Radioactivity
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
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Metrology for Decommissioning and Site Clearance Workshop - Welcome |
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Overview of NPL Nuclear Industry Proficiency Test Exercises |
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Nuclear Decommissioning Metrology - Radiochemical Analysis |
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Sampling Issues |
- 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.
- 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.
- 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 has continued to maintain its gas-counting capabilities and is developing a new standard for radioactive gases used in Positron Emission Tomography (PET).
- 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.
- 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).
- 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.
- NPL can provide advice on a range of radioactivity measurement problems.
- The radioactivity facilities available at NPL.
- The Fidelis Secondary Standard Radionuclide Calibrator comprises the NPL-designed ionisation chamber and a brand new electrometer and user interface unit from Southern Scientific.
- These comparison exercises are aimed to assess the performance of the radioactivity measurement community in the UK and, more recently, participation in the exercises has become an important aspect of UKAS accreditation in this field.
- This service covers the provision of both primary and secondary standards of a range of alpha-, beta- and/or gamma-emitting radionuclides.
- NPL provides a number of services giving traceability for measurements of radioactive gases both within the nuclear industry and for estimating doses to the general public.
- The Radioanalytical Service is aimed at the measurement of a wide range of α, β and γ emitting radionuclides in divers solid and liquid matrices over a wide range of radioactivity concentrations, and is particularly aimed at the decommissioning and remediation sectors.
- Radionuclides calibrator services, including the provision of calibration factors for NPL.
- NPL supplies a range of over twenty different radionuclides for use as chemical yield tracers and calibration of various detector systems.
Standards of radioactive surface contamination for the calibration of surface contamination monitors
NPL's primary and secondary large area proportional counters are capable of calibrating a range of alpha and beta reference sources to Class 1 and Class 2 standards.- NPL provides a performance test for dosimetry services who measure tritium-in-urine as part of their internal dose assessment procedures.
- The aim of these exercises is to assess the performance of UK hospitals' nuclear medicine departments to assay the dose administered to patients undergoing diagnostic and therapeutic treatments, via the use of a Radionuclide Calibrator.
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.
- Details, including downloadable presentations, from Airborne Radioactivity Monitoring Users’ Group (ARMUG) past meetings.
- The IRMF facilitates the exchange of information about UK calibration and testing facilities, for those who must comply with the requirements of the current Ionising Radiations Regulations.
- Details and downloadable presentations from previous IRMF meetings.
- The LSUF is for the benefit of all users of liquid scintillation counting techniques, including those who may be making routine measurements in medical and research situations.
- Metrology for Decommissioning and Site Clearance Workshop Minutes (Thursday 30 June 2005)
- These comparison exercises are aimed to assess the performance of the radioactivity measurement community in the UK and, more recently, participation in the exercises has become an important aspect of UKAS accreditation in this field.
- The NSUF acts as a focal point for discussion of problems and dissemination of information between users of alpha and gamma-ray spectrometry. This forum replaces the alpha- and gamma-spectrometry user fora, which have been merged.
- The RCUF acts as a focal point for discussion of problems and dissemination of information between users of radionuclide calibrators.
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.