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Adopting the International System of Units for Radiation Measurements in the United States: Proceedings of a Workshop (2017)

Chapter: 5 Possible Steps Toward the Exclusive Use of SI Units for Radiation Measurements

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Suggested Citation:"5 Possible Steps Toward the Exclusive Use of SI Units for Radiation Measurements." National Academies of Sciences, Engineering, and Medicine. 2017. Adopting the International System of Units for Radiation Measurements in the United States: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/24645.
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5

Possible Steps Toward the Exclusive Use of SI Units for Radiation Measurements

Discussions presented in this chapter were primarily triggered by remarks made by Dr. Steven Simon, NCI, who chaired the workshop organizing committee. Dr. Simon attempted to distill the overarching workshop themes (organized in this proceedings by the rapporteur in the same-title section) and encouraged workshop participants for a candid exchange of ideas on possible steps toward the exclusive use of SI units for radiation measurements. Topics discussed can be grouped in two categories:

  1. The United States will eventually adopt the SI units for radiation measurements, so no additional action needs to be taken.
  2. The United States will not adopt the SI units for radiation measurements without an organized plan for adoption.

These two topics are discussed in some detail in the following sections.

NO ACTION NEEDED

A few workshop participants talked about the “inevitability” of the exclusive use of SI units for radiation measurements in the future and stated that no action needs to be taken to reendorse SI use for radiation measurements or develop a specific plan for adoption of SI. In their view use of SI units for radiation measurements will continue to increase as regulations, guidelines, and practices slowly adopt SI.

Dr. William Blakely, Armed Forces Radiobiology Research Institute, suggested that at least a small endorsement is warranted and suggested a

Suggested Citation:"5 Possible Steps Toward the Exclusive Use of SI Units for Radiation Measurements." National Academies of Sciences, Engineering, and Medicine. 2017. Adopting the International System of Units for Radiation Measurements in the United States: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/24645.
×

change in all practices to using both SI and conventional units side by side. In his view, this change would be a small step that could be taken today to speed up the exclusive use of SI units for radiation measurements in the future. Other participants said that using the two units side by side would further delay progress toward the exclusive use of SI units as opposed to facilitating it.

DEVELOP A PLAN FOR ADOPTION OF SI UNITS FOR RADIATION MEASUREMENTS

Many workshop participants expressed frustration with the slow progress of adopting the SI units for radiation measurements in the United States. They thought that a regulatory or policy change is needed to reendorse adoption of SI units and develop an adoption plan. They stated that an entity within the U.S. government will need to lead the adoption. Mr. John MacKinney, DHS, Lt. Col. Ricardo Reyes, DOD, and Dr. Armin Ansari, CDC, said that the NRC needs to lead the adoption effort by making regulatory and policy changes that endorse the exclusive use of SI units for radiation measurements in the United States. Dr. Ansari explained why, in his view, the NRC’s refusal to adopt SI units for radiation measurements is inhibiting federal, state, and local governments from adopting the SI units for radiation measurements.

The NRC regulates nuclear power plants and other nuclear facilities. It “encourages” use of SI units but permits use of conventional units in event reporting and emergency response communications between licensees (nuclear power industry), the NRC, and state and local authorities (see Chapter 2). However, all emergency preparedness and response planning around nuclear facilities by the federal government (led by the NRC and FEMA) and state and local governments uses conventional units for radiation measurements. Dr. Ansari noted that this usage ripples down to other federal agencies and nonfederal organizations: EPA, which issues protective action guides to emergency responders, needs to issue its guidance in conventional units for radiation measurements to be useful to the federal and state and local stakeholders who will respond to an emergency; DOE, which supports the NRC and its licensees by providing dose and dose rate information, needs to communicate this information in conventional units.

Dr. Ansari stated that unless the NRC mandates the exclusive use of SI units for radiation measurements for all nuclear power industry practices, this ripple effect cannot be eliminated. He later reformed his statement and suggested the following: The NRC could allow the nuclear power industry to use conventional units for radiation measurements onsite, but any communication and reporting offsite with the NRC and other federal, state, local, and nongovernmental organizations needs to occur exclusively in SI

Suggested Citation:"5 Possible Steps Toward the Exclusive Use of SI Units for Radiation Measurements." National Academies of Sciences, Engineering, and Medicine. 2017. Adopting the International System of Units for Radiation Measurements in the United States: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/24645.
×

units for radiation measurements. This change in practice is similar to the current practice in Canada described by Dr. Du Sautoy (see Chapter 4).

