Life assessment of superheater/reheater tubes in fossil boilers

Conference · Tue Aug 01 04:00:00 EDT 1995

OSTI ID:79834

Viswanathan, R; Gehl, S ^[1]; Paterson, S R ^[2]; Grunloh, H ^[3]

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1. Electric Power Research inst., Palo Alto, CA (United States)
2. Aptech Engineering Services, Sunnyvale, CA (United States)
3. General Atomics, San Diego, CA (United States)

Creep rupture failure of superheater(SH)/-reheater(RH) tubes is a major cause of forced outages of power boilers. A methodology developed recently by EPRI researchers has helped utilities make more informed run/replace decisions for tubes by judiciously combining calculational, nondestructive and destructive evaluations. In this methodology, the tubes/tube assemblies at risk are identified by ultrasonically measuring the thickest steamside oxide scale and thinnest wall thickness in the tubes. The remaining life of each tube/tube assemblies is predicted using a computer code known as TUBELIFE, thus achieving a further level of focus on the tubes/assemblies in the highest risk category. Sacrificial tube samples are then removed from the select locations and subjected to laboratory metallurgical evaluation and isostress rupture testing to refine the remaining life estimates. Research has further refined this methodology by validating the ultrasonic technique for scale measurement, identifying the appropriate stress formula and oxide growth laws and evaluating the limitations of creep damage summation rules and isostress rupture test procedures. This paper provides an overview of the research in the field, and establish a road map for assessing the remaining life of SH/RH tubes.

• OSTI ID: 79834
• Report Number(s): CONF-950414--
• Country of Publication: United States
• Language: English

Related Subjects

20 FOSSIL-FUELED POWER PLANTS
CREEP
FORECASTING
FOSSIL-FUEL POWER PLANTS
RUPTURES
SERVICE LIFE
STEAM GENERATORS
T CODES
TUBES