Considerations on the activity concentrations in the primary circuit of Grafenrheinfeld nuclear power station

Grafenrheinfeld nuclear power station has demonstrated during extraordinarily stable reactor operation in two one year operating cycles that in spite of expensive chemical constraints in relation to corrosion product activity and transport no essential differences exist compared with pressurized water reactors of similar design. The observation of corrosion product concentrations during variations which are inevitable during years of operation within chemical standard values in relation to pH-value, hydrogen concentration and trace pollutants in the same way as insignificant residuals variations in reactor output or average coolant temperatures, indicate no detectable effect on activity concentrations or transmission. However, short term fluctuations in output and boosting of additional operating units certainly cause increases in concentrations. (orig.)