Humboldt Bay Nuclear Plant Decommissioning

Nuclear power plant ventilation stack removal. Due to seismic concerns, PG&E needed to surgically remove a 250′ tall ventilation stack located directly adjacent to the spent fuel storage area.


Humboldt County, CA


Pacific Gas and Electric Company


Burns & Roe Enterprises, Inc.


Bluegrass was contracted to cut the stack into ring sections weighing approximately 7,000 lbs. each. Poor soil load conditions dictated the crane be located a significant distance from the structure, and the extended reach limited the maximum lift weight. Our saws and technicians were operating on an elevated platform where the major challenges were water control and wind.


To address the issue of contaminated water, Bluegrass designed and built a containment box on site where the cutting water was collected and reused for the duration of the job. By definition, the wind was an environmental variable we had to work with. The technicians coped by operating at maximum efficiency to make a cut or drill rigging holes during intervals when the wind dropped below 15 mph, the point at which all elevated work was stopped.

The vent stack ring sections were removed to a metal Kelly building where Bluegrass diamond wire saws segmented them lengthwise for packaging and eventual disposal. The job was completed on schedule with no safety incidents.

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