Since August 17, the personnel of JV Novarka perform the studies of operating ventilation systems of the main capacity and annular space of the New Safe Confinement (NSC) in different modes of equipment operation.

This work is carried out in order to implement the first stage of the Technical Decision "On organization of the ventilation mode of the single NSC-SO complex for the period of ventilation system testing and trial operation of the first commissioning stage (CS-1) of NSC" within the contract for design, construction and commissioning of NSC.

At this stage of ventilation system operation study, the radiation monitoring of radioactive emissions into the environment through ventilation stack of NSC is carried out in accordance with the requirements of the Technical Decision. Also according to the requirements of the Technical Decision, the personnel of the Radiation Safety Shop of SSE ChNPP and the Service of JV Novarka perform additional radiation monitoring of the environment both within the space under the NSC Arch and within the area of ChNPP industrial site and beyond its boundaries.

The key feature of this activity was to redirect the airflow from Shelter Object to the NSC ventilation stack. Prior to NSC construction, the airflow from the Shelter was directed to the ventilation stack of ChNPP Stage II. By activating the NSC ventilation systems, the airflow of SO is directed through the NSC ventilation stack.

Due to this, there was a hazard of increased release of radioactive substances into the environment when activating the NSC ventilation systems because of radioactive dust rise generated from construction activities in the form of sediments on the outer surfaces of the Shelter and steel structures of the space under the NSC Arch.

At the present, according to radiation monitoring results, the exceeding of control levels is not detected. Also, according to radiation monitoring results, the worsening of the radiation situation within ChNPP site area and beyond its boundaries was not registered comparing with monitoring results prior to testing commencement.