Jet Pump Sensing Line Clamp for Vibration Mitigation
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Solution Overview
Problem
Jet pump sensing lines in nuclear reactors face premature failure due to flow-induced vibration and radiation exposure, leading to weld failures and damage, which are difficult to inspect or repair during scheduled outages in Boiling Water Reactors (BWRs).
Innovation Solution
A non-welded clamp assembly with a housing and pads secured by jack screws and ratchet lock springs is used to support jet pump sensing lines, providing a secure and vibration-dampening mechanism that maintains physical properties in a nuclear environment, utilizing materials like austenitic stainless steel and Inconel X-750 to prevent corrosion and galling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding is used to secure sensing lines to the support, then the connection strength is improved, but the reliability deteriorates due to radiation-induced brittling and cracking over time
Solution Approach 1:
The support structure is divided into modular components: a support body with grooves for sensing lines, separate clamps for each sensing line, and individual pads for each line. This segmentation allows each component to be independently replaced if damaged by radiation, improving reliability while maintaining connection strength through the clamp-pad-groove interface.
Solution Approach 2:
Pads are introduced as intermediary elements between the clamps and sensing lines. These pads distribute the clamping force evenly across the sensing line surface, preventing stress concentration that could lead to radiation-induced cracking, while maintaining secure connection through the clamp-pad-groove interface.
2Manufacturing precision
If sensing lines are secured in support grooves, then the positioning precision is improved, but the ease of repair deteriorates during plant outages
Solution Approach 1:
The support system is segmented into a stationary support body with precision-machined grooves and removable clamps with pads. The grooves provide precise positioning during manufacturing, while the removable clamps enable easy repair during outages by simply detaching and replacing the clamp assembly without affecting the support body or sensing lines.
Solution Approach 2:
The clamp assembly is designed as a dynamic, removable component rather than a permanent fixture. The clamp can be easily attached and detached from the support body, allowing rapid repair operations during plant outages while maintaining precise sensing line positioning through the groove interface when installed.
3Reliability
If non-welded clamping is used to secure sensing lines, then the reliability is improved by avoiding radiation-induced weld failure, but the device complexity increases
Solution Approach 1:
The clamping system is segmented into discrete, simple components: a clamp body, individual pads for each sensing line, and mounting features. This segmentation avoids complex welded assemblies while achieving reliable clamping through the simplified clamp-pad-groove interface, where each component has a single, well-defined function.
Solution Approach 2:
The clamp design incorporates self-aligning features where the clamp naturally positions itself on the support body grooves, and the pads automatically align with sensing lines during installation. This self-service capability reduces the need for complex alignment procedures and specialized installation equipment, offsetting the increased component count with operational simplicity.
Data Source
AI summary
A jet pump sensing line support clamp may be used for sensing line repair, replacement, and damage prevention or reduction. The clamp may affix to jet pump sensing line supports and confine the individual jet pump sensing lines. The clamp may provide for further access or securing of the lines in the support through the clamp. Methods of installing the clamp may include attaching and tightening the clamp against the sensing lines.