FirstEnergy filed a preliminary report last week with the Nuclear Regulatory Commission, identifying possible causes for the major corrosion it first reported on March 13 that it had found during a regular inspection of the pressurized water nuclear reactor head at the Davis-Besse unit in Ohio. About 40 pounds of carbon steel was found to have been eaten away, leaving 3/8 inch of stainless steel covering the reactor head at the bottom of the corrosion cavity, creating a potential safety hazard.

The NRC in the meantime has stepped up efforts to identify other potential problem reactors across the country, which has caused concern in the market that extended repair downtime for multiple reactors could affect the power supply this summer. Sixty-eight other reactors, totaling about 65,000 MW, comprising about 70% of the nation’s nuclear fleet, have similar configurations to the Davis-Besse unit, but industry sources say only about 12 reactors are deemed to be actually “susceptible” to the problem. The operators of the similar reactors are due to have plans in to the NRC by the beginning of this week as to how and when they intend to carry out inspections.

About 20,000 MW of capacity already is scheduled for refueling outages between now and June. If the rest also were to be removed from service for inspections, it would mean an additional 5 Bcf/d of natural gas would be required to replace nuclear power production, according to a report by Houston-based Simmons & Co. Even if only 8,000 MW were impacted, Simmons said, an additional 1 Bcf/d of gas-fired power would be needed.

The NRC announced Friday that its own inspection team, which has been working alongside a FirstEnergy team, will hold a meeting, open to the public, with representatives of FirstEnergy to discuss the preliminary findings on April 5. The meeting will be held in Oak Harbor, OH, and NRC staff will answer questions from the public.

The preliminary FirstEnergy report, dated March 22, which appeared and then disappeared from the NRC website, said the likely cause of the problem was “water stress corrosion cracking.” It said the condition had been building for three to four cycles or six to eight years, but could not explain how the damage had reached the extent that it did. A FirstEnergy spokesman Friday continued to say the company expected to have repairs completed and be back online by the end of June. However, the NRC has to approve the company’s repair plan before it can proceed.

Several nuclear power plant operators have revealed plans to conduct inspections for the problem during upcoming refueling and maintenance outages, and one, Progress Energy, says it already has repaired a related problem in one of its units that was not as serious.

Inspection during refueling last fall at Progress Energy’s Crystal River 3 unit in Florida did find leaking, and a crack in a connection on the reactor head, which was repaired, Progress Energy’s Skip Orser said. There was no evidence, however, of the “very much more aggressive cracking and corrosion” found at the Davis Besse plant. Progress Energy repaired the crack, removed insulation and cleaned the reactor head. It also has ordered a new one, which is currently being constructed and will be installed during the plant’s next refueling in fall 2003.

Inspection of its other similar Robinson 2 reactor unit turned up no evidence of problems at all, Orser said.

The cracking problem “has been an issue in our industry for about two years,” since it was first discovered in a Duke Energy reactor, Orser said. “The heads in certain susceptible plants have been found to have a cracking phenomenon.” Operators have been on the lookout for it and have been correcting it, and the NRC had asked inspections of “susceptible” plants be completed by the end of last year.

“We’re still very much in the process of understanding, of coming to grips with the very much more aggressive corrosion (at Davis Besse) that causes a cavity, leading to safety concerns on the part of the NRC.”

Both of California’s major nuclear generating plants, as well as others in the West, are the same pressurized-water reactor design as the Davis-Besse plant. Spokespeople for both California coastal plants said they will handle the situation through inspection and maintenance, concurrent with regularly scheduled refuelings scheduled for this spring and next winter.

The full visual inspection of the reactor heads are not expected to add to the scheduled weeks of outages for each of the nuke units, according to spokespeople for Pacific Gas and Electric Co.’s Diablo Canyon and Southern California Edison Co.’s San Onofre nuclear generating plants. Energy market participants, particularly future price setters, will be watching closely these initial refuelings of single units at each plant in late April and early May to see if they add to a tightening of pressures on supplies and prices for both wholesale power and natural gas.

“Like all pressurized-water reactor plants, we have to respond by today or Tuesday to the NRC,” said Diablo Canyon’s spokesperson, Jeff Lewis. “We had 15 days, and basically what we are going to say is that we are going to examine our reactor head on Unit I during the next refueling outage coming up at the end of April, and be able to determine if we have any problem. We don’t think we do.

“There is sort of an industry analysis of the situation (and relative assessment) for all pressurized-water reactors, and we’re not on the top of the list; we’re somewhere in the middle (among about 68 plants in the U. S.), so we don’t think there is much of a chance that we have this problem. As part of our ongoing tight maintenance we have eliminated drips and things that could contribute to the corrosion problem.

“We will examine the head thoroughly in the next refueling, and then we will examine the Unit II during the refueling next year. We don’t anticipate any problem.”

At San Onofre (SONGS) it is much the same situation, and Edison adds the perspective that any potential problem has been well identified for more than a decade since the French government changed out en masse all of the reactor heads on its extensive national fleet of government-operated nuclear plants in the early 1990s. In the case of SONGS, Edison has what it called “a pretty aggressive program” to examine the reactor system in areas where it could be vulnerable.

“This is not suddenly a new issue for the industry,” said Edison’s SONGS spokesperson Ray Golden. “What is new is the amount of corrosion that occurred on the head of the [Davis-Besse] reactor. That has never occurred before.

“Every refueling outage we do visual inspections in the areas where we can see the base metal. About 30% of the head is visible, the rest of the area is covered by insulation. It isn’t easy to see the base metal (on the other 70% of the surface), but we did commit in August last year to the NRC after more leakage occurred through the heads of several Eastern plants, that we would do a complete visual inspection of the reactor head at our next refueling. That will require removing all of the insulation material, and replacing it with a new type of insulation that will allow us to see much more on a visual basis.”

©Copyright 2002 Intelligence Press Inc. Allrights reserved. The preceding news report may not be republishedor redistributed, in whole or in part, in any form, without priorwritten consent of Intelligence Press, Inc.