Group Pneumatic Lifting for Pebble-Bed Reactor Fuel Cycling

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Solution Overview

Problem

Current pebble-bed reactor systems have limited fuel cycling capability and efficiency due to the sequential pneumatics lifting of fuel elements, which restricts rapid cycling and increases costs and structural complexity, while also affecting reactor safety and power density uniformity.

Innovation Solution

A system and method for pneumatically lifting fuel elements in groups, using a feeder with burnup detection assemblies, a gas power supply, and a single lifting pipeline, allowing for controlled grouping and simultaneous lifting of multiple fuel elements, optimizing lifting capability and delivery efficiency, and reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If fuel elements are lifted one by one sequentially, then the structure is simpler, but the fuel cycling capability and delivery efficiency are limited

Engineering Contradiction:
Improvefuel cycling capabilityVSAvoidstructure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges multiple fuel element lifting operations into a single pipeline by enabling group lifting. Multiple fuel elements are accumulated in the feeder and then lifted simultaneously through one lifting pipeline, combining the functions of what would traditionally require multiple separate pipelines into a single integrated system.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces dynamic control of the lifting process through adjustable gas flow rates and controllable grouping mechanisms. The gas flow rate can be dynamically adjusted to control the lifting speed and the number of fuel elements lifted in each group, allowing the system to adapt to different operational requirements and optimize both productivity and resource utilization.

Inventive Principle:
Principle #15Dynamics

2Productivity

If multiple lifting pipelines are disposed to satisfy fuel cycling capability, then the lifting capability increases, but the costs and structural complexity increase

Engineering Contradiction:
Improvelifting capabilityVSAvoidnumber of pipelines
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent combines the functions of multiple lifting pipelines into a single pipeline by implementing group lifting capability. The feeder accumulates multiple fuel elements and transports them together through one pipeline, eliminating the need for multiple parallel pipelines while maintaining or enhancing the overall lifting capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single lifting pipeline is designed to perform multiple functions: it can lift different numbers of fuel elements in different groups, adjust lifting speeds, and handle various operational modes. This multi-functional design replaces what would traditionally require multiple specialized pipelines.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Productivity

If fuel elements are lifted at high speed to improve delivery rate, then the fuel cycling capability increases, but the impact against reactor core and damage rate increase

Engineering Contradiction:
Improvedelivery rateVSAvoidsafety
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements dynamic speed control of the gas flow to optimize the lifting process. The gas flow rate can be adjusted to achieve optimal lifting speeds that balance delivery rate with safety considerations. The system can accelerate fuel elements during transport and then decelerate them before reactor core entry, reducing impact damage while maintaining high overall delivery rates.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The lifting process uses periodic gas flow patterns with acceleration and deceleration phases. Gas is supplied in controlled pulses that accelerate fuel elements to optimal speeds and then gradually reduce the flow to allow smooth deceleration, preventing high-speed impacts with the reactor core while maintaining efficient overall transport.

Inventive Principle:
Principle #19Periodic action

4Productivity

If the amount of fuel elements lifted per unit time is increased, then the fuel cycling capability improves, but the uniformity of power density distribution may be affected

Engineering Contradiction:
Improvefuel cycling capabilityVSAvoidpower density distribution uniformity
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent uses dynamic adjustment of the grouping size and gas flow rate to control the lifting process. By adjusting these parameters, the system can optimize the balance between fuel cycling capability and power density distribution uniformity according to specific operational requirements, allowing flexible adaptation to different reactor states and fuel configurations.

Inventive Principle:
Principle #15Dynamics

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

This approach enhances fuel cycling capability, improves delivery efficiency, simplifies the reactor structure, and reduces costs by allowing multiple fuel elements to be lifted simultaneously with one pipeline, while maintaining safety and adjusting to varying working conditions.

Implementation Method 1

the fuels after a burnup detecting are lifted perpendicularly from a position below the reactor core to a top of the reactor core by a pushing force of gas flow

Methodology Applied
Scientific EffectPneumatic lifting: Gas Lift

Implementation Method 2

an amount of the fuel elements lifted to the reactor core in the unit time by the pneumatically lifting

Methodology Applied
Scientific EffectPressure difference: Pressure Gradient

Data Source

PatentEP2727117B1System and method for pneumatically lifting fuel elements of pebble-bed reactor group by group
Publication Date: 2017.07.19 TSINGHUA UNIVERSITY
  • EP2727117B1 patent drawingFigure 1
  • EP2727117B1 patent drawingFigure 2~3
  • EP2727117B1 patent drawingFigure 4~5

AI summary

A system and a method for pneumatically lifting fuel elements of a pebble-bed reactor group by group are provided. The system comprises a feeder (4), a tee joint (6), a lifting pipeline (8), a gas diverter (9), a reactor feeding pipeline (11), a gas power supply and at least two burnup detection assemblies.