How far away is Tokomak nuclear fusion? People get confused by the terms megajoules and various kinds of breakeven metrics.
There are simpler ways to look at it.
How fast is the progress?
What has to be achieved for a commercial nuclear fusion reactor?
The JET tokomak reactor has been working for a few decades. JET set record in 1997 by producing 21.7 Megajoules. In 2022, researchers in the EUROfusion consortium released a record-breaking 59 megajoules (MJ) of fusion energy. This was also done at the JET facility. JET was operated for 5 seconds to get 59 megajoules. It needs three times as much energy to heat the fuel. Twenty five years passed between the two records.
59 megajoules is 13 kilowatt hours. A typical US house uses 30-kilowatt hours in a day. The first nuclear fission reactor powered lightbulbs in 1951 and started powering a town in 1952. The 59 megajoules was just waste heat that could not be captured and used. It was detected and measured as a science experiment.
Billions of dollars have been spent on ITER (International Tokamak) and continue to be spent on ITER. ITER was started by US President Ronald Reagan and Russian leader Gorbachev. ITER was started in 1988 and they started building it in 2007. ITER might hit its current total budget of $22 billion but others think it will cost $65 billion. The plans is it will produce around 500 megawatts of power continuously for 400 seconds while only consuming 50 MW of energy to heat the fuel. This mean the reactor produced 10 times more than fuel heating. However, the ITER reactor will need 300 megawatts of electricity to produce 50 megawatts of heat. Heat would have to be converted back to electricity. This would mean getting back 5-10% of the electricity. ITER could start initial tests and operation in 2027 but it could take deep into the 2030s for it reach the goal of 400 seconds of energy-losing operation.
There are 31,536,000 seconds in a year. A normal US fission nuclear reactor operates for over 90% of the year. This means a fission reactor will operate for 28 million seconds for every year. Most are generating 1000 megawatts or more.
The Tokomaks would have to get stabilized to operate for over 5 million times more in a year. The plan is to use another $15-50 billion to get 80 times longer operation from 5 seconds to 400 seconds.
They would then follow up with the DEMO reactor. This could start operating in 2051. It might barely breakeven. It would generate about 750 Megawatts of electricity but it would need about 500 Megawatts of power. DEMO would not operate for very long either. In order to get to operating 50-90% of the time for a commercial reactor another Tokomak reactor to create stable commercial operation would be needed.
So this sounds like another 100 years of work at the current pace. This is to achieve Deuterium-Tritium (D-T) nuclear fusion. Tritium is important. Tritium is not produced in nature (on earth, other than trace amounts from cosmic rays). A commercial D-T fusion plant producing 3 gigawatts of electricity will burn 167 kilograms of tritium per year. There is about 20 kilograms of tritium in the world. DEMO would use 4-15 kilograms of tritium.
A commercial D-T fusion plant producing 3 gigawatts of electricity will burn 167 kilograms of tritium per year. We harvest about 1.8 kilograms of tritium every year from CANDU nuclear fission reactors. Those CANDU reactors are decades old and many are scheduled for shutdown. Most do not have Tritium harvesting set up.
423 nuclear fission reactors are currently operating. Japan could turn on a few more that they had shutoff. The worlds nuclear fission reactors produce 380 Gigawatts of power or about 2700 TWh each year. If the Tokomak nuclear fusion reactors matched the electricity from thecurrent nuclear fission reactors then about 21,000 kilograms of Tritium would be needed every year. This is over 1000 times as much as we have today.
The work on Tokomak fusion is small milestones over decades. They could hope for a commercial reactor by 2100 but then they would also need to scale up the levels of tritium by thousands of times.
Unlimited power except for getting the Tokomaks to work 5 million times more in one year than they currently do. Unlimited power except for the need for many tons of Tritium that we do not have.
Also, if you do solve the Tritium availability problem, then you will have a massive proliferation problem. 4-5 grams of Tritium boosts the explosive power of a nuclear weapon from 300 tons of TNT equivalent up to 100,000 tons. You would thousands of times more of one of the main materials for nuclear bombs.
I am more hopeful about other approaches to nuclear fusion like laser pulse systems. I also like advanced nuclear fission like molten salt fission power systems. There has been funding of over $5 billion into private commercial fusion projects.
I track all of the nuclear fusion and advanced nuclear fission projects.
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
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