Japan"s Nuclear Crisis is Seen Clearly from afar

For the clearest picture of what is happening at Japan's Fukushima Daiichi nuclear power plant, talk to scientists thousands of miles away. Thanks to the unfamiliar but sophisticated art of atomic forensics, specialists around the globe have been able to document the situation vividly. Over decades, they have become excellent at illuminating the hidden workings of nuclear power plants from afar, turning scraps of information in to detailed analyses.

For example, an analysis by a Spanish energy company revealed far more about the condition of the plant's reactors than the Japanese have ever described: water levels at the reactor cores dropping by as much as three-quarters, & temperatures in those cores soaring to  5,000 degrees Fahrenheit, hot to burn & melt the zirconium casings that protect the fuel rods.

Simultaneously, the evaluations also show that the reactors at Fukushima Daiichi escaped the deadliest outcomes a complete meltdown of the plant.

Scientists in Europe & The united states also know from observing the explosions of hydrogen gas at the plant that the nuclear fuel rods had heated to hazardous levels, & from radioactive plumes how far the rods had disintegrated.

Indeed, the detailed assessments of the Japanese reactors that Energy Secretary Steven Chu gave on Friday ,when he told reporters that about 70 percent of the core of one reactor had been damaged, & that another reactor had undergone a 33 percent meltdown  came from forensic modeling.

Most of these computer-based forensics systems were developed after the 1979 partial meltdown at Two Mile Island, when regulators found they were fundamentally blind to what was happening in the reactor. Since then, to satisfy regulators, companies that run nuclear power plants use snippets of information coming out of a plant to create simulations of what is happening inside & to perform a variety of risk evaluations.

The bits of information that drive these analyses range from the simple to the complex. They can include everything from the length of time a reactor core lacked cooling water to the subtleties of the gases & radioactive particles being emitted from the plant. Engineers feed the information points in to computer simulations that churn out detailed portraits of the imperceptible, including lots of specifics on the melting of the hot fuel cores.

Governments & companies now possess dozens of these independently developed computer programs, known in industry jargon as safety codes.Lots of of these institutions  including ones in Japan are relying on forensic modeling to analyze the catastrophe at Fukushima Daiichi to plan for a range of activities, from evacuations to forecasting the likely outcome.

These portraits of the Japanese catastrophe tend to be proprietary & confidential, & in some cases secret. One reason the assessments are enormously sensitive for industry & government is the relative lack of precedent: The atomic age has seen the construction of  600 civilian power plants, but according to the World Nuclear Association, only two have undergone serious accidents in which their fuel cores melted down.

The codes got better & better after the accident at Two Mile Island revealed the poor state of reactor assessment, said Michael W. Golay, a professor of nuclear science & engineering at the Massachusetts Institute of Know-how.

They don't required to go there,said Robert Alvarez, a nuclear specialist who, from 1993 to 1999, was a policyowner adviser to the secretary of energy. The spin is all about reassurance.

Now, because of the crisis in Japan, the atomic simulations recommend that the number of serious accidents has suddenly doubled, with two of the reactors at the Fukushima Daiichi complex in some stage of meltdown. Even so, the public authorities have sought to keep away from grim technical details that might trigger alarm or even panic.

If events in Japan unfold as they did at Two Mile Island in Pennsylvania, the forensic modeling could go on for some time. It took over two years before engineers lowered a camera to visually inspect the damaged core of the Pennsylvania reactor, & another year to map the extent of the destruction. The core turned out to be about half melted.