Backup Inverter Circuit for Nuclear Recirculation Pump Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing power supply systems for primary loop recirculation pumps in nuclear reactors, using current source inverters, are not capable of no-load operation and have a single configuration for the main power gate supply circuit, making them unreliable in case of malfunctions, which can lead to plant shutdowns during turbine trips or load rejections.
Innovation Solution
An adjustable speed drive system with a backup main adjustable speed drive circuit portion and a breaker for switching between incoming and outputting destinations, allowing control signal switching to the backup inverter, ensuring continuous operation of the primary loop recirculation pump even if a single malfunction occurs in the main circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single configuration main power gate supply circuit is used in the inverter system, then device complexity is reduced, but reliability deteriorates due to inability to operate during malfunctions
Solution Approach 1:
The patent applies preliminary action by providing a backup power gate supply circuit that is prepared in advance but remains inactive during normal operation. When a malfunction occurs in the main circuit, the system automatically switches to the backup circuit, ensuring continuous operation without requiring complex real-time decision-making mechanisms. This resolves the contradiction by maintaining high reliability through redundancy while keeping device complexity low through simple switch-over logic.
Solution Approach 2:
The patent applies local quality by providing redundancy only in the critical power gate supply circuit portion rather than throughout the entire inverter system. The backup circuit is specifically targeted at the power gate supply function which is essential for pump operation, while other parts of the system remain single-configured. This selective application of redundancy maintains reliability where needed without unnecessarily increasing overall device complexity.
2Reliability
If a backup main adjustable speed drive circuit portion is added, then reliability is improved through redundancy, but device complexity increases
Solution Approach 1:
The backup adjustable speed drive circuit is prepared in advance and remains standby during normal operation. Upon detection of a malfunction in the main circuit, the system automatically switches to the backup circuit through simple control logic, ensuring continuous pump operation. This approach achieves high reliability through redundancy while maintaining low device complexity by using straightforward switch-over mechanisms rather than complex active redundancy management.
Solution Approach 2:
The patent treats the backup circuit as a standby component that remains inactive during normal operation and is only activated when the main circuit fails. This allows the use of simpler, more cost-effective backup components without requiring the same level of sophistication as the main operational circuit, thereby improving reliability while minimizing the increase in device complexity and cost.
3Ease of operation
If the inverter system is used instead of MG set, then ease of operation is improved with linearity of speed control, but reliability deteriorates due to single configuration and inability to perform no-load operation
Solution Approach 1:
The patent applies preliminary action by providing a backup power gate supply circuit that is prepared in advance but remains inactive during normal operation. When a malfunction occurs in the main circuit, the system automatically switches to the backup circuit, ensuring continuous operation without requiring complex real-time decision-making mechanisms. This resolves the contradiction by maintaining high reliability through redundancy while keeping device complexity low through simple switch-over logic.
Solution Approach 2:
The patent applies local quality by providing redundancy only in the critical power gate supply circuit portion rather than throughout the entire inverter system. The backup circuit is specifically targeted at the power gate supply function which is essential for pump operation, while other parts of the system remain single-configured. This selective application of redundancy maintains reliability where needed without unnecessarily increasing overall device complexity.
Data Source
AI summary
An adjustable speed drive system for a primary loop recirculation pump and method of control in which a first breaker is connected to an auxiliary power supply system, an inverter is connected to the first breaker, a second breaker is connected to an output of the inverter, a gate driver supplies a gate pulse to the inverter, and an inverter control portion drives the gate driver. The adjustable speed drive system is combined with a backup adjustable speed drive system. When a malfunction in a main adjustable speed drive circuit portion including the inverter and the gate driver in the adjustable speed drive system used in a normal operation is detected, the main adjustable speed drive circuit portion is switched to the backup adjustable speed drive system, and an operation of a recirculation pump motor for driving a recirculation pump that controls a flow of a reactor core is continued.