Why Fusion isn't Powering the World...

Ignition Temperatures:

The key problem with fusion power is that you have to put in an incredible amount of energy before you get any out. The ignition temperatures (the minimum temperature at which a given reaction will take place) start at 100 million degrees Kelvin. This is the ignition temperature for the first reaction shown on the Fusion Reactions page. Other ignitions temperatures are between two and ten times higher than that. At this temperature, all gases ionize, which means that their electrons are no longer attached to the nuclei, to form a plasma.

This plasma is much too hot for any conventional container to hold, so plasma containment is the key area of fusion research, which is discussed in the Technical Challenges section.

Some Radioactivity After All...

The fuel used in the most prevalent fusion reaction is made of 50% tritium (T), which is a radioactive gas. Since gas leaks are hard to prevent, this poses a serious problem for future plant operations and workers' safety concerns.

Another disadvantage of fusion is the radioactivity caused by neutron activation. Neutrons are released during the most common fusion reaction with D and T atoms fusing to a He atom. Several other fusion reactions also release neutrons. Theses then collide with the walls of the reactor, turning the containing material radioactive.

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