Originally Posted by
unbound
Haven't seen the series yet, but the high level sounds roughly accurate.
The people that fought the fires to try to prevent them from spreading to the other reactors received massive doses of radiation...many of whom died starting a couple of weeks after through a couple of months, so bleeding through the skin is distinctly possible. One of them received a radiation dose of 20,000 mSv (nearly 10,000 times higher than an abdominal xray).
It wasn't a matter of it being a damaged reactor. They were shutting down the reactor when someone wanted to do a test first. They attempted to restart the reactor when it was starting to power down and ended up raising the control rods too far to reverse the reactor to power up. Because of how that style reactor works (graphite moderated), when it did start powering back up, it powered up fully with the control rods up to high resulting in the reactor going prompt critical. This created a steam explosion which has nothing in common with an atomic bomb.
In regards to the helicopter crash, it did happen, but I'm pretty sure it was because the pilot flew it too close to nearby cables.
If nothing was done, you bet the surrounding countries would have been uninhabitable. They avoided that by pouring literally thousands of tons of boron, dolomite, sand, clay, and lead into the core in the following days, then a large concrete shelter was erected (and further improved shelter was put in place a few years ago) to keep radioactive contamination minimized.