Nuclear Reactor Control Rod Group Eliminates Soluble Boron
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Solution Overview
Problem
Existing small marine reactors face challenges in controlling reactivity due to limited control rod capability, requiring the use of soluble boron for reactivity control, which can lead to accidental dilution accidents and reduced safety.
Innovation Solution
A small nuclear power reactor core design featuring a control rod group with functionally grouped rods for power compensation, reactivity adjustment, temperature adjustment, and shutdown, eliminating the need for soluble boron by using strong neutron-absorbing materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If soluble boron is used for reactivity control in small marine reactors, then reactivity control capability is improved, but safety deteriorates due to risk of accidental dilution accidents
Solution Approach 1:
The invention extracts and removes soluble boron from the reactor system, replacing it with a solid control rod mechanism. The control rods contain neutron-absorbing materials and can be inserted or withdrawn from the core to control reactivity, eliminating the safety risks associated with soluble boron while maintaining reactivity control capability
Solution Approach 2:
The invention replaces the chemical control method (soluble boron concentration adjustment) with a mechanical control system (control rod insertion/withdrawal). The control rods are mechanically positioned to absorb neutrons and control the nuclear reaction, providing safer and more reliable reactivity control
2Device complexity
If control rod group is simplified for compact design, then device complexity is reduced, but reactivity control precision deteriorates
Solution Approach 1:
The control rod group is segmented into four functional types: power compensation rods, reactivity adjustment rods, temperature adjustment rods, and shutdown rods. Each type performs a specific control function, allowing precise reactivity control while maintaining a compact structure. The segmented design enables independent optimization of each control function
Solution Approach 2:
The control rod system is designed with multi-functionality, where the same structural component (control rod assembly) serves multiple purposes: power control, reactivity adjustment, temperature regulation, and shutdown capability. This universal design reduces overall device complexity while maintaining comprehensive control precision
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 design enhances reactivity control and safety by allowing for precise adjustment of reactor power, temperature, and shutdown depth without the need for soluble boron, thereby minimizing the risk of accidental dilution and improving operational safety.
Implementation Method 1
The control rods are all made of strong neutron absorbing material
Data Source
Figure 1
AI summary
The present invention relates to a small nuclear power reactor core and a ship. In the small nuclear power reactor core, twenty-one control rods include four power compensation rods A, five reactivity adjustment rods B, four temperature adjustment rods R, and eight shutdown rods S. The power of the reactor core is adjusted by adjusting the insertion depth of the power compensation rods A; the changes in reactivity of the reactor core caused by fuel burn-up and changes in xenon concentration are compensated for by adjusting the insertion depth of the reactivity adjustment rods B; the average temperature of the reactor core is adjusted by adjusting the insertion depth of the temperature adjustment rods R; the shutdown rods S provides additional negative reactivity to ensure a sufficient shutdown depth during shutdown of the reactor core. The control rods are functionally grouped and their layout is designed such that no soluble boron is required. These functional control rods are respectively used to control the power, temperature, shutdown of the reactor core, and compensate for the changes in reactivity of the reactor core caused by fuel burn-up and changes in xenon concentration, thereby realizing the miniaturization of nuclear power plant cores.