Chevron Neutron Absorber Insert for Spent Fuel Rack
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Solution Overview
Problem
Existing neutron absorbing materials in spent fuel racks deteriorate over time, requiring frequent replacement or addition, complicating handling and leaving cells unprotected during fuel assembly removal, and occupy excessive space with complex designs.
Innovation Solution
A neutron absorbing apparatus with a chevron-shaped structure formed by a corner spine and walls, using a metal matrix composite with neutron absorbing particulate reinforcement, and featuring a guide sheet and locking protuberance for secure retention within fuel rack cells, minimizing space usage and simplifying handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional neutron absorbing material is integrated into fuel rack cell walls, then neutron absorption coverage is improved, but material deterioration occurs over time requiring frequent replacement
Solution Approach 1:
The neutron absorbing material is segmented into removable inserts that can be independently replaced in individual cells, rather than being integrated into the permanent rack structure. This allows targeted replacement without affecting the entire rack system.
Solution Approach 2:
The patent implements a system where deteriorated neutron absorbing inserts are removed and replaced with fresh inserts, while the rack structure itself is preserved and reused. This separates the consumable absorber material from the durable structural components.
2Adaptability or versatility
If removable neutron absorbing assemblies are used, then replacement flexibility is improved, but device complexity increases with multiple welds and securing mechanisms
Solution Approach 1:
The patent extracts the essential function of neutron absorption into simple, standalone inserts that require minimal structural support. By removing unnecessary welds, securing mechanisms, and multi-layered walls from the design, the complexity is reduced while maintaining replacement flexibility.
Solution Approach 2:
The inserts are designed with localized neutron absorbing material positioned precisely where needed within each cell, rather than using complex multi-layered structures throughout the entire rack. This provides adequate neutron absorption with simplified construction.
3Ease of operation
If existing neutron absorbing assemblies are removed with fuel assemblies, then handling procedure is simplified, but cells are left unprotected during removal
Solution Approach 1:
The patent implements preliminary action by ensuring that neutron absorbing inserts remain in place during fuel assembly removal operations. The inserts are designed to stay secured in their cells while fuel assemblies are loaded and unloaded, maintaining continuous protection without requiring complex coordinated removal procedures.
4Strength
If multi-layered walls are used in neutron absorbing assemblies, then structural integrity is improved, but space within fuel rack cells is excessively occupied
Solution Approach 1:
The patent extracts the neutron absorbing function from complex multi-layered wall structures and implements it through simple, thin inserts. This eliminates excessive space occupation while maintaining adequate structural integrity for the absorber components.
Solution Approach 2:
Instead of using thick multi-layered walls throughout, the patent applies neutron absorbing material locally in thin inserts only where needed for neutron absorption, reducing overall space occupation while maintaining structural adequacy.
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 apparatus provides effective neutron absorption, simplifies fuel assembly handling by securing the absorber in place during removal, and optimizes space usage within fuel racks, extending storage duration without the need for frequent material replacement.
Implementation Method 1
a neutron absorbing apparatus for insertion into spent fuel cell transport and/or storage systems
Data Source
AI summary
A neutron absorbing apparatus, for insertion into a fuel cell storage system, includes a corner spine, a first wall and a second wall, each wall being affixed to the corner spine to form a chevron shape. Each wall includes an absorption sheet affixed to the corner spine, each absorption sheet being formed of a metal matrix composite having neutron absorbing particulate reinforcement, and a guide sheet affixed to and covering a fractional upper portion of the absorption sheet and extending over a top of the absorption sheet. The absorption sheet extends along the corner spine a greater length than the guide sheet.