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PhD student finds Soviets misreported Chernobyl accident

By Stacey E. Blau

It is rare, even at MIT, that a doctoral thesis project merits media attention, but Alexander R. Sich PhD '94, a former nuclear engineering graduate student, found that the 1986 Chernobyl nuclear accident released more radiation than the Soviet Union reported.

The findings were still noteworthy after Sich had to scale back part of his results because a computer program he used made inaccurate calculations.

According to Sich's research, the Soviet airlifts of 5,000 tons of concrete meant to smother the burning reactor core did not work. The pilots aimed at the wrong target, a red glow located 50 feet from the core. The core extinguished itself after undergoing a complete meltdown over a 10-day period after the explosion.

Sich found that nine days later, the core melted through the six-foot reactor shield and spilled into a lower level where it spread out sufficiently to cease the nuclear reaction. Because the radioactive material in the core was not shielded immediately, a high emission of radiation occurred, according to Sich's research.

The thesis reported that between 185 and 250 million curies of radiation were released as a result of the nuclear reactor's meltdown. Official Soviet reports pegged the radiation level at 50 million curies. One curie is the amount of radiation given off by one gram of naturally occurring radium per second.

The Nuclear Regulatory Commission conducted an investigation in response to Sich's findings. The commission found that a computer program Sich used was inaccurate and the radiation emission from the accident was 120 million curies, about six-tenths of what Sich originally claimed, but still two to three times greater than original Soviet reports.

The error did not affect Sich's data on radiation exposure to people around the accident site, nor did it affect his assertion that the Soviet helicopter airlifts in the days following the explosion were a failure, according to Professor Emeritus of Nuclear Engineering Norman C. Rasmussen PhD '56, Sich's thesis adviser.