A Decade of REMS
This is a 10-year summary of data collected by DOE’s Radiation Exposure Monitoring System (REMS). Data were analyzed over a ten-year period from 2008-2017. During this time period, more than 885,000 annual monitoring records representing over 223,700 unique individuals from 42 sites were monitored. Of those individuals, over 47,700 individuals (21 percent) received measurable radiation dose.
The goal of this summary is to provide a broad description of occupational radiation exposure data collected across the DOE Complex over the past 10 years through the use of interactive graphics, and to offer explanations for trends seen in these data. The information that follows is divided into different areas that help illustrate the complex nature of the DOE mission and the relationship to occupational radiation dose.
Certain key indicators are useful when evaluating occupational radiation exposures received at DOE facilities. The key indicators are analyzed to identify and correlate parameters having an impact on radiation dose at DOE.Definitions
The Total Effective Dose (TED) is comprised of external and internal dose. The penetrating (deep) photon dose represents the majority of the TED.
The Committed Effective Dose (CED) has generally fluctuated over the last 10 years (with a notable exception for 2010) and is 10 percent higher than in 2008.
Average Measurable TED
Average measurable TED has been at a consistent level within the DOE over the past 10 years.
Doses In Excess of Limits
There were 2 dose limit exceedances over the 10 year period. These exceedances were the result of puncture wounds.
From 2008 to 2017, the collective internal dose fluctuated around the 10 year average of 58.7 rem. CED increased in 2010, primarily due to a substantial internal dose of 32 rems at SRS, which accounted for one-third of the collective internal dose that year. Internal dose decreased from 2011 to 2013. In 2014, the CED increased overall by 21 percent. This was caused by a 25 percent increase in CED at Y-12 due to an increase in work activities after the 2013 response to a government sequestration. The majority of all internal dose every year (greater than 90 percent) can be attributed to uranium enrichment at the Y-12 National Security Complex in Oak Ridge. CED was the smallest component of total dose (6.0-10.1 percent) throughout the 10-year period.
Deep dose (photon) was the largest component of collective TED (72-81 percent) from 2008 to 2017. The trend in deep dose mirrored that of total collective dose; deep dose increased in 2009 and 2010, then decreased again from 2010 to 2013, with a slight increase in 2014. There was a 29 percent increase in deep dose from 2014 to 2015 due to waste management activities at the Idaho Site. Increases and decreases in the deep dose therefore, are the overall drivers in the increase and decrease in the collective TED. Deep dose has fluctuated in the past 10 years in accordance with increases and decreases in D&D activities, production work, and safety practices. A main reason of the decrease since 2006 has been the shutdown of facilities that had contributed significantly to the collective deep dose in the past. Deep dose increased in 2017, likely attributed to the resumption of programmatic activities at WIPP and LANL and increased radiological work at ORNL and SRS. More details are found under the Historical Overview tab of this report.
Neutron dose fluctuated over the past 10 years in relation to activities at large plutonium processing facilities, primarily LANL, Hanford, and SRS. There was an upswing in the neutron component in 2010, attributable to ARRA-funded projects and some sites claim as a direct result of new reporting requirements from the amendment to 10 CFR 835. Neutron dose increased by 27 percent from 2016 to 2017. Neutron dose from 2008 to 2017 comprised 12-21 percent of total dose.
The collective internal dose has generally remained the same across the DOE Complex from 2008 to 2017, with the exception of 2010. The number of individuals with measurable CED stayed generally steady from 2006 to 2008, then increased in 2010 and decreased through the end of 2015. There was a 3 percent increase in the number of individuals with measurable CED in 2017. Typically, over 90 percent of all internal doses are attributable to uranium operations at Y-12 in Oak Ridge.
The collective Committed Effective Dose (CED) has generally fluctuated over the past 10 years with one notable exception. In 2010, a major incident at SRS caused a significant increase in CED. Internal dose decreased from 2011 through 2013, and since then, with the exception of a slight decline in 2015, CED has been increasing slightly for the past few years.
