Suspended Indexing Device Installation Unit for Nuclear Reactor Maintenance
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Solution Overview
Problem
The installation of indexing devices on the ceiling portion in access tunnels of nuclear reactors hinders maintainability and worker passage, making regular inspections less efficient.
Innovation Solution
An indexing device installation unit with a base-mounted indexing device and a lift mechanism that holds the base in a suspended state within the access tunnel, allowing for upward and downward movement using an air motor-driven endless chain system, enabling the indexing devices to be lifted out of the way during maintenance without obstructing passage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If indexing devices are installed on the ceiling portion in the access tunnel, then the indexing devices can guide the guide tube to the nuclear reactor pressure vessel side, but the maintainability of the traversing in-core probe is lowered and worker passage is hindered
Solution Approach 1:
The indexing device is mounted on a movable base that can be suspended at different heights within the access tunnel. The base includes a lift mechanism with an air motor and endless chain that enables dynamic adjustment of the indexing device's position between a lowered state (for maintenance access) and a raised state (for normal operation). This dynamic positioning resolves the contradiction by allowing the indexing device to adapt its installation position based on operational requirements.
2Ease of repair
If indexing devices are installed on a lower part in the access tunnel, then maintainability is improved, but easiness in carrying devices and passage of workers is hindered
Solution Approach 1:
The movable base with lift mechanism allows the indexing device to be dynamically positioned at optimal heights. During maintenance operations, the base is lowered to provide easy access for workers and equipment. During normal operation, the base is raised to clear the passage for workers carrying devices. This dynamic height adjustment simultaneously satisfies both maintainability and worker passage requirements.
Solution Approach 2:
The vertical position parameter of the indexing device is changed based on operational mode. The lift mechanism adjusts the height parameter of the base, transitioning between a low position (prioritizing maintainability) and a high position (prioritizing worker passage). This parameter change enables the system to optimize for different operational requirements at different times.
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
This solution enhances maintainability of traversing in-core probes by allowing unobstructed passage and reducing the risk of electric noise interference, improving the efficiency of nuclear reactor inspections without compromising the performance of installed monitors and sensors.
Implementation Method 1
a lift mechanism (31) moving up and down the base (3) held by the holding part (32) together with the indexing device (5), wherein the base (3) is movable along a moving direction in an vertical direction
Data Source
AI summary
Maintainability of a traversing in-core probe is improved without any hindrance to passage and the like in an access tunnel in which an indexing device of a TIP system is installed. An indexing device installation unit provided in the TIP system includes: a base on which an indexing device of a traversing in-core probe used in a nuclear reactor is mounted; a holding part holding the base in a suspended state in an access tunnel formed in a nuclear reactor containment vessel; and a lift mechanism moving up and down the base held by the holding part together with the indexing device.