[en] Containment leaktightness is verified periodically through pressure tests and the measurement of the subsequent leakage. The verification process is composed of three types of test: Type A tests of the entire containment system; Type B tests of all containment penetrations, except isolation valves; and Type C tests of isolation valves. These tests are conducted in accordance with Appendix J of the Code of Federal Regulations and an industry standard, ANSI/ANS-56.8-1981. Revision of Appendix J, to reflect technological advances and testing experience, has been under consideration for years and has culminated in the issuance of a draft process, a review of the existing and proposed guidelines in light of utility test data and experience was conducted. A review of 49 Type A test reports and 46 Type B and C test reports was accomplished. Exemption requests found in 25 reports and 100 Licensee Event Reports (LERs) were also reviewed. Two major findings of the data analysis were that Type A test durations of less than 24 h are practical and that almost all Type A test failures and delays were caused by excessive leakage through Type B- and C-tested components. The proposed revision to Appendix J appears to be very responsive to the results of test experience and technological changes