Abstract: The decontamination apparatus comprises a rotatable hone capable of being inserted into a heat exchange tube of a steam generator for removing contamination from the inside of the heat exchange tubes. The apparatus also comprises means for advancing and retracting the hone and means for removing contamination from the apparatus as the apparatus is withdrawn from the steam generator.

Abstract: The time taken to reduce concentration of radioactive gas in the coolant of a nuclear reactor to permissible levels during refueling or the like is reduced by injecting into the reactor coolant a quantity large compared to the quantity of fission gas, of stable gas of the same atomic number as each radioactive gas. The fission gas includes both stable and radioactive isotopes, the quantity of stable isotopes being large compared to the quantity of radioactive isotopes. The stable gas added and the fission gas of each atomic number are dissolved as one gas in the reactor fluid and are purged together, the added stable gas accelerating the dissolution of the radioactive gas.