fairchijisback: Rainer is probably the best person to talk on the subject but I am totally convinced that Nuclear is required to bridge the gap. It is not an easy subject.

Since you mentioned me here, John, I thought I’d speak up. Yes, nuclear power is the only way to provide a highly industrialized country with reliable, clean and affordable electricity – unless you have hydropower, and enough of it, to meet your needs.

Trying this only with wind and solar, as my own country Germany does, will fail miserably – and already does. You always need a firm power source for those time when the wind doesn’t blow or the sun doesn’t shine, let alone grid stability issues – you know what I am talking about. And if you haven’t got nuclear, you have to go with high-carbon fossil fuels. And that’s what Germany does. It has to have coal and gas-fired plants running and is one of Europe’s dirtiest carbon polluters – while still spending unbelievable amounts of money on the energy transition.

But let me put two things right:

• The heavy water (D₂O) doesn't slow down the uranium atoms, it slows down the neutrons that are supposed to split the uranium atoms. These neutrons must not be too fast (high-energy) because otherwise they will simply whizz away, hitting only a few uranium atoms, and the chain reaction will come to a standstill before it has started. (This is different in so-called fast neutron reactors, but that's another story).
• The use of unenriched uranium as fuel is not just a thing of the past, but remains the operating principle of Canada’s CANDU reactors, including the 1000 MW CANDU Monarch unveiled last year.

Oh, and in order to maintain the POET context: We have to

• generate electricity reliably, cleanly, and affordably, and
• save that energy resp. use it responsibly. Here’s where POET comes in (among other measures).