Editor's note: This project is a collaboration between Hearst Connecticut Media Group and the New England Center for Investigative Reporting

In an effort to preserve profits, nuclear power-plant operators in New England are stuffing more and more spent nuclear fuel rods into already crowded storage pools that many believe are more dangerous than the reactors.

The spent-fuel pools at New England's oldest plants now hold up to five times more fuel than they were initially designed to handle.

The dramatic increases in the number of rods per pool have been approved by the federal Nuclear Regulatory Commission, partly because a national disposal site for nuclear waste has not been established.

Experts say this federally sanctioned "re-racking" has allowed plant operators to avoid millions of dollars in costs by delaying when the nuclear fuel rods have to be moved to safer but more expensive dry cask storage, which involves sealing the material in giant concrete urns.

Now, though, the operators are running out of time. The NRC estimates that by 2015, many of the nation's spent-fuel pools, particularly in older plants like many in this region, will run out of room. Then, operators will face an unpleasant choice: Move waste into dry casks to free up space in the pools, or shut down their plants.

While the NRC insists the practice is safe, stuffing pools to their limit is inherently dangerous, many scientists and engineers say. They warn that the sheer volume of radioactivity in the pools, often far more than what is in a reactor, could turn an accident or natural disaster into a cataclysm. Also, they worry that the storage pools make tempting targets for terrorists (see accompanying story).

"The New England plants are older, and the issues with older reactors are mostly ignored. These plants are like the canary in the coal mine. They never intended to put lifetime storage into the plans," said David Lochbaum, a former nuclear plant operator and a member of the Union of Concerned Scientists, a group that has sounded the alarm over nuclear safety.

The still-unfolding Japanese nuclear disaster -- spent fuel rods in pools at the Fukushima Daiichi reactors were exposed to the air and released large amounts of radiation after a tsunami knocked out the cooling system -- is a graphic example of the risks inherent in onsite spent-fuel storage. And the Japanese pools that caught fire held much less waste than many of the New England pools.



Nationally, the nation's 104 nuclear power plants are now storing some 63,000 metric tons of spent fuel rods, according to 2010 numbers compiled by the Nuclear Energy Institute.

In New England, the four operating nuclear power plants are storing at least 2,900 metric tons of spent fuel, according to figures provided by two plants and 2002 data available for two others, which is the most recent available. The Indian Point Energy Center in New York state is storing at least 903 metric tons of spent fuel.

New England's plants have re-racked their spent-fuel storage pools many times over the last few decades. In many cases, the stored spent-fuel rods are now packed closer together than ever before -- nearly as close as they were positioned inside the reactor.

The storage pool at Vermont Yankee Nuclear Power Station was originally licensed to hold 600 spent fuel assemblies. There are now 2,935 assemblies in the pool, or 932 metric tons of radioactive waste.

At Millstone Nuclear Power Station in Waterford, the pool at the Unit 3 reactor was originally licensed to hold 756 assemblies. It now holds 1,040 assemblies, or 449 metric tons of waste, and is licensed to handle up to 1,860 assemblies.

Millstone's Unit 2 reactor was originally licensed to hold 677 spent fuel assemblies. It now holds 909 assemblies, or 304 metric tons, and is licensed to hold 1,346 assemblies. The Pilgrim Nuclear Power Generating Station in Massachusetts currently holds 2,918 fuel assemblies. Its original license allowed 880 fuel assemblies, according to NRC documents. The license was later updated to allow for 3,859 assemblies.

The spent fuel pool at Seabrook Nuclear Power Station in New Hampshire, the newest of New England plants (Seabrook came online in 1990) was originally licensed to handle 1,236 fuel assemblies and now has 936 assemblies in its pool. There are also 192 fuel assemblies in dry cask storage.

The Indian Point nuclear plant on the Hudson River in Buchanan, N.Y., has 2,073 spent fuel assemblies at two pools, or 903 metric tons, according to 2002 data compiled by the Department of Energy. NRC records show that Indian Point Unit 2 was originally licensed to hold 478 assemblies. Unit 3 began with a license for 264 assemblies when it came online in 1976 and that was increased to 840 in 1978.

