A method for filtration of harmful gas effluents from a nuclear power plant including the steps of providing a gas effluent from a nuclear power plant, the effluent including a mixture of gases; filtering the harmful, notably radioactive elements from the gas effluent by membrane separation through at least one membrane, the membrane separation being achieved by sifting, sorption and/or diffusion; storing the filtered harmful elements in storage reservoirs, and discharging the processed gas effluent to the atmosphere.