Corrosion fatigue in supercritical waterwalls
- Pacific Gas and Electric Co., Moss Landing, CA (United States). Moss Landing Power Plant
Of the twenty-two boiler tube failure mechanisms, a detailed description and root cause of corrosion fatigue has only recently been understood in depth. Without an understanding of the root cause, it was difficult to develop preventative programs. After the Moss Landing Power Plant suffered several shutdowns of both of its 750 MW supercritical units within one month, it was necessary to tackle this failure mechanism and proactively position the plant to maintain reliability while minimizing factors that would aggravate the failure prone areas until large scale tube replacement could occur. Strengthening programs to reduce corrosion and reduce thermal stress became the two pronged approach to reduce failures due to corrosion fatigue. To repair areas already damaged, an extensive radiographic analysis was performed to determine how large an area was effected. Eventually forty one vertical feet of front and rear waterwall tubing that evidenced cracking was replaced and operating procedures for unit shut down were modified to reduce thermal stress.
- OSTI ID:
- 70130
- Report Number(s):
- CONF-940222--
- Country of Publication:
- United States
- Language:
- English
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