The trouble started with a key that didn't fit.
At the St. Lucie nuclear power station, a technician went below the Unit II control room on Aug. 14 to test a backup shutdown system. It had about two dozen hand-operated switches, and two that require a key, and the key wouldn't go in the hole.
Both locks were plugged with something that looked like Superglue.
This was no accident. Somebody had sabotaged a safety system at a nuclear power plant.
The technician called the control room operators. They called Unit I, which checked the locked switch on its backup shutdown system.
It was glued shut, too.
Those three squirts of glue brought a swarm of guards, engineers and supervisors and an inspection team from the Nuclear Regulatory Commission _ all investigating what an NRC spokesman called the worst case in history of tampering with an operating U.S. nuclear plant.
The glue in St. Lucie's switches "is potentially of enormous significance," said James Riccio of Critical Mass, a nuclear safety advocacy group. "The whole premise that these reactors are even remotely safe is based on having redundant safety systems. Defense in depth. That was obviously lost in this instance."
Two weeks later, no one knows who did the tampering.
But whoever did it had access to restricted areas. Speculation has abounded that this was the work of an angry employee at a nuclear plant that once praised as the best in the business. Florida Power & Light Co., which owns the St. Lucie plant, has been laying off thousands of employees and hundreds in its nuclear division.
To nuclear safety experts, the St. Lucie incident brought troubling questions about the vulnerability of power plants supposedly guarded by the most elaborate safety systems on Earth.
Across the country, electric utilities are preparing for an era of deregulation and competition by cutting costs and laying off nuclear plant workers.
Utility executives say they are achieving greater efficiency without compromising safety standards. Industry critics call it a dangerous trend, raising the risk of a nuclear accident and of intentional damage by a disgruntled worker.
NRC officials, meanwhile, are watching for signs of excessive overtime at nuclear plants with shrinking staffs. And, in the wake of the St. Lucie incident, regional administrator Stewart Ebneter is promising increased attention to the problem of sabotage.
"We need to do more in light of the global environment of terrorism," he said.
A thorough check of St. Lucie's safety systems turned up no further evidence of tampering. Yet the incident left ominous overtones.
It was the fourth suspicious incident at the plant in four months.
The story of St. Lucie and the Superglue saboteur is also the story of a rapidly changing industry.
Florida Power & Light built its largest nuclear facility on a beautiful barrier island about half an hour north of Palm Beach. The sea turtles that nest nearby are featured on the St. Lucie logo.
The first St. Lucie plant began generating 839 megawatts of electricity here in 1976. A twin unit was added in 1983.
Both were partially shut down in 1984 when jellyfish invaded the water intake system, and the plant frightened its neighbors one day in 1985 with an explosive outburst of steam. But mostly its history has been trouble-free.
In a struggling industry, St. Lucie emerged as a model. The NRC cited it in 1991 as one of the three best-run nuclear plants in the nation. In 1992 one unit finished a 502-day run without a shutdown, an industry record. In 1994 the NRC again gave St. Lucie superior marks.
At the same time, Florida Power & Light was undergoing profound changes.
Like many electric utilities, it was being transformed from a regulated monopoly to a business facing new competition from independent power producers and industries that co-generate electricity, and potentially from other utilities in a deregulated retail market.
And it was cutting costs dramatically.
From 1990 to 1995, Florida Power & Light reduced its payroll by more than 4,000 people, a 28 percent staff reduction.
In its nuclear division, which manages four power plants at St. Lucie and Turkey Point, one-fourth of the jobs were eliminated. Some who worked at division headquarters in turn took jobs from people at St. Lucie.
In August 1995, the NRC cautioned managers of a model nuclear plant that they were operating with a less experienced staff.
Hurricane Erin struck the same month.
While Erin inflicted no direct damage, it nevertheless inaugurated a year of trouble at St. Lucie. Both units were shut down as the storm approached, and then plant operators couldn't get Unit 1 restarted for 73 days.
A defective seal on a pump that cools its reactor had to be replaced. Valves leaked. Another set of valves, it was discovered, had been installed backward for a year. A worker accidentally set off a safety system that sprayed radioactive water on the floor of the concrete building housing the reactor.
Problems persisted in 1996. Alarms sounded in the control room while an operator was out microwaving his lunch. The NRC fined St. Lucie for a series of violations and downgraded its rating from superior to good in two of four areas.
In May and June, two mistakes were reported that may or may not have been accidental. In both cases someone set pressure points on safety valves too high.
"Could be poor maintenance, could be tampering," said Mark S. Miller, the senior resident NRC inspector at St. Lucie.
In July, 30 more employees were terminated at St. Lucie. The same month, the NRC cited the plant for letting 50 safety-related employees log excessive overtime _ more than 18 hours in one day or 72 hours in a week.
Sometime that month, somebody started putting glue in the locks.
On July 26, nine padlocks and two door locks at the plant were found to be glued shut.
On Aug. 14, glue was found in three locks on shutdown panels that would be used to cool the St. Lucie reactors if a fire or another emergency required a control room evacuation.
The switches had been disabled anywhere from minutes to a month. All three were designed to aid a smooth, gradual shutdown _ what a utility spokeswoman called the difference between "slowly letting off the accelerator" and "slamming on the brakes."
At Unit II, the key-operated switches would block an emergency system from suddenly flooding the reactor with cooling water.
