Development Of Nuclear Class 1 Low Leakage Ball Valve

Nuclear class 1 low leakage ball valve is one of the key equipment of pebble bed modular high-temperature gas-cooled reactor nuclear power plant(HTR-PM-500) fuel handling system, the fuel handling system between the atmosphere and core and the main equipment with mutual conversion. Main function is to realize the isolation and switching system of atmosphere, prevent radioactive gas leaking into the atmosphere during loading operation; To isolate the system with the core, to ensure the integrity of the primary circuit pressure boundary for safety; to complete connect and cut of main equipment in system, for providing security of equipment with troubleshooting, disassembly and maintenance. The valves research and development has become one of the important problems that must be solved of development process of high temperature gas cooled reactor nuclear power plants in China.This thesis aims to elaborate the research and development in detail of pebble bed modular high-temperature gas-cooled reactor nuclear power plant(HTR-PM-500) from nuclear fuel handling system low leakage ball valve.Described in detail in view of the working condition of high temperature and high pressure, low leakage, high performance,characteristics and requirements, integrated application of mechanical principle, mechanics of materials, theoretical mechanics, fluid dynamics and valve design of verification analysis more professional knowledge, study the structure of the valve design, fabrication, insopection and other specific content; to design calculation and analyze finite element for the design and performance of the products; to confirm the design of the product with the prototype test,inspection, and various evaluation test, and has passed the appraisal of the expert inside course of study. Solved valve sealing performance requirements with adopting the graphite ring with bellows seat structure, under the condition of the 260 ? high temperature and cumulative dose 107Gy; Using valve seat and valve ball hard seal structure, the valve ball's overall spray welding with whole surface grinding processing technology, effectively guarantee the valve requirements of low leakage rate and life; By controlling the passage for each component all-pass runoff junction and contacts of the axial gap and radial gap, meet the pass of nearly spherical components such as diameter, avoid dust and debris accumulation.The development of the valve is a success, to fill the domestic blank, reach the internationaladvanced level, solve the actuality of totally dependent on imports. Papers on the research has important reference value on the development of similar products.