By THE ASSOCIATED PRESS
Published: January 25, 2012
TOKYO (AP) — The Japanese government’s worst-case scenario at the height of the nuclear crisis last year warned that tens of millions of people, including residents of Tokyo, might be forced to leave their homes, according to a report. Fearing widespread panic, officials kept the report secret.
The emergence of the 15-page internal document might add to complaints that the government withheld too much information about the meltdown at the Fukushima Daiichi nuclear plant, the world’s worst nuclear accident since the Chernobyl disaster in 1986.
It also casts doubt about whether the government was sufficiently prepared to handle what could have been an evacuation on an extraordinary scale.
The report was submitted to Naoto Kan, the prime minister at the time, and his top advisers on March 25, two weeks after an earthquake and tsunami devastated the Fukushima Daiichi nuclear power plant, causing three reactors to melt down and generating hydrogen explosions that blew away protective structures.
Workers ultimately were able to bring the reactors under control, but at the time it was unclear whether those emergency measures would succeed. Mr. Kan commissioned the report, compiled by the Japan Atomic Energy Commission, to examine what options the government had if those efforts failed.
The authorities evacuated 59,000 residents within 12 miles of the Fukushima plant, and thousands more were evacuated from other towns later. The report said, however, there was a chance that far larger evacuations might be necessary.
The report looked at several ways the crisis could escalate — explosions inside the reactors, complete meltdowns, and the structural failure of cooling pools used for spent nuclear fuel.
Using matter-of-fact language, diagrams and charts, the report said that if meltdowns spiraled out of control, radiation levels could soar.
In that case, it said, evacuation orders should be issued for residents within and possibly beyond a 105-mile radius of the plant and “voluntary” evacuations should be available to everyone living within 155 miles and beyond.
That would have included the Tokyo area, with a population of 35 million people, and other major cities like Sendai, with 1 million people.
The report further warned that contaminated areas might not be safe for “several decades.”
“We cannot rule out further developments that may lead to an unpredictable situation at Fukushima Daiichi nuclear plant, where there has been an accident, and this report outlines a summary of that unpredictable situation,” said the document, which was written by Shunsuke Kondo, the leader of the atomic energy commission.
After Mr. Kan received the report he and other Japanese officials publicly insisted that there was no need to prepare for more widespread evacuations.
Rumors of the report emerged this month after a panel was created to investigate possible cover-ups. The Kyodo News agency first reported on the contents of the document on Saturday.
Nevertheless, the government continues to refuse to make the document public. Goshi Hosono, the cabinet minister in charge of the nuclear crisis, implicitly acknowledged the document’s existence this month, but said the government had felt no need to make it public.
“Even in the event of such a development, we were told that residents would have enough time to evacuate,” Mr. Hosono said.