Evaluation of steam generator feedwater nozzles for the effects of thermal stratification
- Southern California Edison Co., Irvine, CA (United States)
- Structural Integrity Associates, Inc., San Jose, CA (United States)
The potential for thermal stratification in the main feedwater (FW) line of a Pressurized Water Reactor (PWR) plant exists whenever the auxiliary feedwater is initiated. The thermal stratification phenomenon is attributed to the difference in density between the hotter normal feedwater, initially in the pipe, and the colder auxiliary feedwater introduced into the piping. The effect of thermal stratification on the fatigue life is two fold: the global bending due to the bowing effect caused by thermal stratification, and the local effect due to the fluctuation in the level of the hot-cold interface. This paper deals with the global and local effects of thermal stratification in the main feedwater line on the fatigue life of the steam generator feedwater nozzle. This nozzle, which is attached to the main feedwater line, is subjected to the effects of thermal stratification in the main feedwater line and in the nozzle itself due to the difference in the water density between the auxiliary feedwater and the steam generator. It should be noted that steam generator feedwater nozzle cracking has been a concern in the nuclear power industry since the late 1970`s.
- OSTI ID:
- 136769
- Report Number(s):
- CONF-950740--; ISBN 0-7918-1344-4
- Country of Publication:
- United States
- Language:
- English
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