsive forces strengthen over the cohesive forces. As a result those higher elements keep on losing particles from their nucleus and finally end up as lead where stability again comes into the nucleus. In this process energy is released with each breakup. This process of successively losing charges from its nucleus till the element lead is realised, radiating energy is known as radioactivity. 

It was in 1886 that Henri Becquerel discovered radioactivity from a mineral of Uranium known as Pitchblende.  Uranium was the first discovered radioactive element. Becquerel discovered that such elements continuously give out radiation from their nucleus as they disintegrate. Even after removing Uranium completely from Pitchblende Becquerel found that it is still giving out radiation and requested Madam Curie to find out the reason. Madam Curie along with her husband Pierre Curie researched on it for 2 years and isolated 2 more radioactive elements named Polonium and Radium from it.  Radium had a radioactivity that is 20 lac times that of Uranium. Thereafter, Thorium was discovered and also other radioactive elements. However, the most stable and naturally available radioactive element is Uranium.  It has 92 protons in its nucleus. The most abundant isotope (different number of neutrons) of Uranium is U-238 which has 146 neutrons and U-235 which has 143 neutrons. The latter isotope is very rare in nature. Then there is the U-234 which has 142 neutrons. This is even rarer in nature.  

In U-238 the nucleus is forever in flux and it deteriorates on account of Radioactivity. As already stated earlier all the unstable radioactive elements deteriorate to finally become lead. The time taken for half the material taken to turn into lead is called the half-life of that element. U-238 has a half-life of 450 crore years, but this is a mere 1600 years for Radium.

Till now all we discussed earlier was natural radioactivity. We earlier talked about the cohesive forces that hold the nucleus of protons and neutrons together. When radioactive elements deteriorate to the element lead, the cohesive force that holds the nucleus together gets released in the form of energy, with some of its matter getting completely being destroyed.  

When scientists first estimated the force that is so released, the human race was surprised because some mass of the original element for deterioration was completely lost in the action. And that entire mass got converted into energy. Using the Einstein’s formula of e=mC² the energy so released was enormous because the C in this equation is equal to 299,792,458 and this has to be squared for calculating of energy released.

The mass of an atom is defined in Atomic Mass Units (AMU). The unit is also called the Dalton. It is one twelfth the mass of a C-12 Carbon atom. The atomic mass of a Carbon atom is 1.993*10^-26Kg.

As already stated the most abundant element of Uranium, the U-238 is not very fissile and takes a long time to deteriorate. It can be bombarded with fast moving neutrons to induce speedier radioactivity. However, its isotope U-235 is more fissile and can get split with bombardment of neutrons with lesser speed. The initial atomic devices made in the world including the one exploded on Hiroshima used this U-235 isotope. But this isotope is rare (at a mere 0.72% of all Uranium) and is not available to make many bombs. So scientists have artificially developed an element called Plutonium which is as fissile as U-235. The weapon used on Nagasaki was a Plutonium bomb. If the abundant U-238 is bombarded by fast neutrons then Neptunium is produced, it then deteriorates and produces Plutonium.

What happens when either the U-235 or Plutonium atom is bombarded with neutrons? They would split into two and the process releases 2-3 neutrons, which in turn bombard the other U-235 or Plutonium atoms in the lump and release more neutrons which in turn would bombard the other atoms. So the reaction proceeds without any further intervention and is known as the CHAIN REACTION. Each stage of this reaction releases big energy and as it continues, and as all the U-235 or Plutonium deteriorates massive amount of energy is produced in the form of radiation.

Now here comes another concept called the CRITICAL MASS. The chain reaction cannot continue uninterrupted unless certain amount of U-235 or Plutonium is available. This is known as the critical mass. In the atomic bombs the destructive power of the bomb is limited to the under twice the critical mass. At critical mass the chain reaction automatically takes place without any human intervention. Two quantities of U-235 or Plutonium, both below the critical mass (to prevent immediate Chain reaction) is taken so that neither part would be able to sustain a chain reaction. In an atom bomb an explosive apart from fissile material, is placed to explode which forces the two masses together and that initiates the chain reaction.  

