[en] This part of ISO 7503 applies to the evaluation of tritium contamination on surfaces of equipment and facilities, containers of radioactive materials and sealed sources. It does not apply to the evaluation of tritium contamination of skin and clothing. (orig.)

[en] Practical experience in the use of the Whitlock Tritium Meter in various laboratories and industrial establishments throughout the world has shown that:-a) Measurements by smear/wipe tests can often be in error by three orders of magnitude or more; b) Sub-visual surface scratches (8μ deep) are radiologically important; c) Volatile forms of tritium exist in 20% to 30% of establishments visited. It is concluded that a) the widespread use of smear/wipe techniques for the assessment of ³H surface contamination based on the assumption that 10% of removable activity is collected by the smear/wipe should be re-examined and b) tritium surface contamination assessed as 'fixed' can contain volatile fractions with a hazard potential which may be considerably greater than the hazard from removable activity at present covered by maximum permissible level recommendations. (H.K.)

[en] Normally, beta and alpha surface contamination monitors are used with a simple counting threshold, i.e. any pulse over a predetermined amplitude is counted. This is very different from gamma monitoring, where the use of counting windows is very popular and the use of full multi-channel analysis is common. Many current surface contamination ratemeters have the capacity to drive dual phosphor detectors and can be set up to provide beta and alpha channels. Effectively, the beta channel is a counting window, i.e. all pulses which are bigger than the threshold and smaller than the alpha threshold are counted. Larger pulses go into the alpha channel. This paper addresses how this can be used with beta only and alpha only detectors to provide information on the source. The detector is set up conventionally to a defined point for the lowest beta energy anticipated. The instrument is then switched to alpha + beta mode and the alpha threshold set to 3 times the beta threshold. With this set up, the alpha to beta channel count rate ratio varies smoothly by a factor of 14 between Y-90 (E_max 2.27 MeV) and C-14 (E_max 0.16 MeV). Hence the instrument can be used to estimate the energy of an unknown beta contaminant or to confirm that a mixed beta fingerprint has essentially the same mix. The same approach can be used with alpha probes to confirm the source quality. The main worry with alpha monitoring is the surface condition. A poor surface condition will lead to a low count rate. Using the channel ratio method will identify grubby sources. The resulting ratio can be used either as a go/no trigger, i.e. any surface with a low ratio will be treated as untrustworthy, or alternatively the ratio can be used to correct the reading to give a better estimate of surface activity. (authors)

[en] The authors describe calibration methods applied in Switzerland to determine the surface emission efficiency and the calibration factor of surface contamination meters. In case that for special radionuclides reference sources certified according the appropriate ISO standards are difficult to supply, a calculational method derived from ISO standards is applied. (orig.)

[en] From 2011 the NRC 'Kurchatov Institute' has been carried out the dismantling of the MR multiloop research reactor. Now the reactor and all technological equipment in the premises of the reactor were dismantled. Now the measurements of radioactive contamination in the reactor premises are made. The most contaminated parts of premises - floor and the ground beneath it. In order to measure the distribution of specific activity in the ground the CdZnTe detector (volume 500 mm³) was used. The detector is placed in a lead shielding with a slit collimation hole. The upper part of the shielding is made movable to close and open the slit of the collimator. At each point two measurements were carried out: with open and closed collimator. The software for determining the specific activity of radionuclides in the ground was developed. The mathematical model of spectrometric system is based on the Monte-Carlo method. Measurements of specific activity of the ground were made. Using the results of measurements, the thickness of the removed layer of ground and the amount of radioactive waste were calculated. (authors)

[en] Cartogram is a device able to localize contaminated zones in nuclear facilities. It is made up of a single camera responsive to both light photons and gamma radiations, a hardened transportable computer and a specially designed software. Cartogram achieves in a few minutes'time the superimposition of the real picture of the zone with the map of the gamma contamination. Radioactivity is represented by different colours according to the value of the gamma dose rate detected. A single cable links the camera to the computer (maximal length: 200 m), the camera can be remotely handled through the computer. Cea, Cogema and the French company: Canberra-Eurisys have worked on this project and today 12 Cartogram have already be sold. The price of such a camera varies from 150.000 to 200.000 Euros according to the optional specificities. (A.C.)

[en] A sampling method is a traditional means of determining basic quantitative characteristics and parameters of distribution of radionuclides in a medium. In particular, this method is used to examine soil contaminated as a result of global or accidental fallout. In certain situations, however, the sampling method is hardly practicable. For example, concrete settlers are used for temporary storage of liquid radioactive waste (RW). In the course of the storage radionuclides enter the concrete. A similar situation may occur when solid RW is kept in rooms (storage vaults) with concrete walls and coatings. Upon discharge of the RW it is often necessary to remove an upper layer of concrete that contains radionuclides, therefore it is desirable to have preliminary information on thickness of a layer to be removed. If the sampling method is used for radionuclide content analysis in this case, additional special equipment shall be employed which makes the analysis quite labour intensive. There are field radiometric methods of determining characteristics of soil and bottom deposit contamination that allow evaluating surface activity of radionuclides and thickness of the upper layer of soil that contains more than 80% of the total activity, and establishing some other distinctive features of radionuclide distribution in a medium. (author)

No abstract available

[en] The standard applies to the determination of surface contaminations of all kinds, especially with regard to: Places of work where unsealed radioactive substances are handled, consignments containing radioactive substances, vehicles which have transported radioactive substances. Determination method (direct measurement, smear test, adhesion test), and measurement process, including measurement equipment and recording of the test, are specified. (orig./HP)

No abstract available