Lead-Cooled Fast Reactor Control Drums and Integrated Pump
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Solution Overview
Problem
Lead-cooled fast reactors face issues with large overall dimensions, complex structure, and reliability due to the placement of main pumps and heat exchangers on the reactor's periphery, as well as risks from steam leaks causing criticality and pressure-related safety concerns.
Innovation Solution
A nuclear reactor design with a reactor container, control drum assembly, hot channel, and integrated main pump and heat exchanger arrangement, where the main pump and heat exchanger are fixed on the cover body, reducing radial dimensions and improving reliability, and a sealing sleeve with inert gas spaces to manage steam leaks and pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the main pump and heat exchanger are arranged on the outer periphery of the reactor core, then the heat exchange function is improved, but the overall dimension and radial dimension of the reactor increase
Solution Approach 1:
The patent merges the main pump and heat exchanger into an integrated assembly that is arranged concentrically around the reactor core, with the pump located in the central region and the heat exchanger surrounding it. This integration allows both components to occupy a compact radial space while maintaining their individual functions, thereby reducing the overall radial dimension of the reactor compared to peripheral arrangement.
Solution Approach 2:
The patent transitions from a horizontal peripheral arrangement to a vertical stacked arrangement where the main pump is positioned in the lower central region and the heat exchanger is positioned in the upper central region. This dimensional change from horizontal to vertical placement reduces the radial footprint of the reactor while maintaining effective heat exchange capability.
2Power
If a long-shaft pump is used to ensure driving effect, then the pump performance is improved, but the structural complexity and reliability decrease
Solution Approach 1:
The patent extracts the long shaft component from the pump design and replaces it with a short-shaft pump configuration. The driving effect is maintained through direct coupling of the motor to the pump impeller, eliminating the need for long shafts that would compromise reliability. This simplification reduces structural complexity while preserving the necessary driving capability for coolant circulation.
3Power
If multiple main pumps are provided to ensure driving effect, then the pump performance is improved, but the structural complexity and volume increase
Solution Approach 1:
The patent combines multiple pump functions into a single integrated main pump assembly that is centrally located within the reactor. This unified design achieves the necessary driving effect through a consolidated pump structure rather than multiple separate pumps, thereby reducing structural complexity and overall volume while maintaining adequate coolant circulation capability.
4Temperature
If the heat exchanger is located on the periphery, then the heat exchange area is improved, but the risk of steam leakage to the reactor core increases
Solution Approach 1:
The patent introduces a protective barrier or sealing structure between the heat exchanger and the reactor core that prevents steam leakage. This intermediary element acts as a safety barrier that allows the heat exchanger to be positioned in a location that maintains effective heat exchange while blocking the path of potential steam leakage to the reactor core, thereby eliminating the harmful effect.
5Temperature
If the reactor core is exposed to high pressure steam, then the heat exchange efficiency is improved, but the risk of flash evaporation and flash explosion increases
Solution Approach 1:
The patent introduces a pressure regulation mechanism or expansion chamber between the heat exchanger and the reactor core that acts as a buffer against high-pressure steam. This intermediary structure allows pressure equalization and prevents sudden pressure shocks that would cause flash evaporation or flash explosion, while still maintaining effective heat exchange efficiency.
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 design results in a more compact, reliable, and safer reactor with reduced coolant volume, simplified installation, and enhanced operational safety by preventing steam from reaching the reactor core and mitigating pressure impacts.
Implementation Method 1
control drum assembly arranged on an outer periphery of the reactor core, the control drum assembly including a plurality of control drums, each of the control drums being rotatable around its center
Implementation Method 2
heat exchanger arranged in the reactor container and located on an outer periphery of the hot channel, an inlet of the heat exchanger being in communication with the hot pool passage
Implementation Method 3
main pump fixed on the cover body and having a part arranged in the hot pool passage, the main pump pumping the coolant in the hot pool passage into the heat exchanger
Implementation Method 4
lead-cooled fast reactors refer to fast neutron reactors cooled by liquid lead or lead-bismuth alloy
Data Source
AI summary
A nuclear reactor includes a reactor container, a reactor core, a control drum assembly, a hot channel, a heat exchanger and a main pump. The reactor container contains a coolant; the reactor core is arranged at a lower middle part of the reactor container; the control drum assembly is arranged on an outer periphery of the reactor core, and includes control drums arranged at intervals along a peripheral direction of the reactor core; the hot channel is arranged in the reactor container and located above the reactor core. The hot channel has a bottom hermetically connected to the control drum assembly and a top hermetically connected to an inner top surface of the reactor container. The hot channel has a hot pool passage for the coolant to pass through. The heat exchanger is arranged in the reactor container and located on an outer periphery of the hot channel.