Hacker News Reader

Comment by endisneigh | Hacker News Reader

I liked the website’s explanation but have a question.

So with a regular gas generator you go to the gas station and buy some 93 unleaded gas, then pour it into your generator. You might then pull something or use an electric start to turn on the generator and then you have electricity.

With this power plant the site says it requires helium. Where does this helium come from? Presumably energy is needed to get the helium just like energy is needed to pump natural gas and frack for oil.

Will the total output in electricity be greater than the inputs for this?

Extra: what happens if there’s too much expansion or things are too hot? Could this explode or implode? If so would it be a huge deal?

Cool tech!

View on HN

Helion's scheme would require a specific isotope of helium, of which there's not much of in current stockpiles. Assuming that you had some He-3, remember that since this is a reaction between nucleons, the typical energy scales are a million times higher than typical chemical energy scales. Therefore the amount of fuel (in kg) is a million times smaller. And so, there's a significantly larger margin for extracting and purifying the helium fuel from whatever source.

> Will the total output in electricity be greater than the inputs for this?

Yup, that's the goal!

> Extra: what happens if there’s too much expansion or things are too hot?

Fusion reactions are difficult enough that if it were physically possible to make them run 'hotter' or release energy faster, frankly we would already be doing so.

> Could this explode or implode? If so would it be a huge deal?

The radiation risks from fusion are orders of magnitude smaller than from nuclear fission power. We still need to think about them and make sure that plants are safe, but it should be significantly easier to manage.

> The radiation risks from fusion are orders of magnitude smaller than from nuclear fission power. We still need to think about them and make sure that plants are safe, but it should be significantly easier to manage.

Strictly speaking, it depends on the fuel cycle. They're targeting a fuel cycle (D+He3) with minimal neutron flux.

A commercial D+T fusion reactor would generate much larger neutron flux than a fission reactor. But it still wouldn't generate all the long-lived fission byproducts that are so problematic with (non-breeder) fission reactors (assuming proper sheilding).

The isotope of helium they want to use doesn’t exist on earth in significant quantities. They want to make their own by running another fusion reaction between two deuterium nucleii. Deuterium is plentiful but this reaction will take energy and “activate” (make radioactive) some components of their feeder reactor.

The website answers this question [1]. "Helion produces helium-3 by fusing deuterium in its plasma accelerator utilizing a patented high-efficiency closed-fuel cycle."

Wikipedia provides a bit more detail [2]: "The helium-3 is produced by D-D side reactions and is captured and reused, eliminating supply concerns. Helion has a patent on this process."

[1] https://www.helionenergy.com/faq/

[2] https://en.wikipedia.org/wiki/Helion_Energy

Reply on news.ycombinator.com