Fusion Power on the Grid: In our lifetime?

Physics Department Engineering Talk: Fusion Power on the Grid: In our lifetime?

David Godden gave a very interactive talk on the prospects of utilising fusion energy as a main energy resource. He outlined how the primary energy sources, oil, coal, are unsustainable in the long run. Cracking fusion energy potentially could result in another technological revolution.

He began the talk with a little information about himself. Although David got all five of his UCAS offers, he chose a different route after Sixth Form: he got an apprenticeship which meant that as soon as he left school he started paid work, whilst also working on a part time degree. By the time he finished the apprenticeship, he had work experience and a degree. He urged more people to consider this!

The JET (Joint European Torus) fusion reactor is in Culham, a drive away from Marlborough. The reactor is shaped like a doughnut (thus the name “torus”). It is filled with plasma, the fourth state where the heat is so intense the electrons free themselves from their atoms to produce a hot soup of charged particles. Here, the temperature is greater than the centre of the sun: inside JET is the hottest place in the known universe reaching temperatures of 200 million degrees! (For comparison, the centre of the sun is 15 million degrees). David, and his team of engineers, worked on one of the methods of heating the plasma inside the machine. In running this reactor, it requires 4% of UK’s power from the national grid.
In 1997, JET broke the world record in producing the most fusion power in the world at that time, 16 megawatts! Fusion energy seems to be the perfect energy source: it uses only isotopes of hydrogen, deuterium and tritium, as fuel, it doesn’t produce any carbon emissions or radioactive fallout with long half-lives, and its power output is monumental! David described how it was possible to produce 30 years of energy for the needs of one person using the deuterium and tritium found in half a bathtub of seawater and your computer’s lithium battery. This is compared to 300 barrels of coal required for the same energy production!

Why isn’t fusion energy being used as the main power source then? The main reason is that the power output compared to the power input is still very small. It requires a lot of energy to start fusion in the first place. However, David is optimistic that we will crack fusion in the years to come. ITER, a larger fusion reactor than JET, is being built in the South of France and is due to be completed before 2030. The engineers at JET are aiding in the building of this new reactor which will hopefully break the fusion records. Another reactor, DEMO, is also being designed which will demonstrate how fusion energy can be used commercially. DEMO should be completed around 2050. With all of these future fusion reactors in the works, David is sure that fusion energy will be a reality in our lifetimes.

Review by Elizabeth Tan (CO U6)

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