Occupational Radiation Exposure at Commercial Nuclear Power Reactors and other Facilities 2016: Forty-Ninth Annual Report (NUREG-0713, Volume 38)
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Manuscript Completed: July 2017
Date Published: May 2018
1299 Bethel Valley Road, SC-200, MS-21
Oak Ridge, TN 37830
M.N. Nguyen, NRC Project Manager
Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001
This report summarizes the occupational exposure data that are maintained in the U.S. Nuclear Regulatory Commission (NRC) Radiation Exposure Information and Reporting System (REIRS) database. The bulk of the information contained in this report was compiled from the 2016 annual reports submitted by five of the seven categories1 of NRC licensees subject to the reporting requirements of Title 10 of the Code of Federal Regulations (10 CFR) 20.2206, "Reports of Individual Monitoring." Because there are no geologic repositories for high-level waste currently licensed and no NRC-licensed low-level waste disposal facilities currently in operation, only five categories are considered in this report. The annual reports submitted by these licensees consist of radiation exposure records for each monitored individual. These records are analyzed for trends and presented in this report in terms of collective dose and the distribution of dose among the monitored individuals.
Annual reports for 2016 were received from a total of 193 NRC licensees from the five categories included in this report. The summation of reports submitted by the 193 licensees indicated that 164,984 individuals were monitored, 65,615 of whom received a measurable dose (Table 3.1). When adjusted for transient individuals, there were actually 121,129 unique individuals that were monitored, 50,299 of whom received a measurable dose (see Section 5).
The collective dose incurred by these individuals was 7,057 person-rem (70,570 person-millisieverts [mSv]), which represents a 23 percent decrease from the 2015 value. The 2016 collective dose is a 27 percent decrease from the 5-year average of 9,718 person-rem (2011 – 2015), reflecting a statistically significant change.2 The 2015 – 2016 decrease was due to a reduction in all five reporting categories; commercial nuclear power reactor licensees (24 percent decrease), industrial radiographers (25 percent decrease), fuel cycle licensees (15 percent decrease), manufacturing and distribution (M&D) licensees (8 percent decrease), and spent fuel storage licensees (47 percent decrease). When compared to the 5-year average of collective dose for each category, four of the five categories had statistically significant decreases. The decrease for M&Ds was not statistically significant.
The number of individuals receiving a measurable dose decreased by 15 percent from the 2015 value and decreased 19 percent from the 5-year average, which is statistically significant. When adjusted for transients, the average measurable dose of 0.14 rem (1.4 mSv) decreased by 13 percent for 2016, and is statistically significant when compared to the 5-year average. The average measurable dose is defined as the total effective dose equivalent (TEDE) divided by the number of individuals receiving a measurable dose.
In calendar year 2016, the average annual collective dose per reactor for light-water reactor (LWR) licensees was 54 person-rem (540 person-mSv). This is a 24 percent decrease from the value reported for 2015 (Table 4.3) and a statistically significant 27 percent decrease from the 5-year average. The total outage hours at commercial nuclear power plants decreased 9 percent from 2015 to 2016 [Ref. 1]. The collective dose for this licensee category fell 1,653 person-rem (16,530 person-mSv) to 5,366 person-rem (53,660 person-mSv). The average annual collective dose per reactor was 98 person-rem (980 person-mSv) for the 34 boiling-water reactors (BWRs) and 31 person-rem (310 person-mSv) for 65 pressurized-water reactors (PWRs). The BWR 2016 value is 21 percent below the 5-year average annual collective dose per BWR reactor. The 2016 value for PWR licensees is 36 percent below the 5-year average annual collective dose per PWR reactor. Both of these decreases are statistically significant. The primary driver for the decrease in collective dose for both PWRs and BWRs was a 20% decrease in refueling outage hours from 2015 to 2016. Refueling activities generally result in increased individual and collective doses as the reactor vessel is opened and the spent fuel is removed. A decrease in refueling outages and activities results in lower individual and collective dose.
There were 25,782 individuals that were monitored at two or more licensees during the monitoring year. The assessment of the average measurable dose per individual is adjusted each year to account for the reporting of a measurable dose for transient individuals by multiple licensees. The adjustment to account for transient individuals has been specifically noted in footnotes in the figures and tables for commercial nuclear power reactors.
1 Commercial nuclear power reactors and test reactor facilities; industrial radiographers; fuel processors (including uranium enrichment facilities), fabricators, and reprocessors; manufacturing and distribution of byproduct material; independent spent fuel storage installations; facilities for land disposal of low-level waste; and geologic repositories for high-level waste. There are currently no NRC licensees involved in low-level waste disposal or geologic repositories for high-level waste.
2 This report presents additional Statistical Comparisons in Section 2.2.
Page Last Reviewed/Updated Thursday, March 25, 2021