Quality assurance in the nuclear sector

Abstract

Summary. The nuclear sector in the UK operates under regulation requiring assurance that the quality of radioactive measurements is "fit for purpose". Laboratories operate a quality system under ISO 17025:2005 which is monitored by the United Kingdom Accreditation Service. Few of the test methods used in UK laboratories are based on standard methods so non-standard procedures are validated through the use of certified reference materials, and continued quality assurance is provided through participation in proficiency testing and interlaboratory comparison exercises. The majority of organisations accredited for radioactivity measurements under ISO 17025:2005 in the UK are environmental monitoring laboratories routinely processing soils, vegetation, air filters and water samples. There are no certified reference materials available in the UK or elsewhere adequately supporting the work of these laboratories. The same is true for the nuclear decommissioning and waste management community that regularly analyses concrete, soil, brick, sludge and oils for activities at Low Level Waste and Intermediate Waste Levels. The nuclear sector has a number of issues regarding availability of isotopic tracers for analysis, supplies of material for nuclear medicine, proficiency testing exercises involving representative matrices and activity levels but the most pressing need is in the area of certified reference materials for validation of methods analysing alpha, beta, and gamma emitting radionuclides.

Complete dissolution of solid matrices using automated borate fusion in support of nuclear decommissioning and production of reference materials

“…The lack of suitable reference materials in the NORM industries is a significant issue [2,[7][8][9][10][11][12], which also makes initial validation of procedures challenging. Candidate reference soil and sediment materials from British Geological Survey (BGS) were digested using lithium borate fusion and the concentration of 232 Th and 238 U calculated and compared with the reference values as an initial validation of the method.…”

“…This applies to both the characterisation of NORM and decommissioning materials. Additionally, the accurate characterisation of radionuclides is reliant on measurement of certified reference materials (CRM) that ensure quality control and metrological traceability through method validation and calibration of instruments [7]. Owing to the wide range of sample types across industrial sectors, the current lack of CRM is a significant constraint [2,[7][8][9][10][11][12].…”

“…The high temperatures associated with some fusion processes also means that volatile radionuclides (e.g. 3 H, 14 C, 36 Cl and 129 I) must be selectively removed beforehand, for example using a furnace system to volatilise samples, with volatile radionuclides subsequently trapped in aqueous solution, whilst the solid sample is retained for subsequent digestion [7,32].…”

Are analytical standards and reagents really reliable?

“…The issue of quality assurance (QA) in the analytical chemistry laboratory has become of great importance for many years. [1][2][3][4] Quality control (QC) and QA are particularly essential for pharmaceutical sciences 5 , environmental monitoring 6 but also for nuclear industry 7 . Radioactive waste management is a challenging task faced by nuclear power countries and is a prime concern for the public and therefore for analytical laboratories.…”

“…8 Consequently, analytical laboratories devoted to nuclear waste characterizations must implement validated methods and provide accurate and reliable measurements. 7 All the radiological and chemical analyses require the implementation of different laboratory instruments, such as liquid chromatography systems (High-Performance Liquid Chromatography coupled to Mass Spectrometry HPLC-MS, Ion Chromatography IC) or Liquid Scintillation Counters (LSC). Those instruments must be calibrated with reference materials and standards of known compositions.…”