The New Safe Confinement (NSC or New Shelter; Ukrainian: Новий безпечний конфайнмент, romanized: Novyy bezpechnyy konfaynment) 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.

[4] 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.

[7] The French consortium Novarka with partners Vinci Construction Grands Projets and Bouygues Travaux Publics designed and built the New Safe Confinement.

[15] In the autumn of 1992, Design Group Partnership (DGP) of Manchester was invited to assist the Atomic Energy Authority (AEA) for the UK's submission for the international competition organized by the Ukrainian government.

The study selected the sliding arch concept as the best solution for their further investigations and recommendations, primarily to reduce the chance of the construction workers receiving a harmful dose of radiation.

The French consortium named Novarka eventually won the contract for the final sliding arch design.

On 17 September 2007 Vinci Construction Grands Projets and Bouygues Travaux Publics announced that they won the contract to design and build the New Safe Confinement as 50/50 partners of the French consortium Novarka.

The original 432 million euros contract comprises the design and construction of the New Safe Confinement and planned to employ 900 people at its peak.

A Dutch business handled the lifting and sliding operations, whereas the contractor responsible for the arch cladding was from Turkey.

Internally, polycarbonate panels cover each arch to prevent the accumulation of radioactive particles on the frame members.

Large parts of the arches were shop-fabricated and transported to the assembly site 180 metres (590 ft) west of reactor 4.

The ground upon which the foundation was built is unique in that it contains a technogenic layer just below the surface that is approximately 2.5 to 3 metres (8 to 10 ft) in overall depth.

This option was selected to minimize the cost of the foundation, the number of cuts into radioactive soil layers, dose uptake of workers, and risk to the environment from further contamination.

Special consideration was necessary for the excavation required for foundation construction due to the high level of radioactivity found in the upper layers of soil.

The conceptual designers of the New Safe Confinement recommended the use of rope operated grabs for the first 0.3 metres (11.8 in) of pile excavation for the Chernobyl site.

Deeper excavation for the foundation piles were accomplished using hydraulic clam shells operated under bentonite slurry protection.

As each bay was completed, infrastructure equipment — including that for ventilation systems, radiation monitoring, plumbing, and electrical was installed.

The second option was initially chosen because it would expose workers to a lower radiation dose, and would have moved the structure into its final position in less than 24 hours.

The tools selected for the demolition process were selected based on a number of factors including minimization of individual and collective radiation exposure, the amount of secondary waste generated, the feasibility of remote operation, the cutting efficiency, fire safety, capital cost and operating costs.

[33][34] Processed liquid is turned into solid waste in 200-L barrels where it can then be stored long-term, at a rate of 2,500 cubic meters a year.

Before the slippage procedure began, construction workers may only have been able to stay on the site for 30 minutes at a time due to radiation.

[17] Workers are required to also check their radiation exposure before they leave the New Safe Confinement as an additional measurement for safety.

[25] For the radiation mapping that occurs within the New Safe Confinement, robots have been deployed in both areas of high contamination where humans cannot enter and replacing routes that operators would normally take.

[40] Without posing risk to workers, the implemented systems were able to look inside reactor 4, deep within the New Safe Confinement.

[42] On 14 February 2025, Ukrainian president Volodymyr Zelenskyy said that a Russian drone attack significantly damaged the confinement.

[46] There has been concern about Ukraine's ability to properly maintain the New Safe Confinement, with Deputy project manager Victor Zalizetskyi stating that "It looks like Ukraine will be left alone to deal with this structure"[47] The New Safe Confinement was originally intended to be completed in 2005, but the project suffered lengthy delays.