Integrated LPRM Exchange Tool for Nuclear Reactor Maintenance
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Solution Overview
Problem
The existing methods for removing and replacing Local Power Range Monitors (LPRMs) in nuclear reactor vessels are cumbersome, requiring three tools and uncertainty about nut sizes, which complicates the process.
Innovation Solution
A tool with a structural member, a headpiece, and a nut engaging assembly that includes hex cut portions for both standard and smaller nuts, allowing for the removal and installation of LPRM assembly nuts and seals with a single device, simplifying the process by accommodating different nut sizes and facilitating the exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple tools are used to remove the seal and nut, then the LPRM can be freed from the vessel incore housing, but the device complexity and time required increase
Solution Approach 1:
The patent combines multiple separate tools (seal removal tool and nut removal tools) into a single integrated LPRM exchange tool. The tool integrates a seal engagement portion with multiple nut engagement portions of different sizes, allowing both the seal and nut to be removed using one tool rather than multiple separate tools, thereby reducing device complexity and improving ease of operation
Solution Approach 2:
The LPRM exchange tool is designed with multi-functionality to perform multiple operations: engaging and removing the seal, and engaging and removing nuts of different sizes. The tool includes a seal engagement portion and multiple nut engagement portions, making it a universal tool that can handle various components of the LPRM assembly without requiring separate specialized tools
2Adaptability or versatility
If multiple nut removal tools are carried, then both sizes of nuts can be accommodated, but the quantity of tools and preparation time increase
Solution Approach 1:
The tool incorporates multiple nut engagement portions of different sizes within a single device, allowing it to accommodate both sizes of nuts that may be encountered during LPRM exchange. This eliminates the need to carry multiple separate nut removal tools, reducing the quantity of tools required while maintaining adaptability to different nut sizes
Solution Approach 2:
The patent merges the functionality of multiple nut removal tools with different sized engagement portions into a single integrated tool. By combining these functions, the tool reduces the quantity of tools that need to be carried and prepared, while still providing the versatility to handle both sizes of nuts
3Loss of information
If the nut size is determined by trial and error, then the correct tool can be identified, but the time required for the exchange process increases
Solution Approach 1:
The tool is designed in advance with multiple nut engagement portions of different sizes already incorporated. This preliminary preparation eliminates the need for trial and error during the actual exchange process, as the correct nut engagement portion is already available on the tool, thereby reducing the time required to determine and use the correct tool size
Data Source
AI summary
A tool for use in servicing an LPRM assembly of a nuclear reactor vessel includes a structural member having a first bore that is structured to receive an LPRM device associated with the LPRM assembly, a headpiece provided at a first end of the structural member, and a nut engaging assembly slideably mounted on the structural member. The headpiece has a plurality of projections structured to mate with a plurality of bores provided in a seal of the LPRM assembly to enable the seal to be removed, and the nut engaging assembly has a housing that defines a second bore and that has first and second nut engaging portions. The nut engaging assembly is free to slide along the structural member and over the headpiece to a position wherein the engaging portions extend beyond the headpiece so that they may be used to remove the assembly nut.