Lessons Learned in the Environmental Qualification of Class 1E Equipment at Tennessee Valley Authority

Tennessee Valley Authority has been engaged in an extensive program for the environmental qualification of Class 1E components. This program has been conducted in accordance with the requirements set forth in various industry standards and federal regulations, including IEEE 323-1971, IEEE 323-1974, Nuclear Regulatory Commission (NRC) IE Bulletin 79-01B, NRC NUREG-0588, and the Code of Federal Regulations 10CFR50.49. Valuable lessons have been learned as a result of this program, particularly in the area of environmental qualification testing. This paper describes some unique experiences in the qualification testing of main steam isolation valve control manifold assemblies, control relays, and motor control centers.