Maine Yankee, which was shut down 14 years ago, is storing 1,434 fuel assemblies, or 542 metric tons, in dry cask storage, while Yankee Rowe in Massachusetts, also shut down years ago, is storing 533 metric tons of waste.


New England's nuclear power plants, most of which were built in the 1970s, came online with a promise: the government would take the spent fuel rods that result from nuclear fission and safely store the waste at a national site. In 1982, Congress made that promise into law, and the national repository was scheduled to open in 1998.

That plan officially fell apart last year when the Obama administration, under considerable political pressure from opponents, canceled plans for a nuclear disposal facility in Yucca Mountain in Nevada, which was to be hollowed out to create a repository. That decision came despite the fact that electric ratepayers have contributed $18 billion toward building the national repository through a special assessment included in their monthly bills, according to a 2010 accounting. (See accompanying story).

Spent fuel pools were originally intended to be temporary storage and as a result were not given the same level of protection as reactors. As the volume of spent fuel grew over the years, scientists began warning the pools could be more dangerous than the reactor because they now held more radioactive material. Without a national storage site, plant operators, with the blessing of the Nuclear Regulatory Commission, packed more and more spent fuel rods into the pools.

"There used to be space between them. The assemblies were so far apart they could not go to critical mass. Then they took out the racks. The walls of the pool now have material that prevents a reaction. It's the same size pool with many more rods," Lochbaum said.

Lochbaum said storage pools were reconfigured to handle more fuel rods by redesigning how the rods are placed in the pool, moving them closer together, and adding substances like boron, which restricts nuclear fission.

That closer proximity, however, means rods could heat up much faster if there is a major loss of cooling water, Lochbaum and other experts said.

The alternative to pool storage is a dry cask, which typically is a concrete bunker approximately 20 feet high, 10 feet wide and 20 feet deep, with walls and roof areas up to five feet thick. Spent fuel rods are placed in a steel canister typically capable of holding 32 fuel assemblies and the lid is welded in place. The canisters weigh up to 40 tons fully loaded. The loading procedure occurs under water.

Last summer, Lochbaum testified before the Blue Ribbon Commission on America's Nuclear Future, formed by the Obama Administration, and said all nuclear waste represents a risk but stressed early transfer to dry casks is the best course.

"From the time it is removed from reactor vessels until the time it is shipped offsite, interim storage of spent fuel at nuclear plant sites represents a risk to public and worker safety. The risk from onsite storage is highest during wet pool storage. The risk drops significantly when the spent fuel is transferred to dry-cask storage onsite," Lochbaum said.

A 2010 statement signed by 170 environmental and activist groups declared that "as the amount of waste generated has increased beyond the designed capacity, the pools have been reorganized so that the concentration of fuel in the pools is nearly the same as that in operating reactor cores." "If water is lost from a densely packed pool as the result of an attack or an accident, cooling by ambient air would likely be insufficient to prevent a fire, resulting in the release of large quantities of radioactivity to the environment," the statement continued.

Such conclusions are actually nothing new.

In a 2002 report, Robert Alvarez, a former top official at the federal Department of Energy and a senior scholar at the Institute for Policy Studies, wrote in the Bulletin of Atomic Scientists that if a fire broke out at the Millstone Reactor Unit 3 spent-fuel pool in Connecticut it would result in a three-fold increase in background exposures. That would trigger the NRC's evacuation requirement and could render about 29,000 square miles of land uninhabitable, severely affecting Connecticut, much of Long Island and even New York City.

"On average, spent fuel ponds hold five to 10 times more long-lived radioactivity than a reactor core," Alvarez wrote in his report.

"Particularly worrisome is the large amount of cesium 137 in fuel ponds, which contain anywhere from 20 to 50 million curies of this dangerous isotope. With a half-life of 30 years, cesium 137 gives off highly penetrating radiation and is absorbed in the food chain as if it were potassium. According to the NRC, as much as 100 percent of a pool's cesium 137 would be released into the environment in a fire," Alvarez wrote.

Cesium-137 is known to cause liver cancer and circulates within the body for years. Other isotopes, the byproducts of nuclear fission, are also extremely dangerous: Iodine-131, strontium- 90 and plutonium-239. Iodine-131 can cause thyroid cancer, strontium-90 gets incorporated into bones and teeth and stays there, irradiating the body and causing leukemia. Plutonium-239 is the worst of all; it can be inhaled and cause lung cancer.


