Live-Load Valve Packing: A Proven Maintenance Reducing Technology

Abstract

One of the major problems with valves in nuclear power plants is the leakage through the stuffing box. This paper discusses Live Load Valve Packing, a proven solution to this problem. This unique technology was developed by Atomic Energy of Canada Limited (AECL) and has been successfully implemented in CANDU reactors for over fifteen years. The live-load assembly is fully described and its benefits and applications are discussed, based on AECL's extensive and valuable experience. The applicability of live-loaded stem packing to process valves in water and steam service is demonstrated and two case histories of a valve back-fit program undertaken in the U.S. jointly by AECL and NUS, are described. The performance of the retrofitted valves based on field observations is presented, showing an improvement in the valve stem seal.