NGS decommissioning resumes after four-month suspension
PAGE, Ariz. – After a nearly four-month suspension, the Navajo Generating Station decommissioning project resumed in mid-July with the demolition of the Unit 3 Absorber Pumphouse and the 10-story-high Limestone Prep Conveyor.
Independence Excavating of Independence, Ohio, the contractor in charge of the huge NGS demolition job, calculated how to bring the conveyor down through an engineering analysis. That told the work crew what cable size was needed, where to place them at the foot of the conveyor, and how the conveyor would fall. Once the cables were connected from an excavator, with a tug the long, ramped conveyor leading to the Limestone Prep Building fell to the ground on target within seconds.
Prior to halting decommissioning because of Covid-19, the first structure Independence brought down was the Limestone Handling Building on the south side of the NGS plant site.
Last week, Independence finished demolition of the NGS Absorber Maintenance Holding Tanks. Like the Limestone Handling Building, Limestone Conveyor and Limestone Prep Building, these were part of the sulfur dioxide scrubber equipment. Limestone was crushed to a power and mixed with water. The limestone slurry was then sprayed through flue gas to remove more than 95 percent of SO2 from emissions.
Before NGS stopped making electricity Nov. 18, 2019, work began to dismantle and remove the enormous transformers along the west side of the power block. These sent NGS’s electricity to the switchyard and from there to the grid. This week, the remaining Unit 1 transformers will be removed and shipped to salvage.
Meanwhile, SRP Investment Recovery is in the process of selling and shipping NGS tools, supplies and scrap. In coming weeks, the colossal rows of tall, heavy shelving in the cavernous NGS warehouse will be dismantled, packed and shipped to its new owner.
Environmental work by Clean Harbors, Inc., of Norwell, Mass., continues with asbestos abatement and fluids removal.
Decommissioning is now ramping up following the COVID-19 suspension of work. Within a week or two, an estimated 100 more workers are expected to arrive.
All contractors receive a full safety orientation that now includes COVID-19 protection protocols. In addition to wearing personal protection equipment such as a hardhat, safety glasses and a reflective safety vest everywhere on site, requirements now include wearing a face mask, maintaining six feet of space between individuals, no more than two individuals in a vehicle and frequent hand washing whenever workers are on site.
SRP is a community-based, not-for-profit public power utility and the largest provider of electricity in the greater Phoenix metropolitan area, serving more than 1 million customers. SRP is also the metropolitan area’s largest supplier of water, delivering about 800,000 acre-feet annually to municipal, urban and agricultural water users.