Nuclear Reactor Damping Device Using Coolant Piston

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Solution Overview

Problem

Conventional mechanical damping devices are unsuitable for nuclear reactor environments due to degradation from radioactivity, high temperatures, and chemical incompatibility with coolant, leading to vibration-related damage and component failure.

Innovation Solution

The use of a damping device with a housing filled with reactor-compatible coolant that employs a piston and springs to damp vibration between components, eliminating the need for high-viscosity fluids and minimizing the risk of chemical incompatibility and material degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional mechanical damping devices with high-viscosity fluids are used, then vibration damping is provided, but chemical incompatibility with coolant and material degradation from radioactivity occur

Engineering Contradiction:
Improvevibration damping effectivenessVSAvoidmaterial degradation from radiation and chemical incompatibility
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The damping device uses the reactor's own coolant as the damping fluid, eliminating the need for separate damping fluids that would require maintenance and refilling. The coolant serves dual purposes: cooling the reactor and providing vibration damping, thereby eliminating chemical incompatibility issues and material degradation from radiation exposure to damping fluids.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The reactor coolant serves multiple functions: it cools the reactor core and simultaneously acts as the damping fluid in the damping device. This multi-functionality eliminates the need for separate damping fluids, reducing maintenance requirements and avoiding chemical incompatibility problems between damping fluids and reactor coolant.

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

2Reliability

If conventional damping devices are used in nuclear reactors, then vibration reduction is achieved, but frequent maintenance and refilling are required due to material degradation

Engineering Contradiction:
Improvevibration damping performanceVSAvoidmaintenance and refilling time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The damping device utilizes the reactor's existing coolant system, eliminating the need for separate damping fluid reservoirs that would require maintenance and refilling. Since the coolant is already present in the reactor and continuously circulated, the damping device operates indefinitely without maintenance, eliminating time losses associated with service interruptions.

Inventive Principle:
Principle #25Self-service

3Force

If elastic components like springs are used in damping devices, then restorative force is provided, but material strength degradation from radiation occurs over time

Engineering Contradiction:
Improverestorative force for vibration dampingVSAvoidmaterial strength under radiation exposure
Core Design Contradiction:
ForceVSStrength

Solution Approach 1:

The invention replaces elastic spring components with a hydraulic damping mechanism using the reactor coolant. The coolant provides the restorative force through pressure differential across a restrictor when the piston moves, eliminating the need for elastic materials that would degrade from radiation exposure. The hydraulic system maintains consistent damping characteristics without material strength degradation.

Inventive Principle:
Principle #29Pneumatics and hydraulics

4Reliability

If high-viscosity damping fluids are used, then vibration damping is provided, but chemical incompatibility with reactor coolant causes damage

Engineering Contradiction:
Improvevibration damping effectivenessVSAvoidchemical incompatibility damage
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The damping device uses the reactor's own coolant as the damping fluid, eliminating the need for separate high-viscosity damping fluids that would be chemically incompatible with the reactor coolant. The coolant is already chemically compatible by definition, as it is the reactor's working fluid, thereby eliminating chemical incompatibility damage while maintaining vibration damping effectiveness.

Inventive Principle:
Principle #25Self-service

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 solution effectively reduces vibration and relative movement between nuclear reactor components, maintaining structural integrity and preventing damage from extreme temperatures and radiation, without requiring frequent maintenance or refilling of damping fluids.

Implementation Method 1

Damping is provided by the relative motion of the piston and housing, which will push the damping fluid through a fluid passage that can be either in the housing and/or the piston

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Implementation Method 2

Example embodiments may further include one or more springs that provide(s) an elastic force that opposes movement between the piston and housing

Methodology Applied
Scientific EffectElastic force: Elasticity

Data Source

PatentEP2119936B1Apparatuses and methods for damping nuclear reactor components
Publication Date: 2019.11.13 GE HITACHI NUCLEAR ENERGY AMERICAS LLC
  • EP2119936B1 patent drawingFigure 1~2
  • EP2119936B1 patent drawingFigure 3
  • EP2119936B1 patent drawingFigure 4~5

AI summary

Example embodiment damping devices (100) may include a housing (101) capturing a piston (130). The housing (101) may be filled and/or able to be filled with a damping fluid compatible with the nuclear reactor coolant, so that a leak from the housing (101) or coolant passing into the housing (101) does not damage the reactor or example embodiment devices. Example embodiments may further include one or more springs that provide an elastic force opposing movement between the piston (130) and housing (101). A shaft of the piston (130) and an end of the housing (101) may be connected to two nuclear reactor components with relative motion or vibration to be damped. Example methods may use example embodiment damping device (100)s to reduce and/or prevent relative motion and vibration among components of a nuclear reactor.