Authoritarian regimes don't need to concern themselves with such pesky things as nature protection or people dying in accidents, especially if the workers are basically modern slaves.

If you want an example for what happens when you cut corners in nuclear, just look at Sellafield (UK) or La Hague (France). This shit is why regulations are so tight, and yet even that didn't prevent people from cutting corners which is why a lot of France's nuclear power plants were down for safety maintenance (corroded pipes) last summer, made worse by the drought that forced a lot of the remaining NPPs out of operation.