How do the waste products of nuclear fusion differ from nuclear fission?

Answer 1

Yes, they are quite different. The deuterium-tritium reaction produces a helium nucleus, which is harmless. There will be an intense neutron bombardment of the enclosure holding the fusion plasma, and this will result in the structure becoming radioactive, but that will be a problem for decommissioning rather than operation.

Scientists originally promised fusion as a clean source of energy, and whilst it is not entirely so, it is far cleaner than fission. The only problem is finding how to make it work in a practical power producing plant.

Answer 2

The waste products of fusion are mostly made up of radiologically inert isotopes of Helium. There are some concerns about waste, however. One is that some amount of radioactive tritium is very likely to escape from the process, and get into the environment. Another is that the equipment in the area of the reactor will become radioactive because of its exposure to neutrons, and this means it will have to be disposed of as a radioactive hazard when it is decommissioned. The time this waste is dangerous is said to be about three hundred years.

By contrast, fission produces both low-level nuclear waste, similar to the waste of the fusion reactor, though in much greater quantity, and high-level nuclear waste, which the fusion reactor will not produce at all. The high-level nuclear waste is highly radioactive, and will continue to be dangerous for over a million years.

Answer 3

The fuel in fusion (deuterium plus tritium) is transformed into helium, so that is the main waste product. I don't know if a working power plant would try to collect this or just expel it to atmosphere. Apart from that, there will be radioactive isotopes formed in the material surrounding the reaction chamber, which will receive an intense neutron bombardment, and will in fact be the source of thermal energy, transferring this to a coolant. This is as far as I know an unexplained part of the plant, so I'm not sure if this material will last the life of the plant or have to be renewed at intervals, in which case it will become a waste product and will have to be carefully stored, though I guess it won't be as active as fission products from a fission reactor.

In nuclear fission reactors you get a range of fission products some of which are highly active and have long half lives. The fusion reactor material will become activated but what results will depend on precisely what material is used.

Suggest you look at the Wikipedia article on ITER for the most up to date ideas on what a fusion plant might look like.

Answer 4

Fission waste products:

• fission products - radioactive, mostly short lived beta and gamma emitters
• neutron activated materials - radioactive, mostly beta and gamma emitters
• unburned fissionable material - radioactive, long lived alpha emitters

Fusion waste products:

• fusion products - mostly non-radioactive helium
• neutron activated materials - radioactive, mostly beta and gamma emitters
• unburned fusionable material - non-radioactive deuterium and radioactive tritium, short lived beta emitter

The worst in both cases are the neutron activated materials, as these are parts of the reactor structure itself. The others can be removed from the reactor and reprocessed to separate them for disposal or reuse. To separate out the neutron activated materials you would first have to completely dismantle the reactor!

Answer 5

Fusion is a process in which the nuclei of two atoms combine to form a larger nucleus, while fission during fusion a small fraction of the reactant mass is converted into energy.

While not the only possible fusion reaction, the most commonly known is the fusion of hydrogen to create helium. The product is stable. In contrast, when fission of uranium or plutonium takes place, the resultant nuclei are neutron heavy and therefore will almost certainly be radioactive.

Answer 6

I found the website K1 Project very helpful. They had several articles underneath their Learn/Energy tab which should answer any questions about nuclear fusion.

Answer 7

1 separates[fissin] the other fuses[fushin]

Answer 8

The waste product of nuclear fusion is helium, an inert gas and not radioactive. The waste products of nuclear fission reactions are radioactive.