Nuclear Transmutation: How Elements Change in Nature and Science

What Is Nuclear Transmutation?

Nuclear transmutation is the process by which one chemical element or isotope is transformed into another by changing the number of protons and/or neutrons in its atomic nucleus. Since an element is defined by the number of protons in its nucleus (its atomic number), altering that number changes the identity of the element itself.

There are two main types of changes in the nucleus that can cause transmutation-

• Change in proton number– This results in a different element. For example, if a nitrogen atom gains a proton, it can become an oxygen atom.
  
• Change in neutron number– This results in a different isotope of the same element. For instance, uranium-235 and uranium-238 are both uranium atoms, but they differ in the number of neutrons in their nuclei.
  

 Two Main Types of Transmutation

Transmutation can occur in two ways- naturally or artificially.

A. Natural Transmutation

Natural transmutation occurs without human intervention, as part of natural nuclear processes such as radioactive decay or cosmic ray interactions. These processes occur constantly in nature.

Main Mechanisms-

1. Radioactive decay–
   
   • Alpha decay– A nucleus loses two protons and two neutrons (an alpha particle), changing into a different element.
     
   • Beta decay– A neutron transforms into a proton (or vice versa), changing the atomic number and thus the element.
     
2. Cosmic ray interactions–
   High-energy particles from space (cosmic rays) strike atoms in the Earth’s atmosphere, causing reactions that create new isotopes.
   
3. Neutron capture–
   Atoms in the Earth’s crust or atmosphere can absorb free neutrons, changing into heavier isotopes or different elements.
   

Examples of Natural Transmutation-

• Potassium-40 decaying into Argon-40 through beta decay, which explains the presence of argon gas in the Earth’s atmosphere.
  
• Carbon-14 production when cosmic rays interact with nitrogen-14 in the atmosphere. Carbon-14 is used in radiocarbon dating.
  
• Uranium decay chain, in which uranium undergoes multiple decays to eventually become stable lead.
  

Stellar Nucleosynthesis (Transmutation in Stars)-

Stars are natural sites of continuous nuclear transmutation. Inside stars, high temperatures and pressures cause fusion reactions, where light nuclei combine to form heavier elements.

• In main sequence stars, hydrogen nuclei fuse into helium.
  
• In red giants, helium is fused into carbon and oxygen.
  
• In more massive stars, fusion continues to create heavier elements up to iron.
  
• Elements heavier than iron (such as gold or uranium) are formed in extreme events like supernova explosions or neutron star collisions.
  

These cosmic transmutations are responsible for the creation of most elements found on Earth and in the universe. Without these natural processes, elements such as oxygen, iron, and gold would not exist.

B. Artificial (Induced) Transmutation

Artificial transmutation is a man-made process, where scientists intentionally change one element into another using machines or nuclear reactors. This is done by bombarding atomic nuclei with subatomic particles such as neutrons, protons, or alpha particles.

How it is achieved-

• In nuclear reactors, atoms are exposed to high numbers of free neutrons which can be captured by atomic nuclei, leading to new isotopes or elements.
  
• In particle accelerators, atoms are bombarded with high-speed particles, forcing nuclear reactions.
  
• In tokamaks (experimental fusion reactors), intense heat and magnetic fields are used to cause fusion.
  

Example of Artificial Transmutation-

The first artificial transmutation was performed by Ernest Rutherford in 1919, when he bombarded nitrogen gas with alpha particles and transformed it into oxygen-

714N+24He→817O+11H^{14}_7\text{N} + ^4_2\text{He} \rightarrow ^{17}_8\text{O} + ^1_1\text{H}714​N+24​He→817​O+11​H

This experiment showed that it was possible to change one element into another using nuclear reactions.

