Fascinating in the Extreme: How American Capitalists Industrialized China Without Tariffs.

[John ONeill]

2. BWRX10

GE Hitachi claim their small modular reactor is the apotheosis of ten generations of boiling water reactors. That's a stretch. The last GE design actually built was the Advanced Boiling Water Reactor, of which only four made it into use. Three more, one in Japan and a pair in Taiwan, were suspended part way through construction, while other projects in the USA and the UK were cancelled before construction started. The plants that were operating have all been put on hold now, as Japan gets over the political shock of the Fukushima Daichi meltdowns. Even before that, their uptime was well below that of most modern reactors, some below 50%, others about 70%, compared to 93% fleet average in the USA.
Successor to the ABWR was the Economic Simplified Boiling Water Reactor, which was supposed to be cheaper to build and to run. Power output was raised to 1500MW, and it was designed to use natural convection instead of internal pumps. The disadvantage is that the pressure vessel has to be taller, for convection to do the work normally done by pumps. How it would work in practice has yet to be shown.
The BWRX10 takes most elements of the ESBWR and shrinks the power output 5x. This was supposed to make a lot of the safety systems mandated for larger reactors redundant. In the end, though, the Nuclear Regulatory Agency ruled that they were still required. The original design called for the whole pressure vessel to be underground, because of the rule to be impervious to a large aircraft strike. Excavation was to use a vertical tunnel boring machine. Now the volume of the below ground works is about 5x more, and they have to dig down to 24 metres below grade to accommodate the tall pressure vessel (slightly taller than that of the Westinghouse AP1000, which makes 4x as much power - and of which six are already operating very well, in China and in the US.)
Canada is building an untried reactor, unlikely to ever make cheaper power than a gigawatt scale one, for which they will have to import the enriched fuel, and probably the specialist refuelling crews, from the US. Instead they could export their own design - and possibly team up with India, whose 220 MW version of the heavy water reactor could be used for grids too small for the the larger Candus.