Tuesday, November 22, 2011

Concrete cracks up costs of restart at two reactors

Progress Crystal River and First Energy Davis-Besse have very different problems, but similar concerns about restart

The concrete containment structure that surrounds a nuclear reactor is the last line of defense against release of radiation if there is an accident with the equipment. Examples include coolant leaks, steam problems, and pump failures. In a worst case scenario, such as Three Mile Island, the containment building kept radioactive material inside the concrete shell. The NRC keeps a close eye on the status of containment buildings at all of the nations nuclear reactors which is why cracks in the thick concrete walls get extra scrutiny.

Recently, two reactors with very different cracking problems have been in the news. While there are differences in the severity of the problems, public responses and even alarms, have been remarkably similar. In Florida, critics of efforts by Progress Energy to repair broken panels at one of its reactors have said the best choice is to decommission the reactor.

In Florida, Progress (NYSE:PGN) CEO Vincent Dolan sent a long letter in response to state legislators and the media complaining about "unsubstantiated claims" being made about the utility's plan to repair the damage. Also, he responded to critics who took the utility for task for what the St. Petersburg Times called a "do it yourself" approach to replacing the steam generators.

In Ohio, U.S. Rep. Dennis Kucinich wrote to the NRC claiming First Energy (NYSE:FE) was not telling the whole story about cracks found in its containment structure. First Energy denies that it had hidden anything from the NRC.

The path forward at the two reactor sites is very different regardless of what critics say. Progress is looking at several years of work while Davis-Besse told its investors in a letter it expects to restart the reactor by the end of the month.

This is a complex technical issue and much of the detail about is is outside the scope of a blog to explain everything. This post is a summary of some of the major moving pieces.

Progress seeks progress on repairing concrete

Concrete damage at Crystal River.
Photo: Progress Energy
The replacement of steam generators at Progress Energy's 865MW Crystal River plant 80 miles north of Tampa on the west coast of Florida required the utility to cut through the walls of the containment building. In the process it found crumbling concrete in the areas around a 25 foot square hole it created to replace the equipment.

The containment building is composed of six 42-inch thick panels. Three of them have problems. Progress proposes to replace all six panels. The costs, including replacement power while the reactor is out of service, are rising rapidly raising questions at the Florida Public Service Commission about how much should be passed on to rate payers. Progress wants its 1.6 million Florida customers to pay $670 million of the repair costs. Some of the repair costs, and cost of replacement power, are covered by insurance.

At the same time, Progress is on track to merge with Duke Energy (NYSE:DUK) by the end of the year. While neither firm has commented in public about the potential for the costs, which could be as much as $2.5 billion, to derail the merger, that hasn't stopped the media and elected officials from raising the question whether it would be cheaper to simply shut down the plant.

The St. Petersburg Times reported in November that Progress decided not to use expert contractors skilled in steam generator replacement. Instead, the utility decided to do the work in-house. That led critics to charge the utility was engaged in a "do it yourself" project.

However,. Progress asserted that the problems with "concrete delamination," the technical term for the issue, could not have been predicted by anyone. Critics claim the work of cutting through the containment wall created safety issues. The NRC says not so. In a March 2011 briefing the NRC's engineers found:
  • Delamination was caused during creation of opening in containment.
  • Main cause of delamination was scope and sequence of tendon detensioning, resulting in redistribution of stresses that exceeded concrete tensile capacity.
  • Special Inspection Team (SIT) reviewed licensee’s root cause assessment
  • SIT found that delamination did not represent increase in risk to public.
  • SIT found licensee’s investigation to be thorough and did not identify immediate generic safety concerns associated with the delamination.

Meanwhile, in a June 2011 letter the NRC notified Progress that it will modify the schedule for relicensing once the utility has provided information on its repair plan. The utility will have to prove to the NRC its repairs to the containment building meet the agency's safety requirements before it restarts the relicensing process. For its part, Progress says the repairs, and restart, could take until 2014. During this time it will be buying replacement power, including some from its own coal fired power plants in Florida.

