Westinghouse Electric Corporation

William J Stenger

Robert D Burack

Allen J Baum

Gregg D Auld

Judith B Esposito

Clinton R Wolfe

The reactor coolant system (RCS) of a pressurized water reactor (PWR) is chemically decontaminated and cleaned utilizing apparatus which is comprised of components designed to operate at low pressures while still utilizing installed reactor coolant pumps and/or the residual heat removal pumps to generate the high flow rates required for the process. A high volume diverted flow of reactor coolant from the RCS is passed through letdown valves to reduce the high pressure produced by the installed pumps. Chemical decontamination and cleaning agents are mixed with the low pressure diverted flow and returned to the RCS by high head injection pumps. Contamination solubilized by the decontamination and cleaning agents is removed as the reactor coolant is recirculated through demineralizers. Filters remove particulates, and fines from the demineralizer resins. A surge tank, which may or preferably is not, in the path of the diverted flow provides reactor coolant for backwashing the demineralizers and filters and downloading the demineralizer resins.

Apparatus and method for chemically decontaminating a PWR reactor

An improved method for removing sludge and corrosion products from the interior of a heat exchanger vessel, such as a nuclear steam generator, which comprises the steps of generating a series of pressure pulses within a liquid chelate-containing chemical cleaning agent after the agent has been introduced into the interior of the vessel to create shock waves in the liquid for dislodging, dissolving and fluidizing sludge and corrosion products. The liquid chemical cleaning agent is removed from the vessel after only about 10 to 70 percent of what would have been its normal residence time without the pressure pulses. The method further includes the steps of simultaneously recirculating the chemical cleaning agent through a filter assembly during the pressure pulsing operation in order to remove fluidized sludge and corrosion products dislodged by the pressure pulsing, thereby affording them no opportunity to resettle back onto the surfaces of the heat exchanger vessel and interfere with the chemical cleaning of the vessel. The method reduces not only the time required for a particular chemical cleaning agent to effectively clean the vessel, but further reduces the number of times such chemicals need to be introduced into the vessel, which in turn results in the production of less radioactive liquid waste products.

Chemical cleaning method for steam generators utilizing pressure pulsing

In accordance with the present invention, there is described a method and apparatus for concentrating dissolved and solid radioactive materials carried in a waste water solution containing a hazardous chelating agent used for cleaning nuclear equipment. An oxidizing stage for receiving the waste water containing the radioactive materials and the hazardous chelating agent in the presence of an oxidizing agent oxidizes the chelating agent into non-hazardous constituents including gas and water. A separator coupled to the oxidizing chamber receives the waste water containing the radioactive material and separates the radioactive solids from the waste water containing dissolved radioactive materials. An ion exchange chamber containing an ion exchange resin receives the waste water containing the dissolved radioactive materials and removes the same from the waste water by ion exchange with the resin. A dryer receives the radioactive solids from the separator for removing water of hydration therefrom and producing dry solids. A packaging station receives the dry solids and the spent ion exchange resin containing the removed dissolved radioactive materials for packing them in solid form for disposal.

Growing community of inventors

Penn Township, Westmoreland County, PA, United States of America

William J Stenger