22.05.2020

History of the Shelter

Photo and video

History and some nuances of the construction of the Shelter



After the explosion of the Chernobyl nuclear power plant reactor, absolutely all biological protection barriers and safety systems that protected the environment from radioactive elements of nuclear fuel were destroyed. In the short time after the accident, the issue of preservation of 4 reactors by building a facility that could limit the release of radioactive material from the destroyed reactor into the atmosphere, as well as reduce the radiation background around the reactor itself, became an acute issue.


By a resolution of the Central Committee of the CPSU and the Council of Ministers of the USSR dated May 29, 86, the USSR Ministry of Medium Machine-Building was entrusted with the task of burying 4 reactors. In the future, the sarcophagus built above the reactor will receive the official name Object Shelter.
He headed the work on the burial and decontamination of the territory around the Chernobyl nuclear power plant All-Union Research and Design Institute of Energy Technologies (VNIPIET). He also acted as the general designer of the Shelter.


The problems of the execution of work was that at the time of the accident in 1986 there was no practice in the liquidation of such accidents.


Paying attention to the importance of the Shelter, 18 design options were developed. Almost all of them demanded huge costs for resources, both construction and temporary. Ultimately, after calculating the material costs and dose loads, it was decided to erect a protective structure to the maximum extent possible using the remains of the surviving structures of the 4th power unit. Thus, the entire Shelter object is a combination of the “old” structures of the destroyed 4 blocks and the “new” ones that were built after the accident.


In view of such engineering solutions, an object appeared that has no analogues in the world. Its main purpose is to create a physical barrier to the release of radioactive materials (aerosols, dust) and radioactive radiation into the environment.


These physical barriers are based on external protective structures built after the accident: a cascade wall, buttress and pioneer walls, a covering over the reactor hall, deaerator shelf and engine room (Fig. 1).


The supporting contour, on which the supporting elements of the cover above the reactor rest, are the relatively surviving structures of the power unit 4.


To implement such a design solution, it was necessary to solve two of the most difficult problems. Firstly, it was necessary to examine the technical condition of the surviving structures in extremely difficult radiation conditions. Assess the possibility of their use as structural elements. Secondly, it was necessary to choose such construction methods that would minimize time and radiation impact on personnel.
In a short period of time, all the necessary infrastructure was built for future work on the construction of the “Sarcophagus” (supply bases, concrete plants, points of transshipment of building materials, living quarters for construction personnel, etc.). Safety measures were also organized in terms of the radiation factor, which made it possible to minimize the removal of radioactive elements outside the "dirty zone". Creation of dosimetric posts, decontamination points for vehicles and direct separation of the same vehicles into “dirty” and “conditionally clean” ones.

 

To begin with, it was necessary to prepare a “bridgehead” for future construction, that is, to decontaminate the roofs of the station and surrounding areas from radioactive material. The concept of radioactive material means the remains of the reactor core (graphite, fragments of fuel cartridges), structural elements, fire engines, which in the first hours of the accident took on a huge dose of radiation and also became pieces of highly radioactive waste. It was also necessary to remove the top layer of contaminated soil. All this was done by special engineering equipment, robots and people. First of all, people, because in high radiation fields the equipment simply refused to work.


The construction of the Shelter object required the introduction of such organizational and technological solutions that could reduce to the minimum, as much as possible, the radiation factor for personnel. The most effective was the technology of installation of all structural elements of the Sarcophagus in the "clean zone" and the subsequent installation of these structures using remote control.


Almost all installation and construction works used a unique technique and mechanisms at that time. For example, during the installation of all large structures of the Sarcophagus overlap, Demag crawler cranes with a lifting capacity of up to 650 tons were used. To supply concrete to the upper sections of the cascading walls, the Schwing and Putzmeister telescopic concrete pumps were used.
During the construction of the protective structure, approximately 345 thousand m2 of concrete mix was laid and about 7 thousand tons of metal structures were installed.


For safety in the further operation of the Shelter, dust suppression systems were also created, ventilation was carried out and fire extinguishing systems were organized.


It should be noted that it took 206 days to create such a complex and unique structure under extremely difficult radiation conditions. All construction was carried out in 3 shifts. That is, work was carried out around the clock. On November 30, 1986, Shelter was put into operation.


At the same time, the “Sarcophagus” is not a safe facility since it was created in haste and does not meet the rules and requirements for the construction of such facilities. Also, he never had a so-called “life span”.


Interesting fact. During the acceptance of the “Sarcophagus” there were absolutely no regulatory documents on its operation, there were no safety standards, etc. Simply put, the first problem was solved and that was it.


Time - it was the worst enemy for the Shelter. It was practically impossible to check many metric structural elements for the same metal corrosion due to the limited access to many places of the Shelter object itself. Over time, the degradation of building structures would lead to a deterioration in protection, and, as a result, to the possible destruction of the Sarcophagus.


Today, all these problems have become irrelevant due to the fact that the first Sarcophagus is isolated from the environment. The dome of the new safe confinement closed it from the effects of climatic factors. All these problems became irrelevant, but new ones appeared. There were tasks on dismantling old elements, preventing the release of radioactive materials outside the Arch, etc. But this is a completely different story.

+
Don't rush to close the page

Are you sure you have familiarized yourself with all the offers and promotions of our company?