Framatome Gmbh

Areva Gmbh

Christian Topf

Franz Strohmer

Luis Sempere Belda

Luis Sempere-Belda

Franz Ammann

Jose Pedro Moreira Do Amaral

Silvia Schuß

A method for decontaminating a metal surface exposed to radioactive liquid or gas during operation of a nuclear facility comprises an oxidation step wherein a metal oxide layer on the metal surface is contacted with an aqueous oxidation solution comprising a permanganate oxidant for converting chromium into a Cr(VI) compound and dissolving the Cr(VI) compound in the oxidation solution; and a first cleaning step wherein the oxidation solution containing the Cr(VI) compound is directly passed over an anion exchange material and the Cr(VI) compound is immobilized on the anion exchange material. The method provides for substantial savings of radioactive waste and produces chelate-free waste.

Method for decontaminating metal surfaces of a nuclear facility

A method of decontaminating a metal surface located on a component within a nuclear plant, in particular within the cooling system of a nuclear power plant, which is covered with a metal oxide layer containing radioactive substances, the method including a decontamination step in which a metal oxide layer pretreated in an oxidation step is contacted with an aqueous solution of an organic acid to dissolve the metal oxide layer, forming a decontamination solution containing the organic acid, metal ions and the radioactive substances, and passing the decontamination solution over an ion exchanger to immobilize metal ions and radioactive substances. An oxidant selected from oxygen, air, hydrogen peroxide and ozone is dosed into the decontamination solution to control the dissolution rate of the metal oxide layer. The method is particularly suitable for large-scale system decontamination and ensures high process stability.

Method of decontaminating a metal surface in a nuclear power plant

A method for treating waste water from the decontamination of a metal surface in a primary coolant circuit of a nuclear reactor comprises discharging a predetermined amount of an oxidation solution from the primary coolant circuit into a reduction zone connected to the primary coolant circuit and reacting the oxidation solution with a reducing agent to form a reaction solution that is freed of oxidizing agent, and passing the reaction solution over an ion-exchange resin in order to form a desalinated solution, and returning the desalinated solution to the primary coolant and/or disposing of the desalinated solution. A waste water treatment apparatus for carrying out the method is also provided.

Method for treating waste water from the decontamination of a metal surface, waste-water treatment device and use of the waste-water treatment device

A method of decontaminating metal surfaces in a cooling system of a nuclear reactor comprises: an oxidation step, comprising at least one acidic oxidation step and at least one alkaline oxidation step wherein metal oxides and radioisotopes on the metal surfaces are contacted with aqueous permanganate oxidant solutions; followed by a decontamination step wherein an aqueous solution comprising oxalic acid, formic acid, citric acid, tartaric acid, picolinic acid, gluconic acid glyoxylic acid or mixtures thereof is used to dissolve at least part of the metal oxides and radioisotopes; and a cleaning step wherein radioisotopes are immobilized on an ion exchange resin; wherein at least one treatment cycle includes a high temperature oxidation step, wherein the permanganate oxidant solution is kept at a temperature of at least 100&#xb0; C.

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Forchheim, Germany

Christian Topf