The New Safe Confinement (NSC or New Shelter; ) is a structure put in place in 2016 to confine the remains of the number 4 reactor unit at the Chernobyl Nuclear Power Plant, in Ukraine, which was destroyed during the Chernobyl disaster in 1986. The structure also encloses the temporary Shelter Structure (sarcophagus) that was built around the reactor immediately after the disaster. The New Safe Confinement is designed to prevent the release of radioactive contaminants, protect the reactor from external influence, facilitate the disassembly and decommissioning of the reactor, and prevent water intrusion.

The New Safe Confinement is a megaproject that is part of the Shelter Implementation Plan and supported by the Chernobyl Shelter Fund. It was designed with the primary goal of confining the radioactive remains of reactor 4 for 100 years. It also aims to allow for a partial demolition of the original sarcophagus, which was hastily constructed by Chernobyl liquidators after a beyond design-basis accident destroyed the reactor. The word is used rather than the traditional to emphasize the difference between the containment of radioactive gases—the primary focus of most reactor containment buildings—and the confinement of solid radioactive waste, which is the primary purpose of the New Safe Confinement.

In 2015, the European Bank for Reconstruction and Development (EBRD) stated that the international community was aiming to close a €100 million funding gap, with administration by the EBRD in its role as manager of the Chernobyl decommissioning funds. 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$2.3 billion). The New Safe Confinement accounts for €1.5 billion.

The French consortium Novarka with partners Vinci Construction Grands Projets and Bouygues Travaux Publics designed and built the New Safe Confinement. Construction was completed at the end of 2018.

On 14 February 2025, during the Russo-Ukrainian war, a Russian "Geran-2" drone attack significantly damaged the NSC. Both the internal and external layers were breached during the attack.

Background

The predecessor to the New Safe Containment was a structure formally referred to as the Shelter Structure, and often called the sarcophagus. Built between May and November 1986, the Shelter Structure was an emergency measure to confine the radioactive materials within reactor 4 at the Chernobyl Nuclear Power Plant. The Shelter Structure was moderately successful in confining radioactive contamination and providing for post-accident monitoring of the destroyed nuclear reactor unit; it has been estimated that up to 95% of the original radioactive inventory of reactor 4 remains inside the ruins of the reactor building.

However, the Shelter Structure—constructed under extreme conditions and severe time constraints—was never intended to be a permanent containment structure.Inside Chernobyl's Mega Tomb, https://www.windfallfilms.com/show/6894/inside-chernobyls-mega-tomb.aspx . As such, the shelter's deterioration over the years increased the risk of its radioactive contents leaking into the environment. Additionally the shelter was primarily supported by the remains of the reactor 4 building, which had been damaged by the initial explosion and were considered to be structurally unsound.

Between 2004 and 2008, workers stabilized the roof and western wall of the shelter. However, construction of a new confinement system was deemed necessary to continue confining the radioactive remains of Chernobyl Nuclear Power Plant reactor 4.

History

Design and planning In 1992, Ukraine's government held an international competition for proposals to replace the sarcophagus. 394 proposals were submitted by various construction firms. While a short list of 19 finalists was announced, no design was considered a clear winner.

In a 2006 letter to the editor of New Civil Engineer, British civil engineer David Haslewood alleges that his firm, Manchester-based Design Group Partnership, first developed the idea of an arch built off-site to minimize construction workers' radiation exposure, and then slid over the existing sarcophagus. Haslewood claims that his firm partnered with AEA Technology to submit their proposal to the Ukrainian government's design competition, where it tied for second place. The idea would re-emerge in 1996, when a feasibility study organized by the European Commission programme TACIS included it among its suite of recommendations for future development of the shelter project.

A year later, in 1997, the G7 Nuclear Safety Working Group assembled an international team of experts to create a plan to implement the study's recommendations. The result was the Shelter Implementation Plan (SIP), which outlined the steps required for shelter construction.

The SIP originally called for construction to begin in January 1997, and finish in 2004. However, it quickly became clear that the Exclusion Zone lacked the infrastructure necessary to support such a complex project, which would have to be built before construction could begin. Bureaucratic hurdles and coordination issues between the numerous organizations involved in the project resulted in further delays. Finally, a dispute over contractor selection between the Ukrainian government and the European Bank for Reconstruction and Development, which was providing much of the funding for the project, left the project in limbo for over a year.

As a result, it took until 2007 for a contractor for the project to be selected. On 17 September, the contract was awarded to Novarka, a consortium composed of the French construction firms Vinci Construction Grands Projets and Bouygues Travaux Publics. Novarka did not work alone: the consortium collaborated with both Ukrainian and international contractors throughout construction, with firms from 24 nations ultimately contributing to the project.

