Turbo Pump Manifold Plenum for Reactor Coolant Circulation
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Solution Overview
Problem
Existing reactor coolant pumps in PWR systems operate inefficiently, providing low flow volume with high pressure head, disrupting natural coolant circulation and introducing potential loss of coolant accidents due to vessel penetrations, and are difficult to maintain in high-temperature environments.
Innovation Solution
The implementation of turbo pumps powered by a manifold plenum chamber, where pressurized primary coolant water drives turbines to enhance coolant circulation within the pressure vessel, reducing vessel penetrations and optimizing pump efficiency by transforming excess pressure head into higher volumetric flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If external reactor coolant pumps are used to provide motive force for circulating primary coolant water, then circulation efficiency is improved, but vessel penetrations are introduced that can be locations of loss of coolant accidents
Solution Approach 1:
The pump is completely extracted from the pressure vessel and placed in an external location. The pump draws coolant through a suction line from the pressure vessel and returns it through a discharge line, eliminating the need for vessel penetrations while maintaining circulation functionality. This resolves the contradiction by removing the source of reliability issues (vessel penetrations) while preserving the productivity benefit (active circulation).
Solution Approach 2:
External piping serves as an intermediary between the external pump and the pressure vessel, transferring coolant without requiring direct penetration of the pressure vessel boundary. The suction and discharge lines act as mediators that connect the pump to the coolant system while maintaining the integrity of the pressure vessel.
2Productivity
If reactor coolant pumps operate in high-temperature environments inside the pressure vessel, then coolant circulation is maintained, but maintenance difficulty increases
Solution Approach 1:
The pump is extracted from the high-temperature environment inside the pressure vessel and relocated to an external position. This allows the pump to operate in a more accessible, lower-temperature environment while still performing its coolant circulation function through external piping connections.
Solution Approach 2:
Instead of bringing the pump into the harsh environment inside the pressure vessel, the approach is inverted: the pump remains outside in a benign environment, and the coolant is brought to the pump through external piping. This reverses the traditional arrangement and resolves the maintenance difficulty while preserving circulation functionality.
3Stress or pressure
If traditional pumps are used to provide high pressure head, then pressure differential is achieved, but flow volume is reduced
Solution Approach 1:
The pump characteristics are optimized by selecting or designing a pump that operates at parameters suitable for the specific application - providing sufficient pressure head to overcome system resistance while maximizing flow volume. The pump is sized and configured to match the actual operating conditions of the coolant circulation system rather than relying on high pressure head alone.
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 improves coolant circulation efficiency, reduces the risk of loss of coolant accidents, and simplifies maintenance by operating the external pump outside the pressure vessel, while maintaining high efficiency and reducing the need for internal pump maintenance.
Implementation Method 1
Each turbo pump includes a turbine driving an impeller
Implementation Method 2
Each turbo pump includes an impeller arranged to pump primary coolant water in the pressure vessel
Implementation Method 3
An electrically driven pump operatively connected with the manifold plenum chamber to pressurize the manifold plenum chamber with primary coolant water
Data Source
AI summary
A nuclear reactor includes a nuclear core comprising a fissile material, and a pressure vessel containing the nuclear core immersed in primary coolant water. Turbo pumps disposed in the pressure vessel provide active circulation of primary coolant water in the pressure vessel. Each turbo pump includes a turbine driving an impeller. A manifold plenum chamber is disposed in the pressure vessel, and is in fluid communication with inlets of the turbines of the turbo pumps. An electrically driven pump operatively connected with the manifold plenum chamber to pressurize the manifold plenum chamber with primary coolant water. The turbo pumps may be disposed in openings passing through the manifold plenum chamber. The pressure vessel may be vertically oriented and cylindrical, with a cylindrical riser oriented coaxially inside, and the manifold plenum chamber may be annular and disposed in a downcomer annulus defined between the cylindrical riser and the cylindrical pressure vessel.