As the aftermath of Japan’s March 11 earthquake and tsunami unfolded, many became mesmerized by photos and videos of desperate workers struggling against time to keep the disastrous situation at the Fukushima Dai-ichi Nuclear Power Plant from becoming even worse. Clad in protective gear, they wrestled with fire hoses and power cables in an effort to maintain cooling-water levels and return power to pumping systems, only to be pulled back, time and again, by fears of overexposure to radiation.
One question occurred to many observers during the media coverage of events at the plant: Could a similar disaster happen here?
Many of us have only seen the inside of a nuclear power plant on “The Simpsons.” Thankfully, though, real-world facilities are nothing like the fictional Springfield Nuclear Plant. In fact, nuclear plants are highly regimented facilities, according to Elizabeth McAndrew-Benavides, manager of industry infrastructure for the Nuclear Energy Institute (NEI), the Washington, D.C.-based policy arm of the nuclear-energy industry. She worked in plants and was training to become a senior reactor operator before NEI employed her, and she described it as an experience in which all policies and processes are defined by a need for safety, both of workers and overall plant operation.
The first thing many workers check when arriving at a plant, McAndrew-Benavides said, is the position of the high-voltage breakers connecting the facility’s output to the transmission system. If the breakers are closed—meaning the turbines were spinning—they know what to expect upon entering.
“You feel the vibration from the turbine,” she said. “What the plant feels like if the plant is producing 800 to 1,000 megawatts is awe-inspiring.”
Work shifts in the operations area begin with a meeting reviewing that day’s work assignments, McAndrew-Benavides said. Then task-based teams, including related operations personnel, along with engineering and maintenance staff, meet to go through the “package,” describing the job at hand. A senior reactor operator meets the team at the job site to ensure checklists are in order.
“So, if you were working on a water pump, the senior reactor operator would make sure that, if the pump would be taken out of service, another would be put into service,” she said, describing the check-and-double-check process. “As operators, we say you should never be lucky.”
Within plant operations, senior reactor operators oversee the work of plant operators stationed on the plant floor and control-room operators working in the brains of a plant. Additional departments include quality assurance—another post McAndrew-Benavides held—and plant engineering and maintenance.
Three different levels of safety staff also play roles in how plants operate. Industrial safety personnel are common across all generating facilities—and industrial plants, in general—and these workers oversee adherence to Occupational Safety and Health Administration (OSHA) guidelines and requirements. Radiological safety, called “health physics,” includes professionals trained to minimize and track individual employees’ radiation exposure. Nuclear safety incorporates a strategy in which everything is done to ensure radioactive fuel is safely maintained.
Outside electrical contractors also can be a part of the mix, especially during the outages all plants undergo every 18 to 24 months.
“There’s a lot of work that needs to be done as the plant goes into outages,” said John McGaha, recently retired president of Entergy Nuclear South, who was responsible for five nuclear units at four plant sites; he is an independent consultant. “Electrical contractors would be brought in for upgrade changes and maintenance, repairing underground cables, all the typical things a contractor would do.”
Setting these assignments apart from typical electrical contracting projects, though, is the safety training and procedures everyone working in such a potentially radioactive environment must follow.
“Those individuals aren’t allowed to just walk in,” McAndrew-Benavides said. “They have to go through site-specific emergency training,” which includes, among other things, the need to memorize all emergency phone numbers before entering the plant.
Cheryl Olson, general supervisor for radiation technical services for the Kewaunee nuclear generating station, which is operated by Dominion Resources in Carlton, Wis., helps manage radiation safety at that facility. A member of her staff verifies conditions in every work site located in radiologically controlled areas. In higher risk areas where conditions might change during an assignment, that technician would remain in the vicinity of a work team until the assignment was complete.
“There are a number of in-plant systems that can let us know if we’re starting to see something unusual,” she said, citing advanced air monitors and personal alarming dosimeters as examples. In fact, Olson said that employee exposure levels have been dropping across the U.S. nuclear power industry over the last decade.
Personal radiation doses in normal operations for Dominion employees are limited to two Roentgen equivalent man units (rems) per year, Olson said, though she’s only seen one person at her plant receive more than one rem in a year. Doses are tracked using dosimeter badges that each worker wears under protective clothing. Badge readings also are recorded in an international database, so total exposure levels can be tracked if workers move from one plant—or country—to another.
