|Japanese officials observed the workings of a fuel storage pool last year in the third reactor building at Fukushima Daiichi’s No. 1 plant. (Jiji Press/AFP/Getty Images/2010 File)|
Delays in policy on storing fuel rods compound crisis
NEW YORK — Years of procrastination in deciding on long-term disposal of highly radioactive fuel rods from nuclear reactors are now coming back to haunt Japanese authorities as they try to control fires and explosions at the stricken Fukushima Daiichi Nuclear Power Station.
Some countries have tried to limit the number of spent fuel rods that accumulate at nuclear power plants: Germany stores them in costly casks, for example, while China sends them to a desert storage compound in the western province of Gansu. But Japan, like the United States, has kept ever-larger numbers of spent fuel rods in temporary storage pools at the power plants, where they can be guarded with the same security provided for the plants.
Figures provided by Tokyo Electric Power show that most of the dangerous uranium at the power plant is actually in the spent fuel rods, not the reactor cores themselves. The electric utility said that a total of 11,195 spent fuel rod assemblies were stored at the site. That is about four times as much radioactive material as in the reactor cores combined.
Now those temporary pools are proving the power plant’s Achilles’ heel, with the water in the pools either boiling away or leaking out of their containments, and efforts to add more water having gone awry. While spent fuel rods generate significantly less heat than newer ones do, there are strong indications that some fuel rods have begun to melt and release extremely high levels of radiation. Japanese workers — using helicopters, water cannons, and firetrucks — struggled yesterday to add more water to the storage pool at Reactor No. 3.
Richard T. Lahey Jr., a retired nuclear engineer who oversaw General Electric’s safety research in the early 1970s for the kind of nuclear reactors used in Fukushima, said that the zirconium cladding on the fuel rods could burst into flames if exposed to air for hours when a storage pool lost its water.
Zirconium, once ignited, burns extremely hot and is difficult to extinguish, added Lahey, who helped write a classified report for the US government several years ago on the vulnerabilities of storage pools at American nuclear reactors.