National Physical Laboratory


Accurate radioactivity measurement continues to be a vital aspect of the work of UK industry (e.g. in sectors such as nuclear medicine and nuclear decommissioning). NPL's radioactivity team (part of the Radioactivity and Neutrons Group) combines wide-ranging expertise with state-of-the-art equipment and laboratory facilities to support measurements of this type. The work of the team includes:

  • providing and disseminating primary standards for radioactivity metrology using conventional coincidence counting techniques, as well as newer developments;
  • participating in international comparisons of radioactivity standards (such as those organised by the BIPM) to ensure international equivalence of primary standards;
  • maintaining and developing NPL's radionuclide metrology and radiochemistry facilities;
  • standardising radionuclides routinely used for diagnostics and therapy in nuclear medicine;
  • providing a national measurement infrastructure, via the standardisation and dissemination of solution standards and reference materials, for environmental monitoring of radioactivity;
  • providing a national infrastructure to ensure accurate measurement of the radioactive waste arising from nuclear decommissioning by providing reference materials in appropriate matrices;
  • carrying out evaluations and measurements of nuclear data to improve the quality and accuracy of applications of ionising radiation;
  • undertaking appropriate KT activities, including representation on standards committees and dissemination of the results of research and development work;
  • providing measurement services to the UK user community.

Presentations from the Metrology for Decommissioning and Site Clearance Workshop held at NPL on 11 January 2012

Metrology for Decommissioning and Site Clearance Workshop - Welcome

Overview of NPL Nuclear Industry Proficiency Test Exercises

Nuclear Decommissioning Metrology - Radiochemical Analysis

Sampling Issues

  • NPL continues to support work in the environmental radioactivity field by developing low-level standards and by running laboratory proficiency testing exercises. The last such exercise included a new concrete reference material.
  • As a signatory to the Mutual Recognition Agreement (MRA), NPL has continued to participate in international comparison exercises of radionuclide standards under the auspices of BIPM, including a recent comparison of Fe-55.
  • Work in this field includes the ongoing compilation of a new set of NPL-recommended decay data and the evaluation of actinide decay data for IAEA.
  • Initial research in this area has focussed on establishing user priorities for reference materials to support low-level measurements of waste. A comparison has been run using a new ‘soft-waste’ drum standard reflecting these priorities.
  • Recent work in this area has included the launch of the ‘Fidelis’ instrument and the development of internet metrology software for the Quality Assurance of radionuclide calibrators.
  • NPL continues to maintain the coincidence counting equipment needed to produce primary standards of radioactivity and is also developing the technique of Digital Coincidence Counting (DCC).
  • NPL has continued to maintain its gas-counting capabilities and is developing a new standard for radioactive gases used in Positron Emission Tomography (PET).
  • A wide range of secondary measurement equipment is needed to measure or produce secondary standards that can be disseminated to users, and recent work has been aimed at upgrading this equipment.
In recent years NPL has identified key sectors among the radioactivity user community and has set up ‘measurement infrastructure’ projects to provide a suite of standards and services to support users in each area.

Radioactivity case studies

  • NPL scientists have developed a new instrument called Fidelis (Latin for 'faithful') which will ensure the safety of patients having nuclear medicine treatments.
  • NPL has recently expanded its radiochemistry capability by purchasing a NorthStar Automated Radiochemistry System (ARSIIe) to enable safer, quicker, in situ radioactivity measurements that are essential to ensure safety at nuclear sites.