EP-4742272-A1 - FLUID SEALING DEVICE FOR A MODULAR VESSEL ASSEMBLY

EP4742272A1EP 4742272 A1EP4742272 A1EP 4742272A1EP-4742272-A1

Abstract

A modular vessel assembly and sealing arrangement defining an internal chamber suitable to maintain a vacuum within the chamber to support a magnetically confined plasma. The present vessel and sealing arrangement is formed from a plurality of annular modular sections arranged in fluid sealed abutting contact as a stack of sealed annular rings extending around a central axis of the chamber. A sealing arrangement is provided at the interface between the modules of the stack to create a fluid seal configured to maintain at least a partial vacuum within the chamber. The present fluid sealed modular vessel assembly is suitable for use as a confinement vessel within a fusion reactor such as a tokamak.

Inventors

VERHOEVEN, Roel

Assignees

UK Fusion Energy Ltd

Dates

Publication Date: 20260513
Application Date: 20251006

Claims (15)

A sealing device for sealing an interface between a first annular module and a second annular module forming part of a vessel assembly having an internal chamber, the sealing device comprising: an annular biasing member having a first annular axial end region connectable to a first module, and a second annular axial end region; an annular sealing shoe provided at the second axial end region of the biasing member, the biasing member configured to apply an axial biasing force to the sealing shoe; the first end region of the biasing member configured to sealingly engage the first module and the sealing shoe configured to sealingly engage the second module via the axial biasing force to create an annular fluid seal between the first and the second modules.
The device according to claim 1, wherein the biasing member comprises a resiliently deformable member.
The device according to claims 1 or 2, wherein the sealing shoe comprises: an annular shoe support configured for engagement with an annular surface of the second module via the biasing force; and at least one annular load seal supported by the shoe support such that the biasing force is transmittable from the shoe support to the at least one load seal, wherein the at least one load seal is configured for biased sealing engagement with the annular surface of the second module via the transmitted biasing force; optionally, wherein the at least one annular load seal is housed within the shoe support, and/or comprises a C-shaped cross section.
The device of claim 3, wherein the shoe support is configured to limit the force transmitted from the shoe support to the at least one load seal via engagement between the shoe support and the annular surface.
The device according to any preceding claim, wherein the biasing member comprises a bellows-shaped profile.
The device according to any preceding claim, wherein the biasing member and/or the sealing shoe are formed from metal, e.g. a radiation tolerant metal.
The device according to any preceding claim, wherein the sealing shoe comprises two or more radially spaced annular load seals, each configured for biased sealing engagement with the second module via the axial biasing force to create an annular fluid seal.
The device according to claim 7, wherein the sealing shoe comprises two annular load seals mounted to an annular support, wherein the sealing shoe is configured such that the two load seals, the annular support and the second module define a sealed cavity when the sealing shoe sealingly engages the second module, and wherein the device further comprises a fluid evacuation arrangement configured to create at least a partial vacuum in the sealed cavity.
A modular vessel assembly defining an internal chamber, the assembly comprising: a sealing device as claimed in any preceding claim; and a stack of annular modules stacked along a longitudinal axis of the assembly so as to at least partially define an internal vacuum chamber, wherein the stack comprises a first annular module stacked on top of a second annular module, wherein the first annular axial end region of the biasing member is connected in sealing engagement with the first module; and wherein the biasing member is configured to apply the axial biasing force to the sealing shoe to sealingly engage the second module so as to create the annular fluid seal between the first and the second modules; optionally, wherein the stack of annular modules is toroidal.
The vessel assembly of claim 9, configured such that the biasing member transmits at least part of the weight of the portion of the stack above the biasing member to the sealing shoe to create and/or maintain the axial biasing force, and wherein said weight is sufficient to create the annular fluid seal between the first and the second modules.
The vessel assembly according to claims 9 or 10, wherein an interface region between the first annular module and the second annular module defines an annular recess, the sealing device at least partially accommodated within the recess.
The vessel assembly according to any one of claims 9 to 11, wherein the second module comprises an inboard axially extending annular lip positioned radially inboard of the sealing device and configured to inhibit radial inward displacement of the sealing shoe, and/or wherein the second module comprises an outboard axially extending annular lip positioned radially outboard of the sealing device and configured to inhibit radial outward displacement of the sealing shoe; optionally, wherein the inboard and/or outboard annular lip comprises a chamfered face extending oblique to the longitudinal axis for guiding the sealing shoe into engagement with a sealing surface of the second module as the first module is stacked upon the second module.
The vessel assembly according to any one of claims 9 to 12, wherein the first and second annular modules each comprises an annular abutment portion, the first and second annular modules in contact via their respective abutment portions, wherein at least one of the abutment portions comprises an axial extension configured to contact the other abutment portion so as to limit a compression of the biasing member.
A plasma confinement device, such as a tokamak, comprising a modular vessel assembly according to any one of claims 9 to 13, wherein the device is configured to maintain a magnetically confined plasma in the internal chamber; optionally, wherein the plasma confinement device comprises: one or more field coils for controlling the plasma, e.g. including one or more poloidal field coils and/or one or more toroidal field coils extending around the internal vacuum chamber; and/or a central solenoid aligned with the longitudinal axis.
A method of sealing an interface between first and second annular modules of a modular vessel assembly defining an internal chamber, the method comprising: providing an annular sealing device according to any one of claims 1 to 8; connecting the first annular axial end region of the biasing member in sealing engagement with the first module; and stacking the first module on top of the second module such that the biasing member applies the biasing force to the sealing shoe to bias the sealing shoe into sealing engagement with the second module and create and maintain a fluid seal between the first and second modules.

