The basic design of a nuclear bomb is shockingly easy to find online. Actually building one is an entirely different matter. This article will run through the basics to give you a sense of what’s involved, to better inform you about the crucial issue of nuclear proliferation. 

The Allure of Nuclear Weapons

There are three main reasons some countries want nuclear weapons:

1. Prestige. Only nine countries currently possess these weapons, five of which are permanent members of the United Nations Security Council. The world cannot afford to ignore nuclear-armed countries.
2. Deterrence. Any enemy will pause before considering an attack on a nuclear-armed state. Regimes with powerful enemies can hold even superpowers at bay if they have nuclear arms and the means to deliver them.
3. War-fighting. Nuclear weapons can win a war decisively and quickly against a non-nuclear power. Against another nuclear power . . . it’s sketchy. If you strike first in overwhelming force and disable your enemy, you could pull off a win. But there’s always the danger enough of their weapons will survive to deliver a devastating counter-strike. 

Nuclear Weapons: Why Not?

9 countries have nuclear weapons but many more have the industrial and technical foundation to pursue credible nuclear weapons programs if they wanted to. So why don’t they?

• A nuclear weapons program requires a substantial financial investment that many countries would rather put toward other things. Instead, they can enter an alliance with a nuclear power and enjoy the same deterrent effect without having to build their own weapons.
• There is substantial public opposition to nuclear weapons in many countries, so building them can be unpopular and a hard sell in democratic countries.
• Countries that start nuclear weapons programs may come under international sanctions or even military attack.
• For some countries, nuclear weapons would just be overkill for the types of national security threats they face.
• Nuclear weapons make other countries in the region feel unsafe, so some of them may also pursue their own nuclear deterrents. In the end, the security situation can be much worse for all the countries in the region.  

How Do Fission Weapons Work?

There are two main types of nuclear devices: fission and fusion weapons. Fission weapons split atoms of unstable heavy elements like uranium by firing neutrons into them. Each split atom releases more neutrons and a tremendous amount of energy in a runaway chain reaction until the fuel is consumed.

The weapon design used in the Hiroshima bomb fired a mass of uranium into another to reach critical mass. A different design, used in Nagasaki, used conventional explosives to compress a nuclear core to a supercritical state. 

How Do Fusion Weapons Work?

Fusion devices, or thermonuclear bombs, fuse light elements, like hydrogen, to create heavier ones, like helium, releasing massive energy in the process. They typically use fission devices to achieve the temperature and pressure needed to created a fusion reaction. These types of weapons are many hundreds or thousands of times more powerful than fission weapons. 

Dirty Bombs

A short-cut for countries or terrorist organizations that want to achieve some of the deterrent effects or psychological shock factor of nuclear weapons is a dirty bomb. This is not actually a nuclear bomb that involves an atomic chain reaction. Instead, it is a conventional explosion, as small as a stick of dynamite, that spreads radiation. This could be pulled off by anyone who gained access to radioactive materials without any particular technological expertise. Though the physical damage would be modest compared to a nuclear bomb, a dirty bomb can be enough to induce panic, create an expensive cleanup project, and a major crisis for the country that is victim of it. 

What’s Needed for a Functioning Nuclear Weapon?

But what if a country wants to produce a a functioning fission or fusion device? It requires funding, specialized knowledge, an adequate technical-industrial base, access to radioactive materials, and a delivery system. 

Funding

Building a nuclear weapon from scratch costs billions of dollars, so it is something that can really only be accomplished by a country, not a terrorist organization. Once the technology is acquired, it takes billions of dollars a year to continue building and maintaining the weapons. 

Scientific Expertise

Building a nuclear device takes a whole team of highly capable experts, including nuclear physicists, engineers, materials scientists, chemists, and computer scientists. A country might be able to acquire technology or the services of experts from other countries in exchange for helping them with their own foreign policy or economic goals. Knowing the crucial role these experts play, Israel has assassinated several Iranian scientists to slow down their nuclear program. 

Technical-Industrial Base

A country needs the proper facilities to process and enrich uranium to the level needed for a weapon, equipment and machinery to store and handle radioactive materials, and the ability to build bomb components to precise specifications. This infrastructure is often disbursed to sites around the country and/or constructed in deep underground bunkers to make it more difficult for an enemy to destroy the country’s growing nuclear capabilities in an airstrike. 

Radioactive Materials

In its natural state, uranium is not concentrated enough to achieve critical mass. It must be processed through high-performance centrifuges into uranium-235, which is more fissile. A byproduct of the process is uranium-238, which can be processed into plutonium-239. This is a more fissile product than uranium and can make lighter-weight weapons.

Supplies of uranium are carefully monitored around the world to prevent the materials from falling into the wrong hands. If a country does not have its own domestic resources and the ability to mine and process them, it will have to seek them out on the black market or work out a deal with supplier countries.

Nuclear Testing

A country is usually not considered to be a nuclear power until it has actually tested a device. This requires a remote and controlled test site. It’s a momentous decision, because it is an event that can be measured from sensors in other parts of the world through seismic monitoring for underground tests, hydroacoustic monitoring of underwater tests, and infrasound monitoring of low frequency sound waves moving through the air. It’s also possible to measure elevated radiation levels to understand characteristics of the device that was tested. Almost certainly a nuclear test will result in the country being placed under international sanctions and may expose it to risk of attack by other countries to try to destroy their nuclear capability.

A Delivery System

To make a nuclear explosive device effective as a deterrent or weapon of war the country needs a way to deliver it to its target. This could be as low-tech as smuggling it across the border and driving it in a truck to its destination or concealing it in a cargo ship or train boxcar. It could be dropped from a plane or mounted on a missile. These more high-tech solutions require precise engineering in their own right and an advanced knowledge of bomb and missile guidance and precise detonation mechanisms. 

Securing Nuclear Weapons

During and after the building of a nuclear weapon, a country must be able to handle the elevated national security threat they create for themselves with their program. Aspiring nuclear states will try to keep their ambitions secret as long as possible while they clandestinely build facilities and gather the expertise and materials they need. They must use tools of diplomacy and maintain military readiness to reduce the risk other countries will attack them to destroy their program.

The Future of Nuclear Proliferation

191 countries have signed the Treaty on the Non-Proliferation of Nuclear Weapons. Obviously, though, a rogue state that chooses to pursue them would not be deterred by a signature on a treaty from doing whatever they wanted to do.

For small countries in particular, though, national security depends not only on having the strongest weapons, but the strongest friends. And in free countries, it requires providing a prosperous and improving standard of living to the people that can only be achieved by integration into the global economy. For most countries, then, acquiring nuclear weapons would worsen their security situation and economic stability as the world community ostracized them.

However, for countries that are already pariahs (Iran) or are facing the most severe security threats without a superpower alliance to protect them (Taiwan), nuclear weapons will continue to be an option. As more and more countries acquire advanced technology and over time go through times of extreme threats or misguided leadership, gradual nuclear proliferation to more and more countries is a likely long-term outcome. 

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