SPEEDI report deepens suspicions
[link to www.japantimes.co.jp]

[snip]

SPEEDI, a computer simulation system used to determine or predict dispersions of radioactive substances, is supposed to be utilized during a nuclear disaster to help people evacuate to safe areas.

But in the early stage of the crisis at Tokyo Electric Power Co.'s Fukushima No. 1 nuclear power plant, the government did not make public the predictions made by SPEEDI. In the absence of relevant information, some people fled to places where radiation levels were actually higher.

On July 27, the education and science ministry, which is in charge of SPEEDI, issued a report based on a probe of its handling of SPEEDI data. The report attempted to justify the ministry's decision to withhold SPEEDI-based predictions of the dispersion of radioactive fallout from Fukushima No. 1.
If someone feels that a cover-up is going on in the ministry, he or she cannot be blamed.

SPEEDI — short for System for Prediction of Environmental Emergency Dose Information — is the same system that the Nuclear Safety Commission uses to make risk calculations.

If hypothetical amounts of radioactive substances released from the reactors had been fed into SPEEDI in the absence of real data, SPEEDI could have predicted the directions in which radioactive materials would disperse.