Polyhedral Boron Hydride Anions for Nuclear Fuel Storage

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Solution Overview

Problem

The use of boric acid in nuclear fuel rod storage pools poses issues due to corrosion concerns and limited solubility, which restricts its effectiveness in preventing criticality and emergency situations.

Innovation Solution

The use of aqueous solutions containing polyhedral boron hydride anions or carborane anions, which are more soluble and have a higher boron content than boric acid, providing enhanced neutron absorption and reduced corrosion risk.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If boric acid is used in storage pools, then neutron absorption is provided, but corrosion of racking materials and fuel cladding occurs

Engineering Contradiction:
Improveneutron absorption capabilityVSAvoidcorrosion of racking materials and fuel cladding
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical form of boron from boric acid to polyhedral boron hydride anions (such as B10H10 2-, B11H14 -, B12H12 2-) or carborane anions. These alternative compounds provide the same neutron absorption function while eliminating corrosion problems, as demonstrated by their chemical stability and lack of corrosive properties compared to boric acid.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs composite chemical structures where boron is incorporated into polyhedral hydride frameworks or carborane clusters. These composite molecular structures combine neutron-absorbing boron atoms with stabilizing hydrogen and carbon frameworks, creating compounds that are both effective neutron absorbers and chemically inert toward metal surfaces.

Inventive Principle:
Principle #40Composite materials

2Reliability

If boric acid is used in storage pools, then neutron absorption is provided, but solubility is limited to about 4.7 grams per 100 grams of solution at 20 °C

Engineering Contradiction:
Improveneutron absorption capabilityVSAvoidsolubility of boron in water
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent changes the chemical identity of boron compounds from boric acid to polyhedral boron hydride salts or carborane salts. These new compounds exhibit dramatically enhanced water solubility compared to boric acid, allowing much higher concentrations of boron to be dissolved in the storage pool water, thereby increasing the available neutron absorption capacity.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If higher concentration of boron is used to prevent criticality, then neutron absorption is improved, but corrosion risk increases

Engineering Contradiction:
Improvecriticality prevention capabilityVSAvoidcorrosion risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical form of boron to polyhedral boron hydride anions or carborane anions, which maintain chemical stability even at high concentrations. Unlike boric acid, these compounds do not exhibit increased corrosivity with concentration, allowing high boron concentrations to be achieved for superior criticality prevention while maintaining low corrosion risk.

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

These solutions offer improved boron availability for preventing criticality, increased safety during emergency situations, and reduced system corrosion, enabling more effective storage and handling of nuclear fuel rods.

Implementation Method 1

The polyhedral boron hydride anions or carborane anions absorb neutrons to prevent uncontrolled nuclear fission reactions

Methodology Applied
Scientific EffectNeutron absorption: Absorption (physical)

Data Source

PatentEP3134902B1Nuclear fuel storage pool including aqueous solution of polyhedral boron hydride anions or carborane anions and methods of using the same
Publication Date: 2021.03.31 CERADYNE INC

AI summary

A method of storing nuclear fuel is described. In some cases, the method includes submerging at least a portion of a nuclear fuel rod in a storage pool containing an aqueous solution including at least one of polyhedral boron hydride anions or carborane anions. In some cases, the method includes adding a salt having a polyhedral boron hydride anion or carborane anion to a storage pool containing water and at least a portion of a nuclear fuel rod submerged in it. The method may include both of these. A storage pool is also described. The storage pool includes an aqueous solution having at least one of polyhedral boron hydride anions or carborane anions with at least a portion of a nuclear fuel rod submerged in the aqueous solution. A method of servicing a nuclear reactor core is also described.