Dr. Vincent Holahan, NRC, reiterated that NRC staff considered changing the agency’s metrication policy in 2012 but did not have the Commission’s support to further explore the benefits of adopting the SI units for radiation measurements. Because this recent effort failed and due to current budgetary restrictions (see footnote 6 in Chapter 3), it is unlikely that the agency will be playing a leading role in driving the adoption of SI units.

Mr. William Ostendorff, former NRC commissioner, provided insights as to why the NRC cannot mandate that the nuclear power industry exclusively use SI units for radiation measurements without a well-documented benefit to the safety and security of the nuclear plant, its workforce, and members of the public. A mandate that is not based on well-documented benefits would be noncompliant with the Administrative Procedure Act (PL 79-404, 60 Stat. 237). The act governs the way in which administrative agencies of the federal government may develop and establish regulations.

Dr. Kevin Crowley, the National Academies, noted that it is unlikely that any change in the nuclear power industry’s practices in use of units for radiation measurements will occur because of a change in the NRC’s policies. However, the industry could change its practices if the Institute for Nuclear Power Operations (INPO),1 the organization that establishes practices for nuclear power industry excellence, makes a policy decision to adopt the SI units for radiation measurements. Mr. Willie Harris, Exelon Nuclear, commented that nuclear power plants face financial difficulties because they operate in competitive electricity markets. He implied that the policy change suggested by Dr. Crowley would unlikely to be an INPO priority because of the associated costs of conversion.

It became apparent from the workshop discussions that neither the NRC nor another federal agency is in a position currently to drive U.S. organizations to adopt the SI units for radiation measurements. Dr. Vincent Holahan, NRC, and Mr. John MacKinney, DHS, suggested that an executive order from the White House could assist in reendorsing adoption of SI units for radiation measurements. They noted that OSTP is in the position to lead interagency efforts to establish unified guidance for the federal government related to use of units for radiation measurements. OSTP could, if it supports the effort to further examine the merits of exclusively using SI units, endorse the development of a national plan to adopt the SI units for radiation measurements.

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1 Ms. Anderson said that INPO, an organization founded by the industry after the accident at Three Mile Island, establishes practices in excellence that may go beyond what the NRC regulations dictate. INPO has not endorsed the adoption of SI units for radiation measurements.

Suggested Citation:"5 Possible Steps Toward the Exclusive Use of SI Units for Radiation Measurements." National Academies of Sciences, Engineering, and Medicine. 2017. Adopting the International System of Units for Radiation Measurements in the United States: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/24645.
×

Cost–Benefit Analysis Considerations

Assuming that U.S. federal and state agencies and other organizations consider adopting the SI units for radiation measurements, they will likely perform a CBA to assist them with the decision. CBA is a process for quantifying and comparing pros and cons of a decision, including a government regulatory policy decision. Dr. Joseph Cordes, George Washington University, described how CBA could be used by an agency to weigh a decision about adopting SI units for radiation measurements.

Executive Branch agencies are required to perform CBA when a proposed regulation or change in regulation is estimated to have a cost impact of at least $100 million. CBA informs the regulatory review of the proposed regulation or change in regulation performed by the Office of Information and Regulatory Analysis of the Office of Management and Budget (OMB) within the Executive Office of the President. Independent agencies and government-owned corporations are not subject to the CBA requirement. However, many use some type of CBA in their decision making. For example, the NRC has a CBA process for any changes in the agency’s regulations (also known as backfitting) to help the agency provide informed and transparent decision making.2

Dr. Cordes explained that CBA requires identification of the costs and benefits associated with a decision or potential decision and the development of a monetary value of these costs and benefits over a certain period to allow for a cost–benefit balancing. In the case of adoption of SI units for radiation measurements, for example, the costs are associated with changes in regulations and reporting; replacing or recalibrating instrumentation; training; and costs for inadvertent overexposures that are estimated to result from adoption. Benefits are associated with alignment of the United States with international practice; traceability to the national standard; communications with the public; and simplicity of SI. As noted in Chapter 3 of this proceedings, some workshop participants noted that many of the costs would be one-time costs but the benefits would be long term. In CBA, “long term” is often reflected as a 50- to 100-year time frame.

Dr. Cordes explained that in the case of a policy change to adopt SI, costs would be quantified with and without a change in practice. This is because some of the costs might not be completely attributable to the proposed change. For example, if an organization replaces its instrumentation routinely, then the costs of purchasing new instruments that display SI units may be similar to the costs to purchase instruments that display conventional units, if the instrument was purchased during the routine replacement

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2 The NRC backfitting requirements are described here: http://www.nrc.gov/about-nrc/regulatory/crgr/related-info.html.

