Method for reducing the radioactive contamination of the surface of a component used in a nuclear reactor

Patent metadata

Field	Value
Publication number	US-2016196889-A1
Application number	US-201414909903-A
Country	US
Kind code	A1
Filing date	Aug 8, 2014
Priority date	Aug 14, 2013
Publication date	Jul 7, 2016
Grant date	—

Abstract

The invention relates to a method for reducing the radioactive contamination of the surface of a component used in a nuclear reactor, which component is in contact with radioactively contaminated water, in which method a hydrophobic film is produced on the surface of a component by virtue of the surface being wetted with an aqueous solution which contains a film-forming amphiphilic substance.

First claim

1 . A process for reducing the radioactive contamination of the surface of a component which is used in a nuclear reactor and is in contact with radioactively contaminated water, wherein a hydrophobic film is produced on the surface of a component by wetting the surface with an aqueous solution containing a film-forming amphiphilic substance.

2 . The process as claimed in claim 1 , characterized in that the hydrophobic film is produced on the interior surface of a component of a water-conducting circuit of the nuclear reactor.

3 . The process as claimed in claim 2 , characterized in that the hydrophobic film is produced after a part-circuit or full-circuit decontamination of the circuit.

4 . The process as claimed in claim 2 , characterized in that in the case of replacement of a component by a new component, the hydrophobic film is produced on the new component.

5 . The process as claimed in claim 1 , characterized in that the hydrophobic film is produced at a point in time outside load operation.

6 . The process as claimed in claim 5 , characterized in that the hydrophobic film is produced during the start-up phase of the reactor.

7 . The process as claimed in claim 2 , characterized in that at least one depot substance is applied to the surface before production of the hydrophobic film.

8 . The process as claimed in claim 7 , characterized in that the depot substance is a noble metal.

9 . The process as claimed in claim 7 , characterized in that the depot substance is a salt of chromic acid.

10 . The process as claimed in claim 1 , characterized in that it is an inspection process and the component is a tool used in this.

11 . The process as claimed in claim 10 , characterized in that the tool is dipped into an aqueous solution of the amphiphilic substance.

12 . The process as claimed in claim 10 , characterized in that the surface of the tool is sprayed with an aqueous solution of the amphiphilic substance.

13 . The process as claimed in claim 1 , characterized in that the application of the amphiphilic substance to a surface is stopped when the surface has been covered with the hydrophobic film.

14 . The process as claimed in claim 1 , characterized by the use of an amphiphilic substance which has a polar end formed by at least one polar group and a nonpolar end formed by at least one hydrocarbon radical.

15 . The process as claimed in claim 1 , characterized in that the water contains radioactive colloids and a film is produced by means of an amphiphilic substance which has a polar group having a charge having the same sign as the charge on the colloids.

16 . The process as claimed in claim 1 , characterized in that an amphiphilic substance which contains an aliphatic group as nonpolar radical is used.

17 . The process as claimed in claim 1 , characterized by a nonpolar radical having from 8 to 22 carbon atoms.

18 . The process as claimed in claim 1 , characterized in that an amphiphilic substance which contains an acid group or a primary, secondary, tertiary or quaternary amino group as polar group is used.

19 . The process as claimed in claim 18 , characterized in that the polar group is a phosphonic acid group.

20 . The process as claimed claim 1 , characterized in that the aqueous solution is influenced in such a way that a charge which is opposite to the charge of the polar group of the amphiphilic substance arises on the surface or that a surface charge opposite to that of the polar group of the amphiphilic substance is increased.

21 . The process as claimed in claim 20 , characterized in that the influence on the solution is exerted via the pH of the solution.

Assignees

• Areva Gmbh

Inventors

• Stellwag Bernhard
• Sempere-Belda Luis
• Ramminger Ute

Classifications

• G21F9/004

  of metallic surfaces · CPC title

• G21C17/0225 Primary

  Chemical surface treatment, e.g. corrosion (corrosion prevention in presence of water from scale removal or by modification of the properties of the liquid C02F5/00; inhibiting corrosion by adding corrosion inhibitors C23F11/00) · CPC title

• G21C13/08

  Vessels characterised by the material; Selection of materials for pressure vessels · CPC title

• G21C19/28

  Arrangements for introducing fluent material into the reactor core; Arrangements for removing fluent material from the reactor core (pumping coolant G21D) · CPC title

• G21F9/28

  Treating solids · CPC title