Nuclear Waste Cask Impact Protection with Perforated Aluminum Limiters

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Solution Overview

Problem

Existing impact limiters for nuclear waste transport casks are either non-homogeneous, weather-dependent, flammable, or expensive to manufacture, and they do not provide uniform crush characteristics due to anisotropic materials.

Innovation Solution

A perforated aluminum impact limiter with a deformable annular sleeve having longitudinal passages and a monolithic structure, which absorbs impact forces uniformly and is isotropic, providing improved crush resistance and manufacturing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If wood is used as impact limiter material, then cost is reduced, but reliability deteriorates due to non-homogeneous structure, weather dependence, and flammability

Engineering Contradiction:
Improvemanufacturing costVSAvoidstructural reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies homogeneity by using a homogeneous metal material (such as aluminum or steel) throughout the impact limiter structure, replacing the non-homogeneous wood material. This ensures uniform mechanical properties, consistent crush characteristics, and eliminates the variability inherent in natural wood, thereby improving reliability while maintaining cost-effectiveness through standardized manufacturing processes.

Inventive Principle:
Principle #33Homogeneity

Solution Approach 2:

The patent employs composite material construction by combining metal structural components with energy-absorbing materials (such as foam or honeycomb structures) to create a multi-layered impact limiter. This composite approach provides both the structural integrity and crashworthiness of metal while incorporating energy absorption characteristics, resolving the contradiction between cost and reliability.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If anisotropic materials are used in impact limiter, then manufacturing is simplified, but manufacturing precision deteriorates due to non-uniform crush characteristics

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidcrush uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies homogeneity by using a homogeneous metal material (such as aluminum or steel) throughout the impact limiter structure, replacing the non-homogeneous wood material. This ensures uniform mechanical properties, consistent crush characteristics, and eliminates the variability inherent in natural wood, thereby improving reliability while maintaining cost-effectiveness through standardized manufacturing processes.

Inventive Principle:
Principle #33Homogeneity

3Reliability

If honeycomb impact limiter is used, then impact protection is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveimpact protectionVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by modifying the geometric parameters of the impact limiter, such as the thickness, diameter, and configuration of the tubular structure. By optimizing these parameters, the patent achieves effective impact protection through controlled deformation and energy absorption, eliminating the need for complex honeycomb structures while maintaining or improving protective performance.

Inventive Principle:
Principle #35Parameter changes

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 perforated aluminum impact limiter effectively absorbs impact forces, ensuring uniform deformation and protecting the cask from structural damage while being cost-effective and resistant to environmental conditions.

Implementation Method 1

Each impact limiter may comprise a deformable and crushable annular metallic perforated impact barrel or sleeve

Methodology Applied
Scientific EffectDeformation: Deformation

Implementation Method 2

Impact limiters are fabricated from energy-absorbing materials that prevent or limit structural damage to the transport cask in case of an accident

Methodology Applied
Scientific EffectEnergy absorption: Damping

Data Source

PatentEP4042451B1Nuclear waste cask with impact protection
Publication Date: 2025.07.16 HOLTEC INTERNATIONAL INC
  • EP4042451B1 patent drawingFigure 1
  • EP4042451B1 patent drawingFigure 2
  • EP4042451B1 patent drawingFigure 3

AI summary

A nuclear waste cask with impact protection includes impact limiters detachably coupled to opposite ends of the cask. Each impact limiter may comprise a deformable energy-absorbing perforated sleeve of cylindrical shape comprising an array of closely-spaced longitudinally elongated perforations. The perforations may comprise longitudinal passages having a circular cross-sectional shape in certain embodiments. The perforated sleeve may have an annular metallic body of monolithic unitary structure in which the perforations are formed and a central opening to receive the ends of the cask therein. When exposed to external impact forces such as created by dropping the cask, the perforations collapse inwards in the impact or crush zone to absorb the energy of fall while preventing or minimizing any forces transmitted to the cask to maintain the integrity of waste containment barrier.