Y'all are misremembering what happened at Toshiba. They first bought the Westinghouse nuclear reactor business. Later they bought a nuclear plant construction business and merged it into Westinghouse. Fukushima, rather suddenly, caused the FERC and NRC to significantly upgrade the designs, which caused costs in the power plant construction business [not the reactor business] to exceed the guaranteed price to utility customers.
Imho, this illustrates the foolhardiness of signing fixed price contracts without also fixing the technology those contracts will be applied to. If the bargainers and attorneys had done their job correctly, what would have happened when NRC changed the requirements is that construction would have stopped while the clients considered the suddenly imposed higher costs [and possibly went back to their regulators for permission to either proceed or abandon the project].
Toshiba didn't do its due diligence properly in the purchase of the power plant construction business. So, both it and the reactor business it was merged into (another oops) are now in bankruptcy and the utilities face the same exact situation -- do you proceed and pay much more or stop and abandon all work done to date?
[Yes, I know which way the green lobby wants the decision to go. Fortunately, they aren't in charge -- the public utility commissions are.]