More questions than answers about Japan nuclear crisis

How did Japanese workers at the crippled Fukushima Daiichi nuclear plant jury-rig fire hoses to cool damaged reactors? Is contaminated water from waste pools overflowing into the Pacific Ocean? Who is the national incident commander?

Answers to those and other questions are unclear to U.S. nuclear scientists and policy experts, who say the quality and quantity of information coming out of Japan have left gaping holes in their understanding of the disaster two weeks after it began.

At the same time, they say, the crisis has been growing, judging by releases of radioactivity that by some measures have reached half the level of those released in the Chernobyl accident of 1986, according to new analysis by European and U.S. scientists.

The lack of information has led to growing frustration with Tokyo Electric Power, or Tepco, which operates the nuclear complex, and the Japanese government, which has parceled out information with little context, few details and giant gaps. The international community has been left confused about what is happening and what could come next.

"Information-sharing has not been in the culture of Tepco or the Japanese government," said Najmedin Meshkati, a University of Southern California engineering professor who has advised federal agencies on nuclear safety. "This issue is larger than one utility and one country. It is an international crisis."

Japan has been dealing with an avalanche of miseries that began with a 9.0-magnitude earthquake March 11 that triggered a tsunami, which ravaged the northeast coast. Officials fear more than 27,000 people may have died, and hundreds of thousands were left homeless. The quake and tsunami also damaged the critical cooling system at the Fukushima plant, which overheated and began spewing radiation into the environment.

The nuclear-plant troubles quickly took center stage in the crisis because of the potentially catastrophic national and international implications. Almost every step of the way, problems at the Fukushima plant have been understated by those in charge in Japan, outside experts say, forcing observers to analyze the situation from afar.

The public-health impact is growing with news that radiation has spread, leading to advisories on food and water. An Austrian meteorological institute, the Central Institute for Meteorology and Geodynamics, said this week that computer models showed that the emissions of radioactive cesium from the plant already might amount to 50 percent of what was released from Chernobyl and that releases of radioactive iodine could be 20 percent of the Chernobyl total.

Masaru Tamamoto, a professor of Asian and Middle Eastern studies at the University of Cambridge in Britain, said handling of the crisis by Japanese government and corporate authorities is consistent with a culture that guards information from the public and leaves decisions in the hands of anonymous bureaucrats.

Japan, Tamamoto said, lacks government watchdog organizations that work closely with the media to investigate and publicize government cover-ups. It leaves the public reliant on official pronouncements, he said.

"The public lives this way every day, and that's the way things are," Tamamoto said. "Even if you demanded the information, nobody has the information. Even the prime minister blurted out at one point that he didn't have information."

Tamamoto said even significant nuclear contamination in the country might not be enough to prompt a change. "If this doesn't do it, I can't imagine what else would do it."

It remains unclear whether there is an incident commander managing the day-to-day crisis and who holds the authority for the plant's operations. Tepco officials never have said whether water poured onto the reactors and the pools of still-radioactive spent fuel are draining directly into the Pacific or flooding the sub-basements of the reactor buildings.

"I have this image that they are forcing seawater through the piping somehow," said Frank von Hippel, a Princeton University physicist. He said he didn't know how the repairs were accomplished, but added, "I have a lot of sympathy for these people."

It's also unclear how hydrogen escaped from the reactors and exploded. And while Japanese officials have said there may be a breach in one of the plant's six reactors, they have offered no details, photographs or data about it.

U.S. government agencies, including the Energy Department and the Nuclear Regulatory Commission (NRC), have been circumspect about what's going on at Fukushima, saying they are there at the invitation of Japan and cannot become the primary source of information.

But U.S. officials asserted an independent voice and offered warnings and explicit data in at least two instances. The NRC last week advised U.S. citizens to leave a 50-mile zone around the plant, an area more than double the size that Japan evacuated. The agency this week released radioactivity data that showed a highly radioactive plume on the ground extending northwest from the plant.

Material from The Associated Press is included in this report.