Interesting points:

0:11 - Elephant's foot

1:10 - "Stalactites" likely made up of radioactive corium

1:40 - The Upper Biological Shield (UBS): the 1000-ton lid of the reactor that was lifted from its placement and thrown through the roof of the reactor during the explosion

2:25 - Likely twisted & damaged fuel channels

3:11 - Fuel bundle

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The above, plus what I can only imagine are radiation-caused spotting of the footage, leads me to suspect that whoever filmed this got more than their fair share of radiation. Not exactly smart, although I very much doubt that the filmmakers emphasized such a quality in the first place.