Autonomous Cryogenic Two-Stage In-Loop Sealing of Microdefects Using Circulating Nanocapsulated Agents (ACTIS)

Operation of large-scale cryogenic installations—particle accelerators, fusion reactors, space propulsion stages and quantum systems—demands continuous maintenance of leak-tightness in coolant and liquefied-gas circulation loops. Conventional methods for locating and repairing microleaks through intergranular pores of structural materials and microcracks in welded joints require complete shutdown of equipment, prolonged thermal recovery of isolated sectors and external mechanical intervention. This publication presents a method of Autonomous Cryogenic Two-Stage In-Loop Sealing (ACTIS) in which the working cryogenic fluid itself serves as the carrier medium for functional nanocapsules. The ACTIS method relies on thermodynamic, mechanical, and electro-inductive triggers operating in a dual-stage sequence. Upon entering a microdefect, the vitrified nanocapsules undergo localized geometric confinement and steric jamming driven by hydrodynamic pressure. This forms a temporary solid-state restriction that anchors the agent within the fissure, enabling subsequent thermal activation and polymerisation without cycle interruption. Order-of-magnitude estimates, drawn from scaling considerations and available literature data, indicate that a typical sub-micron to micron-scale defect (width 0.1–10 µm, length 10–100 µm) requires a sealing-agent volume of 10⁻¹⁵–10⁻¹² L. At capsule concentrations not exceeding 0.05 wt% and volume fractions φ ≈ 10⁻⁴–10⁻³, filling is expected to be achieved within the flow transit time (milliseconds to seconds) by means of a hybrid mechanism. The influence of the particles on the properties of superfluid helium-II at these concentrations is assessed as negligible on the basis of existing dispersion studies, though this remains subject to direct experimental verification. A differentiation matrix of technological solutions is proposed, separating the architecture of agents and auxiliary equipment into two independent categories: direct integration into existing systems without modification of their geometry, and incorporation into newly designed installations. The document records the conceptual architecture, protective mechanisms, agent modifications, order-of-magnitude quantitative estimates and the invention formula at the stage of scientific exploration and invention—prior to prototyping and laboratory experiments. The publication establishes worldwide priority (prior art).