DEVELOPMENT OF ENERTECH'S ADVANCED NORMALLY OPEN NOZZLECHECK VALVES FOR GENERATION Ⅲ+ NUCLEAR POWER PLANTS

摘要

Ehertech introduced the first Normally Open NozdeCheck valves to the nuclear power industry nearly 20 years ago. This passive valve design was developed to address reoccurring maintenance and reliability issues often experienced by various check valve types due to low or turbulent flow conditions. Specifically, premature wear on the hinge pins, bushings and severe seat impact damage had been discovered in several applications while the systems were in steady state operating conditions. Over the last two decades, Enertech has continued to improve upon the design of the valve, with the culmination coming most recently in support of Generation Ⅲ+ passive reactor requirements. This entirely new valve is designed with minimal stroke, ensuring quick closure under low reverse flow conditions which no other check valve design could support. Additionally, features such as first in kind test ports, visual inspection points, and the ability to manually stroke the valve in line have resolved many of the short comings of previous inline welded flow check valves. Most importantly, advanced test based methodologies and models developed by Enertech, allow for accurate prediction of NozdeCheck valve performance. This paper presents the development of Enertech's advanced Normally Open NozzleCheck Valve for Generation Ⅲ and Ⅲ+ nuclear reactor designs. The Valve performance was initially determined by using verified and validated computational fluid dynamic (CFD) methods. The results obtained from the CFD model were then compared to the data gathered from a prototype valve that was built and tested to confirm the performance predictions. Enertech has fully tested and qualified the Normally Open NozzleCheck valve which is specifically designed for applications that require a high capacity in the forward flow direction and a quickclosure during low reverse flow condition with short stroke to minimize the hydraulic impact on the system.