Nuclear Fuel Assembly Balancing Plate Joint
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fuel assembly designs for nuclear reactors, particularly boiling water reactors, face issues with uneven lifting forces due to thermal expansion of water rods, leading to potential tilting and handling risks during operations.
Innovation Solution
A joint arrangement with a balancing element and spherically rounded joint surfaces is introduced to secure the handle to the water rods, allowing rotational movement and equalizing lifting forces between multiple water rods, ensuring balanced lifting and alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If water rods are used to transfer lifting forces, then the fuel assembly can be lifted, but thermal expansion of water rods causes uneven lifting forces and tilting
Solution Approach 1:
The joint arrangement allows dynamic adjustment through rotational movement of the balancing element. The spherical joint surfaces enable the connection to adapt its configuration dynamically, allowing the system to self-balance as water rods expand at different rates during operation, thereby maintaining stable alignment while transferring lifting forces.
Solution Approach 2:
The balancing element changes its angular parameter (rotation angle) in response to differential expansion of water rods. By allowing the joint to rotate, the system adjusts its geometric parameters to equalize lifting forces across all water rods, compensating for thermal expansion variations and preventing tilting.
2Temperature
If water rods expand differently during operation, then thermal growth occurs, but this results in imbalance of lifting forces and tilting
Solution Approach 1:
The joint arrangement provides dynamic adaptability through rotational freedom at spherical joints. As water rods undergo thermal expansion at different rates, the balancing element can rotate to adjust the load distribution, automatically equalizing lifting forces despite temperature-induced dimensional changes in the water rods.
Solution Approach 2:
The system utilizes parameter changes in the joint configuration (rotation angles) to compensate for thermal expansion variations. The balancing element changes its orientation to redistribute forces, allowing the fuel assembly to maintain balanced lifting forces even when water rods experience differential thermal growth during reactor operation.
3Strength
If a rigid connection is used between handle and water rods, then structural strength is maintained, but uneven forces cause tilting and handling risks
Solution Approach 1:
The joint arrangement replaces a rigid fixed connection with a dynamic articulated structure. The spherical joints maintain structural integrity and force transfer capability while allowing the balancing element to rotate and adapt to uneven forces from thermally expanded water rods, thereby eliminating tilting and improving handling safety without sacrificing strength.
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 solution effectively balances lifting forces across water rods, preventing tilting and enhancing safety during handling operations by allowing the balancing element to rotate and equalize forces, maintaining alignment between the handle and water rods.
Implementation Method 1
The first joint and each one of said second joints comprise a pair of spherically rounded joint surfaces. The first joint and said set of second joints are configured to allow a rotational movement of said balancing element in relation to said handle as well as in relation to said two or three water rods.
Implementation Method 2
During operation, the water rods may expand/grow slightly (due to thermal/nuclear growth) and one water rod may grow differently than the other.
Data Source
AI summary
A fuel assembly for a boiling water reactor having fuel rods, two or three water rods, a tie plate, spacers, a handle, and a joint arrangement. The joint arrangement is configured to transfer a vertical lifting force from the handle to the water rods. The joint arrangement includes a balancing element arranged between the water rods and the handle. The joint arrangement includes a first joint arranged between the balancing element and the handle and a set of second joints arranged between a respective one of said water rods and said balancing element. The first joint and the set of second joints are configured to allow a rotational movement of said balancing element in relation to said handle as well as in relation to said water rods in order to balance lifting forces in the water rods.