On July 8, the activities on dust fixation on surfaces of collapsed structures, equipment, floor and wall panels were commenced in Unit 4 Turbine Hall near collapse area of roof and wall structures. The personnel of contracting organization “StroyEnergoMontazh” perform the works under “Action Plan for mitigation of consequences from roof collapse and potential risks for available structures and personnel”.

The objective of this measure is to ensure reliable dust fixation on the surfaces of collapsed structures and prevent its spreading beyond containment structure and its entry into the environment as well.

The complexity of these activities is stipulated by the fact that work performance area has high levels of exposure dose rates and surface contamination, moreover, non-uniformity of radiation fields within this area is extremely high. Besides, the work zone includes large areas of vertical and horizontal surfaces of complex configuration. This is provided by the fact that a lot of pre-accidental equipment of the Turbine Hall is being within this area, and accumulation of materials and fragments of building structures of accident origin is recorded.

The total area to be treated is 4,440 cubic meters. The activities will be continued till the end of current month. Following their performance, a polymer film will be formed on all surfaces of the Turbine Hall in axes 49-54, safely fixing and retaining radionuclides. The guaranteed lifetime of the cover is 12 months. This time will be enough to recover collapsed fragments of roof and wall panels and containment structure of Unit 4, consequently.

On July 2, 2013, the testing of installation for dust suppressing inside Unit 4 Turbine Hall were commenced at Chernobyl NPP. A necessity in creating such system is preconditioned by conclusions of the commissions, which investigated reasons of partial destruction of building structures of the Unit 4 Turbine Hall.

As Deputy Head of the Shelter (NSC) Operation Shop Aleksandr Khimach reported, the installation is intended for supplying and spraying water solution. In total, 6 installations will be mounted within Turbine Hall enabling dust suppression over its whole area.

“Complexity of the task set to our staff lies in that technical requirements imposed to the installation, i.e. provision of water jet power, finely dispersive spraying and at the same time easy maintenance stipulated by radiation situation within Unit 4 Turbine Hall, were difficult to implement. Also this task was difficult to solve due to narrow and inconvenient technological passages available in this premise”, A. Khimach said.

It is a reminder that on February 12, 2013, at 14:03, the wall panels and a part of light roof of Unit 4 Turbine Hall partially collapsed. The destruction area was about 600 m2.

During February 13-20, two commissions investigated at ChNPP the reasons of partial destruction of the Turbine Hall building structures. The tasks set to the commissions were to analyze situation led to building structure breakdown, provide proposals on consequence elimination, as well as to develop and agree with SNRIU the corrective measures on management of additional drain waters and contaminated dust which can arise for a period required for recovering damaged roof and side walls of Unit 4 Turbine Hall.

The Vice Prime Minister of Ukraine Aleksandr Vilkul officially visited the Chernobyl NPP and the Exclusion Zone on July 2, 2013. Under his visit, Mr. Vilkul held an offsite meeting in Chernobyl of the Inter-Agency Emergency Response Center for Coordinating Actions of Central and Local Executive Authorities, and checked preparedness of the Chernobyl Exclusion Zone for fire season. The Chief of Defense, the Commander-In-Chief of the Armed Forces of Ukraine Vladimir Zamana, the Chairman of the Government Service of Ukraine for Emergencies Mikhail Bolotskikh, the Deputy Chairman of the Kiev Regional State Administration Vladimir Maksimenko, the Chairman of the State Agency of Ukraine for Exclusion Zone Management Vladimir Kholosha, the SSE ChNPP Director General Igor Gramotkin, and the representatives of central and local authorities have participated in the meeting.

Upon completion of the offsite meeting, the Vice Prime Minister has visited Chernobyl NPP. At the Shelter Observation Pavilion, Mr. Vilkul got familiar with current state of the facility and with outcome of the project “Stabilization of Unstable Building Structures” aimed at improving its safety, following which he visited the construction site for New Safe Confinement, where active operations on the Arch assembling are being performed.

On the 25^th of June the SSE “Chernobyl NPP” received an official report on working results of the IAEA Expert Mission that was held from 03 to 07 June 2013. This report represents an overview of the main findings, observations, acknowledgments and recommendations for improvement identified by the IAEA Mission on partial collapse of Unit 4 Turbine Hall Roof at the Chernobyl NPP.

Full text of the report is available here