Dry Standby Boron Powder Injection System for BWR

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Solution Overview

Problem

Current stand-by liquid control systems for nuclear reactors require frequent maintenance and testing of a wet borated water slurry, which is cumbersome and inefficient.

Innovation Solution

A dry stand-by liquid control system utilizing a standby vessel containing dry boron powder and a high-pressure water supply with an interior pipe system featuring mixing holes, allowing for the injection of a boron solution into the reactor vessel upon activation, reducing maintenance needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a wet borated water slurry system is used, then the reactor shutdown capability is ensured, but the maintenance requirements increase and testing becomes cumbersome

Engineering Contradiction:
Improvereactor shutdown capabilityVSAvoidmaintenance requirements
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system changes the physical state of the boron storage from liquid slurry to dry powder form. This parameter change eliminates the maintenance issues associated with wet slurry while preserving the reactor shutdown capability, as the dry powder can be rapidly converted to liquid form when needed

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The dry powder boron system acts as a disposable or long-term stable storage medium that requires minimal maintenance compared to wet slurry systems. The powder can be stored indefinitely in a stable state and only activated when needed, eliminating the need for periodic testing and maintenance of wet systems

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Reliability

If a wet borated water slurry is periodically tested, then the system readiness is verified, but the maintenance time and complexity increase

Engineering Contradiction:
Improvesystem readinessVSAvoidmaintenance time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The dry powder system is inherently stable and does not require periodic testing to maintain readiness. The system serves itself by maintaining the boron in a stable dry state that naturally preserves its effectiveness without human intervention or testing, eliminating the time loss associated with periodic maintenance

Inventive Principle:
Principle #25Self-service

3Ease of operation

If dry boron powder is stored instead of wet slurry, then the maintenance requirements are reduced, but the mixing and injection system becomes more complex

Engineering Contradiction:
Improvemaintenance requirementsVSAvoidmixing and injection system
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The system segments the boron storage and injection functions into separate components: dry powder storage vessels, water injection systems, and mixing zones. This segmentation allows each component to be optimized independently, reducing overall maintenance requirements while managing the complexity of the mixing system through modular design

Inventive Principle:
Principle #1Segmentation

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 dry system simplifies maintenance by eliminating the need for periodic testing and handling of a wet slurry, while ensuring reactor shutdown capabilities in extreme scenarios.

Implementation Method 1

a high pressure water supply in communication with the standby vessel via a first closed valve. Furthermore, the high pressure water supply is connected to an interior pipe system having a plurality of mixing holes within the standby vessel

Methodology Applied
Scientific EffectMixing:

Implementation Method 2

The steam is directly used to drive a turbine, after which it is cooled in a condenser and converted back to liquid water. The borated water will shut down a reactor and maintain it shut down

Methodology Applied
Scientific EffectNeutron absorption: Absorption (physical)

Data Source

PatentEP4085471B1Dry stand-by liquid control system for a nuclear reactor
Publication Date: 2024.04.03 GE HITACHI NUCLEAR ENERGY AMERICAS LLC
  • EP4085471B1 patent drawingFigure 1~3
  • EP4085471B1 patent drawingFigure 2

AI summary

A boiling water reactor system includes a reactor vessel including a reactor core. A steam line is in communication with the reactor core and a turbine that is connected to an electrical generator. A dry standby liquid control system includes a standby vessel containing dry powder containing boron and including a high pressure water supply in communication with the standby vessel via a first closed valve, wherein the standby vessel is in communication with the reactor vessel via a second closed valve.