Nuclear Reactor Cooling Water Filter for Radiation-Safe Maintenance

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Solution Overview

Problem

The primary circuit of nuclear power plants faces challenges in filtering out small foreign bodies from cooling water due to their size and the complexity and radiation risks associated with installing filters outside the reactor vessel.

Innovation Solution

A filter system that can be attached to the outlet openings of the reactor vessel during inspection shutdowns, allowing cooling water to flow through a filter cartridge before entering the reactor, ensuring all water is filtered before reaching the reactor vessel, and allowing for easy installation and removal without exposing personnel to radiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If filters are installed in the pipes of the primary cooling circuit outside the reactor vessel, then filtering of cooling water is achieved, but the device complexity increases and radiation protection measures become elaborate and expensive

Engineering Contradiction:
Improvefiltering effectivenessVSAvoidsystem modification complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The filter system is segmented into modular components: a filter head that attaches to the outlet opening and filter cartridges that can be independently replaced. This segmentation allows the filtering function to be added without modifying the entire piping system, reducing device complexity while maintaining filtering effectiveness

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The filter head acts as an intermediary component between the outlet opening and the cooling water flow. It provides a standardized interface that connects to existing outlet openings without requiring system modification, thereby achieving filtering while minimizing device complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If filters are installed outside the reactor vessel, then filtering is achieved, but radiation protection measures become elaborate and expensive due to creation of radiation source outside reactor

Engineering Contradiction:
Improvefiltering effectivenessVSAvoidradiation exposure
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The filter cartridges are designed to be extractable from the filter head while remaining underwater. This allows the radioactive filter cartridges to be removed and disposed of without exposing personnel to radiation, as the removal operation occurs underwater where water provides radiation shielding

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The underwater environment serves as a protective medium during filter cartridge replacement. Water provides both radiation shielding and a stable environment for handling radioactive components, eliminating the need for elaborate radiation protection measures

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

3Ease of operation

If filter cartridges are replaced outside water, then maintenance is easier, but personnel are exposed to radiation

Engineering Contradiction:
Improvefilter cartridge replacementVSAvoidradiation exposure
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The filter head serves as an intermediary structure that remains fixed on the outlet opening while allowing filter cartridges to be replaced underwater. This design enables maintenance operations to be performed in the protective underwater environment without requiring personnel to work in radioactive areas

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution effectively filters out small particles, reduces the risk of fuel element damage, and simplifies the filtration process by eliminating the need for external filter installation, thereby enhancing safety and reducing radiation exposure during maintenance.

Implementation Method 1

a filter cartridge (34) which is exchangeably held in the base support (29) and is fluidically coupled to the inlet (30)

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Data Source

PatentEP2513910B1Filter for cooling water of a primary circuit of a nuclear power station, and a method for filtering cooling water
Publication Date: 2014.01.29 AREVA GMBH
  • EP2513910B1 patent drawingFigure 1
  • EP2513910B1 patent drawingFigure 2~3
  • EP2513910B1 patent drawingFigure 4~5

AI summary

The invention relates to a filter (28) for a cooling water (12)-conducting primary circuit (14) of a nuclear power station (2) comprising a reactor container (4) with a discharge opening (20 a, b) for the cooling water (12) that opens into the interior (22) of the reactor container and that can be accessed when the nuclear power station (2) is brought to a stop for revision. Said filter comprises a base carrier (29) with an entrance (30), at least one filter cartridge (34) held on the base carrier (29) such that it can be interchanged and which is fluidically coupled to said entrance (30), and a fixing device (36) that can be fixed to the discharge end (20 a, b) such that the entrance (30) couples fluidically to the discharge opening (20, a b). In a method for filtering cooling water (12) during the revision stop: a filter (28) according to one of claims 1 to 7 is fixed, by means of its fixing device (36), with its entrance (30) in fluid connection with the discharge opening (20 a, b), the cooling water (12) is circulated through said discharge opening (20 a, b), and the filter (28) is removed from the discharge opening (20 a, b).