Tag Archives: Power

Coal plant to remain shut for months

The first of two new coal-fired power plants that We Energies opened in Oak Creek (Milwaukee) in recent years will be out of service for several months after an inspection revealed a problem that could lead to turbine corrosion over the long term.

The problem was detected after the plant was taken offline for inspections and maintenance. The plant remains under warranty to the contractor that built it, Bechtel Power Corp.

Utility spokesman Brian Manthey said deposits were found on blades of the coal plant’s steam turbine. Most of the blades that have deposits are being cleaned but some need to be replaced, a process that will take months.

“It’s likely that we will have it back in the spring,” he said.

The second plant, which opened this year, remains in operation, as does the original Oak Creek coal plant, built in the 1950s and 1960s.

The cause of the problem remains under investigation. The problem did not affect operations of the plant, which was online and operating well during the summer heat wave when demand for power was high, he said.

“It’s a precautionary step so that we prevent any long-term damage,” Manthey said.

The utility hasn’t seen any problems of this type on the second coal plant, which opened early this year. The deposits were found as part of an extensive review of the power plant because the plant was nearing the end of its two-year warranty, he said.

“We’ll do the same planned maintenance and inspection toward the end of the warranty period for that unit as well,” Manthey said. “We don’t have any indication that this is happening there.”

As a matter of routine, utilities take plants out of service in the fall to inspect for problems and conduct repairs. This inspection was extensive because the plant is still under warranty and was nearing the February end of the warranty period, Manthey said.

“You want to take care of these thingsnow while it’s still under warraanty,” he said.

The fact that it is still under warranty means that Bechtel or other contractors may have to foot the bill for the problem rather than We Energies and its customers. But that will depend on the investigation into the cause.

“But this is the time to do that, to determine what you’ve got and to see what repairs need to be made and who’s responsible for it,” he said.

The plant experienced some unrelated problems last year during its full first year in operation. Those problems were in a different part of the plant, the boiler feed pump, and have been resolved.

The Oak Creek project was the most expensive construction project in state history, with a total cost of $2.35 billion. We Energies is the primary owner of the plant, along with Madison Gas & Electric Co. of Madison and WPPI Energy of Sun Prairie.

The plants were built to meet demand for rising demand for electricity after Wisconsin experienced power supply problems in the late 1990s.

Construction costs for the project came in higher than the amount approved by the state Public Service Commission, and a proceeding next year concerning We Energies power rates will wrestle with how much of the higher costs should be paid by utility customers.

SOURCE: http://www.jsonline.com/blogs/business/135459568.html

Coal scrubbers are corroding

Ohio pollution controls are showing wear after as little as a year.

Coal-fired power plants across the country are being checked for corrosion problems on billions of dollars’ worth of equipment that is supposed to cut air pollution. And the results from three power companies in Ohio show that the  scrubbers are corroding at a much faster rate than was expected.

Coal scrubbers – some 15 stories tall — spray a slurry of water and limestone into coal flumes to capture most of the pollutants before they’re released into the air. The scrubbers cost up to $500 million, and are supposed to last 25 years.

But Akron-based FirstEnergy discovered corrosion in three new scrubbers at its plant along the Ohio River. None of is older than a year.  American Electric Power also found corrosion at four plants in Ohio and West Virginia. And Duke Energy found it at its Southwest Ohio plant.

A national inquiry is now underway by The Electric Power Research Institute.

John Shingledecker is the senior project manager for the institute. He says he’s seen corrosion in as little as 11 months, and in wide variety of scrubbers.

“There was some initial thought that there was only one particular alloy that was being affected,” he said.

“But there are now different types of alloys, some that have been used in the past as well. And we’ve seen it in multiple designs and multiple manufacturers.”

Shingledecker says figuring out the cause of the corrosion could  take two years, and  in the meantime coal-fired power plants can use protective coatings or clay tiles to try to stop the corrosion.

But American Electric Power spokesman Pat Hemlepp says his company’s scrubbers are operating safely.

”We are working with the industry to address what happening. As far as an environmental standpoint, the equipment does what it’s supposed to do,” he said. “The equipment is taken down for maintenance routinely just like the plants are. And we’re doing whatever is necessary during those maintenance periods to take care of the corrosion issue. It’s not a safety issue, it’s not a health issue.”

Hemlepp says the cost of maintaining the scrubbers has already been calculated into customer bills.

The Columbus Dispatch reported this week that AEP negotiated a confidential settlement with, a contractor on the scrubbers to address corrosion at its central Ohio plants.