Applications of Artificial Transmutation-

1. Medical uses– Production of radioisotopes used in diagnostic imaging and cancer treatment.
   
2. Fuel breeding– Creating new nuclear fuel, such as converting uranium-238 into plutonium-239.
   
3. Nuclear waste reduction– Converting long-lived radioactive waste into shorter-lived or stable materials.
   

Also Check – What Are Chemical Elements? A Complete Guide for Students

Historical Evolution of Transmutation

Alchemical Origins-

The concept of transmutation has ancient roots. In alchemy, a medieval philosophical and proto-scientific tradition, scholars attempted to turn common metals like lead into gold. Although these efforts were based on mystical ideas and chemical misunderstandings, they led to important discoveries in early chemistry.

Modern science has since shown that chemical transmutation of elements is impossible, as chemical reactions do not change the number of protons in an atom. However, nuclear transmutation (which occurs at the atomic nucleus level) makes such changes possible – but only under conditions involving extremely high energy, such as in nuclear reactors or particle accelerators.

Scientific Discoveries-

• In 1901, Frederick Soddy and Ernest Rutherford discovered that radioactive elements change into other elements through decay. This was the first confirmed case of natural nuclear transmutation.
  
• Between 1921–1925, Patrick Blackett confirmed the reaction where nitrogen was transmuted into oxygen by alpha particle bombardment.
  
• In 1932, John Cockcroft and Ernest Walton successfully used an early particle accelerator to induce a transmutation of lithium into helium – a major breakthrough in nuclear physics.
  

These discoveries laid the foundation for nuclear energy, particle physics, and modern transmutation technologies.

Artificial Transmutation in Technology

In Nuclear Reactors-

In power reactors, transmutation occurs when uranium-238 captures a neutron and transforms into plutonium-239, a fissile material that can be used as nuclear fuel or in weapons.

This process not only contributes to the generation of electricity through chain reactions, but also to the recycling and reuse of nuclear fuel.

For Nuclear Waste Reduction-

Some radioactive waste products, especially those that remain dangerous for thousands of years (such as neptunium-237, americium-241, and curium-244), can be transmuted into shorter-lived isotopes or even stable elements.

This approach, known as partitioning and transmutation (P&T), is being studied as a possible solution to reduce the environmental and storage burden of nuclear waste.

Challenges in Waste Transmutation-

• Some isotopes, like cesium-137 and strontium-90, do not easily absorb neutrons and are hard to transmute efficiently.
  
• The process requires complex chemical separation, high radiation shielding, and sometimes special reactor designs.
  

Technologies for Artificial Transmutation-

1. Fast neutron reactors– These allow for efficient transmutation by using high-energy (fast) neutrons.
   
2. Accelerator-Driven Systems (ADS)– Subcritical reactors that use particle accelerators to maintain a controlled transmutation process.
   
3. Fusion neutron sources– Under development as a possible way to produce high neutron fluxes for more effective waste transmutation.

 Cosmic and Stellar Transmutation

Transmutation is not limited to Earth. In fact, most of the elements we find in nature were formed through nuclear transmutation in outer space. This includes the earliest moments of the universe and the ongoing life cycles of stars.

A. Big Bang Nucleosynthesis

Shortly after the Big Bang, when the universe was still extremely hot and dense, a process called Big Bang nucleosynthesis took place. During this process, the first elements were formed-

• Hydrogen (the simplest and most abundant element)
  
• Helium
  
• Small amounts of lithium and beryllium
  

These light elements made up nearly all of the ordinary matter in the early universe.

B. Stellar Fusion

Stars are natural factories of element formation. Inside stars, nuclear fusion occurs due to extremely high temperatures and pressures. This process involves lighter atomic nuclei combining to form heavier ones. Key stages of fusion include-

• Hydrogen atoms fusing into helium (main sequence stars)
  
• Helium atoms fusing into carbon, oxygen, and neon (in larger stars)
  
• Heavier fusion in massive stars forming elements up to iron (Fe)
  

Fusion up to iron releases energy and supports the star. However, fusion beyond iron does not release energy. Instead, it consumes energy and thus does not occur under normal stellar conditions.

