Shielded Sample-Air Radiation Detection for Nuclear Reactor Coolant Leaks

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Solution Overview

Problem

Current leak detection technologies in nuclear reactor coolant systems are inadequate for detecting small leaks due to high background radiation, limited scope of 16N gamma-ray detection, and increased detection time for small leaks, leading to potential nuclear accidents.

Innovation Solution

An apparatus with a shielded structure and sensors to collect sample air from the primary coolant system, using radiation-resistant detectors and additional sensors for temperature and humidity to determine coolant leaks, maintaining detector integrity and improving detection reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If 16N gamma-ray detection technology is used to detect coolant leaks, then leak detection capability is provided for specific situations, but the scope of application is limited and cannot detect small unconfirmed leaks

Engineering Contradiction:

Improvescope of leak detection applicationVSAvoiddetection reliability for small leaks

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The detection apparatus is designed to detect multiple types of radiation (beta rays, gamma rays, alpha rays) in addition to 16N gamma rays, enabling it to detect coolant leaks in various situations including small unconfirmed leaks, thereby expanding its application scope while maintaining detection reliability

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Speed

If radiation detectors are installed inside the containment building to monitor coolant leaks, then real-time detection is possible, but the detectors are exposed to high-dose background radiation which compromises detection reliability and detector integrity

Engineering Contradiction:

Improvedetection response timeVSAvoiddetection reliability under high radiation

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The radiation detector is extracted from the high-radiation environment inside the containment building and relocated to an external detection room. The system uses sampling ports and conduits to bring coolant samples to the detector, allowing real-time detection while protecting the detector from high-dose background radiation that would compromise its reliability

Inventive Principle:

Principle #2Taking out (Extraction)

3Area of stationary object

If the sump area of containment building is increased to detect small leaks, then detection coverage is improved, but the degree of change in water level becomes very small making detection time increase

Engineering Contradiction:

Improvesump areaVSAvoidleakage detection time

Core Design Contradiction:

Area of stationary objectVSLoss of time

Solution Approach 1:

The system replaces the mechanical water level measurement approach with radiation detection technology. Instead of measuring small water level changes in a large sump area, the system directly detects radionuclides in coolant samples, providing rapid detection of small leaks without being limited by sump size or water level change magnitude

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If vapor sampling is performed to detect coolant leaks, then leak detection is possible, but vapors may condense before reaching the atmospheric humidity meter increasing detection time

Engineering Contradiction:

Improvevapor detection capabilityVSAvoidvapor transport time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system changes the physical parameters of vapor transport by using heated conduits and controlled flow conditions to prevent condensation during sample transport. This maintains vapor integrity from the sampling point to the detection device, reducing detection time while preserving detection reliability

Inventive Principle:

Principle #35Parameter changes

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

Enables real-time detection of small leaks with high accuracy, maintains detector integrity, and enhances leak determination reliability by considering multiple factors beyond radiation signals.

Implementation Method 1

a radiation detector disposed in the internal space of the shield to detect a radiation signal from the sample air

Methodology Applied

Scientific EffectRadiation detection: Radiation

Implementation Method 2

a shield having an internal space into which sample air is introduced

Methodology Applied

Scientific EffectRadiation shielding: Absorption (EM radiation)

Data Source

PatentUS12451261B2Apparatus for detecting nuclear reactor coolant leaks

Publication Date: 2025.10.21 INDUSTRY UNIVERSITY COOPERATION FOUNDATION HANYANG UNIVERSITY

AI summary

The present disclosure relates to an apparatus for detecting nuclear reactor coolant leaks that is capable of maintaining radiation detection reliability and the integrity of a radiation detector from high-dose background radiation inside a nuclear reactor when a coolant leaks from the primary coolant system of the nuclear reactor. The apparatus of the present disclosure includes a shield having an internal space into which sample air containing a coolant leaking from a primary coolant system pipe of a nuclear reactor is introduced. The shield is configured to close the exposed internal space or expand the internal space through detachable coupling. The apparatus of the present disclosure further includes a first sensor disposed in the internal space to obtain a radiation measurement signal from the sample air. The apparatus of the present disclosure further includes a discriminator for determining whether a coolant is leaking based on the radiation measurement signal.