The bomb that was exploded on Hiroshima contained less than 4.4 tons of U-235, but it had an explosive power of 20,000 tons of TNT. The minimum mass required to sustain a chain reaction of U-235 is 52 Kgs. Of course the size varies based on the purity of U-235 used.

Now, what is URANIUM ENRICHMENT? As already stated earlier while U-238 is less fissile, its isotope U-235 is more so and can sustain a chain reaction. Therefore a nuclear device can only be made with U-235 and not with U-238. But as the quantity of U-235 available in a quantity of Uranium is only 0.76%, the U-235 can be obtained by using a centrifuge to separate the two isotopes as the weights of the isotopes U-238 & U-235 are different. The percentage quantity of fissile Uranium 235 present in a Quantity of Uranium is known as the enrichment of Uranium. For nuclear power an enrichment of 3-5% is sufficient while for producing atomic bombs the enrichment should be 90% or more. Iran has enriched the Uranium to 60% or more as per its own admission and claims that it is for peaceful purposes. Actually for that they only require a maximum of 5% enrichment, so no reason whatsoever Iran should enrich Uranium to 60% unless they have an atom bomb in mind.  

Plutonium does not require any enrichment, but first it has to be artificially produced by bombarding U-238 with fast moving neutrons. In Plutonium the critical mass for a chain reaction is between just 10 to 15 Kg. The Nagasaki bomb contained only 6.2 Kg of Plutonium which is the reason why only about 1 Kg of Plutonium fissioned during the detonation.    

In the Hydrogen bomb the explosion is achieved by integrating two atoms into one and it is the opposite of fission. In this, 2 Hydrogen isotope atoms (Deuterium & Tritium) fuse into a Helium atom releasing energy. The bomb would be of more compact size and lesser in weight compared to the atom bombs. Unlike in the atom bombs there is nothing called a critical mass for the Hydrogen bomb and any amount of material can be used, with the capacity of the carrier of the weapon being the only constraint?  Tsar Bomba exploded by the Soviet Union in 1961 is a Hydrogen bomb ( also known as a Thermonuclear device)  and it packed the explosive power of 50 Megatons or 5 crore tons TNT. It is 2500 times more powerful than the Hiroshima bomb. The Tsar Bomba weighed a stunning 27 tons. For detonating a Hydrogen bomb, an atom bomb acts as a trigger by creating immense amount of heat in order for the fusion to occur.    

These nuclear bombs release massive amounts of energy and cause tremendous amount of destruction. Any war involving them would put entire humanity at risk and is not confined to just one or two countries. Therefore, the lesser countries have them, the better. Okay, while nothing can be done to the countries who already have them (9 in number), there is every reason for the world to nip in the bud a nuclear weapons program of any country, if any new country attempts to acquire them. The more the number of such countries, the more the risk to the world.

PLASTIC POLLUTION IN THE WORLD-AN ENVIRONMENTAL THREAT.

 

In the year 2022 based on the data of the Central Pollution Control Board  from 23 states and UTs CSE has concluded that only 12% of plastic waste in India is recycled, 20% of it is burnt and the remaining 68% is unaccounted for which means it is left in the soil.

Little wonder that India emerged as the largest plastic polluter in the world as per a study published in the Sep 24 issue of "Nature" magazine.

Of the 52 million tons of waste plastic produced annually in the world, India accounts for 20% or 9.3 million tons. This is the quantity of waste that is thrust onto the environment.

Burning of plastic generates poisonous gases and every year about 5.8 million tons of plastic is openly burnt in India. 3.5 million tons escapes as loose plastic into the environment which gets into the oceans.

India is actually producing less plastic waste than China but India mismanages that waste and becomes the number 1 plastic polluter in the world.

The 2nd worst polluter in the world is Nigeria with 3.5 million tons....third Indonesia 3.4 million tons and fourth China with 2.8 million tons.....

