Search Results
You are looking at 1 - 2 of 2 items for
- Author or Editor: W. Van Dijk x
- Refine by Access: All Content x
Abstract
In the near future, Dutch legislation will set an upper limit for thenatural radiation exposure of inhabitants in newly built houses. Therefore,it is necessary to have standardized procedures available for the determinationof the radon exhalation rate of and the activity levels in construction materials.In this paper we describe a method for determination of activity levels inconstruction materials. This method comprises radionuclide-specific calibrationof Marinelli-beaker geometries with a range of material densities. This standardmethod was validated in a round-robin involving 6 laboratories, organizedby two of the authors (M.B. and H.J.G.) of this paper. In this paper, resultsobtained according to the norm are compared with results obtained at IRI witha more elegant but possibly less robust method.
Abstract
Gas and oil companies frequently encounter build up of Naturally Occurring Radioactive Material (NORM) in their production and processing facilities. In the Netherlands NORM is subject to strict national regulations and, consequently, installations have to be screened on a regular basis. The availability of accurate and reliable NORM sampling and analysis techniques is therefore essential. A number of years ago, the 
Nederlandse Aardolie Maatschappij B.V.
(NAM) actively initiated an investigation on analysis techniques for NORM samples from gas and oil companies. Within this framework, Shell Research Amsterdam organized a four-stage interlaboratory test programme in which representative samples of increasing complexity were analyzed by a number of Dutch institutes. Whereas a large spread in results was observed in the first stage, results in the last stage deviated less than ±10% from the values certified by an independent referee institute, even for comple, sludge samples. It was found that in particular the use of different values for the 
-yields and branching ratios amongst the institutes was responsible for the initial spread.
