Vermont Yankee’s plans for power production under review

The Associated Press

BRATTLEBORO — Various options for expanding the amount of power produced by the Vermont Yankee nuclear power plant are under review.

The Windham Regional Commission and one industry expert want to know, for example, why Vermont Yankee officials aren’t considering a different cooling system to compensate for the higher temperatures that would result from the nuclear plant’s proposed 20 percent power boost.

In mid-May, consultant John W. Hubenthal reported that he found serious concerns regarding the noise, steam “drift” and higher operating temperatures involved with the plant modifications suggested by Vermont Yankee’s consulting engineer, Stone & Webster. And on Tuesday, Jim Matteau, executive director of the Windham Regional Commission, formally asked the Vermont Public Service Board if the plant owner had investigated the option of using dry cooling as a supplement to its existing cooling tower arrangement. Dry cooling uses air instead of water to cool the superheated steam inside condenser pipes after it has passed through the plant’s turbine.

Owner Entergy Nuclear Vermont Yankee’s proposal to increase the plant’s power output is currently before the board and a decision is expected in late October.

Part of Vermont Yankee’s proposed redesign to handle the higher energy load calls for replacing the current array off 22 125-horsepower cooling fans with the same number of 200-horsepower fans.

Condenser pipes, cooled by river water, convert superheated steam back to water and return it to the plant’s electricity generating turbines. In turn, the fans enhance the cooling process by speeding evaporation of the river water.

Hubenthal, former chief executive officer of the Ceramic Cooling Tower Co., was hired by the Brattleboro-based watchdog group New England Coalition to submit a report on Vermont Yankee’s cooling towers. He said the efficiency of this method of cooling can vary greatly depending on prevailing weather factors.

In Hubenthal’s study of Yankee’s proposed expansion, he maintains that the modifications could create problems with noise, excessively high water temperatures and the “drift” of steam emanating from the cooling towers.

Hubenthal’s report maintains that the water cooling system will not be able to cool the increased volume of steam in the closed-loop system sufficiently after the power modification.

“If there’s a 20 percent power increase, they’re going to have to work harder to dissipate the additional heat, either in the tower or the river,” Hubenthal said. “I don’t think they can operate the plant that way. If my analysis is correct, they’re going to miss performance.”