Czech state-owned power company, ČEZ, says a small modification of the turbine at unit 2 of the Temelin NPP has proved its worth and the power engineers now plan a similar modification for unit 1.
A small adjustment of the turbine bearing means that tremors that were experienced for a short time in July have not recurred. An adjustment of the bearing by only nine hundredths of a millimetre was enough to prevent a recurrence of the increase in vibration which had caused operators to reduce the output of Temelín 2 in July.
Work on unit 1 will begin on 27 August. “We do not want to wait for the outage next year and we will use the summer period when there is usually increased production from renewable sources,” said Bohdan Zronek, a ČEZ Board Member and Director of the Nuclear Energy Division.. “It’s not acute, but from an operational and economic point of view it makes sense to us,”
Work on the turbine should be completed by the beginning of the school year. According to the technicians, the control itself and a slight change in the turbine bearing, which allows it to shift in the event of temperature changes, take only a few hours.
The turbosets in Temelín are the largest such facilities in the Czech Republic. The length of one high-pressure, three low-pressure parts and a generator is 65 metres. The weight exceeds 2000 tonnes and the circumferential speed of the longest blades exceeds twice the speed of sound. After heating to operating temperature, it extends by about 3 centimetres, while it must remain completely tight. That is why there is a possibility of axial displacement with these machines. ČEZ experts are co-operating with turbine supplier Škoda Doosan Power in Pilsen, for the modifications.
