TOKYO -- Two years after a triple meltdown that grew into the world's second worst nuclear disaster, the Fukushima Daiichi nuclear power plant is faced with a new crisis: a flood of highly radioactive wastewater that workers are struggling to contain.
Groundwater is pouring into the plant's ravaged reactor buildings at a rate of almost 75 gallons a minute. It becomes highly contaminated there, before being pumped out to keep from swamping a critical cooling system. A small army of workers has struggled to contain the continuous flow of radioactive wastewater, relying on hulking gray and silver storage tanks sprawling over 42 acres of parking lots and lawns. The tanks hold the equivalent of 112 Olympic-size pools.
But even they are not enough to handle the tons of strontium-laced water at the plant -- a reflection of the scale of the 2011 disaster and, in critics' view, ad hoc decision making by the company that runs the plant and the regulators who oversee it. In a sign of the sheer size of the problem, the operator of the plant, Tokyo Electric Power Company, or Tepco, plans to chop down a small forest on its southern edge to make room for hundreds more tanks, a task that became more urgent when underground pits built to handle the overflow sprang leaks in recent weeks.
"The water keeps increasing every minute, no matter whether we eat, sleep or work," said Masayuki Ono, a general manager with Tepco who acts as a company spokesman. "It feels like we are constantly being chased, but we are doing our best to stay a step in front."
While the company has managed to stay ahead, the constant threat of running out of storage space has turned into what Tepco itself called an emergency, with the sheer volume of water raising fears of future leaks at the seaside plant that could reach the Pacific Ocean.
That quandary along with an embarrassing string of mishaps -- including a 29-hour power failure affecting another, less vital cooling system -- have underscored an alarming reality: two years after the meltdowns, the plant remains vulnerable to the same sort of large earthquake and tsunami that set the original calamity in motion.
There is no question that the Fukushima plant is less dangerous than it was during the desperate first months after the accident, mostly through the determined efforts of workers who have stabilized the melted reactor cores, which are cooler and less dangerous than they once were.
But many experts warn that safety systems and fixes at the plant remain makeshift and prone to accidents.
The jury-rigged cooling loop that pours water over the damaged reactor cores is a mazelike collection of pumps, filters and pipes that snake two and a half miles along the ground through the plant. And a pool for storing used nuclear fuel remains perched on the fifth floor of a damaged reactor building as Tepco struggles to move the rods to a safer location.
The situation is worrisome enough that Shunichi Tanaka, a longtime nuclear power proponent who is the chairman of the newly created watchdog Nuclear Regulation Authority, told reporters after the announcement of the leaking pits that "there is concern that we cannot prevent another accident."
A growing number of government officials and advisers now say that by entrusting the cleanup to the company that ran the plant before the meltdowns, Japanese leaders paved the way for a return to the insider-dominated status quo that prevailed before the disaster.
Even many scientists who acknowledge the complexity of cleaning up the worst nuclear disaster since Chernobyl fear that the water crisis is just the latest sign that Tepco is lurching from one problem to the next without a coherent strategy.
"Tepco is clearly just hanging on day by day, with no time to think about tomorrow, much less next year," said Tadashi Inoue, an expert in nuclear power who served on a committee that drew up the road map for cleaning up the plant.
But the concerns extend well beyond Tepco. While doing a more rigorous job of policing Japan's nuclear industry than regulators before the accident, the Nuclear Regulation Authority has a team of just nine inspectors to oversee the more than 3,000 workers at Fukushima.
And a separate committee created by the government to oversee the cleanup is loaded with industry insiders, including from the Ministry of Trade, in charge of promoting nuclear energy, and nuclear reactor manufacturers like Toshiba and Hitachi. The story of how the Fukushima plant ended up swamped with water, critics say, is a cautionary tale about the continued dangers of leaving decisions about nuclear safety to industry insiders.
When Tepco and the government devised the current plans for decommissioning the plant in late 2011, groundwater had already been identified as a problem -- the plant lies in the path of water flowing from nearby mountains to the sea. But decision makers placed too low a priority on the problem, critics say, assuming the water could be stored until it could be cleaned and disposed of.
According to some who helped the government plan the cleanup, outside experts might have predicted the water problem, but Tepco and the government swatted away entreaties to bring in such experts or companies with more cleanup expertise, preferring to keep control of the plant within the collusive nuclear industry.
Tepco also rejected a proposal to build a concrete wall running more than 60 feet into the ground to block water from reaching the reactors and turbine buildings, and the Trade Ministry did not force the issue, according to experts and regulators who helped draw up the decommissioning plan.
Instead, Tepco made interim adjustments, including hastily building the plastic- and clay-lined underground water storage pits that eventually developed leaks.
It was only after the discovery of those leaks that the regulation agency was added as a full-fledged member to the government's cleanup oversight committee.
But the biggest problem, critics say, was that Tepco and other members of the oversight committee appeared to assume all along that they would eventually be able to dump the contaminated water into the ocean once a powerful new filtering system was put in place that could remove 62 types of radioactive particles, including strontium.
The dumping plans have now been thwarted by what some experts say was a predictable problem: a public outcry over tritium, a relatively weak radioactive isotope that cannot be removed from the water.
Tritium, which can be harmful only if ingested, is regularly released into the environment by normally functioning nuclear plants, but even Tepco acknowledges that the water at Fukushima contains about 100 times the amount of tritium released in an average year by a healthy plant.
"We were so focused on the fuel rods and melted reactor cores that we underestimated the water problem," said Tatsujiro Suzuki, vice chairman of the Japan Atomic Energy Commission, a government body that helped draw up Tepco's original cleanup plan. "Someone from outside the industry might have foreseen the water problem."
Tepco rejects the criticism that it has mishandled the growing groundwater problem, saying that the only way to safely stop the inflow is by plugging the cracks in the damaged reactor buildings. It contends that no company in the world has the ability to do that because it would require entering the highly radioactive buildings and working in dangerously toxic water several feet deep.
"We operate the plant, so we know it better than anyone else," said Mr. Ono, the Tepco spokesman. He then teared up, adding, "Fixing this mess that we made is the only way we can regain the faith of society."
For the moment, that goal seems distant. The public outcry over the plans to dump tritium-tainted water into the sea -- driven in part by the company's failure to inform the public in 2011 when it dumped radioactive water into the Pacific -- was so loud that Prime Minister Shinzo Abe personally intervened last month to say that there would be "no unsafe release."
Meanwhile, the amount of water stored at the plant just keeps growing.
"How could Tepco not realize that it had to get public approval before dumping this into the sea?" said Muneo Morokuzu, an expert on public policy at the University of Tokyo who has called for creating a specialized new company just to run the cleanup. "This all just goes to show that Tepco is in way over its head."
Makiko Inoue contributed reporting from Tokyo, and Matthew L. Wald from Washington.
This article originally appeared in The New York Times.