Secret Study Suggests Nuclear Plant Fiascoes Likely
By Stephen Koff
Equipment breakdowns at nuclear power plants are not unusual. Pipes crack, break or clog, springing leaks with some regularity. Pumps stall or freeze up. Steam generator tubes burst. Steel components can get brittle from being bombarded with radioactivity. Nuclear-industry officials acknowledge as much.
But the problem is getting worse as the nations inventory of nuclear reactors gets older. In addition, the nuclear-power industry is facing increasing competition as the result of deregulation, making it more reluctant to seek out problems that would require the tremendous expense of repair shutdowns. At the same time, the Nuclear Regulatory Commission is facing budget squeezes that make it more difficult to monitor the industry.
The result is growing concern about expensive, potentially dangerous nuclear-plant failures.
Given plant aging and materials issues, cracks and leaks like those that led to the Davis-Besse fiasco, where leaking boric acid ate a hole in the reactor lid, are likely to recur, says a confidential analysis by the influential Institute of Nuclear Power Operations.
Similarly, a research report compiled last year by engineers at several laboratories affiliated with the Nuclear Regulatory Commission warned that the number of occurrences of age-related degradation has been increasing as nuclear power plants age.
Fewer being tested
Aging equipment, whether in a nuclear plant or an automobile, can, of course, be repaired or replaced.
But as many nuclear power plants approach the final 10 years of their 40-year operating licenses, they are undergoing fewer safety tests and inspections, according to engineers with close ties to the nuclear industry. That raises the likelihood that cracks and corrosion will not be caught in time, they say.
The combination of the two trendsfewer inspections and aging componentssets the stage for compounding problems.
The utilities are trying to squeeze down their operation and maintenance costs, says Harold Ornstein, who until 2000 was a senior engineer and technical adviser for the NRC, where his investigations included Three Mile Island. He says utilities are pushing their staffs to keep the plants runningat the expense of finding equipment problems that might require a shutdown.
The idea is to pass the [inspection] test. The idea is not to go out and tell you what the problem is, Ornstein said.
The Institute of Nuclear Power Operations, the industrys own research group, acknowledges the profit pressures. If a plant shuts down its reactor to inspect a potential problem, it has to purchase replacement power. The costs often run into hundreds of thousands of dollars a day.
Pressure on staffs to keep a plant operating was a factor in all but one significant reactor problem since 1993, according to the confidential institute report.
Therefore, given todays competitive environment, pressure to continue operating may be a notable contributor to future significant events, the report said. The institutes analyses are considered among the most credible in the industry, and insurers use them to set rates.
Move on to cut costs
Theres a big move on to reduce costs, to take tests that were once done monthly and now make them quarterly, and things that used to be done quarterly are now done yearly, and so on, says David Lochbaum, a nuclear safety engineer with the Union of Concerned Scientists.
Aging equipment, coupled with fewer safety checks and inspections, makes it more likely that something will break or fail or be degraded below the prescribed safety margins, and not be detected before it is challenged.
That means that when its needed, a safety system could fail.
Though the Davis-Besse incident was considered extreme, nuclear power plants in South Carolina, Virginia, Arkansas, Florida and Michigan have seen signs of similar stress cracks or leaks in nozzles or welds, according to incident reports filed with the NRC.
In other recent signs of aging:
Last December, a backup pump thats designed to send water to steam generators at the Callaway Nuclear Plant in Missouri failed to do its job. A piece of foam from a storage tank seal had weakened with age and broken loose, lodging in the pumps intake valve during a routine test, NRC reports show. Had the other backup pumps been turned on, they too could have ingested loose foam and become clogged, presenting a potential cooling problem if the main systems failed. As had happened at Davis-Besse, the plant had ignored industry warnings and deferred inspections, according to an NRC review.
The previous year, inspectors found cracks, one of them 4 inches long, in the weld of a giant coolant pipe at the V.C. Summer Nuclear Station in South Carolina, where boric acid had been leaking for an undetermined time. Workers failed to find the cracks during a previous inspection, discovering them only when the plant shut down for refueling. Had the cracks burst, a massive amount of radioactive coolant could have escaped.
And last January, a jet pump inside the reactor vessel broke at the Quad Cities Nuclear Power Station in Illinois, requiring a shutdown. Jet pumps increase the flow of water through the reactor core. Although the manufacturer had recommended replacing the jet pumps in the 1980s, Quad Cities never did. Nor had the plant inspected the part that brokebecause a manufacturers guide did not identify it as among the components that could weaken with age.
