Plant-Unique Procedures Applied to Mitigate Wall Thinning of PWR Feed Water Piping due to Flow Accelerated Corrosion
Wall thinning rate due to flow accelerated corrosion (FAC) is determined by material, flow dynamics and water chemistry parameters, and their combinations. Modification of water chemistry parameters is one of the hopeful countermeasures to mitigate wall thinning rate without expensive material exchange procedures and complicated structural modification for flow pattern improvement. However it is effective for the target materials, it often results in serious adverse effects on some other structural materials. The effects of water chemistry improvement on corrosion mitigation of feed water piping and its adverse effects were evaluated by applying the FAC evaluation methods based on the coupled FAC model of static electrochemical analysis and dynamic oxide layer growth analysis. As a result of evaluation of wall thinning rates for PWR plants with different materials systems, plant unique countermeasures for FAC mitigation were proposed. Major conclusions are as follows: (1) Higher pH control is effective for PWR plants without copper heater tubing, and (2) Oxygen injection into the feed water is recommended for those with copper tubing and oxygen concentration at the inlet of a Steam Generator (SG) should be monitored with high temperature water chemistry sensors, e.g., Electrochemical Corrosion Potential (ECP) sensors, to prevent oxygen intrusion into the SG.
Flow accelerated corrosion Wall thinning Water chemistry control Electrochemistry Plant reliability
Masanori Naitoh Shunsuke Uchida Hidetoshi Okada Seiichi Koshizuka
The Institute of Applied Energy Shinbashi SY Bldg., 8F, 1-14-2 Nishi-shinbashi, Minato-ku, Tokyo 105 Graduate School of Engineering, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japa
国际会议
上海
英文
301-312
2010-10-10（万方平台首次上网日期，不代表论文的发表时间）