Thrust Shoe Heat Shield With Stagnant Water Thermal Barrier
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Solution Overview
Problem
Reactor coolant pump thrust bearing failures occur due to uneven temperature gradients during thermal transient events, causing distortion and rupture of the bearing water film, which leads to pump failure.
Innovation Solution
A heat shield made of stainless steel is integrated with the thrust shoe holder to insulate the back side, trapping a layer of stagnant water that mitigates temperature gradients and reduces distortion, while mechanical fasteners and a flex joint groove manage thermal expansion and prevent active water flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If water flows over the back side of the thrust bearing shoe holder during thermal transient events, then heat transfer occurs, but this causes uneven temperature gradients and distortion of the thrust bearing shoe
Solution Approach 1:
A heat shield is introduced as an intermediary component between the water flow and the thrust bearing shoe holder. The heat shield has a first surface facing the water flow and a second surface facing the thrust bearing shoe holder, creating a thermal barrier that prevents direct heat transfer to the shoe holder while maintaining mechanical support functionality
Solution Approach 2:
The patent converts the harmful effect of water flow (which causes uneven heating) into a beneficial controlled thermal environment. By directing water flow over the heat shield rather than directly on the shoe holder, the system transforms uncontrolled thermal exposure into controlled heat dissipation through the shield, preventing distortion while maintaining cooling benefits
2Temperature
If the thrust bearing shoe is insulated from heat, then temperature gradients are reduced, but this may affect heat dissipation from the bearing
Solution Approach 1:
The heat shield provides localized thermal protection only to the thrust bearing shoe holder area that is susceptible to distortion from thermal gradients. The shield is positioned specifically where thermal protection is needed, while allowing other parts of the bearing assembly to maintain normal heat dissipation pathways, thus achieving selective thermal management
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 thrust bearing distortion and prevents failure by maintaining a stable water film during thermal transients, ensuring continuous pump operation.
Implementation Method 1
A heat shield made of stainless steel is integrated with the thrust shoe holder to insulate the back side, trapping a layer of stagnant water that mitigates temperature gradients
Implementation Method 2
trapping a layer of stagnant water that mitigates temperature gradients
Data Source
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AI summary
A heat shield for a thrust bearing assembly of a pump. The heat shield includes a member having an inner surface and an outer surface. A raised flange is formed on a perimeter of the inner surface. The raised flange is configured to seal with a back surface of a thrust shoe holder, and form a cavity between the inner surface and the back surface of the thrust shoe holder. At least one weep hole is on the flange. The weep hole is configured to allow water to enter the cavity to form an insulating stagnant water layer.