system
Given the following post, respond as if you're commenting on Reddit:
human
In the Tv series "Chernobyl" how realisticaly depicted are the effects of intense radiation exposure?

After the explosion they depict an enormous light projecting from, presumably, the exposed nuclear core, it's depicted like a huge cone of light going up in the sky till the eye can see, would an exposed nuclear core in meltdown emit such a huge amount of light?

Also a man is depicted looking directly into the exposed nuclear core, I presume in full meltdown, right after the explosion, immediately his face turns orange reddish and after a couple of seconds he's seriously sick and vomiting blood, is this accurate?

In general this is how it is depicted all the time, as soon as people get in contact with very high dosages of radiation their skin immediately starts to look red/orange and after a while it bleeds.

A firefighter that is in the middle of the rubble of the building is depicted picking up a piece of what presumably is a central part of the core, a piece of graphite, after seconds the hands from his skin looks burned, is this what would happen in such circumstances? would it be that quick?

The nuclear core in full meltdown is depicted as a glowing mass on fire, is that accurate? how would it actually look? what would be the temperature of it?
gpt
The beam of light is ionised air from the radiation of the core. It's gamma radiation from the exposed reactor core knocking electrons out of air molecules and that process, along with the deionisation, emits light.

Yes, the immediate reaction is very similar to extreme sunburn, burning the cells throughout the mans body. The soft tissues inside the body, the throat / mouth are broken faster than tougher skin. The guy is going to be going into shock from all the pain and cell death (which is toxic), looking sick and vomiting are to be expected.

The graphite pieces are going to be emitting a large amount of radiation. The glove will have protected the hand from alpha radiation but effectively all the beta radiation coming out of that graphite would all end up inside that guys hand. All the gamma going through his hand and then his body isn't going to have helped much either. He doesn't hold it for very long but it's going to have caused significant damage, though I've no idea if it would "erode" his hand like depicted.

When the core is on fire it is not melted down. The initial explosion vaporised all the water but the fuel is not hot enough to melt down yet. The graphite is pure carbon, and that carbon is burning with oxygen to form carbon dioxide. When they later put the fire out with the boron and sand the remains of the core and the surrounding material melts down. This is because the sand layer has insulated the core from the outside world heat is unable to escape. The heat from the uranium builds up until eventually it forms a molten lava or "corium".

EDIT: Overstated the effect of beta radiation on ionisation of the air. Beta radiation would definitely affected the guy's hand though, the range of beta particles in flesh is ~1cm.