One worker HAS already died from radiation exposure:
https://www.bbc.com/news/world-asia-45423575 , and many more face increased cancer risk. And that's not to mention the cost of disaster response and cleanup in terms of money, manpower and opportunity costs. The cleanup cost will be more than US$187bn by an official estimate a few years back.
Furthermore, with Fukushima we got lucky! Had it not been for the rapid response nuclear pollution could have affected one of the biggest metropolitan areas and economic engines in the world, and vital fish stocks. The tail risk was real, and the consequences would have been earth-shattering for Japan. In any calculation like this, it's not only the odds of an event occurring that needs to be taken into account, it's the impact of that low-odds event too