A Beginner's Guide to Make an Atomic bomb

We’re going ballistic

Nuclear reactions are events triggered by the tiniest of particles, yet they unleash an immense amount of energy. This energy, though born at the atomic level, holds power vast enough to change the world. When harnessed, it can be used for a wide range of purposes — from generating electricity to powering spacecraft, to making a bomb.

But before we get into its applications, it's essential to first understand the physics that makes it all possible.

RADIOACTIVITY

The last period of the periodic table.

The one line with the most weird and long to pronounce names , an element could have.

It also happens to be the most overlooked period in most of our chemistry textbooks, mainly because they show properties which all the other elements in the table don't exhibit. This period mostly contains the radioactive elements.

<But! Radioactive elements are not limited to the 7th period, there are many scattered throughtout the table >

What are Radioactive elements in the first place?

These are the elements which have too much nuclear charge, causing the nucleus to become too unstable. This causes the nucleus to go through radioactive decay to form a more stable nuclei. (Remember : an atom has a nucleus containing positive and neutral charged particles and the electrons revolve around in orbits)

 And the one of the interesting parts of this process is it defies all logic we have known till now,

Oxygen can't convert into Nitrogen, Aluminium can't convert into gold (unless you are into Alchemy ,that is)

Atoms of an element are different in most aspects to the atoms of another. (A modified version of the Dalton's atomic theory)

That's common sense right?

What if I said it's not always true?

Nope, It has nothing to with the sorcerer's stone ( sadly). This crazy behaviour is what Radioactive elements exhibit

Radioactive decay

These unstable elements of atomic nuclei with excess nuclear charge will produce an impulsive release of radiations. The unstable elements release radiations to achieve stability. The three types of radiations emitted by these elements are alpha particles, beta particles, and gamma rays.

Alpha decay

A throw back to our dear old Rutherford and his obsession with gold foils indeed.

Alpha decay is the process through which the radioactive element 'breaks down' to release a nucleus of Helium (aka Alpha particle). In this process the radioactive element ejects two protons and two neutrons, converting into another atom. Atomic mass decreases by four and atomic number by two

For example :-

Souce: Byjus

Beta decay

This is the process in which the neutrons of the nucleus convert into protons or vice versa!  If a proton (positive charge) is converted to a neutron (neutral charge) , it is known as β+ decay. Similarly, if a neutron is converted to a proton, it is known as β– decay.

Due to the change in the nucleus, a beta particle is emitted. The beta particle is a high-speed electron when it is a β– decay and a positron when it is a β+ decay ( click on the word to know more about it! ) This finally leads to change in the net +ve charge of the particle.

For example:-

source: internet

Gamma decay

We have learnt about the emission of electromagnetic waves ( and spectral lines) by electron as they jump from a higher energy level to lower, what if the nucleus also follows pursuit?

Processes involving the nucleus, like the alpha decay, beta decay etc, causes nucleus to have more energy than normal and the nucleus too has its own energy levels. As it falls from a high energy level to lower, extra energy is dissipated in the form of gamma radiations ( high energy photons). In this process, unlike the alpha and beta decay, there is no physical conversions in the nucleus.

Source: Internet

And those are the major processes through which one element can convert into another element!

Now, you might be thinking,"Okay MP.T, I get all of this, how is the atomic bomb related to any of this ?"

Glad you asked mere dost , onto the next phase of our mission

NUCLEAR FISSION

We have previously discussed how the identity of an atom with too much nuclear charge changes on reaction. There, it emits certain components in the form of 'radiations' to achieve stability

Here we are going to do the opposite.

Let's take an already unstable element like Uranium and bombard it with a tiny neutron.

That tiny thing makes the entire atom fall apart, the Uranium nucleus splits into two. This splitting in turn releases more neutrons which goes and bombards the neighbouring uranium nucleus causing a chain reaction. The process of splitting releases alot of energy.

 This is actually the simple explanation of how it happens ( which to be honest , you can find on the first glance in any book or the net)

But, this particular writer's curiousity lead to an obstinately crazy amount of research on this one question

Why is this energy released?

It finally lead me to rely on the research of international tongue model, Albert Einstein.

E = mc ^2

This in short shows the relation between Energy and Mass. Mass is described to be 'congealed' energy.  Thus, each body of rest mass m possesses mc2 of “rest energy,” which potentially is available for conversion to other forms of energy. The mass-energy relation, moreover, implies that, if energy is released from the body as a result of such a conversion, then the rest mass of the body will decrease.

For the purpose of this blog just remember, energy and mass are proportionate to each other. So this 'rest energy' differs by mass of the body.

So both in the explanation before, we removed something from the nucleus. This removal needs work to be done ( force* displacement)

 Where does this work done go?

According to E = mc^2 , this work done is converted into mass, adding to the mass of the released nucleon. So any free nucleon has more mass than the nucleons in the nucleus ( in combined state) . Conversely, when nucleons bind together to form a nucleus, they release energy, called binding energy, losing the equivalent mass.

The mass per nucleon in the nucleus, greatly depends on which atom it belongs to, the trend clearly shown in the graph below

Fission of uranium produces elements lower on the curve. That lowered mass per nucleon converts to energy via E = mc2.

