Pripyat Blog

Shelter object. Current status

Actually it is possible to consider as established, that inside the Shelter object remains about 90% of fuel, which was in a reactor at the moment of accident. Its total activity makes about 18 mln curies. Destructive processes, occurring in fuel containing materials (FCM), every year increase their hazard. Lava-like FCM destructs spontaneously and radionuclides containing in them are transformed from the bound state in mobile dust particles capable to live the Shelter boundaries with air flows. The radioactive dust amount according to conservative estimations makes about 4 tons.

There is a potential risk of a radioactive dust releases in an environment during probable collapse of supporting constructions, and due to water migration.
At the site near the Shelter under the layer of the ground, sand and concrete there is significant quantity of radioactive substances, non-isolated from hydrogeological environment.

Object’s constructions don’t meet the requirements of the normative and technical documentation on Safety if the field of mechanical durability, structural integrity, constructive reliability and have undetermined operational term.

Due to high humidity level in the “Shelter” premises ferro-concrete constructions are water saturated that results in their degradation. Metal constructions are significantly damaged as a result of corrosion processes. Deformation process proceeds.

The analysis of a constructions status testifies to the critical zones presence, sensible even at insignificant earthquakes, tornado and other natural phenomena, probable in ChNPP site location conditions.
Object’s constructions don’t meet the requirements of the normative and technical documentation on Safety if the field of mechanical durability, structural integrity, constructive reliability and have undetermined operational term. Due to high humidity level in the “Shelter” premises ferro-concrete constructions are water saturated that results in their degradation. Metal constructions are significantly damaged as a result of corrosion processes. Deformation process proceeds. The analysis of a constructions status testifies to the critical zones presence, sensible even at insignificant earthquakes, tornado and other natural phenomena, probable in ChNPP site location conditions.

At the moment it is impossible to ensure completely monitoring of a facility condition, including - nuclear and radioactive materials conditions because of the limited access in some premises which is complicated by high radiation levels.

Fuel Containing Masses monitoring systems “Shatyor” and “Finish” are installed in the Shelter. Prototype of this system “Pilot” is in operation testing to obtain additional information about FCM condition and initial data for nuclear safety monitoring system development. It is impossible to consider as sufficient the scope of monitoring nuclear and radiation parameters, carrying out by existing monitoring systems. In structure of the ” Shelter” monitoring systems there is no regular monitoring system of construction there are no fire safety systems and inside “Shelter” there are approximately 2000 tons of flammable materials - graphite, cables, elastron, wooden constructions. Deterioration of monitoring systems of Fuel Containing Materials condition has came to a critical level.

Current operation
Protection of population, environment and personnel against influence of radioactive materials, being inside the Shelter and at its site is a main goal of any activity at the object. For the carrying out of the considerable volume of works the State Nuclear Regulation Committee of Ukraine issued the Licence No 000033 for the term up to new safe confinement commissioning - “Shelter-2″.
Radiation physical parameters characterising current status of fuel containing materials as sources of nuclear hazard and severest accident consequences and current activity releases monitoring are monitored permanently according to “Technological Regulation of the Shelter object of Chornobyl Unit 4”. Analysis of results totality, obtained since 1995 from all measuring channels allowed to draw a conclusion, that critical processes aren’t occur in controlled FCM. Maximum level of gamma-exposure dose fixed by monitoring system’s detectors inside the Shelter makes about 3300 R/year.
In average 20000 of samples per year are taken to monitor radionuclids content of the air and water. Nowadays Shelter object not influences materially on general radioactive contamination of air environment, which is determined mainly by surface contamination of the territory as a result of accident in 1986.
Every month shelter’s personnel performs dust suppression in destroyed Central hall of Unit 4 (in average 12 times per year), dust suppressive mixture coating in Shelter’s premises (about 180 tons per year) decontamination of premises, equipment and territory to keep radioactive dust within the Shelter and at the site.
Parameters, characterising current radiation influence of beyond-designed accident on the personnel in accessible Shelter premises and at the site are under periodical control. These parameters are measured with portable monitoring equipment.
Parameters, characterising slow process of interaction with the environment are also under control. Such monitoring is carrying out not less than once per quarter and includes monitoring of constructions deformation inside the Shelter and ground waters contamination level monitoring, etc.
Radioactive Waste (RAW) Management
Liquid radioactive waste collection and transfer for processing (approximately 3000 sq.m per year), solid radioactive waste collection and disposal is charring out within the routine Shelter operation. Up to 2002 average volume of solid radioactive waste transported for disposal made 1000 sq. m per year, and since 2002 after beginning preparatory activity implementation (territory cleaning for infrastructure facilities construction within SIP Project) volume of transported for disposal solid RAW made over 16000 sq. m.

via: Chernobyl

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