The 10-year average measurable CED across the Complex was 0.044 rem. The major event in 2010 was an outlier that resulted in an above-average value of 0.058 for that year. Internal doses ranged between 0.033 and 0.038 for the years 2011 through 2013, and increased to 0.045 for both 2014 and 2015. In 2016 and 2017, the internal dose continued to increase above the 10-year average to 0.050 and 0.051 respectively.
Average measurable TED is calculated by dividing the collective TED by the number of individuals with a measurable TED. It is considered to be a good measure of the dose accrued by workers at DOE. However, it should be noted that it does not paint an exact picture of dose distribution across the worker population. Overall, average measurable TED has been fairly consistent over the past 10 years within the DOE. An exception can be seen in 2010, but these increases correlate with major incidents and are largely attributable to unusually high internal exposures (see Doses in Excess of Limits and Internal Dose sections of the Overview).
The average measurable TED has decreased overall by 5 percent from 2008 to 2017.
Two specific TED limits are considered as a measure of high individual doses. The RadCon Manual [Ref. 1] established a maximum 2 rems Administrative Control Levels, and 10 CFR 835 establishes a regulatory TED limit of 5 rems per year. There were 2 doses in excess of these limits in the period 2008-2017; 1 of the exposures was greater than 2 rems and 1 was greater than 5 rems. One of these doses in excess of limits occurred at LANL. The dose was due to plutonium (Pu-238 in combination with Pu-239). Both of these doses in excess of limits were the result of a puncture wound. Both resulted in an occurrence report. In 2010, a puncture wound involving Pu-238 at SRS led to the highest internal dose (CED) in the DOE Complex over the past 10 years (31.6 rems). There have been no doses in excess of limits since then.
 DOE-STD-1098-2017, "DOE Radiological Control Manual," U.S. Department of Energy, January 2017
Over the past 10 years (2008-2017), there have been minor changes in reporting requirements or radiation dose limits. In fact, the current DOE dose limits were implemented in 1989. It is worth noting, however, that the regulation regarding radiation protection standards and program requirements (10 CFR 835) has been amended twice (2007 and 2011). Recent requirements of 10 CFR 835 include the adoption of ICRP 60 neutron weighting factors and the revision of ICRP dose conversion factors. Some sites noted that these new recommendations caused a reported increase in neutron dose but the extent of the increase is not possible to determine from the data in REMS.
DOE Order (0) 231.lA, which outlined the annual reporting requirements for REMS, was issued in 2003 and replaced with DOE O 231.1 B in 2011. DOE Manual (M) 231.1-lA, Environment, Safety, and Health Reporting Manual, was approved in 2004 but has since been replaced by the online REMS Reporting Guide in 2012.
DOE Order (0) 5480.11, Radiation Protection for Occupational Workers (1988), and 10 CFR 835 require that each DOE facility have an ALARA (as low as reasonably achievable) program as part of its overall radiation protection program. According to the ALARA principle, resources spent to reduce dose need to be balanced against the risks avoided. This has been one of the fundamental pillars in radiation protection for DOE since the 1970's. While some sites have reported that the use of ALARA has helped to reduce dose, it is not possible to measure the overall impact from ALARA improvement as there are many other confounding factors such as the closure of facilities, reductions in production, and D&D efforts.
Changes in Mission
The Department of Energy (DOE) was officially created in 1977 with the Department of Energy Organization Act. The mission of the Department was focused on two major areas: defense activities related to nuclear weapons production and testing, and the consolidation of energy related programs. The mission of DOE began to change significantly in the late 1980's as the focus became less oriented around weapons production. Several facilities that historically had produced weapons and related components were no longer in operation by the end of 2014.
ARRA Funded Sites
From 2006 to 2008, collective dose was steadily decreasing across the DOE complex largely due to diminishing production and remediation activities; however, in 2009, the American Recovery and Reinvestment Act (ARRA) was passed, and almost $38.3 billion was allotted to DOE for FY 2009 and FY 2010. Over $5 billion was used to support remediation efforts at several sites and created almost 8,000 jobs. The largest portion of funding went to Hanford, Idaho, Savannah River, and Oak Ridge. An increase in activities and personnel led directly to an increase in collective dose from 2009 to 2012. As ARRA funding decreased, so did projects, resulting in a decrease in dose after 2013.
