Burnable Poison Coating on Nuclear Fuel Rod Cladding

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Solution Overview

Problem

Burnable poisons incorporated into nuclear fuel rods are soluble with aqueous reactor coolant, leading to reduced effectiveness over time and potential for helium gas to over-pressurize the fuel rod.

Innovation Solution

A method involving an application device that sprays abrasive and burnable poison particles onto the nuclear fuel rod's surface at high velocity, causing molecular surface melting and forming a protective oxide layer that prevents dissolution in coolant, with the burnable poison applied in multiple layers to achieve optimal neutron absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If burnable poison is incorporated into nuclear fuel rods, then reactivity control is improved, but the burnable poison dissolves in aqueous reactor coolant leading to reduced effectiveness

Engineering Contradiction:

Improvereactivity controlVSAvoidburnable poison dissolution

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

A protective oxide coating is applied as an intermediary layer between the burnable poison and the coolant. This oxide layer acts as a barrier that prevents direct contact and dissolution of the burnable poison by the aqueous coolant, while still allowing the burnable poison to function effectively for reactivity control.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the chemical state of the burnable poison by converting it into a protected form through oxide coating. This parameter change from exposed burnable poison to coated burnable poison prevents dissolution while maintaining the neutron absorption capability needed for reactivity control.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If burnable poison is applied onto the exterior of nuclear rod cladding, then reactivity control is improved, but helium gas may over-pressurize the fuel rod

Engineering Contradiction:

Improvereactivity controlVSAvoidhelium pressure

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The burnable poison is extracted from the traditional interior fuel composition and applied to the exterior surface of the rod cladding. This separation removes the source of helium gas generation from the pressurized fuel rod interior, eliminating the over-pressurization risk while preserving the reactivity control function.

Inventive Principle:

Principle #2Taking out (Extraction)

3Manufacturing precision

If abrasive material is sprayed onto the nuclear fuel rod surface, then surface preparation is improved, but the surface may become damaged

Engineering Contradiction:

Improvesurface preparationVSAvoidsurface integrity

Core Design Contradiction:

Manufacturing precisionVSStrength

Solution Approach 1:

The patent controls the parameters of the abrasive spraying process, including particle size, spray pressure, and number of passes, to achieve optimal surface preparation. By carefully adjusting these parameters, the surface is sufficiently prepared for coating adhesion without causing excessive damage or compromising structural integrity.

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 method ensures the burnable poison remains effective by forming a protective oxide coating that prevents dissolution in coolant, maintaining reactivity control and preventing helium-induced over-pressurization.

Implementation Method 1

pressurized gas is expelled from the pressurized gas source through the channel of the application device thereby spraying the abrasive particle onto the surface of the nuclear fuel rod

Methodology Applied

Scientific EffectGas flow:

Implementation Method 2

removing a portion of any oxides and surface deposits on the outer surface of the nuclear fuel rod by spraying an abrasive material onto the nuclear fuel rod

Methodology Applied

Scientific EffectAbrasion: Abrasion

Implementation Method 3

applying a burnable poison onto the surface of the nuclear fuel rod by spraying the burnable poison onto the nuclear fuel rod

Methodology Applied

Scientific EffectDeposition: Deposition (physical)

Implementation Method 4

forming a protective oxide coating that prevents dissolution in coolant

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS7815964B2Method of applying a burnable poison onto the exterior of nuclear rod cladding

Publication Date: 2010.10.19 WESTINGHOUSE ELECTRIC CORP

AI summary

A method for applying a burnable poison onto the cladding of a nuclear fuel rod (2) which comprises, providing a nuclear fuel rod (2) and at least one application device (8), rotating the nuclear fuel rod, optionally removing one or more oxides and/or surface deposits on the outer surface of the nuclear fuel rod (2) by spraying an abrasive material onto the nuclear fuel rod via the application device (8) while adjusting the position of the application device in relation to the nuclear fuel rod (2), and applying burnable poison particles (33) onto the outer surface (6) of the nuclear fuel rod (2) by spraying the burnable poison onto the nuclear fuel rod via the application device while adjusting the position of the application device (8) in relation to the nuclear fuel rod, where the burnable poison particles are applied at a velocity sufficient to cause adhesion to the outer surface (6) of the cladding.