At Unit I, the glued lock controlled the power-operated relief valve, which can release steam pressure from a system that routinely heats water to 550 degrees Fahrenheit.
This valve was similar to the one that stuck open at Three Mile Island, triggering a series of errors that culminated in the nation's worst nuclear accident.
Florida Power & Light has offered a $10,000 reward for information leading to the saboteur's arrest and tightened access to the site of the crime.
The good news, according to nuclear division president Thomas Plunkett, is that the saboteur probably did not grasp the significance of the act. The company has narrowed its investigation to people "who have no understanding of safety systems," he said.
Plunkett heads a new management team brought in to restore St. Lucie's record. He is promising to turn its performance around.
He said he recognizes "there is a lot of anxiety here." But "when we enter a deregulated environment, which is coming at us very fast, we have to be efficient."
For company stockholders, 1995 was an excellent year. Florida Power & Light's holding company netted a record $553-million.
Its chief executive, James L. Broadhead, was rewarded with a salary and incentive payments totaling $2.6-million.
At a church supper in Fort Pierce, 8 miles up river from St. Lucie, there is anxious talk about the town's major employer.
Several plant workers have come to St. Andrew's Episcopal for a midweek potluck meal. So have Jim and Deb Piowaty, who have lived directly across the Indian River from the plant for 20 years, and the Rev. Pierre Whalon, a pro-nuclear rector furious about Florida Power & Light's treatment of its employees.
People spend their lives working at St. Lucie, and then one day "the security guard is there along with the pink slip," Whalon said. "I know that all the employees are stressed to the max _ not knowing when the next round of job cuts is coming _ and the management is giving itself bonuses."
David Singleton, an electrician at St. Lucie, is proud of the plant. So are the people he works with. None of them would damage safety equipment, he said.
What has changed since then _ repeatedly _ is the management. "In five years I've seen four department heads and three plant managers," Singleton said. "We need some stability."
The Piowatys worry about the staff reductions. They have a friend who works there, and he seems terribly overworked.
"It's not sabotage," Jim Piowaty remembers his friend saying after the glued safety switches were found. "It's just showing them, by God, we're not happy."
To operate safely, nuclear plants need cooling water to offset the heat of atomic fission and power to operate the water pumps. They use a lot of water. St. Lucie circulates a million gallons a minute from the Atlantic Ocean.
Without water, the fuel in the reactor can get hot enough to melt through the concrete floor of the containment building, theoretically risking a violent reaction when a 100-ton molten mass of radioactive elements reaches the water table.
Nuclear plants are designed to reduce this risk as close as possible to zero with redundant safety systems. If power is lost they have emergency diesel generators. If those don't work there are battery-operated generators. If all else fails, the reactor can be flooded with a blend of water and boron, an element that slows fission.
Psychological tests are used to screen job applicants. Supervisors are trained to watch for unusual behavior. Plant employees pass through metal and explosives detectors and sometimes get patted down for good measure.
Some experts doubt a single saboteur in the control room could cause a major accident if he tried.
Gordon Thompson, the director of a Massachusetts institute that studies reactor safety, thinks the greatest sabotage risk would involve a team effort between terrorists cutting power lines to a plant and a zealot inside. "A single person would have considerable difficulty in causing a severe accident," he said.
At St. Lucie, utility and NRC officials saw no reason to shut down a plant with a sabotaged safety system.
They say the tampering was limited to a backup shutdown system that had never been used, and even if St. Lucie had needed it, its reactors could have been cooled without the disabled switches.
This incident "did not jeopardize public health and safety," said Kerry Landis, who oversees NRC inspections at St. Lucie.
Scott Peters, a spokesman for the industry's Nuclear Energy Institute in Washington, called the St. Lucie incident an isolated case of no great concern. "As I understand it, there were several backups," he said.
Some people familiar with the intricacies of nuclear plant safety systems disagree.
Paul Blanch, an award-winning nuclear engineer in Connecticut who quit the industry, thinks plant managers and federal regulators took an unwarranted risk at St. Lucie.
"There are literally thousands of things that could be done" by an insider, Blanch said.
When the extent of sabotage is unknown, "it's criminal for the utility and the NRC to keep these power plants operating," he said.
On Thursday morning, a team of NRC officials came to visit a troubled member of the Southeast's nuclear family.
In a meeting room, federal regulators and St. Lucie plant managers sat at facing tables to go through a status report that often sounded like the regulatory equivalent of confession.
One by one, managers outlined recent achievements. Then they frankly admitted ongoing problems with equipment, maintenance and engineering, outlined corrective actions and vowed not to stop short of perfection.
"We want to be world-class. That's the bottom line," said quality assurance manager Wes Bladow.
From the NRC side, the regional administrator made it clear he considers sabotaging shutdown panels a serious matter. "Both panels are extremely important panels. Those are not just backups," Ebneter said.
Afterward, Ebneter called complacency St. Lucie's major problem. "They were good performers for a long period of time," he said, and their performance "has declined significantly."
He hesitated to judge whether cost-cutting was part of the problem. The NRC doesn't want to tell utilities how many people to employ. Instead, it looks for signs that performance is suffering, such as excessive overtime and backlogged work orders.
"Every utility I know is doing some sort of downsizing," he said. "The question is how much is too much. We don't have any good indicators."
_ Times staff writer Ian James and researcher John Martin contributed to this report.