CROSS SECTION LAYOUT OF THE SACROPHAGUS

More than 400,000 m3 of concrete and 7,300 tons of metal framework were used during construction with the building ultimately enclosing 740,000 m3 of heavily contaminated debris and soil inside.

The sarcophagus has over 60 bore holes to allow observation of the interior of the core. In places the structure incorporated ventilation shafts to allow for some convection inside. Filtration systems were put in place to prevent radioactive material escaping through these holes.

The construction process consisted of eight stages:

1.Clearing and concreting the area surrounding reactor unit 4

2.Erection of initial reinforced concrete protective walls around the perimeter

3.Construction of separation walls between units 3 and 4

4.Cascade wall construction

5.Covering of the turbine hall

6.Construction of a high-rise buttress wall

7.Erection of supports and installation of a reactor compartment covering

8.Installation of the ventilation system.

“Here I need to pay tribute to comrade Schekalov, the expert from the Institute of Nuclear Energy, and also to the experts from the Ukrainian (Kiev) Institute of Nuclear Research, who made great efforts to find the appropriate paths, put in the necessary sensors, and stretch cables to them. As for neutron sensors, they were the responsibility of CNIIP [Central Science

Research and Project Institute] of the Ministry of Medium Machine Building. The experts from this institute were led by comrade Zhernov. Generally, one of their tasks was to put various sensors in the 4th block for measuring gamma fields, neutron fields, measuring temperature, measuring airflow, measuring the hydrogen concentration sensors should it suddenly appear in the system, etc. These sensors were placed in various spots. This was dangerous and hard work because they had to go inside the block every time and search for the most suitable spots that would reliably diagnose the condition of the 4th block. This was one set of tasks. And there were difficult situations. An attempt to pour concrete in an area was unsuccessful because in there were rather large gaps through which the concrete flowed to the levels below. Methods to hold the concrete in place had to be thought of. Some supports were not strong enough and reinforcement was necessary. This harmonious work of the researchers and the designers, in the end, led to a reliable construction.”

Valery Legasov, recorded from tape 3 side B