SOURCE: http://www.wksu.org/news/story/28895

75 percent of US nuclear sites have corrosion issues — leaking tritium

BRACEVILLE, Ill. (AP) – Radioactive tritium has leaked from three-quarters of U.S. commercial nuclear power sites, often into groundwater from corroded, buried piping, an Associated Press investigation shows.

The number and severity of the leaks has been escalating, even as federal regulators extend the licenses of more and more reactors across the nation.

Tritium, which is a radioactive form of hydrogen, has leaked from at least 48 of 65 sites, according to U.S. Nuclear Regulatory Commission records reviewed as part of the AP’s yearlong examination of safety issues at aging nuclear power plants. Leaks from at least 37 of those facilities contained concentrations exceeding the federal drinking water standard – sometimes at hundreds of times the limit.

While most leaks have been found within plant boundaries, some have migrated offsite. But none is known to have reached public water supplies.

At three sites – two in Illinois and one in Minnesota – leaks have contaminated drinking wells of nearby homes, the records show, but not at levels violating the drinking water standard. At a fourth site, in New Jersey, tritium has leaked into an aquifer and a discharge canal feeding picturesque Barnegat Bay off the Atlantic Ocean.

Any exposure to radioactivity, no matter how slight, boosts cancer risk, according to the National Academy of Sciences. Federal regulators set a limit for how much tritium is allowed in drinking water, where this contaminant poses its main health risk. The U.S. Environmental Protection Agency says tritium should measure no more than 20,000 picocuries per liter in drinking water. The agency estimates seven of 200,000 people who drink such water for decades would develop cancer.

The tritium leaks also have spurred doubts among independent engineers about the reliability of emergency safety systems at the 104 nuclear reactors situated on the 65 sites. That’s partly because some of the leaky underground pipes carry water meant to cool a reactor in an emergency shutdown and to prevent a meltdown. Fast moving, tritium can indicate the presence of more powerful radioactive isotopes, like cesium-137 and strontium-90.

So far, federal and industry officials say, the tritium leaks pose no health or safety threat. Tony Pietrangelo, chief nuclear officer of the industry’s Nuclear Energy Institute, said impacts are “next to zero.”

EAST COAST ISSUES

One of the highest known tritium readings was discovered in 2002 at the Salem nuclear plant in Lower Alloways Creek Township, N.J. Tritium leaks from the spent fuel pool contaminated groundwater under the facility – located on an island in Delaware Bay – at a concentration of 15 million picocuries per liter. That’s 750 times the EPA drinking water limit. According to NRC records, the tritium readings last year still exceeded EPA drinking water standards.

And tritium found separately in an onsite storm drain system measured 1 million picocuries per liter in April 2010.

Also last year, the operator, PSEG Nuclear, discovered 680 feet of corroded, buried pipe that is supposed to carry cooling water to Salem Unit 1 in an accident, according to an NRC report. Some had worn down to a quarter of its minimum required thickness, though no leaks were found. The piping was dug up and replaced.

The operator had not visually inspected the piping – the surest way to find corrosion- since the reactor went on line in 1977, according to the NRC. PSEG Nuclear was found to be in violation of NRC rules because it hadn’t even tested the piping since 1988.

Last year, the Vermont Senate was so troubled by tritium leaks as high as 2.5 million picocuries per liter at the Vermont Yankee reactor in southern Vermont (125 times the EPA drinking-water standard) that it voted to block relicensing – a power that the Legislature holds in that state.

In March, the NRC granted the plant a 20-year license extension, despite the state opposition. Weeks ago, operator Entergy sued Vermont in federal court, challenging its authority to force the plant to close.

At 41-year-old Oyster Creek in southern New Jersey, the country’s oldest operating reactor, the latest tritium troubles started in April 2009, a week after it was relicensed for 20 more years. That’s when plant workers discovered tritium by chance in about 3,000 gallons of water that had leaked into a concrete vault housing electrical lines.

Since then, workers have found leaking tritium three more times at concentrations up to 10.8 million picocuries per liter – 540 times the EPA’s drinking water limit – according to the New Jersey Department of Environmental Protection. None has been directly measured in drinking water, but it has been found in an aquifer and in a canal discharging into nearby Barnegat Bay, a popular spot for swimming, boating and fishing.

SOURCE: http://gazettenet.com/2011/06/17/75-percent-of-nuke-sites-have-leaked-tritium