The utility model discloses an inflation protection device for
welding a
thermocouple penetration piece of a high-temperature gas cooled
reactor pressure vessel, which comprises a protection gas tank, a protection gas main pipeline and at least two protection gas
branch pipelines, one end of the protection gas main pipeline is connected with the protection gas tank, and the protection gas
branch pipelines are respectively communicated with the protection gas main pipeline. The protective gas
branch pipeline is provided with a switch valve, one end, far away from the protective gas main pipeline, of the protective gas branch pipeline enters a
nozzle of the high-temperature gas cooled
reactor pressure vessel, the
thermocouple penetration piece and the
nozzle are sleeved and welded together, and the switch valve is located outside the high-temperature gas cooled
reactor pressure vessel. All
shielding gas branch pipelines required by a certain stage can be arranged in the
pipe nozzle of the high-temperature gas cooled reactor
pressure vessel in advance, and the on-off of the
shielding gas is controlled outside the high-temperature gas cooled reactor
pressure vessel, so that the suffocation risk caused by personnel entering the high-temperature gas cooled reactor
pressure vessel with the
shielding gas can be avoided, the personal safety is ensured, and the working efficiency is improved. Operation is convenient, and construction efficiency is improved.