1. Tamilnadu.     0.8

2. Telangana.     0.5

3. Delhi.               0.4

4. Maharashtra. 0.4

5. Karnataka.     0.35

Plastics take 500 to 1000 years to decompose causing long term accumulation.

They contribute 80% of marine pollution forming huge garbage patches in the oceans. After some time plastics decompose into microplastics causing contamination everywhere. They are eaten by animals along with food.

Plastics contain toxic chemicals including pesticides and flame retardants linked to cancer, heart disease, reproductive and other severe health conditions

Plastic production accounts for 5% of Earth's greenhouse gas emissions.

Global plastic pollution is projected to triple by the year 2040 and it would outweigh all the fish on the earth by the year 2050.

If the type of plastics we use higher numbers are not recyclable.

Only PET and HDPE are freely  recyclable and are often recycled.

PVC, PP, LDPE and PS ( Polystyrene) are not recyclable.

Clearly there is a case for reducing the usage of the latter 4 plastics.

We use LDPE bags freely as though it is our right. Some few places have enforced their ban. But in many other places they are in high use.

BOMBAY AND DELHI - A COMPARISION.

 

I have gone many times to Bombay, but the city never ceases to fascinate me. It is a blend of all the Indian cultures and its inhabitants have their own unique behaviour and are very cultured. Unlike Delhi which has a strong Punjabi culture, Bombay is very metropolitan and is a mixture of all cultures.  

Ask anyone a location in Bombay and he would take pains to guide you there. So mutual cooperation between people at Mumbai is its first tenet. This is in typical contrast to Delhi where people don’t even respond to you, or even if they do it would be very cursory. Speech wise the Bombayite is soft and understanding while a Delhiite is rough and  loud.

This in fact reminds me of what one of my daughters classmates from Lucknow surname Nigam (I don’t remember her first name now) told me. They were originally from Lucknow but her father was working at Delhi so she comes from there. She said uncle most of our time is taken up at Delhi in trying to watch our step so that no one would cheat us and that always keeps us busy.

Bombay is the safest city in India for women. They roam freely even after 12 PM in the night returning back from parties and nothing happens to them. One day one taxi driver from UP told me that it is common to get drunk girls returning from parties much later than even 12 PM. 

He told me that one day one girl got into his taxi at about 2 AM fully drunk. So drunk that she could hardly tell him her address and then passed out on the backseat. That guy half carried her to her house and her family appreciated him very much. A Sub Inspector of Police from Bombay told me that if any girl complains of harassment, the first thing they do is to catch hold of the guy and throw him in jail without asking any questions. That is the extent  of safety girls have in Mumbai.

Yes, in the year 2014, one AP girl from Machilipatnam was killed at Mumbai, but that happened only because she rode a bike with some unknown person at 5 AM in the morning from the Lokamanya Tilak station.

The first time I ever went to Delhi was in 1987. I did not know any Hindi at all and I was right royally cheated by one Sardarji auto driver. It was January and I was not knowing about the extreme chill of Delhi and was wearing a casual half sleeves shirt. The train was supposed to reach Delhi at 8 PM in the night. There was some derailment and our train was halted at Bina for quite some time. Finally reached Delhi at 3 AM.

By that time it became very cold and I was shivering from it. I got down at Nizamuddin Station and got into an auto driven by a Sardarji, but only after asking him as to how much he would charge to the nearest Hotel for staying. Of course this I conveyed only with broken Hindi. He promptly said pay me as per the meter. I felt very happy that I could get such a nice auto driver as friends have warned me that Delhi auto drivers are notorious and I have to be very careful. The Sardarji saw me shivering and even offered me the blanket with which he was covering himself. I was very happy with his behaviour.

