Backflow Electromagnetic Pump Layout for Liquid Metal Coolant Reversal

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Solution Overview

Problem

Liquid metal-cooled nuclear reactors face challenges in mitigating coolant backflow due to primary electromagnetic pump failures, which can lead to reduced coolant circulation and heat rejection, necessitating reactor shutdown.

Innovation Solution

The integration of backflow electromagnetic pumps (EMPs) within the reactor pressure vessel, coupled in series with primary EMPs, allows for selective activation to generate pressure resistance against backflow, thereby mitigating coolant backflow and enabling continued reactor operation even with partially failed primary EMPs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If primary electromagnetic pumps are used to circulate liquid metal coolant through the reactor core, then coolant circulation and heat rejection are improved, but system reliability deteriorates due to pump failure causing coolant backflow

Engineering Contradiction:
Improvecoolant circulationVSAvoidsystem reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The backflow EMP is installed in series with the primary EMP to preemptively counteract the harmful backflow effect before it can occur. When the primary EMP fails, the backflow EMP immediately activates to generate opposing pressure resistance, preventing coolant from flowing backward through the reactor core and maintaining system reliability.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The backflow EMP acts as an intermediary device between the primary EMP and the reactor core. It mediates the coolant flow by providing pressure resistance against backflow, serving as a protective buffer that isolates the reactor core from the harmful effects of primary EMP failure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If backflow electromagnetic pumps are added to mitigate coolant backflow, then system reliability is improved, but device complexity increases

Engineering Contradiction:
Improvesystem reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The backflow EMP is designed with multi-functionality to reduce overall system complexity. It can operate in multiple modes: normally remaining inactive to allow full coolant flow, activating to counteract backflow when primary EMP fails, and potentially serving as a backup pumping mechanism. This universal design consolidates multiple functions into a single device.

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

Solution Approach 2:

The backflow EMP is equipped with sensors and control systems that enable it to automatically detect primary EMP failures and activate without external intervention. The device monitors coolant flow conditions and independently determines when backflow mitigation is needed, reducing the need for complex external control systems and manual operations.

Inventive Principle:
Principle #25Self-service

3Reliability

If primary EMP failure occurs, then coolant backflow increases causing heat rejection problems, but reactor shutdown is avoided through backflow mitigation

Engineering Contradiction:
Improvecontinuous operation capabilityVSAvoidheat rejection efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The backflow EMP provides partial action by generating just enough pressure resistance to counteract backflow and maintain adequate coolant circulation through the reactor core. It does not need to fully replace the primary EMP's pumping capacity, only sufficient to prevent harmful reverse flow and maintain minimum heat rejection requirements, allowing continued operation at reduced but acceptable efficiency.

Inventive Principle:
Principle #16Partial or excessive action

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 configuration allows the reactor to maintain operation with reduced power levels and delays the need for shutdown, reducing operational interruptions and capital expenditures by preventing immediate reactor shutdown and minimizing alterations to the reactor size.

Implementation Method 1

electromagnetic pumps (EMPs) configured to circulate the conductive liquid metal coolant

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

one or more electromagnetic pumps (EMPs) configured to circulate the conductive liquid metal coolant through the nuclear reactor

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP4016548B1Nuclear reactor liquid metal coolant backflow control
Publication Date: 2024.08.28 GE HITACHI NUCLEAR ENERGY AMERICAS LLC
  • EP4016548B1 patent drawingFigure 1
  • EP4016548B1 patent drawingFigure 2
  • EP4016548B1 patent drawingFigure 3

AI summary

A liquid metal-cooled nuclear reactor includes, within a reactor pressure vessel, a primary electromagnetic pump (EMP) circulating liquid metal coolant through the reactor core and a backflow EMP. The nuclear reactor may be configured to at least partially mitigate liquid metal coolant backflow in response to a primary EMP failure. The backflow EMP is coupled in series with the primary EMP within the reactor pressure vessel. The backflow EMP may be selectively activated in response to failure of the primary EMP to mitigate liquid metal backflow through the primary EMP. The primary EMP and backflow EMP may receive power from separate power sources. Multiple backflow EMPs may be coupled in parallel to the primary EMP via parallel liquid metal coolant lines. A nuclear reactor may include multiple primary EMPs and multiple sets of backflow EMPs, where each separate set of backflow EMPs is coupled to a separate primary EMP.