Device and method for detecting leakproofness of plutone-238 simulated heat source

The invention provides a sealing performance detection device for a plutone-238 simulated heat source. The sealing performance detection device comprises a high-purity helium bottle, a pressurizing container, a vacuum bubble leakage detection container, a vacuum leakage detection container, the plutone-238 simulated heat source, a helium mass spectrometer and a vacuum exhaust table, wherein the pressurizing container, the vacuum bubble leak detection container and the vacuum leak detection container are arranged on the vacuum exhaust table in parallel; the helium mass spectrometer is used for continuously measuring the second leak rate of the plutone-238 simulated heat source when the vacuum bubble leak detection container measures the first leak rate of the plutone-238 simulated heat source, the second leak rate of the plutone-238 simulated heat source can be measured through the vacuum leak detection container and the helium mass spectrometer according to the helium mass spectrum backpressure leak detection