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Physics/Fusion reactor power output


I've read that fusion reactions produce around 3 to 4 the energy that fission produces. A typical fission reactor produces about 1 gigawatts of energy so does that mean that a fusion reactor would produce 3-4 gigawatts of energy? I know that ITER produces 500 megawatts but ITER is just a prototype and the prototype fission reactors produced only a small fraction of energy that the reactors nowadays produce. So how many times more power will fusion probably produce in your opinion?

There are two VERY different situations at work here -- do NOT confuse them!!

When one atom of uranium-235 absorbs a neutron and then splits into its fission products, about 211 MeV of energy is released.  That's less than one MeV per nucleon (ie, 200 MeV divided by 92 protons and 144 neutrons).

When one deuterium nucleus (two nucleons) slams into a tritium nucleus (three nucleons), and they fuse together to form helium and one neutron, the energy released is 17.6 MeV. That's over three MeV per nucleon. THIS is what is meant by "fusion reactions produce around 3 to 4 times the energy that fission produces."

The problem is this: on a technological level, it's VERY easy to both (1) cause a lot of enriched U-235 to engage in a fission process and (2) use the heat from this reaction to generate electrical power in a commercially viable manner. For a fusion reactor, we've haven't mastered the technology ability to do EITHER! Scientists and engineers have been working on this problem for over sixty years, and we don't seem to be any closer to a solution than we started -- the problems always seem to be just a decade or so from their solutions.

The present plan (and it involves a LOT of 'ifs'!!) is to have a 500 MW fusion generator by 2028 -- about 70 years behind the original schedule.


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I can help with understanding physics that does not involve eggs. I will NOT help with academic or professional questions, which are NOT limited only to homework. Please do not waste your time by asking a question that comes out of ANY kind of academic, professional, or business matters.


Have been fascinated by physical laws ever since I learned, at age seven, that magnets work under water. My study continued through college and has not ceased even after I retired.

B.A. in Physics (with honors) from University of California at Berkeley.M.A. in Physics (with honors) from University of Texas Austin.

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