Almost 60 years later, the gas holder building of the former Siberian Nuclear Power Plant in Seversk, associated with the complex of the first industrial uranium-graphite reactor I-1, which was used for the production of weapons-grade plutonium, has been dismantled. The work was carried out by the Experimental Demonstration Center for the Decommissioning of Uranium-Graphite Reactors.

The I-1 reactor was launched in 1955 at the Siberian Chemical Combine site. Its main task was the production of plutonium-239 for the Soviet nuclear program. Fuel irradiated in the reactor was sent for radiochemical reprocessing, where plutonium was extracted from it. The resulting material was used in the creation of nuclear warheads and became one of the key components of the Soviet nuclear arsenal.

The liquidation of the building began back in 2013: at that time, specialists removed more than 3097 m³ of radioactive waste and decontaminated the structures. The main dismantling continued in 2025. Building structures and the foundation were dismantled with heavy machinery after removing soil from the embankment and the metal roof cladding.

After the dismantled structures were removed, the pit was filled with inert material. A radiological survey of the area of 3048 m² confirmed its safe condition. Another part of the infrastructure of the Soviet atomic project has disappeared from the site of the former Siberian Nuclear Power Plant. This happened decades after the reactor was shut down.