December 2025: New Standards Enhance Radioactivity Measurement and Uncertainty Analysis

Metrology’s rapidly evolving landscape received a significant boost in December 2025 with the international publication of five critical standards dedicated to radioactivity measurement and the quantification of measurement uncertainty. These newly released documents address everything from in situ gamma spectrometry and advanced statistics in measurement precision to sophisticated approaches for determining detection thresholds in ionizing radiation. As industry professionals seek to align their practices with the latest scientific rigor and regulatory compliance, these standards form the cornerstone for ensuring safety, accuracy, and operational excellence in radiation measurement and related metrological activities.

Overview / Introduction

Metrology—the science of measurement—and the assessment of physical phenomena, particularly radioactivity, are foundational to modern industry, public safety, and scientific research. Accurate, reproducible, and internationally comparable measurement results are essential in domains such as environmental monitoring, nuclear facility operations, healthcare, and laboratory testing.

International standards in this domain provide unified methods, reliable quality assurance protocols, and robust data interpretation frameworks. In this article, we examine five new or revised standards published in December 2025, each contributing vital updates or new methodologies for radiation detection, measurement accuracy, and uncertainty analysis. Readers will learn about:

• State-of-the-art protocols for in situ measurement of gamma-emitting radionuclides in soil
• The latest procedures for collaborative determination of repeatability & reproducibility
• A comprehensive framework for determining characteristic measurement limits and intervals for ionizing radiation
• The evolution of uncertainty modeling in radiation measurement

This guidance is crucial for engineers, quality leaders, compliance managers, laboratory staff, and researchers who must maintain alignment with international best practices or regulatory mandates.

Detailed Standards Coverage

EN ISO 18589-7:2025 - In Situ Measurement of Gamma-Emitting Radionuclides

Measurement of radioactivity in the environment - Soil - Part 7: In situ measurement of gamma-emitting radionuclides (ISO 18589-7:2025)

Scope & Application: This standard details the protocol for identifying and quantifying both artificial and natural gamma-emitting radionuclides directly in soil using portable detection systems, such as those equipped with germanium or scintillation detectors. It enables rapid, large-area assessment and is ideal for routine surveillance, incident investigations, decommissioning, remedial action, and exposure evaluation inside buildings or during waste operations.

Key Requirements:

• Use and calibration of portable gamma spectrometry devices
• Procedures for field-of-view determination, detector setup, and system calibration
• Protocols for quality assurance, including method verification and quality control documentation
• Calculation of activity per surface area, standard uncertainty, decision thresholds, and ambient dose rates

Who Must Comply:

• Environmental monitoring agencies
• Nuclear power plant operators
• Waste management companies
• Laboratories providing in situ measurements

Practical Implications: This standard streamlines on-site gamma spectroscopy, helping organizations quickly assess contamination levels, support remediation plans, and verify regulatory clearance for materials. The new edition corrects formulae, unit expressions, and clarifies calculation procedures for field applications.

Key highlights:

• Standardizes rapid, high-reliability on-site measurement methods
• Explicit procedures for detector calibration and uncertainty evaluation
• Updates to calculation protocols for field application accuracy

Access the full standard:View EN ISO 18589-7:2025 on iTeh Standards

ISO 5725-2:2025 - Determination of Repeatability and Reproducibility

Accuracy (trueness and precision) of measurement methods and results - Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method

Scope & Application: Building on ISO 5725-1, this document presents the fully detailed method for estimating repeatability and reproducibility of measurement procedures via collaborative interlaboratory experiments. The approach is particularly suited for laboratories validating or accrediting their standard methods for continuous-scale measurements.

Key Requirements:

• Experiment design for estimating precision using uniform-level, balanced experiments
• Statistical tools for analysis: outlier identification, variance calculations, and graphical techniques
• Roles and responsibilities for all participating personnel (panels, statisticians, supervisors)
• Reporting procedures and documentation requirements

Who Must Comply:

• Analytical testing laboratories
• Calibration facilities
• Industry and regulatory auditors
• Organizations seeking ISO/IEC 17025 accreditation

Practical Implications: By following this standard, laboratories enhance their capability to produce comparable and accurate measurement data. The revised edition addresses terminology consistency, reference updates, and clarifies statistical evaluation procedures.

Key highlights:

• Standardizes interlaboratory precision experiments
• Methods for outlier handling and variance analysis
• Supports laboratory accreditation and quality management

Access the full standard:View ISO 5725-2:2025 on iTeh Standards

EN ISO 11929-1:2025 - Characteristic Limits in Ionizing Radiation (Elementary Applications)

Determination of the characteristic limits (decision threshold, detection limit and limits of the coverage interval) for measurements of ionizing radiation - Fundamentals and application - Part 1: Elementary applications (ISO 11929-1:2025)

Scope & Application: The first in a four-part series, this standard specifies procedures for calculating the decision threshold, detection limit, and coverage interval limits for non-negative measurands in ionizing radiation metrology, with a focus on elementary, single-channel applications.

