Units 2 and 3 at the Czech Republic's Dukovany NPP will undergo extended checks on pipe welds this year in an effort to clear up any safety concerns, Czech utility CEZ said. Welds at all four Dukovany units were checked in 2015 after it was found that x-ray checks by a subcontractor were flawed. There are four Russian-designed VVER-440 units at the Dukovany site. The extension of checks is intended to remove any doubts about the reliability and safety of the facilities, CEZ said in a statement. CEZ said the current outage at Dukovany 3, which began on 23 April, will now continue until 19 October. The planned shutdown of Dukovany 2 will begin on 16 September and continue into 2017. CEZ said Dukovany 4 should restart on 14 May following its recent shutdown. In March the Czech State Office for Nuclear Safety extended the operating licence of Dukovany 1 for an "indefinite" period.