Segmented Pipe Clamp for Nuclear Riser Elbow Reinforcement
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Solution Overview
Problem
The existing pipe clamp designs for jet pump riser assemblies in boiling water nuclear reactors fail to effectively address stress corrosion cracking, hydraulic forces, and thermal stresses, leading to potential separation of the riser pipe elbow from the thermal sleeve, and they are difficult to install in confined spaces.
Innovation Solution
A clamp comprising two semicircular segments with ridges and fingers that match the curvature of the elbow and thermal sleeve, allowing secure mating and reinforcement of the connection between the elbow and thermal sleeve, with means to draw the segments together using bolts, and features like tapered fingers and pockets to minimize leakage and accommodate the reduced thickness of the elbow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing clamp designs are used to support the jet pump riser elbow, then some support is provided, but they fail to effectively address stress corrosion cracking and hydraulic forces, leading to potential separation of the elbow from the thermal sleeve
Solution Approach 1:
The clamp is divided into two separate segments that can be installed independently around the elbow and thermal sleeve connection. Each segment has fingers that engage with pockets in the elbow and ridges that engage with grooves in the thermal sleeve, providing distributed support that addresses stress corrosion cracking by preventing concentrated loads on the weld joint.
Solution Approach 2:
The clamp segments are designed with different features at different locations: fingers with tapered ends engage with pockets in the elbow to provide localized support at the elbow end, while ridges engage with grooves in the thermal sleeve to provide localized support at the sleeve end. This local differentiation allows the clamp to address the reduced thickness of the elbow while maintaining connection integrity.
2Reliability
If a clamp is designed to provide adequate support for the elbow-thermal sleeve connection, then connection integrity is improved, but the clamp becomes difficult to install in confined spaces
Solution Approach 1:
The clamp is segmented into two separate pieces that can be installed independently, allowing each segment to be maneuvered into the confined space between the reactor pressure vessel sidewall and the shroud. This segmentation eliminates the need to install a single large clamp in a tight space, significantly improving ease of installation while maintaining connection integrity.
3Reliability
If the clamp applies sufficient axial pressure to minimize leakage, then connection integrity is improved, but the clamp may compromise the reduced thickness of the elbow
Solution Approach 1:
The clamp segments are designed with fingers that have tapered ends that engage with pockets in the elbow, and ridges that engage with grooves in the thermal sleeve. The fingers apply localized pressure at the elbow pockets while the ridges apply localized pressure at the thermal sleeve grooves, distributing the axial pressure load to avoid compromising the reduced thickness of the elbow while maintaining leakage prevention.
4Ease of operation
If the clamp is designed to accommodate the reduced thickness of the elbow, then ease of installation is improved, but the clamp may not provide sufficient support for both the elbow and thermal sleeve
Solution Approach 1:
The clamp segments are designed with fingers that engage with pockets in the elbow to accommodate the reduced thickness of the elbow, while ridges engage with grooves in the thermal sleeve to provide support for the thicker sleeve. This local differentiation ensures that each component is supported appropriately for its thickness while maintaining overall connection integrity and support adequacy.
Data Source
AI summary
A pipe clamp for reinforcing a welded joint between two pipes, having a plurality of circumferential clamp segments that are bolted together around the joint. One axial end of the clamp has circumferentially extended ridges that project inward and seat in corresponding circumferential grooves in a pipe on one side of the joint. The other axial end of the clamp has circumferentially spaced fingers that extend inward and fit into corresponding pockets on the other side of the weld joint. Either or both the ridges or the fingers have a taper whose cross-section reduces in an inward direction and fits in complimentary grooves or pockets on either side of the joint. The taper forces the opposite sides of the weld joint toward each other as the clamp segments are tightened together.