Monitoring method for support plates of nuclear power station steam generator

The invention discloses a monitoring method for support plates of a nuclear power station steam generator. The method comprises steps as follows: the outlet saturated steam pressure P1 of the steam generator is measured, the pressure P2 of recirculated and saturated water separated from a separator is approximately equal to P1, and the specific enthalphy value hsat of the recirculated and saturated water is obtained; the inlet feed-water temperature T0 of the steam generator is measured, and the inlet feed-water pressure P3 is approximately equal to P1, and the inlet feed-water specific enthalphy value hfw is obtained; the outside wall temperature T1 of a lower cylinder of the steam generator is measured, the feed-water temperature T2 of a descending channel is approximately equal to T1, the feed-water pressure P4 of the descending channel is approximately equal to P1, and the feed-water specific enthalphy value hdc of the descending channel is obtained; the circulating ratio CR is calculated, and whether a s