In other words, the plants owner was inspecting the jet pumps in what it thought were the most vulnerable areas, but they were wrong, UCS Lochbaum said.
Even defenders agree
Even the staunchest defenders of nuclear power acknowledge that parts and systems are vulnerable to the ravages of time.
In fact, more than 30 percent of nuclear power plant equipment failures in recent years were at least partly a result of the equipment having aged, according to a presentation at a conference in 2000 by Steve Nichols, a senior evaluator in the Institute of Nuclear Power Operations engineering department. Nichols said he could not comment, citing institute policy.
Researchers working in concert with the government have quietly voiced concerns for nearly a decade about the consequences of plant aging.
Effects of aging degradations, if they are not mitigated, will eventually lead to failures that could adversely affect plant safety and performance, said a 1993 study by the Oak Ridge National Laboratory, one of the research institutions that works with the NRC.
Yet, so far, the safety and backup systems at nuclear power plants have prevented life-threatening catastrophes in the United Statesa fact that the industry and regulators cite to dispel fear and criticism.
High-level NRC executives like to note that for all the expense and negative publicity generated by the 1979 Three Mile Island partial meltdown, the public was not harmed. And American officials say that plants in the United States have so many backup and safety systems that the massive radiation release and deaths from the 1986 Chernobyl disaster could never happen here.
Its not the perfect system from the standpoint of nothing will ever fail. You will have failures. You will have things that leak. You will have cracks, acknowledges Alex Marion, director of engineering for the Nuclear Energy Institute, the industrys lobbying and trade group.
The challenge, of course, is to have inspection and maintenance programs in place where you can identify these kinds of situations prior to having a serious problem at a plant.
I think what the public ought to feel good about, adds Stephen Floyd, the Nuclear Energy Institutes senior director of regulatory reform, is the defense in depth thats built into the plants. Not everything breaks at the same time, fortunately. Serious incidents decline
NRC officials agree, rejecting the contention that nuclear plants are risking safety under the agencys watch. In fact, the number of serious incidents at nuclear power plants has steadily fallen, agency officials say, which is one reason the NRC lets power plants operate longer without shutting down for inspections or repairs.
The agency periodically issues warnings for parts known to fail or crackincluding the nozzles that guide nuclear fuel rods, which in the case of Davis-Besse had been leaking boric acid for years. Before it will give a plant permission to operate beyond its initial 40-year license, the NRC requires a thorough inspection that covers passive components such as buried pipes. Many of the nations 103 operating plants are expected to go through a re-licensing inspection in the next decade.
Yet its still no guarantee. In the case of the Oconee Nuclear Station in South Carolina, a re-licensing front-runner, the cracks were not noticed when it underwentand passedan extensive inspection to renew its license for an additional 20 years. After the NRC granted the renewal, the cracks appeared.
What is more, critics say that while the number of serious incidents is down, that trend is likely to reverse, turning higher simply as a function of age.
Still, industry defenders say, the problem at Davis-Besse was not so much a failure of aging equipment but, rather, simply of FirstEnergy Corp. to adequately investigate what it should have known was a potential problem.
Safety culture includes a good questioning attitude on the part of the plant personnel, says George Apostolakis, a nuclear engineering professor at Massachusetts Institute of Technology and chairman of an NRC committee that advises regulators on reactor safeguards. There were several indications [of problems] there that people didnt seem to interpret correctly.
But the NRC is far from blameless. A lessons learned task force assembled by the agency to assess the Davis-Besse incident concluded among other things that the agency, beset with staffing and resource allocation issues, had too few inspectors at the plant and missed several opportunities to find the problem.
Davis-Besse has forced the industry and federal regulators to focus on how they can make sure the right prevention programs are, in fact, in place.
Without a probing, questioning attitude, NRC Chairman Richard Meserve said at a nuclear-energy conference in Mexico last week, problems are not going to be detected as quickly as they should be.
That doesnt mean aging parts wont fail or need replacing. But its an acknowledgment that the industry and agency need to inspect more aggressively for susceptible parts before they break.
Asked what concerns him about aging nuclear plants, Marion, the engineering director of the Nuclear Energy Institute, said, The only thing that concerns me is whether or not we can position ourselves to be a little more proactive. . . .
Its a very challenging effort, as you can imagine, as far as, How do you predict theres going to be a crack or a flaw in a piece of metal? What do you do to identify it before it becomes a significant concern?
The Plain Dealer, November 29, 2002