Cryogenic system with inert gas isolation

A cryogenic system configured to cool down at least one electrical or electronic component on-board an aircraft, the cryogenic system comprising:

• a cryogenic fluid storage tank,
• a housing,
• a thermal coupling system able to thermally connect the cryogenic fluid storage tank and the housing,
• the housing being airtight and being arranged to contain the at least one electrical or electronic component,
• an inert fluid tank configured to deliver an inert fluid, the inert fluid comprising at least one chemical element belonging to a family of inert gas or to nitrogen,
• a first opening connected to the inert fluid tank, each opening enabling a fluid to pass from inside to outside the housing,
• means configured to inject the inert fluid into the housing at a first predefined pressure value,
• a second opening connected to a relief valve configured to release gas from the housing only when a pressure inside the housing exceeds a second predefined pressure value, the second predefined pressure value being lower than the first predefined pressure value,
• a third opening connected to an exhaust line being connected to air at a third predefined pressure value, the third predefined pressure value being lower than the first predefined pressure value and equal to or lower than the second predefined pressure value,
• a shut-off valve disposed on the exhaust line,
• a composition sensor configured to detect a gas composition inside the housing, and
• a control unit comprising electronic circuitry configured to maintain the shut-off valve in an open position as long as an inert fluid proportion inside the housing is lower than a predefined proportion threshold and to close the shut-off valve when the inert fluid proportion inside the housing reaches or exceeds the predefined proportion threshold.