Fukushima failed because power failed, failing the coolant systems. That was an active system and not a passive. Look at MSR test that were done at the Idaho National Research Laboratory. The heat transference of using molten salt shutdown the react even in the absence of power. This is a passive system.
The EBR-II tests you're referring to were liquid metal sodium, not molten salt. Molten salt is much different (though it also can be used in reactors and may be able to demonstrate passive safety as well)
Three meltdowns, up to 1 death total from radiation (acutely and estimated long-term). That's a huge improvement over Chernobyl, which killed ~60 acutely and up to 4000 long term from early cancer deaths.
The real death toll of fukushima is the extra climate change deaths resulting from the hysteria it produced. Radiation wise it was really not that big of a deal.
