PRIPYAT (QHA) - Workers at the Chernobyl nuclear power plant in Ukraine have begun dismantling a ventilation stack that has filtered radioactive gases from the reactor that was destroyed in an accident in 1986, New York Times informs. The first section, weighing 33 tons, was lifted off the stack Thursday for storage in the plant’s turbine hall, according to a report on the plant’s website. The work is expected to take about five weeks. The distinctive red-and-white tower is being removed to allow a new arch-shaped enclosure to be placed over the concrete sarcophagus that was built after the disaster to entomb the wrecked reactor. The arch, scheduled to be completed in 2015, will allow workers to eventually dismantle the old sarcophagus and dispose of the radioactive fuel. As part of the preparation for the work, a new, smaller ventilation stack for removing radioactive aerosols that remain in Reactor 4 was built nearby. Note: Chornobyl Nuclear Power Plant is a decommissioned nuclear power station near the city of Pripyat, Ukraine. It is known for a catastrophic nuclear accident that occurred on 26 April 1986 . The station was under the direct jurisdiction of the central authorities of the Soviet Union. An explosion and fire released large quantities of radioactive particles into the atmosphere, which spread over much of the western USSR and Europe. The Chernobyl disaster is widely considered to have been the worst nuclear power plant accident in history.