Condenser Leaks Plague Vermont Yankee Plant
04/11/12 5:31PM By John Dillon  Download MP3
(Host) Vermont Yankee is operating at reduced power while technicians continue to trouble-shoot problems with its steam condenser.
The condenser is a key component of the nuclear plant.
As VPR's John Dillon reports, the condenser contains thousands of tubes, some of which have started to leak.
(Dillon) Picture a giant radiator as big as a house. That's the condenser at Vermont Yankee. It's designed to turn the super-heated steam that spins the plant's turbines back into water.
The problem is that over the 40-year life of the plant the thousands of narrow condenser tubes can develop small leaks.
(Hofmann) "There's just a lot of wear and tear after this many years of operation."
(Dillon) Sarah Hofmann is deputy commissioner of the Department of Public Service, the state agency that watchdogs utilities.
She says eventually Entergy Vermont Yankee will have to replace the condenser. Some estimates have put the cost at $150 million.
(Hofmann) "In the meantime I think they're just trying to keep it going as best they can to keep it keep it running without that large expense."
(Dillon) Hofmann says there are two issues with the condenser right now. First, the tubes are not working as efficiently as they should to transfer heat - most likely because of a plastic epoxy coating that was applied to contain leaks. And second, a new leak was discovered recently.
(Hofmann) "There are leaks in water-box four and that's why the plant is at lesser power now while they're trying to fix those."
(Dillon) The plant has been operating this week at about one-third power.
Ray Shadis is a technical advisor to New England Coalition, which wants Yankee shut down. Shadis points out that the condenser does not leak water into the environment. Instead, the leaks draw water from the Connecticut River into the plant.
(Shadis) "The problem is that the water, the cooling water on the outside, is not pure water and it may contain chlorides or other contaminants. If those are drawn into the reactor over time it will have an adverse effect on the condition of the reactor internal components, and most importantly on the fuel, on the jacketing on the fuel."
(Dillon) Yankee spokesman Larry Smith said the condenser leaks do not threaten public health or safety. He said the most recent incident involved additional leaks that were discovered during the initial repair job.
(Smith) "When we went in there to plug that tube that had a leak, we also found four other tubes that had a leak. We plugged those, buttoned up the waterbox and we are in power ascension to return to full power."
(Dillon) The state Department of Public Service says it will follow the repairs closely, since the condenser issues seem to be a symptom of aging plant components.
For VPR News, I'm John Dillon in Montpelier.