CEO Dolan wrote in his letter to the state legislature , , , "While some would have you believe that we took an inappropriate approach to this work, nothing could be further from the truth," Dolan stated in the Nov. 16 letter. "Outside experts have been engaged since day one. … We have been prudent in our actions and decision making."

Davis-Besse buttons up

Davis-Besse Plant Photo: NRC
In Ohio the planned replacement of a reactor pressure lid at First Energy's Davis-Besse 913 MW plant has been completed and the 25 x 36 foot hole in the containment building closed up. During the procedure, the utility found some hairline cracks in what it called "non-safety, non-load bearing" elements of the building.

In a letter to investors, Ronald E. Seeholzer, vice president for investor relations at FirstEnergy, told investors the subsurface hairline cracks were found in most of the building's architectural elements.

"The Shield Building is a two-and-a-half foot-thick reinforced concrete structure that provides protection from natural phenomena including wind and tornados. This building surrounds the one-and-a-half-inch carbon steel containment vessel.

The architectural elements of the Shield Building protrude up to 18 inches from the main portion of the building. During investigation of the crack at the Shield Building opening, concrete samples and electronic testing found similar sub-surface hairline cracks in most of the building’s architectural elements.

The team of industry-recognized structural concrete experts and Davis-Besse engineers evaluating this condition has determined the cracking does not affect the facility’s structural integrity or safety.

Our investigation also identified other indications. Included among them were sub-surface hairline cracks in two localized areas of the Shield Building similar to those found in the architectural elements.


We have determined these two areas are not associated with the architectural element cracking and are investigating them as a separate issue. Our overall investigation and analysis continues. We currently expect Davis-Besse to return to service around the end of November."

Viktoria Mityling, a spokeswoman for the U.S. Nuclear Regulatory Agency. told the news media in Ohio the agency has not said the reactor cannot restart, but she also declined to confirm a date when it would get back into revenue service.

FirstEnergy spokeswoman Jennifer Young said she could not discuss a reopening date for the plant. She confirmed that a late November date is still a target. Like Progress, First Energy is buying replacement power from fossil plants until Davis-Besse can return to revenue service.

"We did find some very tight, hairline, subsurface cracks," she said. "They don't go through the building."

Young said the cracks are several inches beyond the surface. Even so, she said, the building is still considered safe for its intended purpose.

This is the area where Congressman Kucinich enters the picture with a his letter to the NRC. While the plant is not in his Congressional district now, it may be for the 2012 election if redistricting as planned in Ohio goes through. It appears, cracks or not, that Kucinich is already playing to public fears about nuclear energy ahead of them being in his district. Kucinich has been a frequent critic of the Davis-Besse plant in the past so his latest letter is part of a consistent pattern.

Nuclear plant life extension

Technical resolution of the concrete problems in Florida and Ohio are part of a much larger problems which is how long a nuclear reactor can be in service. The original licenses for the nation's nuclear plants were set to 40 years. The NRC has relicensed more than half the nation's fleet of reactors for another 20 years including two of the oldest reactors - Oyster Creek in New Jersey and Vermont Yankee in Vermont.

Both Crystal River and Davis-Besse are in the midst of their relicensing processes. It will bear watching to see how the NRC deals with the cracks in the containment structures at both reactors not only in terms of restarts, but also in terms of relicensing.

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1 comment:

Jack Keeling said...

Both these plants have B&W reactors. My experience from Rancho Seco is that small utilities without deep pockets built plants with B&W reactors, usually one-unit plants. After plant completion these utilities skimped on training and maintenance. We heard stories from Rancho Seco until it was closed. We continue to hear stories from Davis Besse and Crystal River, including this narrative. Even though the small, shallow-pocket utilities have merged, the attitude at the plants continue, and will until they, like Rancho Seco, are shut down.

B&W plants can be run safely. Duke Energy and Entergy have shown this to be the case.