In Japan they shut down each plant yearly for inspection. Everywhere else it's done on the refueling cycle. The plant I worked at was on a two year cycle so each year one of the two plants shut down for about an 8 week refuel/overhaul outage.
It's one thing to implement and andon cord, but it's quite another to get workers to actually use it.
1 The plants were antiquated 1970's US GE equipment https://en.wikipedia.org/wiki/Fukushima_Daiichi_Nuclear_Powe...
2 Japanese business culture is very deferential and top down. The amount of lying and covers ups around the Fukushima disaster was and is horrifying. Having worked for Sony I can say that there is an awful lot of dead wood in Japanese class system culture just as there is in the English class system, and that is not a healthy way to run something potential deadly on a global scale. I'm on the fence about nuclear power largely because of the above. It's not the technology, it's human and bureaucratic fallibility and greed that is the weak link