C. Supernovae and Neutron Star Mergers

To form elements heavier than iron (such as gold, uranium, and platinum), much more extreme environments are required.

• Supernovae– Explosions of massive stars at the end of their life cycles. These events produce powerful shockwaves and huge energy releases, allowing the formation of heavy elements.
  
• Neutron star mergers– Collisions between two neutron stars can also create extremely heavy elements through rapid neutron capture.
  

These events eject heavy elements into space, enriching the interstellar medium. Eventually, this material condenses to form new stars, planets, and ultimately, life.

6. Is It Possible to Make Gold Through Transmutation?

The Answer- Yes, But It Is Not Practical

In modern physics, it is technically possible to create gold by changing one element into another using nuclear transmutation. However, the process is extremely expensive, complex, and inefficient, making it impractical for commercial purposes.

Key Experiments-

• In the 1980s, Nobel laureate Glenn Seaborg succeeded in creating tiny amounts of gold from bismuth using a particle accelerator.
  
• Between 2002 and 2025, CERN scientists performed high-energy experiments that transformed lead and uranium nuclei into gold using particle collisions.
  

Despite these achievements, the amounts of gold produced were microscopic, and the energy input far exceeded the value of the gold produced. Therefore, while the transformation is scientifically possible, it is not economically viable.

Transmutation of Nuclear Waste

One of the major challenges in nuclear energy is the long-term storage of radioactive waste, especially isotopes that remain hazardous for thousands of years. Scientists are exploring the use of artificial transmutation to reduce the danger and volume of this waste.

Partitioning and Transmutation (P&T)

This is a two-step strategy-

1. Partitioning– Separating long-lived radioactive elements from used nuclear fuel.
   
2. Transmutation– Converting these hazardous isotopes into shorter-lived or stable ones through nuclear reactions.
   

Target Elements for Transmutation-

• Actinides (heavy radioactive elements like-
  
  • Plutonium-239
    
  • Neptunium-237
    
  • Americium-241
    
  • Curium-244
    can be converted into fission fragments, which are less radioactive and easier to manage.
    
• Long-Lived Fission Products (LLFPs) such as-
  
  • Technetium-99 (99Tc)
    
  • Iodine-129 (129I)
    

These elements are especially important targets due to their long half-lives and mobility in the environment.

Long-Lived Fission Products and Their Transmutation Potential

Some radioactive isotopes are particularly concerning because they stay active for thousands to millions of years. Below is a summary of key long-lived fission products (LLFPs), their challenges, and possible solutions.

Nuclide	Half-life (years)	Challenges	Potential Solutions
Technetium-99 (99Tc)	211,000	Easily moves in the environment	Can absorb neutrons and become stable ruthenium (Ru)
Iodine-129 (129I)	15.7 million	Toxic and mobile	Transmutation in fast neutron reactors
Cesium-135 (135Cs)	2.3 million	Very low neutron absorption	Requires high neutron flux for transmutation
Zirconium-93 (93Zr)	1.6 million	Chemically stable but weakly reactive	Still under study for transmutation potential
Palladium-107 (107Pd)	6.5 million	Produced in small amounts	May not require transmutation
Tin-126 (126Sn)	230,000	Complex decay pathway	Transmutation is technically difficult
Selenium-79 (79Se)	327,000	Very low production yield	Possibly better left to decay naturally

Some of these isotopes can be efficiently transmuted, especially in fast reactors or accelerator-based systems, while others are less reactive and may need to be stored securely until they decay.

Nuclear transmutation is not only the natural process that created the elements forming your body, Earth, and stars – but also a cutting-edge technological tool in nuclear medicine, energy, and waste management.

While alchemy failed in turning lead to gold, modern physics has done it, albeit inefficiently. And though we cannot yet transmute everything we want, the future of cleaner nuclear technology likely rests on how well we master transmutation.