it is worth pointing out that the Fukishima plant had it's seawall bellow regulation height and had it's meltdown after seawater flooded the backup generator. This was an easily preventable disaster if they had just followed the law about nuclear safety
You ever hear of the bikeshed effect? It's the idea that if you get a committee of laymen to make a decision on something extremely complex, like a nuclear power plant, they'll hyperfixate in on the one thing that they think they understand - the bike shed. So instead of oversight and planning of the important bits of the plant like the reactor or the safety system, each decision maker will take their turn altering the color and the dimensions and the positioning of the bike shed.
I'm gonna guess that the wall was their bike shed.
There's a bit more nuance here. Fron this article, the plan is to treat the water to decontaminate it, then dilute it as much as possible because the treatment cannot remove some isotopes which could cause problems. The 30 year plan is actually a good thing since this would dilute the isotopes further making the risk minimal according to IAEA and the US. There are some independent labs that voice concerns for more data though.
The main issue is that the tanks that are supposed to hold the contaminated cooling seawater are filling up quick, so they need to add some space. Unless there's a better plan, it's either that or the tanks overflow.
You can't undo years of release if theres problems down the line
Current science says that this release is probably fine, but as you said independent labs and neighboring countries have posed objections based on insufficiency of evidence
"Current science" is really key here because it wasn't so long ago that science was convinced that heroin could be given to babies, smoking was harmless, and leaded gasoline is safe. Our state of the art has a habit of becoming the next generation's "how could they be so stupid?"
There have been alternative treatment and disposal options proposed and the Japanese government just happened to chose the cheapest one? That doesn't pass the sniff test.
Even if the release turns out to be completely safe in retrospect, all of the factors above will cause a significant amount of people to turn their opinions against nuclear power because it sets a precedent for perceived reckless handling of nuclear waste.
These are valid criticisms and they should be addressed. I think the main issue is that this is urgent and we can't wait to do the amount of surveying or studying enough to guarantee a safe dumping. I'm just assuming here since no one said anything about that. But I think it's a valid assumption since the disaster is 12 years old. If they are rushing this after let's say 8 years of studying it, then whatever time they have left to fill up the tanks is probably not gonna be enough.
Every single decision we make is based on "current science" since we didn't invent a time machine just yet to look at the future. Just because science has messed up in the past, doesn't mean we should paralyze ourselves now.
What are these alternative treatments that the government rejected? How much more effective are they vs how much more do they cost? If treatment "A" gives us a 5% chance of a better outcome and costs 80% more, then it makes sense. If it was an 80% better outcome for 80% more cost then yeah they did mess up.
"Current science" is really key here because it wasn't so long ago that science was convinced that heroin could be given to babies, smoking was harmless, and leaded gasoline is safe.
Science as a whole never was, there was just a shitton of money going to anybody publishing studies saying so. There's not a cannon of grant money fired at any scientist who says "radiation is good actually".
The lead gas thing is as you described but heroin and tobacco especially were in wide use for many years without anyone really knowing the full extent of damage they caused. Sometimes it does actually just take science a while to gather the data and catch up.