Suggested Citation:"5 Possible Steps Toward the Exclusive Use of SI Units for Radiation Measurements." National Academies of Sciences, Engineering, and Medicine. 2017. Adopting the International System of Units for Radiation Measurements in the United States: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/24645.
×

cycle. In this case the organization is required to estimate whether the cost of the instrumentation that reads SI versus conventional units is different.

Dr. Cordes noted that budget, administrative, and purchasing data, as well as surveys of stakeholders such as the one performed by Mr. Frazier Bronson and presented at this workshop (see Chapter 3), are useful in quantifying current and future costs. A bigger challenge is quantifying benefits. CBA analysts are often faced with situations in which they can quantify some but not all benefits. OMB admonishes agencies that when less tangible benefits are hard to quantify, they should be discussed and illustrated with some information that could help a decision maker understand the nature and scale of the benefit.

As noted in Chapter 3 of this proceedings, some workshop participants discussed that converting from conventional to SI units for radiation measurements could improve communications with the public and increase public trust. As a result, members of the public will more likely follow government instructions during a radiological emergency. Dr. Cordes noted that this benefit can be quantified by estimating the cost to the government and others incurred when members of the public do not follow instructions, for example, to remain in their homes as opposed to evacuate during a radiological incident. If people evacuated, despite not ordered to, the government might incur costs to facilitate these evacuations.

Ms. Rajah Mena, DOE, provided a second example and subsequent returns of communication benefits: continuing use of conventional units caused delays in producing radiation contamination mapping products during the Fukushima response, and there was less time allowed for checks and reviews of the data used for mapping. The supposition is that adopting the exclusive use of SI units would help produce better-quality maps in a timely manner.

Dr. Cordes said that to quantify this benefit, the CBA analyst would need to estimate the costs for producing maps more expeditiously if only SI units are used. In addition, the analyst would need to know how these better-quality products that are delivered faster to the stakeholders affect their decision making.

Dr. Cordes noted that there will be differing opinions in what the costs and benefits are and their associated monetary value over a certain period. The current best practice in CBA is to estimate the variability and uncertainty in cost and benefit outcomes using a sensitivity analysis. Dr. Ansari, CDC, commented that costs related to adopting SI units for radiation measurements need to be scrutinized, because persons and organizations that oppose adoption may tend to inflate them without supporting evidence.

Economists generally advise not to use CBA as the standard for decision making. It is, however, a useful decision-making tool because it provides a structured process for identifying the costs and benefits for a change

Suggested Citation:"5 Possible Steps Toward the Exclusive Use of SI Units for Radiation Measurements." National Academies of Sciences, Engineering, and Medicine. 2017. Adopting the International System of Units for Radiation Measurements in the United States: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/24645.
×

in practice. Dr. Cordes noted that CBA related to adopting the SI units for radiation measurements could be informed by the experiences of other countries.

Transition Period

Some workshop participants noted that a rapid change to the exclusive use of SI units for radiation measurements can minimize confusion compared to a prolonged transition period during which both conventional and SI units are used side by side. This proposed “cold turkey” adoption of SI was compared to the transition from left-hand traffic to right-hand traffic in a single day.3

Workshop participants who favored no transition period offered the following comments in support of their positions:

  • Dr. Paul DeLuca, University of Wisconsin School of Medicine, Madison, said that “the longer one persists in putting down both units and not accepting the SI units, the longer it will be before we eliminate issues associated with the use of conventional units.”
  • Mr. Michael Boyd, EPA, said that the continuing use of conventional units side by side with SI units “coddles” the user community and does not really force a switch to learning how to get conformable thinking in SI units.
  • Mr. Peter Burgess, Radiation Metrology Ltd., United Kingdom, said that continuing to put SI and conventional units side by side encourages people “to hang on to the old.”
  • Mr. Willie Harris, Exelon Nuclear, noted that a phased approach, that is, adopting SI gradually in nuclear power plants, would not work because of the frequent relocation of nuclear workers from one plant to another, for example, during an outage. He also argued against phasing the modifications of instrumentation used by the nuclear workforce.

Ms. Binika Shah, World Nuclear Association, was in favor of some transition period to allow the nuclear power industry to absorb the large costs of conversion.

