Scientists have known how to use the process of nuclear fusion as a weapon for over 50 years at this point. However, we have yet to find a way to repurpose it as a safe, nearly unlimited energy source.
One of the main issues that researchers are facing with trying to tackle this issue is that that nuclear fusion requires an extremely high activation energy. As a weapon, this activation energy was provided by first detonating an ordinary fission bomb. It is easy to see how this process would not be ideal for creating clean fusion energy. Instead, scientists are now trying to heat nuclei using magnetic fields and lasers, neither of which has yet been able to provide the necessary temperature.
Another issue scientists face is creating a container out of materials that will be capable of withstanding assaults from the products of fusion reactions. First of all, the temperatures to kick off nuclear fusion are so hard that just finding a method of heating nuclei that could also survive high temperatures itself is already a challenge. Also, nuclear fusion releases some short-lived radioactive byproducts, and so the materials will need to be able to both extract heat effectively and survive battering from these particles at the same time.
There is much dispute over the use of nuclear energy today because of a public conception that nuclear power is a dangerous energy source. Although accidents are rare and nuclear power plants are pretty safe today, it is true that a serious accident could release massive amounts of radiation. However, rather than releasing radiation, the product of nuclear fusion is non-radioactive Helium and thus it does not share the same risk. It is for this reason that scientists are optimistic about using it as a power source in the future.
