Performance of containment of Indian PHWR

This paper summarizes the various requirements and activities relevant to the testing of containment system of Indian Pressurized Heavy Water Reactor (PHWR). All Indian PHWR containments are constructed from concrete either reinforced or prestressed or a combination of both and lined with polymeric coating based on Epoxy or Vinyl in order to achieve the leak tightness necessary from the radiological considerations following an accident. The current concept includes a complete double containment (except the base raft) extended to all penetrations and some of the pipings (those open to the containment atmosphere). The primary containment fitted with a passive pressure suppression system is enveloped in the secondary containment (confinement) where slight vacuum is maintained during normal operation as well as post accident condition. The Integrated leakage Rate Test (ILRT) conducted so far on the containment indicate that the overall leakages from the containment are lower than those necessary to meet the radiological limits following a postulated accident and interception of leakages by secondary containment as per design. The details of the, tests, repairs carried out and observations are given in this paper. The experience of ILRT also indicate improvement in leak tightness in many areas. (author)