Polyhedral Boron Hydride Anions for Nuclear Reactor Emergency Cooling

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Solution Overview

Problem

The use of boric acid in emergency shutdown procedures for nuclear reactors is limited by its low solubility, requiring large amounts of water, potential for safety seal rupture, and corrosiveness, which can lead to reactor core unrecoverability and corrosion issues.

Innovation Solution

An aqueous solution comprising polyhedral boron hydride anions or carborane anions, such as B10H10^2-, B11H14-, or B12H12^2-, which are more soluble and have a higher boron content than boric acid, is used for faster reactor quenching with less water and reduced corrosion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If boric acid solution is used for emergency shutdown, then the reactor can be quenched, but large amounts of water are required which can rupture safety seals

Engineering Contradiction:

Improvereactor shutdown capabilityVSAvoidamount of water required

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent changes the chemical composition parameter from boric acid to polyhedral boron hydride anions or carborane anions. These alternative compounds have significantly higher solubility in water, allowing the same neutron poisoning effect to be achieved with much lower water volumes, thereby preventing safety seal rupture while maintaining reliable reactor shutdown capability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses composite aqueous solutions containing polyhedral boron hydride anions (such as B10H10^2-, B11H14^-, B12H12^2-) or carborane anions combined with appropriate cations. These composite materials provide both the necessary neutron absorption properties and enhanced solubility characteristics to resolve the contradiction between effective quenching and water volume constraints

Inventive Principle:

Principle #40Composite materials

2Reliability

If boric acid is introduced during emergency shutdown, then the reactor can be quenched, but boric acid deposits cause corrosion leading to reactor core unrecoverability

Engineering Contradiction:

Improvereactor shutdown capabilityVSAvoidcorrosion from boric acid deposits

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical identity parameter from boric acid to polyhedral boron hydride anions or carborane anions. These alternative compounds do not form corrosive deposits like boric acid, thereby eliminating the harmful corrosion effect while preserving the essential reactor shutdown function through neutron absorption

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention converts the harmful property of boric acid (corrosiveness) into a beneficial alternative by selecting polyhedral boron hydride anions or carborane anions that provide the same neutron poisoning function without the corrosive side effect, thus transforming a harmful chemical property into a safe operational characteristic

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of operation

If boric acid is used to control neutron flux during normal operation, then neutron flux can be controlled, but corrosiveness limits its utility

Engineering Contradiction:

Improveneutron flux controlVSAvoidcorrosiveness

Core Design Contradiction:

Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameter from boric acid to polyhedral boron hydride anions or carborane anions for use in controlling neutron flux during normal reactor operation. These alternative compounds maintain the neutron absorption capability necessary for flux control while eliminating the corrosiveness that limited the utility of boric acid

Inventive Principle:

Principle #35Parameter changes

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 solution allows for faster reactor core quenching with less water, preserving safety seals and reducing corrosion, while providing higher boron availability and solubility, making it more effective than traditional boric acid solutions.

Implementation Method 1

The polyhedral boron hydride anions or carborane anions...have a high affinity for neutrons and are useful for quenching a fission reaction in a nuclear reactor

Methodology Applied

Scientific EffectNeutron absorption: Absorption (EM radiation)

Implementation Method 2

contacting the nuclear reactor core with an aqueous solution comprising at least one of polyhedral boron hydride anions or carborane anions

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2973590B1Method of cooling nuclear reactor and nuclear reactor including polyhedral boron hydride or carborane anions

Publication Date: 2019.04.24 CERADYNE INC

AI summary

A method of cooling a nuclear reactor core is disclosed. The method includes contacting the nuclear reactor core with an aqueous solution comprising at least one of polyhedral boron hydride anions or carborane anions. Nuclear reactors are also disclosed. The nuclear reactor has a neutron moderator that is an aqueous solution comprising at least one of polyhedral boron hydride anions or carborane anions, or the nuclear reactor has an emergency core cooling system including a vessel containing a volume of an aqueous solution comprising at least one of polyhedral boron hydride anions or carborane anions. The nuclear reactor can also have both an aqueous solution comprising at least one of polyhedral boron hydride anions or carborane anions as a neutron moderator and an emergency core cooling system that includes an aqueous solution comprising at least one of polyhedral boron hydride anions or carborane anions.