Independent of the approach, there was some agreement that advance notice of the adoption date for the exclusive use of SI units would allow stakeholders to prepare for the conversion. For example, Mr. Frazier Bronson, Canberra Industries, said that the instrumentation industry needs

___________________

3 For example, at 5 AM on September 3, 1967, the traffic everywhere in Sweden switched from the left to the right side of the road.

Suggested Citation:"5 Possible Steps Toward the Exclusive Use of SI Units for Radiation Measurements." National Academies of Sciences, Engineering, and Medicine. 2017. Adopting the International System of Units for Radiation Measurements in the United States: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/24645.
×

time to prepare for a burst of purchasing of instruments that display SI units. Mr. David Musick, FEMA, noted that regional communities may need a 2-year advance notice of the adoption date in order to comply with legislative requirements related to changes or modifications in emergency management plans.4 Ms. Alexis Reed, Counterterrorism Operations Support program, noted that a messaging campaign with appropriate webinars, publications, and newsletters could assist both radiation experts and members of the public with the adoption of SI units. She also suggested joint drills and exercises soon after the conversion to SI units to ensure that it is implemented effectively.

SUMMARY

The workshop discussions summarized in this chapter can be organized in the following theme (Theme 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 prepare for the conversion.

___________________

4 Information was provided to National Academies staff member Dr. Ourania Kosti by Mr. David Musick, FEMA, during the proceedings review (January 14, 2017).

Suggested Citation:"5 Possible Steps Toward the Exclusive Use of SI Units for Radiation Measurements." National Academies of Sciences, Engineering, and Medicine. 2017. Adopting the International System of Units for Radiation Measurements in the United States: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/24645.
×

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Suggested Citation:"5 Possible Steps Toward the Exclusive Use of SI Units for Radiation Measurements." National Academies of Sciences, Engineering, and Medicine. 2017. Adopting the International System of Units for Radiation Measurements in the United States: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/24645.
×
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Suggested Citation:"5 Possible Steps Toward the Exclusive Use of SI Units for Radiation Measurements." National Academies of Sciences, Engineering, and Medicine. 2017. Adopting the International System of Units for Radiation Measurements in the United States: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/24645.
×
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Suggested Citation:"5 Possible Steps Toward the Exclusive Use of SI Units for Radiation Measurements." National Academies of Sciences, Engineering, and Medicine. 2017. Adopting the International System of Units for Radiation Measurements in the United States: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/24645.
×
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Suggested Citation:"5 Possible Steps Toward the Exclusive Use of SI Units for Radiation Measurements." National Academies of Sciences, Engineering, and Medicine. 2017. Adopting the International System of Units for Radiation Measurements in the United States: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/24645.
×
Page 46
Suggested Citation:"5 Possible Steps Toward the Exclusive Use of SI Units for Radiation Measurements." National Academies of Sciences, Engineering, and Medicine. 2017. Adopting the International System of Units for Radiation Measurements in the United States: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/24645.
×
Page 47
Suggested Citation:"5 Possible Steps Toward the Exclusive Use of SI Units for Radiation Measurements." National Academies of Sciences, Engineering, and Medicine. 2017. Adopting the International System of Units for Radiation Measurements in the United States: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/24645.
×
Page 48
Suggested Citation:"5 Possible Steps Toward the Exclusive Use of SI Units for Radiation Measurements." National Academies of Sciences, Engineering, and Medicine. 2017. Adopting the International System of Units for Radiation Measurements in the United States: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/24645.
×
Page 49
Suggested Citation:"5 Possible Steps Toward the Exclusive Use of SI Units for Radiation Measurements." National Academies of Sciences, Engineering, and Medicine. 2017. Adopting the International System of Units for Radiation Measurements in the United States: Proceedings of a Workshop. Washington, DC: The National Academies Press. doi: 10.17226/24645.
×
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Most countries in the world use the SI (Système International, also known as the metric system) units for radiation measurements in commercial and technical activities. The United States, in contrast, uses a mix of SI and conventional units for radiation measurements, despite 30-year-old national and international recommendations to exclusively use SI. Radiation professionals in the United States are faced with the need to understand both systems and make conversions between the two.

In September 2016, the National Academies of Sciences, Engineering, and Medicine organized a workshop to explore potential communication improvements associated with adopting the international system of units (SI units) for radiation measurements in the United States. Participants discussed potential improvements in the effectiveness of responding to national and international radiation emergencies, international experiences in adopting the exclusive use of SI units of radiation measurements, and steps needed to adopt the exclusive use of SI units in the US in terms of timing, implementation, and ways to overcome or manage technical, economic, and policy barriers. This publication summarizes the presentations and discussions from the workshop.

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