So that is why energy is released (phew, what a journey it has been)

Now, onto the part we’ve all been waiting for — after climbing the mountain of Physics, it’s finally time to enjoy the view and have some fun!

LET'S MAKE AN ATOMIC BOMB!!

Step. 1

The Radioactive element - fuel

(Nope, your burning anger and annoyance towards that person isn't enough to fuel the reaction)

Uranium, the most commonly used radioactive fuel comes in two isotopes - 235 and 238.

Both are radioactive and will decay into other elements, given time, but only 235 can be forcibly split when neutrons are fired at it. But natural uranium overwhelmingly consists of the 238 isotope, which bounces back any neutrons striking it - useless then for a bomb. To make a bomb, natural uranium needs to be treated to concentrate the 235 isotope within it.

This is the major reason the entire world is not run over by nuclear weapons.

Because though the actual reaction is natural hence easy to intiate, the raw materials required is difficult to extract. For every 25,000 tonnes of uranium ore, only 50 tonnes of metal are produced. Less than 1% of that is uranium 235.

No standard extraction method will separate the two isotopes because they are chemically identical.

Instead, the uranium is reacted with fluorine, heated until it becomes a gas and then decanted through several thousand fine porous barriers. This partially separates the uranium into two types.

For bombs, the uranium has to be atleast enriched ( basically, concentrated with U- 235) to 80 -90 percent. (In contrast, nuclear reactors only need it to be enriched 20 percent)

Get around 50kg of this enriched uranium - the critical mass - and you have a bomb. Any less and the chain reaction would not cause an explosion.

Back Up Plan

So, Uraniums isn't that easy to get. Lets switch to our alternate fuel.

Plutonium , could also be used as a fuel. This is the preferred material because it makes much lighter weapons that can be mounted on to missiles.

Only around 10kg of Plutonium is needed for a bomb.

Yeah, ONLY 10 KG .

But the catch is ,an average power plant needs about a year to produce enough and expensive reprocessing facilities are required to extract the plutonium from the fuel.

Step 2

Structure

Once you get your fuel, tbh the rest of the process is pretty easy. If you are too much in a hurry , you could go ahead and throw the Uranium at the person right now.

The only purpose of this step is to make sure, the bomb doesn't blow up on your face before throwing it.

For the bomb to explode, it is essential for it to have the critical mass required.

A bomb structure uses this logic.

It needs to kept in sub-critical mass ( less than critical mass) seperately and then throwing the parts together is all that is needed. Of course 'throwing' isn't always practical ( and kinda indignified too ain't it, after all the trouble you are going through to extract the uranium, you might as well do the iconic moment in style)

source : Internet

The core of an implosion-type atomic bomb consists of a sphere or a series of concentric shells of fissionable material surrounded by a jacket of high explosives, which, being simultaneously detonated, implode the fissionable material under enormous pressures into a denser mass that immediately achieves criticality.

And unlike a nuclear reactor, which needs several safety parts to make sure the reactions doesn't go out of control, a bomb doesn't need them. It is meant to go out of control and wreck havoc.

Voila, Your own atomic bomb!

( Hopefully, the person learns not to mess with you again)

The Hiroshima - Nagasaki Incident

Jokes apart, It is very important to understand how powerful and dangerous a nuclear bomb can be ( and the reasons on why the world is a better place without it).

Most of us have read about the infamous World War 2 in history, and how it ended with Japan being blown to smithereens because of an American bomb.

The Americans , having made the first atomic bomb, released two atomic bombs 'little boy' (ironic isn't it?) and 'fat boy' over the cities of Hiroshima and Nagasaki respectively.

By the end of 1945, the bombing had killed an estimated 140,000 people in Hiroshima, and a further 74,000 in Nagasaki. In the years that followed, many of the survivors would face leukemia, cancer, or other terrible side effects from the radiation.

Lakhs of people, common citizens, families and children who had no say or relation whatsover in the world war, whose only sin was to have been living in those cities, with a particular nationality - succumed to death.

If a nuclear weapon were to be detonated over a city today, first responders - hospitals, firemen, aid organisations - would simply be unable to help. This is what happened in Hiroshima and Nagasaki. In Hiroshima 90 per cent of physicians and nurses were killed or injured; 42 of 45 hospitals were rendered non-functional; and 70 per cent of victims had combined injuries including, in most cases, severe burns. Many suffered to death because no one could help.

The people with the knowledge or power to help died due to the impact, the people who tried entering from out , died from radiation.

(The Americans really presented a checkmate, didn't they)

It takes around 10 seconds for the fireball from a nuclear explosion to reach its maximum size, but the effects last for decades and span across generations.

And for all survivors, cancers related to radiation exposure still continue to increase throughout their lifespan, even to this day, seven decades later.

This is why Nuclear weapons should be banned and abolished in all countries. 10 seconds is the time it takes for a bomb to explode, killing lakhs of people ,destroying the lives of a million more.

If world governments don't understand the value of a human life and prioritise power and victory over it, I have no clue where this world is heading.