Scientists at LLNL in California have made a breakthrough in nuclear fusion technology. Nuclear fusion is brought about by fusing two hydrogen atoms to create helium. In the process, large amount of energy is released.

Lasers were used to bombard hydrogen isotopes held in superheated plasma state in order to fuse them into helium. A neutron is released and carbon-free clean energy is released.

Scientists wanted to produce more energy than it consumes. That was elusive so far. In the current experiment, 2.5 megajoules of energy was produced whereas the energy consumed to power lasers was 2.1 megajoules. Thus it is a breakthrough.

In nuclear fusion, the reaction creates new atoms from old. Lighter nuclei, say of hydrogen, are smashed together, to make heavier nuclei. And lots of energy. The energy comes from Einstein equation, i.e. E=mc2. Fusion is significant. It makes the Universe light up — it powers the stars. The reaction creates most elements we are made of. Fusion creates clean, safe, low radioactivity energy for everyone.

This has the potential to change the global energy landscape.

The experiment used Internal Confinement Fusion, with three key parts. A gold cavity with an opening at either end called hohlarum. A fuel capsule at hohlarum’s centre. A layer of deuterium-tritium fuel.

Laser beams (up to 192) are fired into hohlarum. It creates superhot plasma ( a gas stripped of electrones). X-rays (from the effect of the laser on the hohlarum) blow off the surface of the capsule. There is a reaction creating conditions for fusion. If the heat spreads rapidly enough through fuel, the energy yield could be more than the input. It is called ignition.

It is the Holy Grail of nuclear science — it imitates reactions on the sun. Fusion is the process that powers the sun and other stars. It involves two atoms joining or fusing together to form an atom of heavier element. Inside the sun, two H atoms produce a helium atom. It could lead to endless, cheap, clean, carbon-free energy. This is not going to happen in the short-term. Commercialisation would take some years — even decades. To do this on a near-continuous basis to make it a viable source of energy is a big challenge.

Nuclear energy is obtained either by fission or fusion. Fission-based power plants have been around since the 1950s. Scientists have been working on a reactor that uses nuclear fusion. It could be a source of clean, abundant and safe source of energy. It ultimately leads humanity to break its dependence on fossil fuels.

A nuclear fission reactor uses uranium which is not commonly found. The uranium atom is exposed to neutron radiation. It becomes excited and unstable. It splits into smaller atoms of elements like barium and krypton. It releases neutron radiation, which breaks apart uranium atoms, causing a chain reaction. In the process, energy is released. It is used to produce steam, and run turbines to produce electricity. Some by-products of fission remain radio-active for a long time. Fission generates 10 per cent of the world’s electricity. Fusion scores over fission because it can yield several times more energy without radioactivity. Fusion experiment at LLNL used hot fusion with ultra-high temperature. However, some scientists have theorized that cold fusion is possible at or near room temperature.

There are two types of technologies being researched for creating conditions for fusion.

Tokamak: It is the Soviet technology universally used. The nuclei here are heated into a plasma and then compressed magnetically.

Internal Confinement: It compresses and heats targets filled with thermonuclear fuel. This technology has been used by LLNL in California. It is called ignition.