CALCULATION RESULTS FROM RADIATION EMBRITTLEMENT OF VVER PRESSURE-VESSEL AT KOZLODUY NPP

A calculational procedure for the evaluation of the transition tempera ture shift on the basis of neutron fluence has been applied for assess ing the reactor pressure vessel (RPV) embrittlement and life time for a VVER-440/230. The calculated results are lower than the passport val ues, because the real fuel regimes, the low-leakage schemes and loadin gs with dummy cassettes have been taken into consideration in neutron fluence calculation. The temperature of the outer wall of the RPV has been measured. No significant deviation between the measurement and th e data given in the reactor passport has been observed. This shows the correct application of the calculational procedure.