Nuclear Fuel Assembly Positioning Indicator Mechanism
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Solution Overview
Problem
Existing systems for transporting nuclear fuel assemblies lack effective means to quickly and safely verify the positioning of the assemblies within their housings during loading and unloading, due to restricted visual and manual access caused by locking systems, which increases operator exposure time in nuclear environments and risks of improper assembly.
Innovation Solution
A control device with movable abutment members and a positioning indicator that can be retained in different positions to indicate whether the assembly is properly positioned for transport or unloading, allowing operators to verify the assembly's position without direct access to the housing, using a combination of pushers, pivoting arms, and elastic return mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking system is fitted to the open end of the housing to reinforce retention of the nuclear fuel assembly, then the maintenance of the assembly in the housing is improved, but visual and manual access to the interior of the housing becomes extremely restricted
Solution Approach 1:
A positioning indicator is introduced as an intermediary element that provides information about the assembly's position without requiring direct visual or manual access to the housing interior. The indicator acts as a mediator between the locked assembly and the operator, enabling verification of positioning while the locking system remains in place.
Solution Approach 2:
The positioning indicator creates a visible representation or copy of the assembly's position state. Instead of requiring direct observation of the assembly, the indicator provides a simplified visual copy (such as a flag or marker in different positions) that conveys the essential positioning information to the operator.
2Reliability
If the locking system is in position above the housing, then the assembly is securely retained, but the operator cannot quickly control the assembly positioning
Solution Approach 1:
The positioning indicator provides immediate feedback to the operator about the assembly's position without requiring extended exposure time. The visual signal (such as a flag in a specific position) gives instant information about whether the assembly is correctly positioned, allowing the operator to make quick decisions and minimize time in the nuclear environment.
Solution Approach 2:
The mechanical system of direct visual inspection and manual verification is replaced by an automated indicator mechanism that provides position information automatically. This substitution eliminates the need for the operator to physically access or closely observe the housing interior, reducing exposure time while maintaining reliability.
3Reliability
If the locking system is tightened to ensure axial tightening of the assembly, then the transport safety is improved, but the operator cannot verify the correct positioning of the assembly
Solution Approach 1:
The positioning indicator serves as an intermediary that translates the internal positioning state of the assembly (which is difficult to detect) into an easily observable external signal. The indicator mechanism is actuated by the assembly's position relative to the locking system, providing indirect but reliable verification of positioning without requiring direct observation of the assembly itself.
4Ease of operation
If the locking system is released to allow unloading, then the assembly can be removed, but the operator cannot verify that the assembly is in the correct unloading position
Solution Approach 1:
The positioning indicator provides continuous feedback about the assembly's position throughout the unloading process. When the assembly reaches the correct unloading position (such as being fully lowered or aligned with a specific reference), the indicator changes state to provide clear visual confirmation, enabling the operator to verify proper positioning without difficulty.
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 enables quick and unambiguous verification of the assembly's position, reducing operator exposure time and ensuring safe transport and unloading by providing clear, all-or-nothing indication of correct positioning, thus enhancing the safety and efficiency of nuclear fuel handling.
Implementation Method 1
a positioning indicator suitable to be retained in abutment by the movable abutment member in a first position
Data Source
Figure 1~2
Figure 3
Figure 4a~4b
AI summary
The invention concerns a device for controlling (20) positioning of an assembly containing nuclear fuel (4) in a housing of a storage basket (2). The invention is characterized in that it comprises at least one mobile stop member (24, 26, 28) as well as a positioning indicator (30) adapted to be retained abutted by the mobile stop member in a first position indicating that the assembly occupies a first positioning, said mobile stop member being arranged so as to be brought, by contact with the assembly located in a second positioning inside its housing, into a position allowing it to release the positioning indicator designed to be moved automatically from the first position to a second position indicating that the assembly occupies the second positioning.