Xcel Energy engineer Terry Pickens, left, was scanned for radioactivity after spending time in the Monticello nuclear power plant.
Jim Gehrz, Star Tribune
State's 2 nuclear plants will get post-Fukushima upgrades
- Article by: DAVID SHAFFER
- Star Tribune
- March 5, 2012 - 6:38 PM
The owner of Minnesota's two nuclear power plants says it is preparing to spend $20 million to $50 million on safety upgrades and studies based on the lessons of the nuclear catastrophe in Japan a year ago this month.
Like other U.S. nuclear plant owners, Xcel Energy is buying more diesel pumps and portable generators that could be quickly deployed at its Monticello and Prairie Island plants if all backup electricity went out, as it did at Japan's Fukushima Daiichi plant.
"We are talking about large diesel pumps, with the capability of sucking water from the river and pumping it into the reactor vessel, similar to what the Japanese ultimately ended up doing," said Dennis Koehl, chief nuclear officer for the Minneapolis-based utility and a member of the industry's post-Fukushima steering committee.
The U.S. nuclear industry says these and other actions over several years will enhance the safety of the nation's 104 reactors at relatively modest cost. The U.S. Nuclear Regulatory Commission (NRC) last week approved the first post-Fukushima measures, and plant owners likely will receive specific orders this week, just days before the March 11 anniversary of the disaster.
Yet some U.S. nuclear critics question whether the actions are sufficient, pointing with skepticism to the purchase of off-the-shelf pumps and backup generators, rather than more expensive equipment designed for nuclear power plants.
"This is a public relations measure to create the illusion that the industry is jointly taking the issue seriously," said Christopher Paine, who directs the nuclear watchdog program for the Natural Resources Defense Council (NRDC), a nonprofit environmental group.
Regulatory Commission Chairman Gregory Jaczko, who was among the four commissioners to approve the Fukushima-related orders last week, expressed concern about delays, especially for plants needing study of earthquake risks. "I simply cannot accept a timeline that puts this issue well into the later part of the decade," he wrote.
Xcel's two nuclear plants are the two-unit Prairie Island station near Red Wing, 50 miles southeast of the Twin Cities, and the one-unit plant at Monticello, 40 miles to the northwest. Monticello has a General Electric Mark 1 boiling water reactor like those damaged in Japan.
Koehl said in an interview that Xcel's safety costs could climb as high as $250 million if the utility is required to purchase nuclear-qualified equipment and take other costly steps such as building earthquake-proof off-site buildings to store and protect it.
The Nuclear Energy Institute (NEI), which represents the industry, has directed its members to order portable response equipment this month. Xcel has already acquired five additional pumps, adding to the two it purchased after 9/11.
Last week at Monticello, Xcel officials showed two of the pumps that are parked in a warehouse not far from the reactor building. Trailers hold fire hoses and other equipment to bring river water to the plant in an emergency.
Under the industry's "flexible coping strategy" for a disaster, big-ticket items like filtration systems for radioactive water will be purchased by all plant owners and stored at one or more U.S. locations -- ready to be flown to a stricken plant.
Lessons from a disaster
Three of six Fukushima units were running when a record earthquake struck last March. The subsequent tsunami wiped out power lines and in-plant diesel backup generators, leaving about eight hours of battery life to control the plant.
Operators couldn't cool the reactors, resulting in damage to nuclear fuel and reactor cores, according to the NRC's account. At three units, hydrogen produced during the crisis exploded, damaging upper walls and roofs, exposing pools of spent fuel rods and releasing high levels of radioactivity.
It took the rest of the year for plant owner Tokyo Electric Power Co. to bring the damaged units into a state called cold shutdown.
One of the lessons the U.S. industry and its critics don't dispute is that nuclear power plants need more battery time to cope with a complete loss of power. That's something the NEI says has happened only once in the United States, at a Georgia reactor in 1990 and without disaster.
At many U.S. plants, including Monticello and Prairie Island, key batteries are rated for just four hours. Plant owners now are expected to extend that coping time, though the NRC hasn't said how or for how long, leaving plants to propose solutions to regulators.
At Prairie Island, for example, that may mean switching emergency lighting to other batteries that aren't critical to plant control, Xcel officials said.
Industry officials argue that many nuclear power plants, including Monticello, have multiple transmission lines connecting them to the grid, which lowers the risk of losing power. On the other hand, multiple-unit plants like Prairie Island have long counted on getting help during a disaster from an adjacent unit -- an assumption that proved wrong in Japan.
U.S. regulators, in the first of three phases of their post-Fukushima response, are expected this week to order plant owners to restudy earthquake and flood risks, improve emergency response and begin other safety-related improvements. Even in Minnesota, seismic studies are required, along with a fresh look at worst-case flood risks such as multiple dam failures.
Two other lessons from Japan are getting special attention. U.S. regulators want existing hydrogen vents on boiling-water reactors to be reliable during a crisis, which may require design changes. They also want more gauges to monitor pools holding spent fuel, which was exposed in the Japan disaster. Those fixes may not be in place for four years or more.
That's partly because engineers can't safely modify some equipment until plants are powered down for refueling, which typically occurs at intervals of 18 months or more, said Adrian Heymer, the NEI's executive director for Fukushima regulatory response.
"You don't want someone prying around in the back of a control cabinet or control room while you are at power," he said.
Safety measures not taken
Two nuclear industry watchdog groups have unsuccessfully urged regulators to consider doing more.
The Union of Concerned Scientists says the NRC should make operators of boiling-water reactors move spent fuel into dry steel casks in five years, instead of the more typical 10. The nonprofit group, which does not oppose nuclear power, also has urged better emergency cooling for the pools.
David Lochbaum, director of the group's nuclear safety project, said the explosions at Fukushima -- and subsequent open-air water pumping into the fuel pools -- prove that such changes are necessary.
"Had hydrogen not exploded those buildings, it would have been difficult to prevent damage to those pools," he said. "They would have no means to deliver water."
The NRDC's Paine unsuccessfully urged the NRC to order in-plant emergency systems driven by reactor steam. He said he now worries that the lessons learned in Japan will be lost in the NRC's slow, bureaucratic regulatory process.
"These serious accidents ... can happen and do happen, and they may happen more frequently as these plants get older," Paine said.
But Heymer of the NEI said the industry has learned from earlier accidents, and is doing the same after Fukushima.
"If you look at the improvements the industry has made, the possibility of getting to a reactor-damage situation have been reduced over the years quite dramatically," he said.
David Shaffer • 612-673-7090
© 2013 Star Tribune