Fuel Bundle Design Perturbation for Enrichment Simplification

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Solution Overview

Problem

Designing fuel bundles for boiling water nuclear reactors (BWR) that meet local peaking and R-factor requirements while minimizing the number of different fuel rod enrichments to reduce manufacturing complexity and cost is challenging due to the need for varied enrichment values across rods.

Innovation Solution

A method that creates an ordered list of fuel rod types, perturbs less frequent enrichment types, and uses a response matrix to generate perturbed fuel bundle designs within a predetermined threshold, ensuring the designs meet BWR constraints with a reduced number of enrichment types.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If fuel bundles are designed with various enrichment values to meet local peaking and reactivity requirements, then the reactor performance requirements are satisfied, but the manufacturing complexity and cost increase

Engineering Contradiction:

Improvereactor performance requirementsVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by systematically varying the enrichment values of fuel rods within defined ranges to generate multiple candidate designs. This allows exploration of different enrichment configurations that meet reactor performance requirements while identifying simpler alternatives with fewer unique enrichment types, thus resolving the contradiction between performance reliability and manufacturing complexity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses local quality by assigning different enrichment values to specific rod positions within the fuel bundle lattice based on local power distribution requirements. The method evaluates local peaking factors and R-factors for each rod position, enabling targeted enrichment assignments that satisfy local reactor performance requirements while potentially reducing the total number of unique enrichment types needed across the entire bundle

Inventive Principle:

Principle #3Local quality

2Reliability

Engineering Contradiction:

Improvereactor performance requirementsVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent systematically changes enrichment parameters to generate candidate designs and evaluate their performance. By exploring parameter space efficiently, the method identifies designs that meet reactor requirements with minimized numbers of unique enrichment types, directly addressing the cost implication of manufacturing complexity

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses response matrix analysis to estimate the impact of enrichment changes on nearby fuel rods, allowing rapid evaluation of candidate designs without full-scale simulations. This copying approach enables efficient screening of multiple enrichment configurations to identify cost-effective designs that meet performance requirements

Inventive Principle:

Principle #26Copying

3Device complexity

If the number of different enrichment values in a bundle is reduced to simplify design and manufacturing, then manufacturing complexity decreases, but the ability to satisfy local peaking and reactivity requirements may be compromised

Engineering Contradiction:

Improvedesign simplicityVSAvoidlocal peaking and reactivity requirements

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent applies partial action by selectively perturbing only certain rod enrichments in candidate designs rather than all rods. This allows the method to explore simplified designs with fewer unique enrichment types while maintaining the ability to meet local peaking and reactivity requirements through targeted enrichment adjustments in critical positions

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent incorporates feedback through iterative evaluation of candidate designs using response matrix analysis and full-core simulations. The method uses feedback from performance evaluations (local peaking factors, R-factors, exposure peaking factors) to guide the search toward designs that satisfy reactor requirements even with reduced enrichment variety, continuously refining candidate designs based on performance metrics

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS7472045B2Method for perturbating a nuclear reactor core fuel bundle design to generate a group of designs

Publication Date: 2008.12.30 GLOBAL NUCLEAR FUEL AMERICAS LLC

AI summary

A method has been developed to select fuel rod enrichments for a fuel bundle of a nuclear reactor, the method including: creating an ordered list of fuel rod types in an initial fuel bundle design; perturbing at least a subset of the fuel rod types in the initial fuel bundle design to generate a plurality of perturbed fuel bundle designs; selecting perturbed fuel bundle designs having fuel rods with allowable fuel enrichment types and an allowable average enrichment for the perturbed bundle; determining a difference between each of the selected perturbed fuel bundle design and the initial fuel bundle design, and creating a group of the perturbed fuel bundle design having a difference less than a predetermined threshold difference value.