First contact made with melted nuclear fuel at Fukushima plant

Radiation is a funky and tricky topic and frequently results in confusing cases like this. Let me try to explain (trying to keep things simple, so there's more nuance than what I'm writing).

Bq is a measurement of activity. That means the number of decays per second. That actually doesn't tell you the strength of that decay, the particle type, or the effective dosage one would receive. BUT it is still an incredibly important number. It will give you an indication of the half-life of the material and how much there is. A high Bq suggests low half life while a low Bq means a long half-life. OR a high Bq can tell you that there's A LOT of a material. This should make logical sense because Bq is telling you how fast it is decaying, and the more of a material there is the longer it takes to decay. Frequently if a material is known people will refer to its Bq as a way to tell someone else how much of the material there is. (yes, this can get confusing and there are two things it can be used to tell you. You have to pay careful attention. Context matters. In our case of the link you provided it tells you how much of the material there is.)

You'll also see Sieverts[0] listed commonly. This is a SI unit that tells you the effective dosage (REM is the equivalent). That means it considers the weighting that happens because of different particle types as well as where it impacts the body (you're in more danger if you swallow radioactive material than if you touch it with your hand). Which is important for maps like this one [1]. This is easier to understand.

On the other hand, there is grays (rads) is pretty similar to Sv but does not include particle weighting. In fact Sv is derived from Grays. They call this absorbed dosage.

So knowing this you should be able to conclude that the most dangerous material is something that has a high activity and has a high particle weighting.

For some comparisons, 137Cs has a half life of 30 years and decays with a beta- of 0.5Mev and a gamma at 0.7MeV. 235U on the other hand has a half life of 730Myr and decays an alpha particle at 4.8MeV.

[0] https://en.wikipedia.org/wiki/Sievert (There's a break down and link to the other units discussed here at the bottom).

[1] https://jciv.iidj.net/map/

That it takes so long now in the west is because we're not building enough of them, thus losing the advantage of experienced workforces and inability to leverage mass-manufacturing of standardized designs.

It's also slow because of onerous safety regulation seeking to make nuclear too safe, when we consider the result of a slowdown in commissioning of new reactors, thus increasing the reliance on coal killing way more people than if we were to hypothetically mass manufacture relatively unsafe reactor designs from the 60s today.

[0]https://www.finder.com/life-insurance/odds-of-dying

Not even that. People seem to forget that most utilized energy is eventually dissipated in heat in the atmosphere!

Any unlimited and extremely cheap energy source would only encourage more unsustainable consumption.

Not to mention that many industrial products that lead to pollution (e.g. plastic) are correlated to the cost of electricity. Give the world free energy and people will want a new smartphone every month.

(let's sit back and count the downvotes now...)

> ...its assessment of the exposures and effects due to the nuclear accident after the 2011 great east Japan earthquake and tsunami... It had concluded in that report that, in general, doses were low and that therefore associated risks were also expected to be low. A discernible increase in cancer incidence in the adult population of Fukushima Prefecture that could be attributed to radiation exposure from the accident was not expected. Nevertheless, the report noted a possibility that an increased risk of thyroid cancer among those children most exposed to radiation could be theoretically inferred, although the occurrence of a large number of radiation-induced thyroid cancers in Fukushima Prefecture—such as occurred after the Chernobyl accident—could be discounted because absorbed doses to the thyroid after the accident at Fukushima were substantially lower. It had also concluded that no discernible changes in birth defects and hereditary diseases were expected and that any increased incidence of cancer among workers due to their exposure was expected to be indiscernible because of the difficulty of confirming a small increase against the normal statistical fluctuations in cancer incidence. The effects on terrestrial and marine ecosystems were expected to have been transient and localized.