Heat transfer and associated surfaces in nuclear reactors are decontaminated by treating the surface with ozone to oxidize acid-insoluble metal oxides to a more soluble state, removing oxidized solubilized metal oxides, and removing other surface oxides using low concentrations of decontaminating reagents. Ozone treatment has been found very effective with alloys having surface metal oxides rendered more easily dissolved by ozone oxidation especially with chromium or chromium-nickel containing alloys.

Nuclear reactor decontamination

In a web packaging machine ( 10 ) and method packaging a food product (P) between upper and lower webs ( 14 and 25 ), wherein the lower web ( 14 ) is transported through a series of stations which form the lower web ( 14 ) into a component of a package at a forming station ( 18 ), and receive the food product (P) at a loading station ( 20 ), and close the package with the upper web ( 25 ) at a closing station ( 26 ), a pasteurization station ( 300 ) is provided between the loading station ( 20 ) and the closing station ( 26 ) and pasteurizing the food product (P).

Web packaging pasteurization system

OF THE DISCLOSURE A process is described for oxidizing pretreatment of chromium (III) oxide containing films, resulting from corrosion of base metal surfaces of piping systems and the like, to render the corrosion films more amenable to conventional chemical cleaning treatments. The process uses a dilute aqueous solution of an iron (VI) salt (FeO42-).

Process for treatment of oxide films prior to chemical cleaning

A steam generator chemical solvent mixing system and method is provided. The chemical solvent mixing system includes a pump, having a discharge port fluidly connected to a discharge line and a suction port fluidly connected to a suction line. An upper level injector, including an injector nozzle extends through one upper access opening in the outer casing of a steam generator and extends into the annulus of the generator between the tube bundle shroud and the outer casing, the upper level injector being fluidly connected to the discharge port of the pump. A lower access eductor is provided, including an eductor nozzle extending through one lower access opening of the outer casing and adapted to discharge solvent through one passageway in the tube bundle shroud and into the tube bundle of the generator, the lower access eductor being fluidly connected to the discharge port of the pump. A gas injection line is provided, fluidly connected at one end to a gas source and at the other end to the lower access eductor. A return line fluidly connects at one end to a second lower access opening and at the other end to the suction port of the pump. A method for chemically cleaning a steam generator is also provided utilizing the system to fill the steam generator with solvent and circulate the solvent within the generator.

Steam generator chemical solvent mixing system and method

The invention provides a method of decontaminating a metal surface in a heavy water cooled and moderated nuclear reactor, wherein the metal surface is coated with one or more metal oxides including radioisotopes, and wherein the metal surface is in contact with a heavy water coolant or moderator, the method comprising one or more treatment cycles each comprising an oxidation step wherein the metal surface is contacted with a solution of an oxidant in heavy water; a decontamination step wherein the metal surface subjected to the oxidation step is contacted with a decontamination reagent in heavy water for dissolving the one or more metal oxides and the radioisotopes in a decontamination solution and immobilizing the radioisotopes on an ion exchange resin; and a decomposition step wherein the decontamination reagent in the decontamination solution is decomposed; and wherein the oxidant, the decontamination reagent and the ion exchange resin are provided in a deuterated form and/or are free of active hydrogen. A heavy water nuclear reactor is adapted to perform the decontamination method.

Method of decontaminating metal surfaces in a heavy water cooled and moderated nuclear reactor

A HEAVY WATER COOLED AND MODERATED REACTOR, ITS NUCLEAR FUEL ASSEMBLIES, ATTACHED PIPINGS AND CONTAINER CAN ADVANTAGEOUSLY BE DECONTAMINATED BY EMPLOYING A HEAVY WATER SOLUTION OF DEUTERATED OXALIC ACID. THE RADIOACTIVE SUBSTANCES, REACTOR MATERIALS, AND/OR NUCLEAR FUELS ELUTED IN THE SOLUTION ARE REMOVED BY DECOMPOSING THE DEUTERATED OXALIC ACID BY MEANS OF AN IONIZING RADIATION.

Y Sasaki

Papers

Method of decontaminating heavy water cooled and moderated reactor