Reactor Cited for Minor Violations By Nuclear Regulatory Commission

Worker Exposed to Nearly a Year’s Safe Dose of Radiation in One Day

The MIT Nuclear Reactor Laboratory was cited by federal officials for violating regulations because a worker was exposed to nearly a year’s worth of radiation in just one day.

According to a U.S. Nuclear Regulatory Commission report, MIT discovered on Oct. 17 that a worker had been exposed to four rems of radiation. This exposure is 80 percent of the yearly safe amount. A reading of 0.5 rem or less is typical for the type of work which led to the exposure.

The NRC investigated MIT’s reactor from October to November. It concluded that MIT had violated two safety requirements at “Severity Level IV,” which according to the NRC report means that they have very low safety significance. (Violations are assigned a severity level ranging from Severity Level I for the most significant to Severity Level IV for those of more than minor concern, according to the NRC.)

The worker, whose job was to load and unload material from the nuclear reactor, failed to survey the area for radiation levels as the procedure required, said NRC spokesman Neil Sheehan. The worker failed at least five times to survey the area for radiation levels when working with magnesium-encased silicon ingots. The worker’s oversight created “a plane source of radiation to which the individual was exposed during each work period,” according to the NRC report.

The worker also improperly attached his dosimeter, a device used to measure radiation levels, Sheehan said. While handling irradiated material, the worker wore the device, a finger ring, backwards — the sensor chip was facing outward instead of inward.

The violations are not serious enough to impose a fine, Sheehan told The Cambridge Chronicle. “If they have any additional violations in the next two years, they could face civil penalties,” Sheehan said.

The MIT Nuclear Reactor Laboratory responded to the report of irradiation by immediately stopping operations to study the problem, said Claude R. Canizares, vice president for research.

“Basically, a human error took place,” Canizares said. Canizares said the errors revealed the need for more stringent training, and MIT has reviewed its training procedures.

The NRC’s findings are “relatively minor,” said David E. Moncton PhD ’75, director of the MIT Nuclear Reactor Laboratory. The high dosimeter reading was an unexpected consequence of improving the way the worker handled the material, he said.

Handling procedures and the training process, which were “pretty good to begin with” have been revamped, Moncton said. “We don’t take [these findings] lightly” even though the dosimeter reading was well below any legal or health limit, he said.

According to MIT’s statement on the issue, “The MIT reactor lab has one of the best safety records of any reactor — research or power — in the country, based on routine inspections by the NRC. The situation posed no danger to public health and safety or to the environment.”