DOE has been in the process of remediating many sites, and several major ones were closed in the recent past including Fernald (2004). Additionally, the gaseous diffusion plants at Portsmouth were placed in cold shutdown status in 2005. Cleanup was officially declared complete at Rocky Flats (2005), and remediation began at Moab, UT (UMTRA) in 2008. Some decisions made in 2002 set the tone for the ten-year period of this report. DOE, EPA, and the State of Washington agreed to accelerate the cleanup at Hanford. In addition, operations at Idaho were transferred from the Office of Environmental Management to the Office of Nuclear Energy, although remediation still remained a priority. Environmental remediation continues at other large sites including Savannah River and Oak Ridge.
In addition to cleanup activities, DOE has also allocated more funds to non-nuclear research, including nanotechnology, renewable energy, and advanced materials. This shift in research priority has continued to lessen the radiation exposure that workers receive. ALARA continues to be a pillar of radiation worker protection in DOE, but the combination of safer work practices along with diminished weapons production, site closures, and shrinking environmental footprints for remediation have all contributed to an overall downward trend in dose for the past 10 years.
Collective TED has been decreasing for this group of sites since 2015. There was a 35 percent increase in collective TED from 2014 to 2015. This increase was primarily due to increased cleanup activities at SPRU. Collective TED in 2016 decreased by 8 percent as SPRU finished the removal of the more significant source term activity.
2017 saw a 24 percent decrease in collective TED from the previous year.
The five sites shown contribute the majority of the collective radiation dose at DOE. The examination of these sites and the changes in dose experienced at these sites is instructive due to the contribution of these sites to the overall DOE collective dose.
Los Alamos National Laboratory
Savannah River Site
The DOE Idaho Site, located at Idaho Falls, Idaho, consists of four facilities: Idaho National Laboratory (INL), the Advanced Mixed Waste Treatment Project (AMWTP), the Idaho Cleanup Project (ICP), and the DOE Idaho Operations Office. From 2008 to 2017, over 68,000 annual monitoring records were submitted. Total collective dose was generally low from 2012 to 2014, as well as in 2016 and 2017. The composition of dose at Idaho Site is consistent with most DOE sites, in that the greatest component of dose is deep dose.
Collective dose increased in 2010 and 2011 related to increased D&D activities under ARRA in 2010 and an incident in 2011, which led to internal exposure of 16 workers at the Materials and Fuels Complex Zero Power Physics Reactor (ZPPR) Facility. Dose decreased significantly in 2012, to a level comparable to 2003. This decrease was due to a shutdown of the Materials and Fuel Complex, continuing safety enhancements at AMWTP, and the completion of some high-dose jobs regarding cleanup activities. In 2013 and 2015, dose increased due to increased Department of Homeland Security training exercises and accelerated waste processing operations to meet contractual obligations. In addition to the increased waste processing, the waste processed had a higher average exposure rate than processed waste in 2012. Collective dose in 2017 decreased by 15 percent from 2016 as the result of decreased decontamination activities, along with decreased level of radioactivity of the waste that was handled.
Hanford, located near Richland, Washington, consists of the Hanford Site, the Office of River Protection (ORP), and the Pacific Northwest National Laboratories (PNNL). From 2008 to 2017, over 98,700 annual monitoring records were submitted. While collective dose fluctuated over the ten-year period, the general trend was a 39 percent decrease in dose over the past 10 years.
