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The objective of this document is to characterize the gaseous effluents tritium and carbon-14 generated by nuclear facilities during operation and decommissioning and occurring in the same chemical species as hydrogen and carbon, e. g. as water vapour (HTO), hydrogen gas (HT, TT), carbon dioxide (14CO2), carbon monoxide (14CO), methane (CH3T, 14CH4). It concerns measurements on samples that are representative of a certain volume stream or volume of discharge during a given period of time and of the corresponding volume discharged. The result is therefore expressed in becquerels. This document applies to samples that were obtained by sampling methods according to ISO 20041-1 and describes — analysis methods for the determination of tritium and carbon-14 activities by liquid scintillation counting and — calculation methods to determine the tritium activities discharged as tritiated water vapour (HTO) and tritium in other chemical compounds (non-HTO) as well as carbon-14 activities discharged as carbon dioxide (14CO2) and carbon-14 in other chemical compounds (non-14CO2). This document does not apply to tritium and carbon-14 activity concentrations in the environmental air, e. g. in the vicinity of nuclear installations. The accountability rules of the activities discharged necessary for the establishment of regulatory reports do not fall within the scope of this document and are the responsibility of the regulatory bodies.

This document specifies a screening test method to quantify rapidly the activity concentration of gamma emitting radionuclides, such as 131I, 132Te, 134Cs and 137Cs, in solid or liquid test samples using gamma ray spectrometry with lower resolution scintillation detectors as compared with the HPGe detectors (see IEC 61563[7]). This test method can be used for the measurement of any potentially contaminated environmental matrices (including soil), food and feed samples as well as industrial materials or products that have been properly conditioned.[8] Sample preparation techniques used in the screening method are not specified in this document, since special sample preparation techniques other than simple machining (cutting, grinding, etc.) should not be required. Although the sampling procedure is of utmost importance in the case of the measurement of radioactivity in samples, it is out of scope of this document; other international standards for sampling procedures that can be used in combination with this document are available (see References [9], [10], [11], [12], [13], [14]). The test method applies to the measurement of gamma-emitting radionuclides such as 131I, 134Cs and 137Cs. Using sample sizes of 0,5 l to 1,0 l in a Marinelli beaker and a counting time of 5 min to 20 min, decision threshold of 10 Bq·kg−1 can be achievable using a commercially available scintillation spectrometer [e.g. thallium activated sodium iodide (NaI(Tl)) spectrometer 2” ϕ × 2” (50,8 mm Ø x 50,8 mm) detector size, 7 % resolution (FWHM) at 662 keV, 30 mm lead shield thickness]. This test method also can be performed in a “makeshift” laboratory or even outside a testing laboratory on samples directly measured in the field where they were collected. During a nuclear or radiological emergency, this test method enables a rapid measurement of the activity concentration of potentially contaminated samples to check against operational intervention levels (OILs) set up by decision makers that would trigger a predetermined emergency response to reduce existing radiation risks[2]. Due to the uncertainty associated with the results obtained with this test method, test samples requiring more accurate test results can be measured using high-purity germanium (HPGe) detectors gamma-ray spectrometry in a testing laboratory, following appropriate preparation of the test samples[15][16]. This document does not contain criteria to establish the activity concentration of OILs.