Then he took me to the Jungpura Extension hardly about 2.5 Km from the station, one hotel was full, so he took me to another hotel in the next lane. We would have hardly travelled about 3 Km in all. After confirming the hotel had a room I came to pay the driver and asked him how much. That guy tells me Rs 80. Now in 1987 that was a big sum for payment to an auto. It would have cost me no more than Rs 12 from the station to that place. Petrol was costing only about Rs 8 per litre at that time. So that is like asking for some Rs 600-700 of today.

Immediately I looked at the meter and found that it was showing Rs 82 something. Actually in that cold and shivering I never bothered to look at the meter and it must have run even before I got into the auto. Then I explained the problem to the Hotel fellow in English and told him that I came only from Nizamuddin station and requested him to tell that to the auto driver that he is charging too much. 

However, the hotel guy did not speak a word to the auto guy probably because he brings customers to him. I then went to the Sardarji and told him that I would pay no more than Rs 20 for the ride. Even that is like paying Rs 200 today for a 3 km drive. That fellow said no you keep it yourself I don’t want it. With that I just turned back to go in disgust when that fellow came to me again and accepted the money.

Then I asked the room tariff. The guy said he only had deluxe rooms left and the charge is Rs 1600 per day. That got me floored. As a PO of State Bank, I was just drawing a little over Rs 2000 then and the room tariff was as good as my monthly salary. But I had no choice as I was shivering with cold and was frustrated and did not sleep in the night. 

By that time it was 4.30 AM and the check out time was 12 noon which means for 7.5 hours I am shelling out Rs 1600. The room was beautifully furnished and had a thick carpet on the ground and was large. But when I slept on the bed only one thing kept coming back to me Rs 1600 for 7.5 hours. I could not sleep at all thinking about it. I vacated the room at 12 in the afternoon and shifted to one of my relatives house instead, to where I could not go late in the night.

So that was my first experience at Delhi which certainly introduced me to the place and its pitfalls. It is not my intention to say that all Bombayites are good and all Delhiites are bad and there are certainly many exceptions in both the places. Nevertheless, I found that a large number of Bombayites are more cooperative and soft than the Delhiites. 

No doubt at the time of Dawood Ibrahim etc. things were pretty bad at Bombay, but with time the city evolved out of such violence with the help of a very tough Police force which brought all the gangsters to heel. 

I give below a short history of Bombay as I have a particular liking to the city. 

The 7 islands of Bombay were earlier inhabited by Kolis. It consisted of the 7 islands of Parel, Mazagaon, Mahim, Colaba, Worli and Old Woman’s Island.

Sultan Bahadur Shah of Gujarat ceded the 7 islands of Bombay to the Portuguese in 1534 AD. 

In 1661 the islands of Bombay were passed on to the English as dowry by Catherine Braganza of Portugal who married Charles II of England. The population of Bombay was then only about 10,000.

In 1668, England leased these islands to the British East India Company for an annual payment of just 10 pounds. The population rapidly grew to 60,000 by 1675 AD. In 1687 Bombay has become the headquarters for the East India Company in India. By the middle of the 18^th century it started growing into a major trading town.

By 1845 the 7 islands of Bombay came together by way of large scale land reclamation by the “Hornby Vellard” project. In 1853 the first passenger railway line between Bombay and Thane was established. During the American civil war, Bombay became the worlds leading cotton trading market resulting in a boom to its economy.

The opening of the Suez canal in 1869 transformed Bombay into one of the largest seaports in the Arabian sea.

The years between 1990 – 2010 saw and increase in violence and terrorist activities in Bombay.

After the Babri Masjid incident, there were Hindu Muslim riots in 1992-93 in which 1000 people died.

In 1993 13 bombs went off at several places in the city killing 257 people and over 700 injured.

In 2006 when 7 bombs exploded in the city’s suburban trains another 200 people were killed and over 700 injured.

In 2008 a series of 10 coordinated attacks by armed terrorists for 3 days resulted in 173 deaths and over 308 wounded.

In July 2011 3 coordinated bomb explosions in Opera House, Zaveri Bazar and Dadar killed 26 people and injured over 130 people.

However, after 2011, Bombay had been quiet and hopefully would preserve its peace.

