MONAP Reagent for Nuclear Decontamination Corrosion Control

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Solution Overview

Problem

Conventional decontamination methods for nuclear power plant systems face challenges in preventing local corrosion and minimizing secondary waste, with existing reagents either producing excessive secondary waste or causing high corrosion rates in metal parts.

Innovation Solution

A modified oxidative decontamination reagent (MONAP) composed of an oxidizing agent, a metal ion, and an inorganic acid is developed, which regulates the electric potential of metal parts to a passive state, reducing the risk of local corrosion and secondary waste by incorporating a metal ion such as Cu2+ or Zn2+, thereby inhibiting corrosion and minimizing waste production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If alkaline permanganate (AP) decontamination reagent is used, then corrosion resistance on metal parts is excellent, but massive production of secondary waste occurs

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidsecondary waste production

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent modifies the conventional AP reagent by adjusting chemical parameters (adding specific oxidizing agents and controlling pH) to achieve effective decontamination with reduced waste production while maintaining corrosion protection

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite decontamination reagent system combining multiple chemical components (oxidizing agents, alkaline substances, and specific additives) to simultaneously achieve corrosion resistance and minimize secondary waste

Inventive Principle:

Principle #40Composite materials

2Loss of substance

If nitric permanganate (NP) decontamination reagent is used, then production of secondary waste is low, but high corrosion rate of metal parts occurs

Engineering Contradiction:

Improvesecondary waste productionVSAvoidcorrosion resistance

Core Design Contradiction:

Loss of substanceVSReliability

Solution Approach 1:

The patent adjusts the chemical composition and pH parameters of the reagent system to reduce the aggressive corrosive effects of nitric permanganate while preserving its low waste production advantage

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention introduces intermediary substances that mediate between the oxidizing action and the metal surface, reducing direct corrosive attack while maintaining decontamination effectiveness

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If oxidative decompostion is performed to remove dense radioactive oxide layer, then decontamination efficiency is improved, but local corrosion of metal parts occurs due to reagent permeation through cracks

Engineering Contradiction:

Improvedecontamination efficiencyVSAvoidlocal corrosion

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies protective measures before oxidative decomposition by pre-treating the metal surface or adding corrosion inhibitors to the reagent system, cushioning against potential local corrosion before it occurs

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The invention uses intermediary substances that prevent direct contact between the aggressive oxidative reagent and the metal surface, particularly protecting crack regions where reagent permeation would cause local corrosion

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The MONAP reagent effectively prevents local corrosion and reduces secondary waste while maintaining the passive potential of metal parts, ensuring efficient decontamination of dense radioactive oxide layers without damaging the metal surfaces, as demonstrated by reduced weight loss and observed corrosion inhibition in experimental examples.

Implementation Method 1

oxidative decontamination reagent for removal of the dense radioactive oxide layer on the metal surface including an oxidizing agent

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

regulates the electric potential of metal parts to a passive state, reducing the risk of local corrosion

Methodology Applied

Scientific EffectElectric potential regulation: Electrostatics

Data Source

PatentUS9390822B2Oxidation decontamination reagent for removal of the dense radioactive oxide layer on the metal surface and oxidation decontamination method using the same

Publication Date: 2016.07.12 KOREA ATOMIC ENERGY RES INST

AI summary

The present invention provides an oxidative decontamination reagent for removal of the dense radioactive oxide layer on a metal surface, which comprises an oxidizing agent, a metal ion, and an inorganic acid. The oxidative decontamination reagent of the present invention is characteristically prepared by adding a metal ion to the conventional oxidative decontamination reagent containing an oxidizing agent and an inorganic acid. When the oxidative decontamination reagent of the present invention is used, electric potential of the metal parts of the primary system of the nuclear power plant can be regulated as passive potential owing to the added metal ion during the oxidative decontamination of the primary metal part of the nuclear power plant. Therefore, by maintaining electric potential of the metal part as passive potential, local corrosion can be inhibited and at the same time secondary waste can be significantly reduced.