Sludge Handling via In-Situ Freezing and Filtered Collection
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Solution Overview
Problem
Current methods for handling radioactive sludge from the bottom of nuclear fuel storage basins stir up the sludge, leading to inefficient collection and rapid water accumulation in tanks, requiring extensive equipment and prolonged sedimentation times.
Innovation Solution
A method involving freezing the sludge in situ using a coolable surface, followed by collection in a container with a filter, and subsequent thawing to form larger aggregates that sediment easily, allowing for efficient transport and storage, while minimizing water content and avoiding sludge stirring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sludge is collected by suction from the bottom of the basin, then sludge can be removed from the basin, but the sludge is stirred up and particles sediment again on the bottom, reducing collection efficiency
Solution Approach 1:
The sludge is frozen in situ before collection, transforming it from a suspended state to a solidified state. This preliminary freezing action prevents the sludge from being stirred up during subsequent suction operations, ensuring particles remain settled and can be collected completely without re-suspension.
Solution Approach 2:
The physical state of the sludge is changed from liquid/suspended to solid frozen state. This parameter change (temperature) allows the sludge to be collected without stirring, as the frozen state maintains particle settlement while enabling efficient suction removal.
2Productivity
If sludge is collected by suction from the bottom, then sludge can be removed, but a lot of water is brought into the tank, allowing only a small portion of the bottom to be cleaned
Solution Approach 1:
The sludge is frozen in situ before suction, creating a solidified mass that can be removed without bringing in large quantities of water. The freezing action occurs before the suction process, so the sludge is already in a state that minimizes water entrainment during removal.
Solution Approach 2:
Changing the sludge from liquid to frozen solid state reduces its volume and prevents excessive water from being drawn into the collection tank during suction, thereby reducing the total quantity of water that needs to be handled.
3Productivity
If sludge is collected by suction, then sludge can be removed from the basin, but the tank fills rapidly with water, requiring prolonged sedimentation time before reuse
Solution Approach 1:
The sludge is frozen before collection, transforming it into a solid state that can be removed quickly without requiring prolonged sedimentation time. The preliminary freezing action eliminates the need for extended waiting periods that would otherwise be required for water to settle and clear the tank.
Solution Approach 2:
The temperature parameter is changed to freeze the sludge, which accelerates the collection process and eliminates prolonged sedimentation time. The frozen state allows for rapid removal and reduces the time the tank needs to be idle for sedimentation.
4Productivity
If conventional suction methods are used, then sludge can be collected, but extensive equipment and complex processes are required
Solution Approach 1:
The freezing and collection processes are merged into a single integrated operation. The freezing device is positioned in the basin and the sludge is frozen in situ, then collected in the same operational sequence, eliminating the need for separate complex equipment for each function.
Solution Approach 2:
The system uses the existing basin environment and simple freezing mechanism to achieve sludge collection. The process leverages the natural setting of the basin and requires minimal additional equipment beyond the freezing device and collection container.
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 approach enables faster, more efficient sludge collection and compacting, reducing water content and the need for extensive equipment, thereby alleviating the drawbacks of existing methods.
Implementation Method 1
freezing the sludge in a portion of the bottom of the basin
Implementation Method 2
thawing the frozen sludge in the container
Implementation Method 3
container comprises a collecting filter
Data Source
Figure 1~2
Figure 3
AI summary
A method for handling sludge arranged on the bottom (2) of a water filled basin (1), wherein the water defining a surface, is described. The method comprises the steps of freezing the sludge in a portion of the bottom (2) of the basin (1), arranging a closable container (3) in the basin (1) below the surface of the water, which container (3) comprises a collecting filter, moving the frozen sludge into the container (3) to a position above the collecting filter, closing the container (3), and thawing the frozen sludge in the container (3). An apparatus for performing the method is also described.