Key Issues
Radiation Safety at Nuclear Power Plants: Studies Look at Public, Workers
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National Academy Reviews Radiation Risk
The BEIR VII report is the updated scientific basis for radiation safety standards in the United States. NAS last addressed this topic in the BEIR V report, issued in 1990. NAS formed the BEIR VII committee in 2000 to review the large body of scientific research on radiation health effects that has accumulated over the past 15 years.3 “In general, BEIR VII supports previously reported risk estimates for cancer and leukemia, but the availability of new and more extensive data have strengthened our confidence in these estimates,” said Dr. Richard Monson, chairman of the BEIR VII committee and associate dean at the Harvard School of Public Health.
The study found that 1 percent of individuals receiving a dose of 10 rem would be expected to develop cancer, compared with the 42 percent likely to develop cancer from other causes. A 10,000-millirem dose is twice the NRC’s annual occupational limit.
The BEIR VII committee said it is difficult to estimate cancer risk from radiation doses of 10 rem or less. However, the committee said the BEIR VII study continues to support the “linear-no-threshold model” for radiation exposure. The model holds that risk declines commensurate with lower radiation exposures; very low exposures mean that the risk to an individual is very low but cannot be assumed to be zero. “The preponderance of information indicates that there will be some risk, even at low doses, although the risk is small,” Monson said.
Studies of children whose parents were exposed to radiation have found no adverse health effects that could be attributed to radiation. The committee said that the failure to observe such effects in human studies probably reflects that the genetic risks are very small.
Radiation Health Effects On Public Near Plants
Although nuclear power plants represent one of the smallest sources of radiation exposure to the public, a large number of scientific studies have focused on ensuring that they are not a risk to people living nearby.
Several uncertainties are inherent in any study of the effects of radiation. First, it is extremely difficult to identify an appropriate control group of unexposed individuals who are otherwise identical to the exposed population. Second, there are likely to be “confounding variables” among the exposed population—such as exposure to chemicals or cigarette smoke—that are linked to health problems and therefore complicate data interpretation. Third, it often is difficult to determine the exact radiation doses to individuals in the exposed group. For these reasons, it is necessary to carefully scrutinize the methodology of studies whose conclusions deviate from the general scientific consensus about the effects of radiation. Scientific studies include the following:
National Cancer Institute Study. In September 1990, the National Cancer Institute (NCI) of the National Institutes of Health announced that a large-scale study found no increased incidence of cancer mortality for people living near 62 nuclear installations in the United States. The research, which evaluated mortality from 16 types of cancer, showed no increase in the incidence of childhood leukemia mortality in the study of surrounding counties after start-up of the nuclear facilities.
In 1987, the NCI initiated the broadest study of its kind ever conducted, partly in response to a study by the United Kingdom’s Office of Population Censuses and Surveys (see below). The NCI surveyed 900,000 cancer deaths in counties near nuclear facilities that had operated for at least five years prior to the start of the study—the minimum time considered sufficient for related health effects to appear.
National Academy Reviews Radiation Risk
The BEIR VII report is the updated scientific basis for radiation safety standards in the United States. NAS last addressed this topic in the BEIR V report, issued in 1990. NAS formed the BEIR VII committee in 2000 to review the large body of scientific research on radiation health effects that has accumulated over the past 15 years.3 “In general, BEIR VII supports previously reported risk estimates for cancer and leukemia, but the availability of new and more extensive data have strengthened our confidence in these estimates,” said Dr. Richard Monson, chairman of the BEIR VII committee and associate dean at the Harvard School of Public Health.
The study found that 1 percent of individuals receiving a dose of 10 rem would be expected to develop cancer, compared with the 42 percent likely to develop cancer from other causes. A 10,000-millirem dose is twice the NRC’s annual occupational limit.
The BEIR VII committee said it is difficult to estimate cancer risk from radiation doses of 10 rem or less. However, the committee said the BEIR VII study continues to support the “linear-no-threshold model” for radiation exposure. The model holds that risk declines commensurate with lower radiation exposures; very low exposures mean that the risk to an individual is very low but cannot be assumed to be zero. “The preponderance of information indicates that there will be some risk, even at low doses, although the risk is small,” Monson said.
Studies of children whose parents were exposed to radiation have found no adverse health effects that could be attributed to radiation. The committee said that the failure to observe such effects in human studies probably reflects that the genetic risks are very small.
Radiation Health Effects On Public Near Plants
Although nuclear power plants represent one of the smallest sources of radiation exposure to the public, a large number of scientific studies have focused on ensuring that they are not a risk to people living nearby.
Several uncertainties are inherent in any study of the effects of radiation. First, it is extremely difficult to identify an appropriate control group of unexposed individuals who are otherwise identical to the exposed population. Second, there are likely to be “confounding variables” among the exposed population—such as exposure to chemicals or cigarette smoke—that are linked to health problems and therefore complicate data interpretation. Third, it often is difficult to determine the exact radiation doses to individuals in the exposed group. For these reasons, it is necessary to carefully scrutinize the methodology of studies whose conclusions deviate from the general scientific consensus about the effects of radiation. Scientific studies include the following:
National Cancer Institute Study. In September 1990, the National Cancer Institute (NCI) of the National Institutes of Health announced that a large-scale study found no increased incidence of cancer mortality for people living near 62 nuclear installations in the United States. The research, which evaluated mortality from 16 types of cancer, showed no increase in the incidence of childhood leukemia mortality in the study of surrounding counties after start-up of the nuclear facilities.
In 1987, the NCI initiated the broadest study of its kind ever conducted, partly in response to a study by the United Kingdom’s Office of Population Censuses and Surveys (see below). The NCI surveyed 900,000 cancer deaths in counties near nuclear facilities that had operated for at least five years prior to the start of the study—the minimum time considered sufficient for related health effects to appear.
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