In-Core Neutron Instrument Drive Safety Circuit for Cover Interlock
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Solution Overview
Problem
The conventional drive device for in-core neutron instrumentation systems poses risks of injury and electric shock during maintenance and inspection due to the ability to operate with the cover member removed, allowing contact with energized internal components.
Innovation Solution
A safety circuit is integrated between the power supply and the drive motor, enabling power supply to be switched on or off based on the mounted state of the cover member, ensuring the drive device is only powered when the cover is securely closed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cover member is removed for maintenance and inspection, then accessibility to internal components is improved, but operator safety deteriorates due to risk of contact with energized rotating components
Solution Approach 1:
The safety circuit performs preliminary detection of the cover member's mounted state before allowing power supply to the drive motor. This prevents the harmful effect from occurring in the first place by ensuring the cover is properly mounted before the device can be energized, thus maintaining operator safety while enabling maintenance access when needed.
2Productivity
If the drive device is powered during maintenance with cover member removed, then operational capability is maintained, but safety risks increase due to exposed rotating components
Solution Approach 1:
The safety circuit acts as an intermediary between the power supply and the drive motor, controlling power supply based on the cover member's mounted state. This intermediary mechanism ensures that the drive motor can only operate when the cover is properly mounted, thus maintaining operational capability while eliminating safety risks associated with exposed rotating components.
3Object-affected harmful factors
If the cover member is securely mounted, then operator safety is improved by preventing contact with internal components, but accessibility for maintenance deteriorates
Solution Approach 1:
The safety circuit dynamically adjusts the power supply state based on the cover member's mounted state. When the cover is mounted, the device operates safely; when the cover is removed for maintenance, the power supply is automatically cut off. This dynamic control resolves the contradiction by adapting the operational state to the current configuration, ensuring both safety and maintenance accessibility.
Data Source
AI summary
A drive device for an in-core neutron instrumentation system includes a safety circuit between a power supply and a drive motor. The safety circuit is provided inside the cover member, and switches between a conductive state in which power can be supplied to the drive motor and a cut-off state in which power cannot be supplied thereto depending on a mounted state of the cover member. The safety circuit is controlled to be in the conductive state in response to a state in which the cover member is mounted on the base member, and is controlled to be in the cut-off state in response to a state in which the cover member is not mounted on the base member.