Neutron dose increased from 15 rems in 2009 to 35.9 rems in 2010 due to cleanout and removal of glove boxes at the Plutonium finishing Plant (PFP). These activities were funded by ARRA, and neutron dose steadily decreased from 2010 to 2012 as these glove box activities decreased along with ARRA funds. Total collective dose increased until 2010 due to increased D&D activities related to ARRA-funded work; however, dose decreased again through 2012 due to a decrease in ARRA-related D&D activities. In 2013, dose decreased due to reductions in work regarding budgetary constraints. In 2014, the primary reasons for the decrease in collective TED was a change in the work scope at DOE-RL to include more work involving heavy equipment which increased the distance between workers and source terms and the implementation of long-length tools at DOE-ORP. Increases in 2015 were primarily related to work at the plutonium finishing plant facility, including the dismantlement of two large glove boxes in the process lines and the cleanout of the plutonium recovery facility canyon. Decreases in 2016 were related to decreases in work activities at the plutonium finishing plant facility. In 2017, a transition in work activities from source term removal to facility demolition at the Plutonium Finishing Plant (PFP) facility and the continued operation of several projects at minimal levels due to changes in funding, contributed to decreases in dose.
Los Alamos National Laboratory (LANL) is located 35 miles northwest of Santa Fe, New Mexico, includes more than 2,000 individual facilities and currently employs over 10,000 individuals. From 2008 to 2017, nearly 110,000 annual monitoring records were submitted. While there is no clear trend in the total collective dose over the past 10 years, the total dose has been below the 10-year average (120 person-rems) except for the period from 2010 to 2013 and in 2017. The composition of dose at LANL is unusual because the largest component is neutron dose, which accounted for 42–57 percent of total dose in the 10-year period. This is the only site out of the top five contributors that has this characteristic; this is explainable by the fact that LANL processes plutonium in gloveboxes, which can result in a neutron dose from the alpha/neutron reaction and from spontaneous fission of the plutonium. There was one reportable incident at LANL in 2008.
Within the 10-year period, the highest collective dose (160 person-rems) occurred in 2017. Programmatic work at TA-55 was fully resumed and the facility was operating at normal capacity following a shutdown in 2013; and solid waste handling work that was curtailed in early 2015, due to a contamination release event at the Waste Isolation Pilot Plant (WIPP), resumed in 2017. Towards the end of 2007, another safety concern caused operations to be shut down until September 2008, which significantly decreased dose. Once operations resumed, dose gradually increased from 2008 through 2013. The majority of dose at LANL is attributable to increased operations at TA-55 (Plutonium Processing Facility). Additional operations at the TA-50 and TA-54 waste facilities and TA-53 [Los Alamos Neutron Science Center (LANSCE)] led to increase in dose from 2008 to 2013. Work with solid waste was curtailed early in 2014 due to the radioactive material release event at the Waste Isolation Pilot Plant and its relation to LANL waste packaging. (See Occurrence Report EM-CBFO-NWP-WIPP.) This caused a 31 percent decrease in collective TED in 2014.
The Oak Ridge Site includes operations from Y-12 National Security Complex (Y-12), Oak Ridge National Laboratory (ORNL), the Oak Ridge Institute for Science and Education (ORISE), and the East Tennessee Technology Park (ETTP), formerly known as the K-25 Site. Over 141,000 annual monitoring records were received from Oak Ridge during the last 10 years (2008-2017). Collective dose at Oak Ridge fluctuated around the 10-year average (131.4 person-rems), but since 2016, the collective dose has been above average, primarily due to due to maintenance and waste handling activities at neutron research and radiochemistry facilities, and increased project work activities at hot cell and radiochemistry facilities.
Overall, there is no clear trend over the past 10 years at Oak Ridge regarding total collective dose with the exception that isotope production at ORNL is the primary driver behind the total collective dose for Oak Ridge. It is clear that Oak Ridge is unique in that the largest component of dose has consistently been internal dose (ranging from 31–55 percent). No other site in the top five contributors to dose has this characteristic as typically over 90 percent of all internal dose throughout the complex originates at Y-12 during uranium processing. Usually, one-third of all internal dose measurements taken are through air sampling.
