Drillhole Waste Canister Retrieval With Corrosion-Resistant Latching

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Solution Overview

Problem

The safe and reliable retrieval of hazardous waste, particularly nuclear waste, from deep underground storage after extended periods, such as 100 years, is challenging due to potential corrosion, mechanical failure, and the need for robust latching mechanisms in conventional storage methods.

Innovation Solution

The implementation of corrosion-resistant materials for casings and canisters, sacrificial anodes, corrosion inhibitor fluids, and robust latching mechanisms, along with redundant access pathways, ensures the retrievability of hazardous waste by minimizing corrosion and maintaining structural integrity over a century.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional storage methods are used, then storage capacity is achieved, but corrosion and mechanical failure occur over extended periods

Engineering Contradiction:

ImproveretrievabilityVSAvoidstorage duration

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The canister employs a composite structure consisting of an inner corrosion-resistant liner (such as stainless steel or nickel alloy) and an outer structural shell (such as carbon steel or concrete). This multi-material construction provides both immediate corrosion protection and long-term structural integrity, enabling reliable retrieval after extended storage periods while maintaining storage capacity.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention applies corrosion inhibitor fluids and sacrificial anodes before waste emplacement to create a protective chemical environment. These measures are implemented in advance to prevent corrosion attacks on the canister and surrounding rock formation, cushioning against degradation mechanisms that would otherwise compromise retrievability over centuries of storage.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If robust latching mechanisms are implemented, then retrieval reliability is improved, but device complexity increases

Engineering Contradiction:

Improvelatching reliabilityVSAvoidmechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The latching mechanism is extracted as a separate, modular component that can be independently tested and replaced. The caliper assembly with latching arms and locking mechanisms is designed as a distinct tool that can be lowered on wireline, engaged with the canister's external features, and operated without complex integration with other system components, thereby reducing overall system complexity while maintaining reliability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces intermediary features on the canister surface (such as external ribs, grooves, or protrusions) that serve as mediation points for the latching calipers. These intermediary elements simplify the latching interaction by providing clear engagement points, reducing the complexity of the latching mechanism itself while ensuring reliable attachment for retrieval operations.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Strength

If corrosion resistant materials are used, then structural integrity is maintained, but manufacturing cost increases

Engineering Contradiction:

Improvestructural integrityVSAvoidmanufacturing complexity

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The canister is segmented into distinct functional zones with different material requirements. The inner liner contacting the waste is made of corrosion-resistant materials (stainless steel, nickel alloy), while the outer structural shell may use more economical materials (carbon steel, concrete). This segmentation maintains structural integrity where needed while reducing overall manufacturing complexity and cost through selective material application.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Corrosion-resistant properties are applied locally to specific areas of the canister where they are most critical, such as the inner surface contacting the waste and areas subject to direct chemical exposure. This local application of high-performance materials maintains structural integrity in critical zones while avoiding the need to manufacture entire canisters from expensive corrosion-resistant alloys, thereby reducing overall manufacturing complexity.

Inventive Principle:

Principle #3Local quality

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

Ensures the reliable retrieval of hazardous waste after 100 years by preventing significant corrosion and mechanical failure, thereby enhancing the safety and efficiency of waste management systems.

Implementation Method 1

corrosion inhibitor fluids

Methodology Applied

Scientific EffectCorrosion inhibition: Electrochemiluminescence

Implementation Method 2

sacrificial anodes

Methodology Applied

Scientific EffectGalvanic protection: Galvanometer

Data Source

PatentUS20260085594A1Retrieving hazardous waste stored in a drillhole

Publication Date: 2026.03.26 DEEP ISOLATION INC

AI summary

A hazardous waste canister includes a housing that defines an interior volume configured to store nuclear waste, the housing configured to enclose the nuclear waste in a human-unoccupiable drillhole formed from a terranean surface into a subterranean formation; and a knob coupled to the housing at an end of the canister, the knob configured to attach to a set of latching calipers of a latching assembly coupled to a downhole conveyance for moving the canister from the human-unoccupiable drillhole to the terranean surface.