Boiling Water Reactor Control Rod Blade Segmentation
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Solution Overview
Problem
Boiling water reactor control rod blades pose challenges in storage and disposal due to their size, configuration, embrittlement, and radiological activity, with existing methods being inefficient and potentially hazardous, especially when attempting to reduce volume for transportation and disposal.
Innovation Solution
A method involving the longitudinal segmentation of the central spline into four sections, followed by lateral segmentation of each section using malleable metal sleeves to create manageable, sealed segments that can be safely transported and stored, minimizing radioactive debris release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control rod blades are stored in-pool, then they can be stored safely, but storage space efficiency is extremely poor
Solution Approach 1:
The control rod blade is divided into multiple segments by making longitudinal cuts through the central spline and lateral cuts through the panels. This segmentation reduces the overall volume occupied by the control rod, allowing for more efficient stacking and storage in spent fuel pools while maintaining safe handling of radioactive materials.
2Object-affected harmful factors
If control rod blades are cut vertically near the central spline, then radioactive gases are contained, but the segments remain too long for efficient storage and transport
Solution Approach 1:
The invention combines longitudinal segmentation (vertical cuts near the spline) with lateral segmentation (horizontal cuts through the panels) to create smaller, manageable segments. This two-dimensional segmentation approach reduces both the length and volume of individual segments, making them suitable for efficient storage and transport while maintaining radioactive gas containment through the longitudinal cuts near the sealed spline.
3Length of moving object
If control rod blades are horizontally segmented, then segment length is reduced, but neutron absorber rods are cut and radioactive gases may be released
Solution Approach 1:
The invention performs longitudinal cuts through the central spline first, creating separate longitudinal sections that each contain intact sealed neutron absorber rods. Then lateral cuts are made through the panels of these sections. This sequence ensures that the spline seals remain intact and radioactive gases are contained, while still achieving the desired reduction in segment length through the lateral cuts.
4Volume of moving object
If control rod blades are segmented into smaller pieces, then storage volume is reduced, but the complexity of the segmentation process increases
Solution Approach 1:
The invention uses a systematic two-step segmentation approach: first making longitudinal cuts through the central spline to create sections, then making lateral cuts through the panels. This structured approach, combined with using portable cutting equipment and sleeves to contain debris, reduces the overall complexity compared to attempting complex three-dimensional segmentation in one step, while achieving significant volume reduction for efficient storage.
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 method effectively reduces the storage volume and facilitates safe transportation of boiling water reactor control rod segments by creating smaller, sealed, and more manageable pieces that fit within standard transport casks, enhancing storage efficiency and safety.
Implementation Method 1
a sleeve is wrapped laterally around the longitudinal section at the identified elevation, with the sleeve extending an incremental distance on either side of the elevation. The method then laterally shears at least one of the longitudinal sections at the elevation and substantially simultaneously seals the sleeve against an opposite side of the sleeve as it is sheared.
Data Source
AI summary
A method of reducing the volume of a blade section of a boiling water reactor control rod for transport or storage that cuts the control rod spline into four substantially equal longitudinal sections, with each longitudinal section including one control rod blade. Each longitudinal section is radiologically characterized and the locations of desired lateral segmentation are identified. A band of malleable metal is wrapped around each longitudinal section at each of the locations and the bands are sheared to separate segments of the longitudinal section and the ends of the bands are crimped at the point of shearing to seal the interior of the segments.