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Sich Scales Back Chernobyl Findings

By Stacey E. Blau
Staff Reporter

Alexander R. Sich PhD '94, a former graduate student in the nuclear engineering department, scaled back his findings that the Chernobyl nuclear meltdown was far worse than previous Soviet reports. This was in response to a subsequent investigation last spring.

"The British code that he used for the calculation said that there were more curies of radiation released than there actually were," said Professor of Nuclear Engineering Norman C. Rasmussen PhD '56, Sich's doctoral thesis adviser.

Sich's thesis, published last January, originally reported that between 185 and 250 million curies were released as a result of the 1986 meltdown. Official Soviet reports said that the release was 50 million curies. A curie is the amount of radiation released by one gram of radium.

An investigation conducted by the Nuclear Regulatory Commission last spring in response to Sich's report found that the British program that Sich used was inaccurate. The commission reported that the radiation emission was 120 million curies, about six tenths of what Sich originally claimed but still two to three times original Soviet reports.

"The error was buried in the code," Rasmussen said. "[Sich] agreed that there was an error and redid the calculation." Sich added an erratum to his thesis on July 21 correcting his error. "I don't think it was serious," Rasmussen added.

The error does not affect Sich's data on radiation exposure to people around the meltdown site, nor does it affect his assertion that the Soviet helicopter airlifts in the days following the explosion were a failure, Rasmussen said.

According to Sich's research, the 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 which proved not to be the core, which was located about 50 feet away. 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 6-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.

Numerous studies have linked the high radiation release to increased incidence of thyroid problems, diabetes, and cancer in the region surrounding Chernobyl, where millions of people still live. The official Soviet death toll from the accident is 33, but some medical experts say that thousands may have died later as a result of radiation exposure.

Three of the four Chernobyl plant reactors continue to operate. Reactor number four, which underwent the explosion and meltdown, is encased in concrete and steel. The other three reactors supply nuclear energy to the Ukraine, where the plant is located.

Sich is presently working for the World Bank in London, where he is "evaluating nuclear projects for which countries around the world require loans," Rasmussen said. Sich's job is to determine whether or not the projects "make technical sense," Rasmussen said.