Nuclear accidentsNuclear accidents pose “essentially zero risk" to public health

Published 9 February 2012

A new study by the U.S. Nuclear Regulatory Commission (NRC) concluded that there is only a “very small” risk to public health if a severe nuclear accident were to occur in the United States

A new study by the U.S. Nuclear Regulatory Commission (NRC) concludedthat there is only a “very small” risk to public health if a severe nuclear accident were to occur in the United States.

The NRC said, in the event of an accident, reactor operators would have enough time to prevent core damage and reduce the release of harmful radioactive materials, thus sparing nearby residents of any exposure to dangerous radiation.

Successful implementation of existing mitigation measures can prevent reactor core damage or delay or reduce offsite releases of radioactive material,” the study said. “As a result, the calculated risks of public health consequences from severe accidents modeled in the severe accident study are very small.”

In a worst case scenario of an earthquake causing a facility wide blackout, according to the study, core damage could begin in one to three hours and reactor vessel failure could begin in roughly eight hours. Based on those estimates, the NRC said plant operators would have enough time to restore core cooling mechanisms and prevent vessel failure.

In the event that cooling capabilities are not restored, radioactive materials could be released in about eight hours from the Peach Bottom nuclear plant in Pennsylvania and twenty-five hours from the Surry nuclear plant in Virginia, the two nuclear facilities the NRC used to conduct the study.

The study was based on the Peach Bottom and Surry nuclear plants as these two facilities use the two reactor types most commonly found throughout the United States. Approximately one third of the country’s 104 nuclear plants use a similar General Electric boiling water reactor found at Peach Bottom, while roughly two-thirds use a Westinghouse pressurized water reactor design found in Surry.

The study analyzed various scenarios that could hinder nuclear operations including the loss of power as a result of an earthquake. At the Fukushima Daiichi nuclear power plant, the devastating 11 March earthquake and tsunami knocked out the facility’s cooling systems and the lack of power prevented operators from pumping water around the reactor fuel, leading to the rods overheating, melting down, and the release of radiation.

In the event of a similar accident in the United States, the NRC noted that portable diesel driven pumps could move water through U.S. reactors to keep nuclear fuel rods cool and prevent a serious accident from occurring.

The report concluded that there was “essentially zero risk” to the public from fatalities due to radiation exposure following a sever accident. According to the study, there is less than a one in a billion chance of dying from cancer as a result of radiation exposure from an accident.