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.