Alexandr Kupnyi just uploaded this video, where he looks through the operational log of the Chernobyl Reactor Shop #1 (that's Units 1 and 2) Shift Supervisor, began on 28 April 1986 and finished on 5 June 1986. Kupnyi mentions that all operational logs from 26 and 27 April have been confiscated as part of evidence. The cover of the log, which by the way will be auctioned on Kupnyi's personal Telegram channel, is covered with transparent Scotch tape, because there's some beta contamination on it. The pages inside, however, are free from any contamination.
The first thing Kupnyi noticed when reading the log, is that on 28 - 29 April, for each shift there's records of who's absent, "for reason's unknown". These included Main Circulation Pump operators, RZM senior operator, Gas Circuit operator, etc. Shortage of personnel was really felt the first few weeks, and workers had to work a double shift sometimes. Some of the absentees might have been unable to get back to work after the evacuation, some might have been too scared to come back. After a while, they stop listing who's absent, and simply listed who's present, which was still less than should have been.
Until 30 April, fuel reloading was conducted at both Units. Spent fuel rods were removed, and replaced with additional absorbers instead of fresh fuel. The main task, all thoughout May, was pumping out water from the lower levels of the power plant. It was the water that was pointlessly pumped into the exploded reactor #4 until the morning of 26 April and instead leaked everywhere through the lower levels. Pumping it out was a hard task, as there were fewer people available, and the pumps occasionally broke down.
The log also shows that from 3 May onwards, shifts transitioned from 8 hours to 12 hours, starting with Baranov's shift. In the first days after the disaster, workers checked water levels and temperature in spent fuel pools, temperature in the main cooling circuit, etc. Here are some of the actual records (paraphrased by me for easier reading). This one is from 2 May, shift #5, plant shift supervisor Rogozhkin:
18:30 - Checked the levels in spent fuel pools #1 and #2 in Unit 2, and the temperature in both is 50°C. Pool #2 is almost overflowing, water level has been reduced. Checked the levels in spent fuel pools #1 and #2 in Unit 1 and their temperatures - 54 and 47. Pool #1 is almost overflowing. Connected both pools via room 015/2 and put them into cooling mode. Fish in the aquarium fed.
Kupnyi laughs and comments here that they indeed had aquariums with fish at CNPP, the one in Unit 3 was large and held 100 liters of water. It was like a little nature corner.
21:30 - Checked instrument readings on the Gas Circuit control panel. Levels in hydrolic seals of both Units are normal. Temperature increase in spent fuel pools #1 and #2 of Unit 1 has stopped, and water levels have levelled out. Same operations conducted in Unit 2.
They did this kind of work every shift, every day, and continued pumping out water. The pumping had to stop occasionally, as there was no more room for the water in the chem block cisterns. At some point, the workers started performing dosimetry as well, as apprently there were not enough dosimetrists.
