Spring-Loaded Sealing Plug for Boiling Water Reactor Drive Casing
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Solution Overview
Problem
In boiling water reactors, the drive casing pipe remains open during dismantling or repair, posing a risk of primary coolant leakage, and existing solutions fail to provide a simple and reliable sealing mechanism.
Innovation Solution
A device featuring a closing plug with a downwardly open plug casing, an axially movable sealing element, and a rotatable locking element, supported by a spring, which allows for secure sealing and easy removal of the drive casing pipe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a simple closure device is used to seal the drive casing pipe, then ease of operation is improved, but reliability of sealing is worsened
Solution Approach 1:
The patent employs a flexible sealing element (dichtungselement) that can deform to conform to the pipe orifice surface, ensuring reliable sealing through elastic deformation rather than rigid mechanical interference. This flexible membrane approach maintains sealing effectiveness while allowing simple operational movement of the closing plug.
2Reliability
If a locking mechanism is added to secure the closing plug, then reliability of fixation is improved, but device complexity is worsened
Solution Approach 1:
The closing plug incorporates a self-locking mechanism where the plug casing (stopfenhaus) itself provides the locking function through its geometric design. The plug casing features external locking protrusions that engage with corresponding features on the drive casing pipe, allowing the device to lock itself without requiring separate active locking components or complex actuation mechanisms.
3Reliability
If the sealing element is resiliently mounted to press against the pipe orifice, then sealing reliability is improved, but force requirements are worsened
Solution Approach 1:
The sealing element is pre-loaded by a spring mechanism that stores elastic potential energy, creating a cushioning force that continuously presses the sealing surface against the pipe orifice. This beforehand cushioning ensures reliable sealing contact is maintained throughout operation without requiring large external forces to be applied during closure.
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 device effectively seals the drive casing pipe by pressing the sealing element against the pipe orifice with spring force and can be reliably locked and unlocked from a distance, ensuring secure closure and easy removal.
Implementation Method 1
a spring (26) which is supported with its upper end on the plug casing (10) and with its lower end on the sealing element (13) and at the same time holds the latter in a lower end position or loads it with a spring force in the direction of this end position
Data Source
AI summary
The invention relates to a device for closing a pipe opening, opening upwards, of a drive casing pipe accommodating the control rod drive of a boiling water reactor, said device comprising a closure plug with a plug housing, opening downwards, a sealing element guided axially so as to be movable within the plug housing, which element has a sealing face providing a sealing contact with an annular counter face defining the pipe opening, a locking element provided to fix the plug housing on the drive casing pipe, and a spring, which is supported by the upper end thereof on the plug housing and by the lower end thereof on the sealing element and holds said element in a lower end position.