Pressurizer Valve Piston and Bellows for Reactor Overpressure Relief

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Solution Overview

Problem

Conventional pressurizer valves in small modular reactors fail to promptly open, leading to increased internal pressure in the reactor vessel, potentially exceeding design pressure and causing damage.

Innovation Solution

A pressurizer valve device with a valve piston that automatically opens and closes a communication hole based on reactor vessel pressure, using control fluid and a bellows mechanism to prevent delayed opening and maintain pressure within design limits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the pressurizer valve is opened only when pressure exceeds a high threshold, then the valve structure can be simpler, but the reactor vessel pressure may exceed design pressure causing damage

Engineering Contradiction:

Improvevalve structure complexityVSAvoidreactor vessel pressure control

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent introduces a bellows mechanism as an intermediary component between the valve piston and the pressure control system. The bellows expands and contracts in response to pressure changes, mechanically amplifying the pressure differential effect and enabling the valve to open at a lower pressure threshold without requiring a more complex control system.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the physical state and volume of the bellows component in response to pressure variations. As pressure increases, the bellows expands, which mechanically assists the valve piston to open the valve at a lower pressure threshold. This parameter change enables timely valve opening while maintaining structural simplicity.

Inventive Principle:

Principle #35Parameter changes

2Volume of stationary object

If the containment vessel has a large accommodation space, then steam discharge is easier, but the reactor system becomes less suitable for small modular reactor applications

Engineering Contradiction:

Improvecontainment vessel spaceVSAvoidreactor system adaptability

Core Design Contradiction:

Volume of stationary objectVSAdaptability or versatility

Solution Approach 1:

The patent segments the pressure control function into distinct components: the bellows mechanism for pressure sensing and amplification, the valve piston for valve actuation, and the communication hole for steam discharge. This segmentation allows each component to be optimized independently, enabling effective pressure control in small modular reactors with limited containment space.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention introduces dynamic elements including the expandable bellows and the movable valve piston that responds to pressure changes. This dynamic design allows the system to adapt to varying pressure conditions and steam discharge requirements, making it suitable for different reactor scales and configurations.

Inventive Principle:

Principle #15Dynamics

3Reliability

If the pressurizer valve opens at a lower pressure threshold, then the reactor vessel is protected from overpressure, but the valve requires more frequent opening and closing cycles

Engineering Contradiction:

Improvereactor vessel pressure protectionVSAvoidvalve operation duration

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent enables periodic opening and closing of the pressurizer valve through the bellows mechanism that continuously monitors pressure and mechanically actuates the valve piston when thresholds are reached. This periodic action maintains pressure within safe limits while the mechanical design minimizes wear through controlled cycling.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The bellows mechanism provides a mechanical cushioning effect by expanding gradually in response to pressure increases, which smooths out pressure fluctuations and reduces the frequency and intensity of valve opening cycles. This beforehand cushioning protects the valve mechanism from excessive wear while maintaining reliable pressure control.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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

Prevents reactor vessel pressure from exceeding design limits by timely discharge of steam, thereby protecting the reactor from damage and ensuring safe operation.

Implementation Method 1

a valve piston disposed to be movable in one direction in the interior of the valve housing, and configured to open and close the communication hole depending on a change in a vessel pressure in the reactor vessel

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

the bellows may divide the inner space of the valve housing to block steam from being discharged to the outside

Methodology Applied

Scientific EffectPhysical barrier: Physical Containment

Data Source

PatentUS20250336553A1Pressurizer valve device and reactor facility including the same

Publication Date: 2025.10.30 KOREA ATOMIC ENERGY RES INST

AI summary

A pressurizer valve device comprising: a valve housing disposed in a reactor vessel accommodated in a containment vessel, and having a communication hole through which steam in the reactor vessel is introduced, a discharge hole, through which the steam introduced into an interior of the reactor vessel is discharged to the containment vessel, and a connection hole, through which a control fluid is introduced; and a valve piston disposed to be movable in one direction in the interior of the valve housing, and configured to open and close the communication hole depending on a change in a vessel pressure in the reactor vessel.