From atomic to thermonuclear bombs

The Manhattan Project was the codename for the secret US government research and engineering project during the Second World War that developed the world’s first nuclear weapons. President Franklin Roosevelt created a committee to look into the possibility of developing a nuclear weapon after he received a letter from Albert Einstein in October 1939. Einstein warned the president that Nazi Germany was likely already at work on developing a nuclear weapon. By August 1942, the Manhattan Project was underway.

Robert Oppenheimer, a physicist, headed the Los Alamos National Laboratory, situated in the desert near Los Alamos, New Mexico, and it became the Manhattan Project’s principal research and development facility. Private corporations assisted in the preparation of weapons-grade uranium and other components needed to make the bombs.

The very first atomic bomb was detonated in the early morning darkness on 16 July 1945, at a military test facility at Alamogordo, New Mexico. The intense brightness of the explosion’s flash was followed by the rise of a large mushroom cloud from the desert floor. House windows more than fifty miles away shattered.

Hiroshima and Nagasaki

Although Germany had been defeated in May 1945, the war with Japan continued, however, and In August military advisers to President Harry S. Truman warned that a ground war would result in hundreds of thousands dead. Japan ignored a demand by the U.S. to surrender resulting in Truman giving authorisation to the military to use the atomic bomb on Japan.

On 6 August 1945 an American B-29 bomber named the “Enola Gay” dropped the first atomic bomb on the city of Hiroshima. The device exploded over the city with a force of 12 500 tons of TNT. About 140,000 people were killed instantly or died due to injury or radiation poisoning within months of the blast. Known as ‘Little Boy’ was a Uranium-235 gun-type fission weapon. A small explosive in the back launches a hollow uranium "bullet" to the front of the bomb, where a target cylinder or spike is situated. Once the spike at the front is pierced, the atoms split, causing an explosion, along with a mushroom cloud.

On 9 August, about 80,000 people died after the United States dropped a second bomb on Nagasaki. Named ‘Fat Man’ this was an imploding-type bomb that was more powerful, and more complex. The material that fuelled it was Plutonium-239. Conventional explosive, surrounded by Uranium-238, was placed around the plutonium core, and when they exploded, they sent a shock wave of energy and force, which was reflected by the U-238 by its neutron-reflecting properties, to the core, causing it to undergo nuclear fission.

To date, these have been the only nuclear bombs to be used in times of war.

‍Treason at Los Alamos

Spies within the research and development facility at Los Alamos - most notably the scientist Klaus Fuchs – provided the Soviet Union with information about the nuclear programme that helped the Soviets develop their atomic weapon by 1949.

Atomic bombs only utilise nuclear fission.

When a neutron strikes the nucleus of an atom of uranium-235 or plutonium-239 isotopes, it causes that nucleus to split into two fragments, each of which is a nucleus with about half the protons and neutrons of the original nucleus. As it splits a great amount of thermal energy, as well as gamma rays and two or more neutrons, is released. Under certain conditions, the escaping neutrons strike and thus fission more of the surrounding uranium nuclei This process re-occurs until it ends in a chain reaction in which nearly all the fissionable material is consumed and explodes.

Nuclear bombs are thermonuclear bombs, also known as hydrogen bombs, hydrogen bombs, thermonuclear bombs, neutron bombs, and dirty bombs which use the process of nuclear fusion to some degree.

In a thermonuclear weapon, the fission process is only the beginning. Modern nuclear weapons, such as the United States B83 bombs, use a similar fission process to that used in atomic bombs. This initial energy then ignites a fusion reaction in a secondary core of the hydrogen isotopes deuterium and tritium. The nuclei of the hydrogen atoms fuse to form helium, and again a chain reaction results in an explosion - this time a much more powerful one.

In contrast to the earlier atomic bombs, thermonuclear bombs (often called hydrogen bombs) rely on fusion instead of fission. This process is closer to Doc Ock than Doc Opp. Instead of splitting heavy atoms into lighter ones, fusion works by combining two light elements into a heavier one. They are commonly called hydrogen bombs because they use the hydrogen isotopes deuterium or tritium, the same stuff used in fusion reactors, to fuel them.

The explosive power of a thermonuclear bomb can be hundreds or thousands of times more powerful than atomic bombs. While the force of the bombs dropped on Hiroshima and Nagasaki was measured in kilotons (one thousand tons) of TNT, the force of thermonuclear bombs was measured in megatons (a million tons).

While they are a different class of nuclear weapons, thermonuclear bombs often have smaller atomic bombs inside of them. That’s because the fusion reaction they need to achieve requires incredible amounts of heat and pressure.

Thermonuclear bombs utilise the energy released when two light atomic nuclei combine, or fuse, to form a heavier nucleus beginning with the fission of plutonium facilitated by a sphere of conventional explosives. When the explosives detonate inward, they compress the plutonium causing fission. That reaction further compresses the core of the bomb where hydrogen fuel made of tritium and deuterium is housed. Once enough heat and pressure are achieved in the core, hydrogen atoms begin to fuse into helium, as in the core of the Sun, releasing neutrons, gamma, and X-rays.

These bombs can be hundreds or even thousands of times more powerful than atomic bombs. The explosive yield of atomic bombs is measured in kilotons while the explosive power of thermonuclear bombs is frequently expressed in megatons.

Despite their incredible explosive power, thermonuclear bombs can be made small enough to be easily transported. The smallest of them are referred to as neutron bombs because of the neutron radiation they release. Because neutron radiation falls away quickly, neutron bombs can be used to target specific locations while minimising the impact on surrounding areas and populations.

What Is a Dirty Bomb?

They are different from true nuclear weapons in one critical way. A dirty bomb is not as powerful; there is no nuclear reaction, instead, they rely on conventional explosives mixed with radioactive materials. When the bomb goes off, the radioactive materials are spread throughout the blast zone. The blast zone and the downstream fallout are significantly lower than with an actual nuclear weapon.

Is nuclear war a possibility?

Several countries possess nuclear bombs but to date, these have not been used. Mankind unfortunately is seldom satisfied and stronger, more lethal use of nuclear power can be part of the world’s future.