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The New Safe Confinement (NSC or New Shelter) is a structure intended to contain the nuclear reactor at Chernobyl, Ukraine, part of which was destroyed by the Chernobyl disaster in 1986. The primary goal of the NSC is to prevent the reactor complex from leaking radioactive material into the environment and the secondary goal is to allow a future partial demolition of the old structure. A part of the Shelter Implementation Plan funded by the Chernobyl Shelter Fund, the NSC is designed to contain the radioactive remains of Chernobyl Unit 4 for the next 100 years. It is intended to replace the present sarcophagus, which was hastily constructed by Chernobyl liquidators after a "beyond design-basis accident" destroyed reactor 4 on April 26, 1986. The word "confinement" is used rather than the traditional "containment" to emphasize the difference between the "containment" of radioactive gases that is the primary focus of most reactor containment buildings, and the "confinement" of solid radioactive waste that is the primary purpose of the New Safe Confinement. The NSC is designed and built by the French consortium Novarka with 50/50 partners Vinci Construction Grands Projets and Bouygues Travaux Publics〔 and is expected to be completed in 2017. In 2015, the London-headquartered bank also said that there is a €100 million funding gap which the international community, whose contributions the EBRD is administering as manager of the Chernobyl decommissioning funds, is aiming to close. The New Safe Confinement will make the old Chernobyl shelter and remnants of the damaged reactor safe and environmentally secure. Completion of the project is scheduled for the end of 2017. The total cost of the Shelter Implementation Plan, of which the New Safe Confinement is the most prominent element, is estimated to be around €2.15 billion (US$3.09 billion). The New Safe Confinement alone accounts for €1.5 billion.〔 ==Existing shelter== (詳細はradioactive materials within reactor unit 4 at the Chernobyl nuclear power plant (ChNPP). The shelter was constructed under extreme conditions, with very high levels of radiation, and under extreme time constraints. The Object Shelter was moderately successful in containing radioactive contamination and providing for post-accident monitoring of the destroyed nuclear reactor unit. The existing Object Shelter is primarily supported by the damaged remains of the Unit 4 Reactor Building, which are largely considered to be structurally unsound as a result of explosive forces caused by the accident. Three major structural members support the roof of the Object Shelter. Two beams, usually referred to as B-1 and B-2, run in an east-west direction and support the roof beams and panels. A third, more massive member, the "Mammoth Beam", spans the largest distance across the roof from east to west and assists in supporting the roof beams and panels. The roof of the shelter itself consists of diameter steel pipes laid horizontally north to south and steel panels that rest at an angle, also in the north-south direction. The south wall of the Object Shelter is formed by the steel panels of the roof as they make an angle of approximately 15 degrees from vertical. The east wall of the shelter is formed by the reactor building itself, and the north wall by a combination of the reactor building and concrete segments. The west wall is constructed of large concrete sections reinforced by buttresses. The complexity of the segments of the west wall necessitated their construction off-site; they were then lifted into place by a remotely operated tower crane. It is these buttressed sections of the Object Shelter that are most often recognized in photographs of the sarcophagus. The Object Shelter was never intended to be a permanent containment structure, despite rumors to the contrary. Its continued deterioration has increased the risk of its radioactive inventory leaking out into the environment. Upgrades to the site made sometime prior to 2007 include pathways for roof access, roof repairs, the installation of a dust control system, and the installation of a long-term monitoring system. However, substantial upgrade or replacement of the shelter will be necessary in the near future in order to continue containing the radioactive remains of ChNPP reactor 4. It has been estimated that up to 95% of the original radioactive inventory of reactor unit 4 still remains inside the ruins of the reactor building. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Chernobyl New Safe Confinement」の詳細全文を読む スポンサード リンク
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