On the 22^nd of April 2013 within the framework of Shelter Object transformation into an ecologically safe system the SSE ChNPP obtained a separate written authorization from the State Nuclear Regulatory Inspectorate of Ukraine giving the right to perform works on construction and assembly of the First Commissioning Stage of the Shelter Object’s New Safe Confinement (NSC CS-1).
The authorization was issued under the results of the state expert review of nuclear and radiation safety of the Design “New Safe Confinement (NSC). Commissioning Stage-1 (CS-1). Licensing Package - 6 (LP-6). Design “Protective Building with Technological Life Support Systems and Necessary Infrastructure”.
The authorization was issued in accordance with requirements of the regulatory legal act “Conditions and procedure for issuance of written authorization for types of works or operations on Shelter Object transformation into an ecologically safe system”, as well as conditions of the license for Shelter Object operation.
The activities on the abovementioned design will be implemented by the SSE ChNPP Contractor – JV “Novarka” (France), involving Ukrainian and foreign subcontracting organizations.

On April 18 in the morning, the Prypiat River water level reached 107 meters of gauge height (under Baltic System). According to internal documents of Chernobyl NPP, the specific flood-protection activities are introduced at the enterprise when flood waters reach specified level. The objective of these activities is to prevent damage of the cooling pond dam and ingress of service water into the Prypiat River.

Pursuant to internal procedures, the round-the-clock duty charts for engineering staff of the hydro-technical facilities are established during flooding. Among these activities, there are dam detours twice a day, additional surveys of downstream side of dam and channels, their cleaning if required.

Moreover, the inventory of construction materials is currently prepared for elimination of dam defects, if they occur, and for detours using special transport, which could be needed in case of threat for dam body damage.

It is also assumed to keep continuous communication with Hydro-Meteorological Center of Ukraine, Meteorological Station located in Chernobyl town, “Ecocenter” enterprise, etc. to specify meteorological forecasts and situation in the river.

Prior to flood occurrence, the enterprise commission has reviewed and drew up an act for a dam, and its state was recognized satisfactory.

The State Nuclear Regulatory Inspectorate of Ukraine agreed upon the technical decision on eliminating the defects of SSE ChNPP II Generation New Ventilation Stack (NVS) metal structures.
The Action Plan on eliminating the defects is attached to the technical decision. According to this Plan a working documentation on remedial measures that improve the NVS reliability and on eliminating the defects of NVS tower’s metal structures should be developed within 30 calendar days after the agreement by the Designer (KSK Consortium composed of Kyiv Institute “Energoproekt”, Scientific Research Institute for Building Structures and Institute for NPP Safety Problems) with the involvement of the Nominated Subcontractor – Ye.Paton Institute. Welding work technology will be developed in parallel. After the working documentation review by the Employer and expert assessment at the SE “Ukrderzhbudexpertise”, the work execution projects, in accordance with which the physical activities on eliminating the defects to be performed, will be developed and then reviewed by the SNRIU.
The measures on designing, agreement and execution are envisaged for five months. The works will be financed at the expense of the Chernobyl Shelter Fund.

FYI
Construction and erection works on assembling the NVS metal structures were performed under the relevant contract within the Shelter Implementation Plan (SIP) in March 2012.
On July 11, 2012, during the routine inspection of the NVS metal structures’ condition by the designer's supervision personnel, the defects of joint welds in gusset plates of the NVS tower at marks 100.00, 107.56 and 114.76 in the form of “hair” cracks along the welding joints, which connect the gusset plates 12 mm in thickness and a pipe 325 mm in diameter, were detected.  The cracks development was observed in the top-bottom direction. These joint welds were produced at the manufacturing factory (Kharkiv).
“The Action Plan on the NVS engineering survey, investigation of causes for defects and measures on their repair” was developed by the SSE ChNPP for determining the causes for defects of the NVS metal structures and elaboration of high priority measures on their elimination. It was submitted to the SNRIU on 13.09.2012. The NVS Project Designer, KSC Consortium, carried out additional surveys and developed the Report “Analysis of causes for formation of cracks in the NVS structures and recommendations on further actions”. The technical decision on eliminating the defects of the New Ventilation Stack metal structures was developed based on these documents.

On April 18 in the morning, the Prypiat River water level reached 107 meters of gauge height (under Baltic System). According to internal documents of Chernobyl NPP, the specific flood-protection activities are introduced at the enterprise when flood waters reach specified level. The objective of these activities is to prevent damage of the cooling pond dam and ingress of service water into the Prypiat River.

Pursuant to internal procedures, the round-the-clock duty charts for engineering staff of the hydro-technical facilities are established during flooding. Among these activities, there are dam detours twice a day, additional surveys of downstream side of dam and channels, their cleaning if required.

Moreover, the inventory of construction materials is currently prepared for elimination of dam defects, if they occur, and for detours using special transport, which could be needed in case of threat for dam body damage.

It is also assumed to keep continuous communication with Hydro-Meteorological Center of Ukraine, Meteorological Station located in Chernobyl town, “Ecocenter” enterprise, etc. to specify meteorological forecasts and situation in the river.

Prior to flood occurrence, the enterprise commission has reviewed and drew up an act for a dam, and its state was recognized satisfactory.