Subsea Waste Disposal Riser Guidance and Docking
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Solution Overview
Problem
Existing methods for disposing nuclear waste into a subtending tectonic plate face challenges in accurately relocating drilled boreholes, leading to potential environmental disasters due to radioactive debris scattering during positioning operations.
Innovation Solution
A method and system involving a wellhead with a subsea blowout preventer, a docking station, and a carrier system that allows for safe disposal of waste into a drilled borehole by maintaining a connected riser for guidance and sealing, using a waste passageway or robot arm for radial waste introduction, and optionally drilling curved paths for increased storage capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a revolving cylinder or hopper at the tip of a drill string is used to deposit waste material, then waste can be disposed into the borehole, but it becomes difficult to relocate the drilled borehole and position the waste deposition apparatus accurately
Solution Approach 1:
The system separates the drilling function from the waste deposition function. The wellhead and BOP remain fixed at the original borehole location, while the carrier with waste can be transported independently to the precise borehole position using the riser as a guide, eliminating the need to relocate the entire drilling apparatus.
Solution Approach 2:
The riser serves as an intermediary structure that connects the surface vessel to the wellhead at the seabed. It provides a stable reference and guidance path for positioning the carrier at the borehole location, enabling precise waste deposition without requiring complex relocation of drilling equipment.
2Productivity
If manual manipulation of waste by an apparatus on the seabed is performed to position the revolving cylinder on the borehole, then waste can be deposited, but radioactive debris may scatter over the seabed causing environmental disaster in case of accident
Solution Approach 1:
The hazardous waste manipulation operation is extracted from the open seabed environment and transferred into the enclosed, controlled passageway of the carrier. The waste remains contained throughout the transfer process via the waste passageway, eliminating the risk of scattering radioactive debris over the seabed.
Solution Approach 2:
The carrier and its enclosed passageway act as a protective shell that contains the waste material during transport and deposition. This enclosed structure prevents accidental release of radioactive debris while allowing controlled transfer to the borehole.
3Adaptability or versatility
If the riser is disconnected from the wellhead during waste introduction, then the carrier can be positioned at the docking station, but the closed system is broken increasing leakage risk
Solution Approach 1:
The riser serves multiple functions simultaneously: it provides structural support, acts as a guidance rail for the carrier, maintains the closed system for safety, and enables the docking station to function. The docking station is integrated into the wellhead structure, allowing the carrier to dock without requiring riser disconnection.
Data Source
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AI summary
A method and waste disposal system is provided for disposing a waste into a drilled borehole in a subtending tectonic plate. Herewith, waste can be disposed in a safe manner. The waste is transported from sea-level to the seabed by a carrier and introduced into a drilled borehole by using a docking station. The docking station allows a riser to remain connected to a wellhead during the introduction of the waste. Advantageously, the riser can be used as a guidance for the carrier. Additionally, the riser can be used after introducing the waste e.g. to seal the borehole or to introduce a dart to push waste further into the borehole. A further advantage is that the borehole is drilled along a curved path including a substantially horizontal section which contributes to an increased length of the borehole which advantageously allows an increase in storage of waste.