International protocols mandate such tracking, and the employees at the Fukushima plant likely followed them. Part of the power of those heroic Fukushima images lies in their anonymity. The identical white safety overalls and face-obscuring respirators can create the impression that the same group of 50 individuals was returning again and again to radioactive hot zones. In reality, it was more likely to be multiple teams, frequently replaced, whose radioactive exposure was closely monitored. This certainly is dangerous work in an unpredictable environment, but U.S. nuclear professionals say risks of permanent injury were lower than many might have thought.
“I’d call them heroes, but I wouldn’t call them martyrs,” McGaha said. “Looking at the latest data I have, the general radiation levels are high, but not so high that they can’t protect their workers.”
Outside contractors might have been a part of those response teams, according to McAndrew-Benavides. In addition, those workers might have included members from all three nuclear-plant operational levels, along with technical advisers, radiation health and safety professionals and, possibly, maintenance technicians.
By the Numbers
Coverage of recovery efforts at the Fukushima Dai-ichi nuclear plant used multiple terms to define workers’ radiation exposure. Following are definitions of the most common measurement units.
Roentgen equivalent man units: The U.S. unit of radiation-dose measurement. Roentgen equivalent man units (rems) may be subdivided into millirems or thousandths of a rem. According to the Nuclear Regulatory Commission, we all are exposed to an average of 620 millirems per year of radiation from both natural and medical-related sources.
Sievert/Millisievert: The international unit of radiation--dose measurement. One Sievert equals 100 rem. This means the annual worker dose limit in Sieverts is 50 millisieverts (mSv).
Dose limits for Japanese workers have been extended to 100 mSv. Tokyo Electric Power Co. officials attempted to raise that limit to 250 mSv, but outside contractors refused to accept those higher levels for their employees.
Could it happen here?
So, how likely is it that we might see our own people as members of a similar response team? Officials around the world are trying to answer this frightening question. Germany has shut down operations at three of its plants and is looking closely at others in its fleet. In the United States, such fears may complicate some plant owners’ efforts to renew operating licenses. As reported in the February issue of Electrical Contractor (“To Infinity and Beyond”), these operators are hoping to extend original 40-year plant lives to 60 or even 80 years.
Ask this question of a nuclear professional, and you’re likely to get a two-part answer. First is the assessment of the plant design itself.
“This was an above-design-basis accident, so you’d have to start with that premise,” said Ken Anderson, president of CKA Associates, a Brewster, Mass.-based nuclear-industry consulting firm. “That would go to the layout of the plant and how it was sited.”
The phrase “design basis” refers to the set of worst-case assumptions engineers work from when designing a nuclear power plant. Fukushima’s designers underestimated the severity of any possible tsunami. As a result, generators supplying backup power to fuel-system cooling pumps were inadequately protected when a greater-than-anticipated tsunami washed over plant seawalls.
However, Anderson said, one also should look at the response of plant operators once this disaster occurred. Managers were unable to get alternative solutions into place in the 4- to 8-hour window enabled by backup battery systems. Even given the extraordinary stress facing plant personnel, he said, “there was an unusually slow response. You have to move fairly quickly when you’re on a timeline like that.”
So, would U.S. operators have reacted differently? Of course, lining up exactly the same sequence of events is impossible, but former Entergy South’s McGaha points to his experience helping lead operations at the Waterford 3 nuclear generating station in Killona, La., when Hurricane Katrina forced that plant to rely on generator power.
“That plant had its challenges,” he said, “but we had more help than you can imagine, with people volunteering to fly equipment and people in.”
A sport utility vehicle, equipped with the latest communications technology available, was one such piece of volunteered equipment, and it proved invaluable to efforts to maintain plant connections with the outside world.
McGaha sees that level of cross-industry cooperation as a keystone of the U.S. nuclear system. It’s led by the Institute for Nuclear Power Operations, an industry-backed safety group established in the wake of the 1979 accident at Three Mile Island, along with the Nuclear Regulatory Commission. At an international level, the World Association of Nuclear Operators seeks to broaden those connections globally, recognizing the impact any single event can have on nuclear energy’s future around the world.
“We didn’t need the Japanese plant to happen to realize that we’re at risk if any of these 60 countries [operating or planning nuclear plants] don’t do it right,” he said. “And we’re at risk if we don’t help each other.”
ROSS is a freelance writer located in Brewster, Mass. He can be reached at email@example.com.