The Tritium Process Laboratory (TPL) at the Japan Atomic Energy Research Institute (JAERI) has been operated with tritium for the R&D activity of the fusion fuel cycle since March 1988. The maximum amount of tritium which was permitted in TPL is 6 × 105 Ci. The concept of triple confinement is applied to the safety system of TPL and their detritiation systems based on the catalytic oxidation-molecular sieve adsorption process. The average tritium release to the environment is 15 mCi/month since TPL has been under operation with tritium, which is 1/200 smaller than the regulation value. The safe operation of TPL has been giving useful information on the operation and improvement for fusion safety systems. This paper presents the operation and improvement experience on the safety system at TPL with accumulated failure data.