I was there when the issues were happening. Most of us commented on how inexperienced most of the holtec workers seemed. I talked to a couple of guys that work for holtec at another plant I worked at later...they said it all boiled down to many of the people there were somebody's relative or neighbor who had been recently hired with little experience....
This is what we had at Humboldt Bay, a group of folks with bridge building and road construction experience. We were certainly concerned, but it turned out to be a great group. The key is to invest in quality training time with them. We made all of our Rad-Worker and GET classroom courses with an actual instructor. Along with that quality training, we provided more focused mentorship in the field and we ended up with a really good crew.
The key thing is to have a Management team that is willing to make the extra investment. Otherwise, I could see this being a real challenge with potentially severe consequences.