To extract uranium from the sea water is more expensive than the traditional mining. If they have made no breakthroughs in efficiency, that doesn't matter.
CNNC has started the extraction of uranium from Sea Water. Looks like the technology is getting commercialized and the are reach kg scale projects.
Thorium is a game changer on multiple levels - higher Carnot efficiency, vastly greater fuel supply, greater fuel efficiency due to cleaner burning fuel cycle with less long lived nuclear waste (because those waste products are also fissioned), etc. I don't think China will abandon it. Being careful is fine when it's something as high stakes as this.In my opinion the most interesting reactors currently being built or planned in China are the CFR-1000 and the TMSR-LF2. I have to say however that the TMSR project is progressing surprisingly slowly, from 2MW(t) to 60MW(t)/10MW(e) to potentially 100MW(e). The road to GW(e) scale reactors will be a very long one. It is understandable that such a novel design to take significant amounts of time, however there is always the danger of it getting bogged down and abandoned along the way.