Jet Pump Plug Seal with Embedded Washer for Nuclear Reactor Maintenance
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Solution Overview
Problem
Conventional jet pump plugs in nuclear reactors are prone to detachment during maintenance, leading to potential blockages in peripheral fuel orifices and reactor vessel clogging, which can cause system degradation and safety issues due to their physical size and material properties.
Innovation Solution
A plug design featuring a polyurethane ester body with an embedded stainless steel washer, configured to melt at high temperatures, ensuring complete dissolution and preventing blockages, and a thin metal disk for improved retention, allowing the plug to pass through orifices and maintain reactor integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional plugs are used to seal jet pump nozzles, then the nozzles are effectively sealed, but the plugs may detach and block peripheral fuel orifices or clog the reactor vessel
Solution Approach 1:
The plug material is changed from conventional non-decomposing materials to a biodegradable material that decomposes under reactor conditions. This parameter change allows the plug to maintain its sealing function during installation and operation, then automatically decompose after use, eliminating the blockage risk while maintaining sealing effectiveness
Solution Approach 2:
The invention uses a disposable biodegradable plug that is designed to decompose after a single use. The plug serves its sealing purpose temporarily during maintenance operations, then decomposes to prevent blockage, embodying the concept of short-living objects that are discarded after completing their function
2Ease of operation
If the plug material is made flexible to pass through orifices, then the plug can navigate the system, but it may be captured inside fuel cell filters
Solution Approach 1:
The material composition is changed to a biodegradable polymer that maintains structural integrity during installation and operation, then decomposes into small particles that can pass through filters without being captured, resolving the contradiction between mobility and filter capture risk
3Reliability
If the reactor vessel is flooded to a level above the nozzles, then the nozzles are submerged for operation, but negative pressure may pull the plug off the fixture and into the nozzle
Solution Approach 1:
The plug material is changed from conventional materials to a biodegradable material with specific mechanical properties that provide adequate retention under negative pressure during operation, then decompose to eliminate the hazard. This parameter change allows the plug to withstand operational pressures while preventing blockage after use
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 minimizes the risk of flow blockages, maintains fuel integrity, and ensures safe reactor operations by eliminating the risk of plug detachment and clogging, while being compatible with existing tooling and reducing maintenance delays and costs.
Implementation Method 1
configured to melt at high temperatures, ensuring complete dissolution
Data Source
AI summary
A jet pump plug and methods of forming a seal with a plurality of nozzles of a jet pump are disclosed. The plug has a plug body and a washer embedded within and bonded to the plug body. The washer has a center opening that cooperates with the plug body to define a central bore extending through the plug and the central bore can be configured to receive a fastener. A plurality of the disclosed plugs can be positioned in alignment with a respective nozzle, with each plug being sealed to the respective nozzle to form a seal.