Penstock evaluation using risk assessment methodologies
- PG&E, San Francisco, CA (United States); and others
The Pacific Gas & Electric Company (PG&E) owns and operates a hydro electric system that includes 72 powerhouses containing a total of 114 generating units. Half of these facilities were constructed prior to 1931. In order to optimize the integrity of the penstocks feeding these powerhouses, PG&E developed a risk assessment methodology that assesses penstock hazards and consequences to determine risks. The risk assessment program is used to manage risk by prioritizing penstocks for evaluation, determining the cost effectiveness of various inspection programs, and planning future work. The methodology requires that the engineer estimate failure rates due to hazards significant to each penstock and the probable costs associated with possible failure scenarios. The data initially input to the risk assessment program is based upon historic failure information, drawings, specifications, start-up test data, etc. After the initial analysis, areas where mitigation measures, or additional information, would provide cost effective risk reduction are identified and prioritized for future study. Results of the mitigation or studies are fed back into the analysis and the priorities are revised. The methodology allows PG&E to manage the risk associated with the operation of its water conveyance system in a manner that assures public and employee safety while meeting the needs of an increasingly competitive industry.
- OSTI ID:
- 220156
- Report Number(s):
- CONF-9507190--
- Country of Publication:
- United States
- Language:
- English
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