Total collective dose gradually increased from 2008 through 2012. The reasons for the increase are: an increase in cleanup activities at ETTP and Y-12, an increase in production at Y-12, and also an increase in waste operation and isotope production at ORNL. Above average doses from 2010 to 2012 are attributed to activities funded by ARRA. The primary reason for collective dose decrease in 2013 was an approximate 2-month decrease in production work at Y-12 in preparation for the government shutdown during sequestration in October 2013. Likewise, the slight increase in 2014 dose was caused by the increased activity required to recover from the actions associated with the 2013 government sequestration. A 10 percent decrease in 2015 was the result of intermittent work stoppages throughout the year at Y-12 from weather and other factors and a decrease in collective TED at the transuranic waste processing center. A 21 percent increase in 2016 was the result of increased activities at the radiochemistry facilities in addition to increased maintenance and waste handling activities. A 13 percent increase in 2017 was attributed to maintenance and waste handling activities at neutron research and radiochemistry facilities, and increased project work activities at hot cell and radiochemistry facilities.
The Savannah River Site (SRS) is a 310 square mile DOE site located near Aiken, South Carolina. It includes multiple organizations, including DOE Savannah River Operations Office, the NNSA Savannah River Site Office, and the Savannah River National Laboratory (SRNL). Over 70,000 annual monitoring records were submitted from 2008 to 2017 at SRS. SRS received $1.6 billion in ARRA funding to accelerate the cleanup of legacy waste, which led to an increase in total dose from 2010 - 2012. In 2010, one individual received an internal dose of 32 rems. Total collective dose remained below the 10 year average (127 person-rems) from 2013 to 2016.
The addition of and expansion of work activities led to a moderate increase in collective dose in 2008, but this decreased again in 2009 because some high dose-rate work was postponed or reduced. As mentioned previously, collective dose increased significantly in 2010 due to an increase in ARRA-funded D&D activities. A major contributor to this increase was a large internal exposure (32 rems) from an intake of plutonium in one individual, which contributed to 18 percent of collective TED for 2010. Collective dose then decreased and remained steady in 2011 and 2012 (between 145 and 150 person-rems). This reduction in dose is attributable to the implementation of a variety of tools and techniques to reduce dose and the reduction in ARRA-funded activities. The collective dose decreased significantly in 2013 due to a host of budget issues that arose during the year and many ALARA initiatives that were employed. In 2014, a slight increase in collective dose was attributed to completing projects like the SRNL Cell Window replacements. Increases in 2016 were attributed to the remediation of 1950s era storage tanks and resuming process operations in portion of the H Canyon. The 35 percent increase in collective dose from 2016 to 2017 can be attributed to more workers engaging in activities with a high potential for exposure such as the 3H evaporator pot repair and the Defense Waste Processing Facility Melter 2 removal and replacement.
Collective dose in the DOE Complex increased by 10 percent from 2008 to 2017. Many factors led to this including an increase in D&D activities at major sites (Oak Ridge, Hanford, and Idaho).
Beginning in 2009, dose increased as ARRA related funding helped secure additional sources of funding for D&D activities at multiple DOE sites, primarily Hanford and Idaho, and for increased production work at Oak Ridge, LANL, and Pantex. In 2010, collective dose rose to its highest level since 2005 due to the additional work funded by ARRA. However, as ARRA-related funding began to diminish, so did work activities and dose, as collective TED decreased from 2010 to 2014.
The decrease in collective dose from 2006 to 2008 is not attributable to any one particular policy or procedure, but rather a decrease in activities throughout the complex. While DOE Order 231.lA (2003) and 231.1B (2011) were implemented in regards to reporting, no significant changes were seen. The amendments to 10 CFR 835 appear to have had minimal impact on the collective dose as operational changes in mission were more significant. There does appear to be some dose reduction from 2011 to 2012 due to better ALARA awareness and use of safety technology, but this is confounded by a reduction in ARRA activities as well. In 2013, the overall decrease in collective TED was attributed to preparation for government shutdown during October sequestration and work reductions due to budget constraints. The slight collective TED decrease in 2014 was attributed to curtailing work with solid waste and changes in work scope to incorporate ALARA processes. Increases in 2015 and 2016 were the result of increased cleanup activities at SPRU in 2015 and increased activities at WVDP, SRS, ORNL, and Pantex in 2016. Dose increased by 7 percent in 2017; mainly due to increased work activities at LANL, SRS, and Oak Ridge.