Improved Radiation Measurement Infrastructure for Occupational Radiation Protection

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Objective for MPD C.17.3

  • Improve the occupational radiation measurement infrastructure throughdevelopment and implementation of measurement standards and accreditation programs on a national and an international level.

Background: The infrastructure that supports radiation measurements for purposes of occupational radiation protection has two major components: standards and accreditation programs. Standards for radiation calibration are required to ensure that calibrations (and inter-pretation of occupational risk) are consistent on both a national and an international basis. The standards must describe the generation and calibration of radiation fields in terms of standardized quantities and the use of a consistent set of conversion coefficients to interpret the fields in terms of worker risk. The ongoing standards development work of the ISO must be encouraged and expanded. Accreditation programs provide a method of ensuring that calibrations, dosimeter processing or test measurements are performed in a quality manner consistent with established stan¬dards or criteria, thus providing assurance that the results are consistent with national needs. In addition, it is necessary to ensure that the accreditation programs are consistent, cost effective, and appropriate in terms of national and international needs. Although the critical elements of a complete measurement quality assurance (MQA) program are required for accreditation under each of the four existing secondary laboratory accreditation programs, they do not use the same general or specific criteria to evaluate candidate laboratories. Questions have been raised about the comparability (equivalence) of accreditation granted by the various programs. An obvious major improvement would be the adoption, by all the programs, of the new standard ISO/IEC 17025 (cancels and replaces ISO/IEC Guide 25), which establishes general criteria for laboratory performance. Through meetings and information exchange, CIRMS makes continual progress in this area with recent incorporation of ISO/IEC Guide 25 into the programs. The stage must be set to upgrade to ISO/IEC 17025.

A recent innovation is the consideration of total measurement uncertainty as a basis for dosimetry system approval. Germany has developed pattern tests based on total system uncertainty that will be used for approval of dosimetry systems in the future. The HPS is developing a standard for evaluating dosimeter uncertainty, and the International Electrotechnical Commission (IEC) is working on a standard for evaluating the uncertainty of measurements. These standards consider a greater range of influence quantities than the NVLAP and DOELAP standards and provide a rational basis for evaluating dosimetry against guidance by the International Commission on Radiological Protection (ICRP). CIRMS efforts will include looking at evaluating total uncertainty as a basis for evaluation of measurements in radiation protection.

Currently, a national effort is underway to accredit organizations using ISO Guide 58, “Calibration and Testing Laboratory Accreditation Systems-General Requirements for Operation and Recognition (Revision of ISO/IEC Guides 38, 54, and 55)”. CIRMS can assist by providing the technical expertise needed to achieve an orderly acceptance of these efforts. Operating the accreditation programs through an organization that is accredited based on internationally accepted criteria will provide significant benefits: improve acceptance of the programs by the regulators and the customers (an accreditation certificate has not been universally recognized as an indicator of program quality), and provide international acceptance of the accreditation pro-grams. CIRMS acts to improve the technical basis for the programs, as well as facilitates the relationship of users, program developers, and NIST in the development and implementation of accreditation programs and must continue this effort.

CIRMS members need to meet with national/international standards developers to make sure that needed standards are identified and approved for development. CIRMS members have been and should continue to be active in the development and review of conversion coefficients used in ISO standards, as well as in the development of international standards for beta, photon and neutron reference radia¬tions. Review of standards has resulted in changes that ensure compatibility with US practice and US regulations. Information exchanges at CIRMS annual meetings can identify new standards. Special meetings to address implementation of standards and accreditation programs will be needed. An ad hoc working group should be formed through CIRMS to study the pattern testing/type testing philosophy and make recommendations.

Action Items:

1 – Identify and participate in the development of national and international standards that are needed to support the radiation measurement infrastructure for the protection of occupational workers, including providing supporting data such as conversion coefficients.

2 – Seek broader national and international acceptance of existing laboratory accreditation programs, improve upon their inter-comparability and provide guidance and assistance as needed.

Resource Requirements:

1 – Funding to facilitate annual meetings to monitor the progress on the above.

2 – 1/2 person-year per year over a three-year timeframe to study the evolving methodologies and criteria for personnel radiation protection and accreditation of laboratory protocols.