One of the landmarks at the Dukovany NPP in the Czech Republic will soon disappear. Workers have begun to dismantle the 100-metre-tall gas flue/chimney using a special excavator suspended from a crane with a load capacity of 500 tonnes at the NPP site. The work should be completed by the end of September.
The chimney was part of the auxiliary boiler room which began operating in the mid-1970s, heating the construction site and supplying the heat needed to start the first units. The four VVER-440 units at Dukovany were commissioned between 1985 and 1987 and will continue to operate during the demolition work.
Nuclear currently provides about a third of the Czech Republic’s electricity from Dukovany and two VVER-1000 units at the Temelín NPP, which began operation in 2000 and 2002.
The Dukovany auxiliary boiler room heated construction site equipment, a dining room, administrative buildings, and supplied the heat needed for the first units. “We stopped using it in 1987 and we don’t need it anymore,” said Dukovany Plant Director Roman Havlín. The chimney is double-skinned with three walkways. The inner part of the chimney is made of fireclay bricks and the outer shell consists of concrete blocks. The diameter of the chimney is 6.69 metres at the base and 2.69 metres at the top. Havlín explained that this type of demolition is not easy at an operating NPP. “Therefore, we chose a relatively demanding method of gradual degradation using a special technique.”
At a height of 100 metres, the special demolition excavator is remotely controlled by workers from the platform of a second crane at the same height. The work is therefore dependent on the weather and has to stop in the event of extremely strong winds.
“Removal of the chimney is just one of a number of steps in the gradual modernisation of the Dukovany NPP,” said Bohdan Zronek, a board member of power utility ČEZ and Nuclear Energy Division Director. “The long-term safe operation of our nuclear units obviously requires investment in the maintenance and replacement of equipment. And of course we always choose the safest and most effective methods.”
Every year, ČEZ invests around CZK4bn ($187m) in the nuclear Dukovany and Temelín NPPs. This year, Dukovany is changing some parts of pipeline routes or cables and continuing the reconstruction of switchboards. At Temelín, part of the key control and management system of the plant is being replaced.
