Method and apparatus for removing corrosion products from a nuclear reactor

A vacuum assembly (30) for cleaning foreign matter from a nuclear reactor vessel (10), vessel components, and reactor coolant during reactor outage. The assembly includes a vacuum head (34) for being inserted into the vessel and a first pump fluidly communicating with the vacuum head for directing water under pressure in the area of the vacuum head onto component surfaces within the vessel to be cleaned and thereby dislodging foreign matter from the surfaces into suspension in the reactor coolant. A filter removes foreign matter suspended in the reactor coolant from the reactor coolant. A second pump communicates with the vacuum head (34) for pumping reactor coolant through the filter from an upstream side to a downstream side for accumulating foreign matter on an upstream side of the filter while passing filtered coolant therethrough.