Sewage treatment method and system for sewerage system of nuclear power plant evaporator

The invention relates to the technical field of nuclear power plant three-waste treatment systems, in particular to a sewage treatment method and system for a sewage discharge system of a nuclear power plant evaporator. The method comprises the following steps: cooling sewage of a steam generator through a heat exchanger to obtain cooled sewage; performing pressure relief treatment on the cooling sewage through a pressure reducing valve, and filtering the cooling sewage through a filter to obtain filtered sewage; performing radiation detection on the filtered sewage through a radiation detection device to obtain a sewage radiation value of the filtered sewage; when the sewage radiation value is greater than or equal to a preset radiation threshold value, starting a first sewage treatment device to purify the filtered sewage to obtain first purified water; when the sewage radiation value is smaller than a preset radiation value threshold value, a second sewage treatment device is started to purify the filtered