The NRC's official position is that there is nothing dangerous about more densely packed storage pools.

"Let me begin by saying public health and safety is protected by the safety and security features associated with storage of spent fuel in either pools or casks," said Diane Screnci, an NRC spokeswoman.

"The NRC, after careful study of the safety and security issues, concluded that fuel is safely stored in wet pools or dry storage casks. There is no justification, from a safety or security viewpoint, for removing fuel from pools and loading it into casks in order to return to low density racking," Screnci said.

The details of the NRC's storage-pool studies are not public due to national security concerns.

A nuclear reactor is surrounded by six to nine inches of steel, and sits within a containment dome some three to four feet thick. But a spent-fuel pool at a pressurized water reactor, like the Millstone Nuclear Power Station in Connecticut and the Seabrook Nuclear Power Station in New Hampshire, is located outside the containment dome and housed in a steel industrial building.

At a boiling water reactor, like Fukushima Daiichi in Japan, the Vermont Yankee Nuclear Power Plant and the Pilgrim Nuclear Generating Station in Massachusetts, the pool is several stories above ground level, within the containment dome.

In testimony last year before Obama's Blue Ribbon commission, Lochbaum told the panel that "better management of the wet-pool risk is particularly crucial at boiling water reactors with pools located inside secondary containment. A reactor accident at such plants can initiate a wet pool accident and vice-versa."

Nuclear power plants create electricity by placing nuclear fuel rods consisting of uranium pellets close together within a water filled reactor vessel. A controlled atomic fission is created as the uranium atoms split and their mass is converted to energy. The resulting heat is used to turn liquid water into steam, which then turns turbines connected to electric generators to make electricity.

About every 18 months, one third of the reactor core is spent and the fuel rods are removed and placed in a nearby storage pool. Although no longer efficient for heating water within the reactor, the rods remain highly radioactive and very hot. Over time, they cool while resting in the pool and the radioactivity lessens.


Clay Turnbull, director of the New England Coalition on Nuclear Power, said it costs plant owners about $1 million per dry cask and that's why the fuel remains in pools. Other estimates place the price tag per-cask at about $1.5 million.

"It's a lot of money to move them around. If you need 50 casks, that's $50 million at least," Turnbull said, adding that nuclear plants operate on a tight profit margin so any additional costs are a disincentive.

"The plants are resisting this, going to dry casks," Lochbaum said. "When the space in the pool is filled, then they go to dry cask. They move it only when needed. By doing this, the risk to the pool is as high as it can be."

Power plant officials disagreed and insisted that economics has nothing to do with fuel remaining in wet storage for so long.

"When we opened, the expectation was the fuel would be taken in 25 years and reprocessed," said Holt, the Millstone spokesman.

"We never thought we would have to contain fuel for the full life of the plant," Holt said.

Still, Holt acknowledged cost is an issue. "Both are safe. But there is a cost element to dry cask and it is a fairly heavy cost and a major factor in why we have not pulled fuel sooner. It's true that dry casks use a passive storage system that is not dependent on pumps and mechanical systems."

Larry Smith, a spokesman for Vermont Yankee, acknowledged there are hefty costs involved in moving fuel from pools to casks.

"We believe pools are perfectly safe. It was designed to be safe and there are redundant systems so there is never a loss of coolant," Smith said.

Tom Kaufman, spokesman for the pro-nuclear Nuclear Energy Institute, said operators would not put residents or workers at risk just to save money.

"No [operator] would jeopardize safety for cost, if that's what the implication is. That's wrong. All of the pools meet the requirements of the NRC and have to have the right procedures in place," Kaufman said.

"The individual operators have held up their end but the federal government has not come through with a disposal regime," Kaufman said "The fact is it's a matter of science. There are materials that absorb the neutrons and control this. When they run out of storage space, they will have to move it to dry cask," Kaufman said.

At Maine Yankee, activists have recently called on the federal government to finally remove the dry casks stored there since the plant was shut down in 1996. The Blue Ribbon

Commission on America's Nuclear Future, formed by the Obama Administration, is studying what to do with the nuclear waste and recently visited Maine Yankee to look over its cask storage.