Participants of the September 29-30, 2016, National Academies of Sciences, Engineering, and Medicine (the National Academies) workshop on Adopting the International System of Units for Radiation Measurements in the United States provided perspectives from the radiation protection and user communities on potential communication improvements associated with adopting SI units for radiation measurements in the United States. Much of the discussions were focused on communications during emergency response and were triggered from the experience of the U.S. response to the 2011 Fukushima Daiichi Nuclear Power Plant accident in Japan. The workshop discussions can be organized in the following themes:
THEME 1: (Chapter 1) The United States has a long history of government policies supporting the adoption of SI units for all measurements. National and international organizations have recommended the exclusive use of SI units for radiation measurements for more than 30 years. However, the United States continues to use conventional units for radiation measurements. As a result, most radiation professionals in the United States must understand both conventional and SI units for radiation measurements and make conversions between the two.
THEME 2: (Chapter 2) SI units for radiation measurements are finding increasing use in the United States. However, the variability in the degree of current use of these units in the U.S. government is considerable. Some agencies (for example, the Department of Transportation and the National Institute of Standards and Technology) use SI units exclusively; others
(for example, the Nuclear Regulatory Commission, the Department of Defense, and the Department of Energy) use a mix of SI and conventional units, and a few (for example, the Federal Emergency Management Agency’s Radiological Emergency Preparedness program and the Occupational Safety and Health Administration) still use only conventional units for radiation measurements. The use of SI units for radiation measurements is also increasing in state and local governments, as well as in medicine and scientific publications. The nuclear power industry exclusively uses conventional units for radiation measurements and has no plans currently to adopt SI units.
THEME 3: (Chapter 3) Several workshop participants noted that the continuing use of conventional units for radiation measurements is problematic, particularly with respect to emergency response. Workshop participants from several agencies, including the Centers for Disease Control and Prevention, the Department of Homeland Security, the Department of Defense, the Department of Energy, and the Environmental Protection Agency, said that their agency’s credibility and trust was placed in jeopardy during the response to the 2011 Fukushima Daiichi Nuclear Power Plant accident because of near-miss conversion mistakes and other related issues. The exclusive use of SI units for radiation measurements has benefits, including alignment of the United States with international practice and improving communications with the public. There are several associated costs to the adoption of SI units related to changes in regulations, reporting, training, and instrumentation. Some budgetary relief in the form of grants or tax exemptions could assist various stakeholders, including state and local governments and nuclear and instrumentation industries, with the adoption of SI units for radiation measurements.
THEME 4: (Chapter 4) Experience from Canada and the United Kingdom related to converting from conventional to SI units for radiation measurements in the 1980s indicates that radiation professionals can adapt quickly to the change. The harmonization of radiation protection standards (including use of units for radiation measurements) within the European Union facilitated Europe’s response to the 2011 Fukushima Daiichi Nuclear Power Plant accident.
THEME 5: (Chapter 5) Several workshop participants noted that the adoption of SI units for radiation measurements is slow and a regulatory or policy change is needed to reendorse adoption of SI units and develop an adoption plan. Many workshop participants suggested that the Nuclear Regulatory Commission’s refusal to require SI units for radiation measurements is inhibiting federal, state, and local governments from adopting the
SI units for radiation measurements. However, some workshop participants noted that it is unlikely that the Nuclear Regulatory Commission will readdress its policy in the near future. The Office of Science and Technology Policy (OSTP) could lead interagency efforts to establish unified guidance for the federal government related to use of units for radiation measurements. OSTP could further examine the merits of exclusively using SI units and support a plan to adopt the use of SI units for radiation measurements.
Assuming that U.S. federal and state agencies and other organizations consider adopting the SI units for radiation measurements, they will likely perform a cost–benefit analysis to assist them with the decision. The cost–benefit analysis expert invited to speak at the workshop noted that the costs and benefits related to adopting SI would need to be quantified based on the impact of the policy change over time. Many of the costs would be one-time costs but the benefits would be long term. Many workshop participants proposed a “cold turkey” approach to adopting SI units with advance notice of the start date to allow stakeholders time to prepare for the conversion.
This proceedings has been prepared by the workshop rapporteur as a factual summary of what occurred at the workshop. The workshop planning committee was solely responsible for organizing the workshop, identifying topics, and choosing speakers. The views contained in the proceedings are those of individual workshop participants and do not necessarily represent the views of all workshop participants, the planning committee or the National Academies.
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