The whole story, detailed in an amazingly honest fashion by World Nuclear News today details the procurement bribery scandal that rocked the Korea Hydro and Nuclear Powerworkforce be extended to sub-contractors (from whence the bribery originated).
Obviously this raises many question including how long this has been going on (probably since the start of the program in 1977) to how extensive and 'effective' it has been to issues of government collusion to the biggest one of all: safety.
On the latter, it appears that safety overall has not been effected. It's hard to hide nuclear malfeasance. People tend to find out about it, like the recent emergency shutdown of a plant that had auxiliary diesel start up issues and was hidden from Korean's nuclear safety regulator by plant management.