Description

Field of invention The present invention relates to a sealing device for sealing an interface between annular modules forming part of a vessel assembly having an internal chamber and in particular, although not exclusively, to a sealing device to provide a fluid seal at a chamber configured to confine a plasma suitable to support a fusion reaction. Background Fusion power is the subject of extensive research and development due to its potential to provide clean, safe and cost-efficient electricity via abundant sources of the necessary hydrogen isotope fuel (such as sea water, which contains deuterium). A fusion reactor is adapted to harvest energy released from the fusion of isotopes of hydrogen that are collided together to form heavier nuclei and release large amounts of energy in the process. The heat from such reactions may be used to generate electricity using steam turbines and the like. The fusion reaction is typically undertaken and controlled within a reactor device, such as a tokamak, that is adapted to create specifically orientated magnetic fields that confine and control the plasma within the reactor internal chamber of the high structural integrity vessel. Such vessels are designed to maintain an internal vacuum and be compatible for use with the powerful magnetic fields generated by the external confinement magnets and a central solenoid that drives circulation of the plasma within the chamber (whilst also facilitating start-up and shutdown of the plasma). These vacuum vessels are typically manufactured from panels of stainless steel that are welded together to form a unitary vessel having a toroidal shape configuration. Plasma within the fusion reaction is formed from a super-heated gas and is a collection of positively charged ions and negatively charged electrons. The plasma is an electrically conductive fluid that is responsive to electric and magnetic fields within which the fusion reaction occurs between the atomic isotopes. The walls of a plasma confining vessel are adapted to withstand significant thermal load, magnetic distortions, electromagnetic forces and energetic particle bombardment. The extreme operating conditions of confinement vessels such as those used in tokamaks, require regular maintenance to avoid operational failures. As will be appreciated, maintenance is complicated by the high radiation environment created by the deuterium/tritium fusion reaction phase of operation. Additionally, due to the unpredictable behaviour of the plasma and the fine tolerances for achieving energy efficient fusion reactions, device shutdown and reaction process restarts are to be minimised. Accordingly, there remains a need for improvements to vacuum vessels and specifically vessels suitable to confine a plasma. Summary of the invention It is an objective of the present invention to provide a modular vacuum vessel and sealing arrangement suitable for use to confine highly energetic plasma and in particular, a plasma configured as a fluid medium to enable and support a fusion reaction. It is a further specific objective to provide a vacuum vessel and sealing arrangement that may be serviced and maintained including repair and maintenance of the structural integrity of the vessel and associated sub-modules including all regions of the vessel including radially inner and radially outer wall sections. The objectives are achieved via a sealing arrangement for a modular vessel assembly according to the present concept that is configured to create and maintain a fluid-tight seal at an internal chamber of a vessel constructed from individual vessel modules being separate annular segments divided in planes aligned perpendicular to a longitudinal axis of the vessel. Such modules or segments may be stacked together axially as a unitary structure and sealed via the present sealing devices provided at the respective interfaces between the modules. Such a modular construction and fluid sealing of the modules greatly facilitates inspection, servicing, maintenance and repair of both the vessel and other functional components, assemblies, devices and mechanisms associated and forming part of a plasma confinement device such as a tokamak, stellarators and the like. Specifically, the present modules and components may be removed, repaired, serviced and/or replaced with fewer disconnection and reconnection steps relative to existing vessels. The modules of the present vessel assembly and respective sealing devices comprise a generally annular configuration to be consistent/compatible with the toroidal shaped reaction chamber. That is and preferably, the modules of the present vessel assembly have a configuration being a torus, in particular a ring torus, often referred to as a doughnut in which the chamber extends in a circumferential direction around a central core or region. The modular vessel and sealing devices are formed from annular modules/device that may be considered to comprises ring-like shape confi