A key component of one of the water outlet valves at our Healy Power Plant went missing this spring.
During break up, a big chunk of ice came down the Nenana River and ripped the operating mechanism (called the bonnet) right off the valve. The valve was stuck in a closed position.
The Healy Power Plant has two water outlet valves. Water is drawn from the river, used for cooling purposes in the power plant and returned. The process does heat the water, but it is permitted by the state and the EPA.
In general, to maximize efficiency, water is discharged through the downstream valve in the summer and the upstream valve in the winter. However, with the loss of the bonnet and the downriver outlet valve stuck in the closed position, water had to be discharged through the upstream valve.
Once the river water level subsided this summer, one of our Healy mechanics spotted the bonnet in the middle of the river. This was a lucky find, as the river could have carried it away.
Healy mechanics went to the rescue. Using an excavator and a chain, they were able to hook up to the top of the bonnet and pull it out of the river.
In late August, the mechanics reinstalled the bonnet; the valve is back in business.
Photos courtesy of Brett Baysinger.