EXPERINCES IN MY LIFE-KEDARNATH TRIP

After coming back to Rudraprayag from Badrinath, we stayed there in the night. Next day morning at around 10 AM we started for Kedarnath. For this we had to go on road up to Gaurikund (Altitude 1980 meters)  and from there had to trek 16 Km to reach Kedarnath (Altitude 3550 Meters). That means we had to climb about 1600 meters in the 16 Km trek, which means 100 meters climb for every KM.   Gaurikund was just 75 Km from Rudraprayag and we reached it in a couple of hours’ time by 1 PM. We then had our lunch there. From there we had the option to trek to Kedarnath, but my daughter Vineela was too small and it would have been very difficult. So we opted for a pony to take us up.

Ponies were freely available at Gaurikund but they are expensive at Rs 400 per pony in 1992 when as a Scale II officer, my salary would have hardly been Rs 4000 a month at that time. We hired 2 ponies, 1 for myself and daughter and 1 for my wife. But that journey took us a solid 3 hours with a break in between for refreshment. The path was lined with stones and is pretty steep. On a couple of occasions my pony’s hoof slipped on the stones, on the 2^nd occasion substantially. There was a big drop right by our side and that too unfenced and unguarded. A slip there would have been fatal.

I was alarmed and that too my daughter was sitting in front of me and called the pony owner. He was walking beside me and told me “Sir there is no problem at all. The horse is as scared as you and I are about the fall and would protect itself sab, so just relax and enjoy the trip.”

The view by the side of the path into the valley was very beautiful with lovely greenery dotted with flowers. After the valley rose another mountain range. Every now and then we saw waterfalls coming down the range. There was a tall Mountain towering above us and visible in the distance. We had to raise our heads up in order to view its peak, and we were already well over 2000 meters when we started at Gaurikund. We were told that it is Chaukamba, the 4^th tallest mountain in India. Chaukamba is double Kedarnath’s altitude of  3500 meters.

The upward pathway was too beautiful even to describe. On one side of the path on occasions there was an upward sloping mountain while on the other side is the valley described in the previous paragraph. The mountain on which we were passing too had lovely flowers and small waterfalls all along the way. We came across a little bigger waterfall and the pony owner stopped the ponies for drinking water from the fall.

We got down and felt the water it was chilling cold coming down from melting ice. We too had a taste of the invigorating water and started again. There were many tourists trekking up the slope as we passed and every one of them was really enjoying it. We reached Kedarnath by 4 PM and went round the place taking photographs. Kedarnath looked magnificent with Chaukamba at its back. The mountain appeared so very near, as though it was right at the back of the temple. One feels that one can just go out of the temple at the back and can walk down a few hundred meters to get there. But the mountain is a solid 21 Km away and one wonders at the optical illusion.

I heard Bengali being spoken by many people, so assumed that Bengali’s travel a lot. At Badrinath too many people were speaking Bengali. Also, that was the time of the Durga Pooja holidays, and I supposed many of them like to travel during that occasion. We stayed there overnight in a Dharmasala.

The night at Kedarnath was truly chilling, even more chilling than at Badrinath, and one has to even dread going to the bathroom. Exposing the skin to the chill there made ones teeth chatter.

We visited the Kedarnath temple the next morning. Of the 3 dhams we visited in the trip, this is the only temple where I went inside for the Darshan. Of course my wife and daughter had Darshan in all the three. We then visited the Samadhi of Sankaracharya right by the side of the temple. We then had lunch and caught hold of the pony guys who were waiting for us. The downward trek took about 2 hrs and we reached Gaurikund by about 3 PM. We started from there and reached Rudraprayag by 5.30 PM.

We then left our luggage at the hotel and visited the confluence of Alaknanda and Mandakini which takes place at Rudraprayag. The confluence was magnetic as the 2 rivers meeting merged with their waters cutting each other as they combined and formed into one. We sat there for some time taking pictures. The area had great serenity and was sublimely beautiful.