ISO 20042:2019
Measurement of radioactivity — Gamma-ray emitting radionuclides — Generic test method using gamma-ray spectrometry
Measurement of radioactivity — Gamma-ray emitting radionuclides — Generic test method using gamma-ray spectrometry
- Статус документа:
- Действующий
- Формат:
- Электронный (PDF)
- Количество страниц:
- 50
- Дата публикации:
- 4 июня 2019 г.
- Издание:
- ISO IS 20042 edition 1 version 1
- ICS:
- 13.280
This document describes the methods for determining the activity in becquerel (Bq) of gamma‑ray emitting radionuclides in test samples by gamma-ray spectrometry. The measurements are carried out in a testing laboratory following proper sample preparation. The test samples can be solid, liquid or gaseous. Applications include: — routine surveillance of radioactivity released from nuclear installations or from sites discharging enhanced levels of naturally occurring radioactive materials; — contributing to determining the evolution of radioactivity in the environment; — investigating accident and incident situations, in order to plan remedial actions and monitor their effectiveness; — assessment of potentially contaminated waste materials from nuclear decommissioning activities; — surveillance of radioactive contamination in media such as soils, foodstuffs, potable water, groundwaters, seawater or sewage sludge; — measurements for estimating the intake (inhalation, ingestion or injection) of activity of gamma-ray emitting radionuclides in the body. It is assumed that the user of this document has been given information on the composition of the test sample or the site. In some cases, the radionuclides for analysis have also been specified if characteristic limits are needed. It is also assumed that the test sample has been homogenised and is representative of the material under test. General guidance is included for preparing the samples for measurement. However, some types of sample are to be prepared following the requirements of specific standards referred to in this document. The generic recommendations can also be useful for the measurement of gamma-ray emitters in situ. This document includes generic advice on equipment selection (see Annex A), detectors (more detailed information is included in Annex D), and commissioning of instrumentation and method validation. Annex F summarises the influence of different measurement parameters on results for a typical gamma-ray spectrometry system. Quality control and routine maintenance are also covered, but electrical testing of the detector and pulse processing electronics is excluded. It is assumed that any data collection and analysis software used has been written and tested in accordance with relevant software standards such as ISO/IEC/IEEE 12207. Calibration using reference sources and/or numerical methods is covered, including verification of the results. It also covers the procedure to estimate the activity content of the sample (Bq) from the spectrum. The principles set out in this document are applicable to measurements by gamma-ray spectrometry in testing laboratories and in situ. However, the detailed requirements for in situ measurement are given in ISO 18589-7 and are outside the scope of this document. This document covers, but is not restricted to, gamma-ray emitters which emit photons in the energy range of 5 keV to 3 000 keV. However, most of the measurements fall into the range 40 keV to 2 000 keV. The activity (Bq) ranges from the low levels (sub-Bq) found in environmental samples to activities found in accident conditions and high level radioactive wastes.
Abstract
Overview
ISO 20042:2019 - Measurement of radioactivity - Gamma‑ray emitting radionuclides - Generic test method using gamma‑ray spectrometry - is an international standard that defines a generic laboratory and in‑situ framework for determining the activity (Bq) of gamma‑ray emitting radionuclides. It applies to solid, liquid and gaseous samples, covers photon energies from 5 keV to 3 000 keV (most measurements 40–2 000 keV), and addresses activities ranging from sub‑Bq environmental levels to high‑level accident wastes.
Key technical topics and requirements
- Principle and analysis methods: Describes spectrometric approaches including summing and fitting methods for spectrum analysis.
- Validation and commissioning: A 7‑step process for validating measurement systems (requirements capture, technical design, installation, validation studies, robustness, operation and maintenance).
- Detector energy and efficiency calibration: Requirements for energy calibration, efficiency calibration using reference sources and numerical methods, and verification procedures.
- Sample handling and preparation: Guidance on representative sampling, homogenization, container loading and general sample preparation; references to specific standards where required.
- Spectrum processing and corrections: Procedures for spectrum recording, background correction, decay data selection, true coincidence/summing and matrix/geometry correction factors (illustrated in Annex F).
- Quality assurance and uncertainty: QA/QC program guidance (Annex A), uncertainty budgeting (Annex C), and routine maintenance recommendations (electrical testing of detectors excluded).
- Software and data management: Assumes data collection/analysis software complies with relevant software lifecycle standards (e.g., ISO/IEC/IEEE 12207).
- Informative annexes: Detector types (Annex D), worked examples for activity calculation and characteristic limits (Annex E), and simulation of correction factors (Annex F).
Practical applications
ISO 20042:2019 is designed to support reliable, comparable gamma‑ray spectrometry results for:
- Environmental monitoring and surveillance of releases from nuclear installations and NORM sites
- Emergency response, incident investigation and remediation planning after radiological events
- Assessment of contaminated materials during nuclear decommissioning and waste management
- Monitoring radioactivity in soils, foodstuffs, potable water, seawater and sewage sludge
- Estimating intake (inhalation/ingestion/injection) of gamma‑ray emitting radionuclides for dose assessment
- Laboratory accreditation, interlaboratory comparisons and proficiency testing
Who should use this standard
- Nuclear and environmental testing laboratories
- Radiation protection specialists and environmental monitoring teams
- Decommissioning and waste management professionals
- Emergency response organizations and regulatory authorities
- Instrument manufacturers and service providers for gamma‑ray spectrometry
Related standards
- ISO 18589‑7 (in‑situ gamma measurements - detailed in‑situ requirements are outside ISO 20042 scope)
- ISO/IEC 17025 (laboratory quality management and competency)
- ISO/IEC/IEEE 12207 (software lifecycle processes for measurement software)
ISO 20042:2019 provides the generic technical foundation for accurate, traceable measurement of gamma‑ray emitting radionuclides - essential for environmental protection, public safety, regulatory compliance and nuclear industry operations.
Технические детали
- Технический комитет
- ISO/TC 85/SC 2 - Radiological protection
- SKU
- ISO 20042:2019
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