fusion reactor

[claymore]

When we finally get a fusion reactor up and running .will it create dangerous radioactivity and radioactive waste the same as the reactors do now?

[jake-the-peg]

Yes and No.

A fusion reactor will create a high concentration of neutron radiation.

This means that although there will be no radioactive spent fuel the way that you get in fission reactors the body of the reactor will become intensely radioactive.

However that means that you can make intelligent choices about what you build it from to avoid long lived radioisotopes.

For example much of the waste from decommisioning the ITER reactor will be safe for normal disposal after 100 years as opposed to hundreds of thousands of years.

The big safety feature of fusion reactors though is the fueling. A typical Fission reactor might run with months worth of fuel in it's core. If something goes wrong you can get a Chernobyl.

A Fusion reactor has maybe a few seconds worth of fuel and the problem is actually keeping it running.

This makes Fussion reactors inherently much safer than fission ones

[beso]

It is woth noting that the fusion energy in ordinary water is equivalent to the energy in the same volume of petrol.

At least the fuel is plentiful.

[Teddio]

No commercial fusion reactors are planned and the engineering constraints are enormous. Most current proposals would use a fuel mix of Hydrogen, Deuterium and Tritium. H and D have almost infinite abundance but the T would have to be bred from Lithium, not a particularly abundant element.
Tritium is a radioactive gas, a beta emitter, with a very high activity (and consequently a short half-life)
Most proposed fusion reactions will produce an intense neutron flux which will put great constraints on the choice of reactor materials. Careful material choice will minimise the activity of the reactor at the end of its life.
Abundant energy from sea water sounds very attractive. It will be so cheap the energy companies won't bother to send out any more bills. Where have I heard that before?

[jake-the-peg]

That's a little misleading.

there is an active roadmap to commercial fusion reactors.

JET in Oxfordshire achieved fusion
ITER is currently being constructed in France and will be capable of exceding Breakeven
DEMO is then intended to be the world's first electricity generating fusion plant - probably in Japan.

The fuel availability is often exagerated but Lithium is actually quite abundant

http://lithiumabundance.blogspot.com/

Fusion will never produce "free electricity" but it will not run out nor will it produce greenhouse gasses.

What's more unlike renewables it can be on when you need it, you're dependant on the weather for generation.

It's the long term card in the world's hand - probably starting to be a major resource when oil starts to become just too expensive to extract - just when we'll need it most.

It'sd an investment for our children - so they know we didn't screw everything up