Many countries do it, with random controls such as statistics checks (like revenue vs employees count, compared to similar businesses) and random visits.
This does not eliminate illegal labor completely but significantly reduces it.
I had this issue with internal domains indexed by Google. The domains where not published anywhere by my company. They were dcanned by leakix.net which apparently scans the whole web for vulnerabilities and publishes web pages containing the domain names associated with each IP address.
I guess they read them from the certificates
This event happened in 2022. this is the only year since 1995 where nuclear production fell below 300TWh (278TWh in 2022 vs 360 in 2021 and 320 in 2023).
These cracks are not the only factor for the poor performance on nuclear in 2022 : several reactors had to do their 10-year maintenance (grand carénage), which had been delayed because of the pandemic.
It's hard to extrapolate reliability issues from an event that happened once in 30 years.
This does not eliminate illegal labor completely but significantly reduces it.