Ambient temperature decontamination of nuclear power plant component surfaces containing radionuclides in a metal oxide

• US 9,793,018 B2
• Filed: 10/29/2013
• Issued: 10/17/2017
• Est. Priority Date: 10/29/2013
• Status: Active Grant

• Current Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Original Assignee: Westinghouse Electric Company LLC (Brookfield Asset Management Incorporated)
• Inventors: Crytzer, Kurtis R., Ikeda, Lauren R., Vitale, Nicole D.
• Primary Examiner(s): Keith, Jack W
• Assistant Examiner(s): Wasil, Daniel
• Application Number:
  US14/065,741
• Publication Number:
  US 20150117587A1
• Time in Patent Office: 1,449 Days
• Field of Search: 376306, 25238952, 25240052, 510110
• CPC Class Codes: G21C 17/0225 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 Class Codes: G21C 19/28 Arrangements for introducing fluent material into the reactor core; Arrangements for removing fluent material from the reactor core pumping coolant G21D
• CPC Class Codes: G21C 19/307 specially adapted for liquids decontamination of liquids G21F9/04
• CPC Class Codes: G21F 9/004 of metallic surfaces
• CPC Class Codes: G21F 9/30 Processing separating different isotopes of the same chemical element B01D59/00
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

This invention generally concerns radioactive decontamination of deposits on components in a nuclear power plant and is specifically concerned with improved compositions, systems and methods for disrupting, dissolving, removing and reducing at ambient temperature radionuclides formed on the primary side surfaces of components in a pressurized water reactor and the internal components of a boiling water reactor. The methods include identifying the structure, taking the structure out of operational service, contacting the structure with an aqueous solution (e.g., a recirculating flow or static immersion), and adding an effective amount of elemental metal in solid form to the aqueous solution.

Claims

1. A composition effective to at least partially disrupt and dissolve radioactive deposits formed on a surface of a structure in a nuclear water reactor when the composition is in contact with the surface of the structure during non-operational conditions, the composition consisting essentially of:

an aqueous component at ambient temperature;

from about 0.001 M to about 2 M based on the composition, of at least one elemental metal additive to the aqueous component, selected from the group consisting of zinc, beryllium, aluminum, magnesium, iron, lithium, and mixtures thereof, in particulate, powder or colloidal form;

from about 0.025 weight percent to about 5.0 weight percent based on total weight of the composition, of an additive selected from the group consisting of a sequestering agent, a chelating agent, and mixtures thereof;

optionally a dispersant;

optionally an oxygen scavenger;

optionally a pH adjustment agent; and

optionally a reducing agent;

wherein the radioactive deposits comprise oxide-containing radionuclides deposited on the surface, and wherein the surface is a primary side structure surface in the nuclear water reactor.

2. The composition of claim 1, wherein the elemental metal component is zinc.

3. The composition of claim 1, wherein the elemental metal is in colloidal form.

4. The composition of claim 3, wherein the colloidal form contains particles selected from the group consisting of micron-sized particles, nano-sized particles and combinations thereof.

5. The composition of claim 1, further comprising a dispersant.

6. The composition of claim 1, wherein the aqueous component has a pH in a range from about 3.0 to about 13.