TSO support to the State Nuclear Regulatory Committee of Ukraine in the licensing of Rovno 4 and Khmelnitsky 2 NPP units (K2R4)

In 2003 the Ukrainian government decided to complete the construction without loans from the EBRD and the EU and to start-up Rovno 4 and Khmelnitsky 2 NPP units (K2R4) in 2004. K2R4 are two VVER-1000 reactors under construction since 80th. At request of EBRD and EC RISKAUDIT assessed the to be implemented safety upgrading measures at the time of commissioning as it is planned currently by NAEK against the safety upgrading measures in the K2R4 modernisation programme planned in 2000. In deviation of the modernisation programme 2000 the operator NAEK changed the technical contents for the solution of 3 issues (issues ''develop and introduce new programme of surveillance specimens'', ''rigid support of steam and feed-water lines at the outlet of the reactor building'' and ''analyses to determine extent of pipeline breaks'') and 19 measures were postponed from the pre-commissioning package to the phase after commissioning. The changed technical solutions for the above mentioned 3 issues would not allow resolving of the safety concerns. On demand of the regulator SNRCU the operator NAEK will implement an upgraded surveillance programme for the RPVs and the application of the no-break zone concept on main steam lines and main feedwater lines. The correct realisation of these measures allows solving of the 3 safety issues. The impact on the safety due to the postponing of those 19 measures is acceptable due to the fact that adequate preventive and/or compensatory measures are foreseen. All 19 postponed measures will be completed in the three year period after commissioning. The actual scope of measures allows upgrading K2R4 to a safety level which is acceptable for commissioning. (orig.)