Their safety record is good, but can they generate power at a cost that's commercially competitive? If it's too expensive then the plan doesn't work.
Thats the issue with those AGR reactors the brits have IIRC, perfect (or close enough) safety record, super complex and not economical to run.
They're expensive because of, arguably, over regulation. The are not inherently expensive, we've just declared them so. The next response will be "all that regulation is needed" but it's arguably that the over regulation is killing people by the unintended consequences of keeping things like coal viable, etc...