Construction

The construction of the New Safe Confinement (NSC) was plagued by delays and budget overruns. Ultimately, the project took nine years to complete, and cost €1.5 billion.

Structural construction and the "slipping" procedure

In 2009, stabilization efforts for the existing sarcophagus were completed, with the structure considered stable enough for another 15 years. The following year, the infrastructure upgrades to the Exclusion Zone undertaken in preparation for NSC construction were completed. These included road and rail connections, site services (power, water, drains, and communications), facilities for workers (including medical and radiation protection facilities), and the installation of a long-term monitoring system.

With the necessarily preparations complete, Novarka began construction of the NSC itself in September 2010. The first six months of construction were spent on preparatory work such as the NSC's pilings, as well as further improvements to the Exclusion Zone's infrastructure.In April 2012, steel erection began. The first part of the structure to be worked on was its eastern arch. However, its steel frame was initially constructed at the western edge of the NSC's track system, as far from the sarcophagus as possible, to minimize workers' radiation exposure. On 26 November 2012, the completed top section of the arch was raised to allow work on lower sections. The process was repeated in June 2013. Finally, in April 2014, the completed arch was moved eastward on its rails to clear the construction area for building the western arch. The construction of the western arch followed a similar process, with completed sections being raised on 4 August 2014 and 12 November 2014. In April 2015, the two arches were welded together, and construction began on the structure's exterior wall. This work was completed in April 2016, finishing the construction of the basic arch structure.On 14 November 2016, Novarka began to "slip" the arch structure over the existing sarcophagus. The arch was pushed across Teflon pads by laser-guided hydraulic pistons. The process took a total of 15 days, with the arch reaching its final location on 29 November 2016.

Subsystem construction and testing With structural construction complete, work began on the NSC's various subsystems, such as the radiation monitoring system, the back-up power supply system, the fire protection system, as well as lighting, communication, and HVAC. However, this work was interrupted in December 2017, when the extremely high level of radiation forced workers to limit their presence at the site. This and other bugs delayed further construction by almost a year.

While construction of the NSC itself was on hold, Rodina Consortium - Enerparc AG began construction on the first solar power project to be developed within the Chernobyl exclusion zone. 3,762 solar modules would eventually be installed at the site, with a generation capacity of .

In late 2018, Novarka announced that construction of the NSC's subsystems had completed, and they would now begin testing their performance. In February 2019, Novarka announced that all major subsystems had passed their individual tests, and the structure as a whole had passed an integrated test. On 22 April 2019, the NSC began a final 72-hour trial operation test; when it concluded three days later, every system and subsystem passed with flying colors.

Completion and opening ceremonies

The NSC was officially declared finished in July 2019. On 3 July, journalists were invited to tour the completed structure. A week later, on 10 July, Ukrainian President Volodymyr Zelenskyy and other Ukrainian government officials attended a ceremony where ownership of the NSC was formally transferred to the Ukrainian government.

Russian invasion of Ukraine

On 24 February 2022, during the Battle of Kyiv, Russian forces captured Chernobyl. The occupation of the plant lasted until 31 March, when Russia was forced to withdraw from Kyiv Oblast. While the occupation did cause an increase in radiation in the area, this was due to Russian forces disturbing the soil in the Red Forest and releasing radioactive dust. The New Safe Confinement survived the occupation undamaged.

On 14 February 2025, a Russian "Geran-2" attack drone struck the New Safe Confinement, causing significant damage. The power plant released a statement indicating that the outer cladding of the structure had been penetrated and that the inner cladding had been damaged as well, with fires affecting the layer of insulation. The innermost layer of the structure was not breached, because the drone struck the northern garage of the gantry crane, which received structural damage but was not fully penetrated. Russia denied it was responsible, and the IAEA has not attributed blame to either side. Early estimates put the cost of repairs at USD$25 million.

In the immediate aftermath of the strike, limited repairs were made to the shelter's roof. Nine months later, an IAEA team arrived to inspect the damage caused by the strike. On 5 December, the organization announced that the New Safe Confinement had "lost its primary safety functions, including the confinement capability". While the shelter's structural supports and monitoring systems had sustained no permanent damage, the IAEA stressed that more comprehensive restoration would be needed in the near-term future to prevent the structure from degrading any further. The European Bank for Reconstruction and Development pledged to provide financial support for the repairs in 2026.

On 1 October 2025, the Ukrainian Energy Ministry stated that power to the structure had been cut for three hours due to Russian airstrikes on the neighboring town of Slavutych. Ukrainian president Volodymyr Zelenskyy accused the Russians of deliberately trying to create a nuclear incident, as they would have been fully aware that the strikes would endanger the New Safe Confinement's power supply.