Abstract: The influence of thermomechanical heat treatments, aging conditions (temperature and time) on helium bubble precipitation in tritiated HR-2 stainless steel was deal with. Helium was generated by the radioactive decay of tritium (tritium trick). The concentration distribution of tritium and ³He in tritiated HR-2 stainless steel vessels was calculated based on diffusion and decay theories. The results show that concentration distribution of tritium is about 110 μL/L homogeneous in depth during the storage of tritium at the pressure of 0.131 MPa for 8 h at 780 ℃, and the concentration distribution of helium is about 60 μL/L homogeneous in depth later exposed to air for about 6 a. The bubbles can be observed in the stainless steel aged at 550 ℃/1 h. The large bubbles in grain boundaries and dislocation present aged at 950 ℃/1 h and 1 050 ℃/1 h and bubble dragging by dislocations toward the grain boundaries. The larger bubbles are about 100 nm and the smaller bubbles are about 30 nm in diameter.