Reply To: What can we do with $189 Billion?

[zapkitty]

vansig wrote: http://nextbigfuture.com/2014/07/helion-energy-plans-to-enable.html

Helion’s “Fusion Engine” (FE) concept is a neutronic D-T design… a standard deuteriun-tritium burner.

In other words while it would be an immense improvement over fission it’s still “dirty” fusion which needs a radioactive fuel (tritium) and would produce high-powered radioactive waste via neutron activation of its burn chamber components.

Their current PR push can be a bit… misleading. Unless it’s parsed carefully you could almost swear it was an aneutroic fusion design. 🙂

Fusion is clean, safe, and generates no hazardous byproducts

D-T fusion is safe, vastly safer than fission, and it doesn’t leave massive amounts of white-hot radioactive fuel byproducts behind… but it will leave a trail of very radioactive burn chambers behind.

Like all neutronic fusion waste these will be highly radioactive, lethally so, but thermally cool and inert with a hazardous lifetime of maybe ~300 years … instead of the hazardous lifetime of many thousands of years of fission waste.

Indeed, one of the design features of the FE is that the burn chamber is separate from the plasma injectors and thus can be replaced as a module when needed.

Fusion energy is converted directly to electricity, eliminating capital costs

Apparently an MHD design driven by the fusion products in the burn chamber reacting against imposed magnetic fields.

Speculation is rife on this part but it seems that if they’re omitting the steam cycle totally they’ll give up a large portion of the possible fusion power output in return for much cheaper and more compact direct conversion gear buit into the reactor itself.

But it seems more likely that they’ll use MHD to tap the fusion products for enough energy to power the device itself… but still needing to have a separate steam cycle for net power output to the grid. If that’s the case then perhaps a more accurate phrasing would be “eliminating [em]some[/em] of the usual capital costs associated with neutronic fusion”

Energy Generation -Fusion plasma is converted to i) direct energy ii) fuel for further operation

This implies a standard D-T setup… breeding tritiium from a lithium blanket surrounding the burn chamber.