Key Requirements:

• Guidance for modeling counting measurements, accounting for background rates, calibration, and sample treatment
• Methods for uncertainty quantification according to ISO/IEC Guide 98-3
• Calculation of primary measurement uncertainty, decision-making thresholds, and result documentation

Who Must Comply:

• Radiation protection professionals
• Nuclear facility operators
• Laboratories performing environmental radioactivity measurements

Practical Implications: This part provides a robust, statistics-based approach for deciding whether radiation is present and for determining the minimum activity that can be reliably detected. The updated edition refines formulae and terminology, improving clarity for practical users.

Key highlights:

• Foundation for all subsequent parts of the ISO 11929 series
• Applies Bayesian uncertainty analysis to measurement interpretation
• Enhanced documentation and reporting guidance

Access the full standard:View EN ISO 11929-1:2025 on iTeh Standards

EN ISO 11929-2:2025 - Advanced Applications for Characteristic Limits

Determination of the characteristic limits (decision threshold, detection limit and limits of the coverage interval) for measurements of ionizing radiation – Fundamentals and application – Part 2: Advanced applications (ISO 11929-2:2025)

Scope & Application: Expanding upon the elementary framework of Part 1, this document covers advanced statistical methods for evaluating uncertainties, particularly in measurements that rely on complex modeling or Monte Carlo methods (per ISO/IEC Guide 98-3:2008/Suppl 1:2008). It addresses scenarios with low count numbers or multivariate influences, enabling broader applicability.

Key Requirements:

• Propagation of probability distributions using both analytical and Monte Carlo methods
• Inclusion of covariances/correlations in input quantities
• Extension to multivariate and advanced radiation measurement scenarios
• Documentation and reporting for advanced calculations

Who Must Comply:

• Research laboratories with advanced metrology needs
• Organizations conducting complex environmental or nuclear measurements
• Analysts requiring Monte Carlo uncertainty evaluation

Practical Implications: This standard is essential when dealing with complex radiation fields, low-level activity, or when regulatory directives require advanced uncertainty analysis. It offers state-of-the-art support for decision thresholds under challenging real-world conditions.

Key highlights:

• Incorporates Monte Carlo and advanced analytical methods for uncertainty
• Enables rigorous confidence in low-activity and complex measurements
• Facilitates compliance with stringent regulatory demands

Access the full standard:View EN ISO 11929-2:2025 on iTeh Standards

EN ISO 11929-3:2025 - Applications to Unfolding Methods

Determination of the characteristic limits (decision threshold, detection limit and limits of the coverage interval) for measurements of ionizing radiation – Fundamentals and application – Part 3: Applications to unfolding methods (ISO 11929-3:2025)

Scope & Application: This part addresses the evaluation of measurement uncertainty and characteristic limits when measurements employ unfolding techniques—essential in multi-channel spectrometric settings (e.g., alpha/gamma spectroscopy). The standard covers advanced models for measurement results derived from spectrum deconvolution (unfolding) and includes sophisticated statistical treatments for correlations and covariances.

Key Requirements:

• Models and procedures for spectrum unfolding in complex radiation measurements
• Special focus on multivariate uncertainty propagation using Monte Carlo or analytical approaches
• Steps for documentation, including reporting results with their full uncertainty structure

Who Must Comply:

• Nuclear laboratories specializing in spectrometric analysis
• Developers of radiation detection software and hardware
• Regulatory authorities overseeing advanced nuclear facilities

Practical Implications: With unfolding methods increasingly central to high-resolution nuclear and environmental analysis, this standard supports accurate, reliable measurement and interpretation. The 2025 revision harmonizes terminology and mathematical approaches across the ISO 11929 series.

Key highlights:

• Specialized for multi-detector and spectrum unfolding methodologies
• Robust guidance for uncertainty in complex, multivariate measurements
• Improves reproducibility and regulatory assurance in advanced applications

Access the full standard:View EN ISO 11929-3:2025 on iTeh Standards

Industry Impact & Compliance

These five standards collectively set a new benchmark for quality and comparability in radioactivity measurement and the quantification of measurement uncertainty. Organizations across environmental monitoring, nuclear energy, waste management, and analytical testing must:

• Review and update laboratory procedures to conform with the revised methodologies
• Train staff and calibrate equipment according to the explicit requirements and protocols outlined
• Update quality assurance and control documentation to address new calculation methods and reporting requirements
• Coordinate with regulatory bodies to demonstrate compliance with international best practices, especially when operating under strict national or regional radiological safety rules

Failure to implement these standards can result in regulatory non-compliance, data misinterpretation, or delayed site clearances—potentially carrying significant legal, financial, or reputational risk.

Benefits of adoption include:

• Enhanced reliability and international comparability of measurement data
• Streamlined regulatory reporting and audits
• Reduced measurement uncertainty, bolstering stakeholder confidence
• Improved safety outcomes in nuclear and environmental operations

Technical Insights

Common Technical Requirements: All five standards emphasize a rigorous approach to measurement uncertainty, calibration, and statistical treatment of data. Key shared requirements include:

• Calibration of detection systems (portable or laboratory)
• Analytical/statistical methods for repeatability and reproducibility
• Step-by-step calculation of decision thresholds, detection limits, and intervals of coverage
• Documentation and transparent reporting of uncertainty and results
• Quality assurance procedures and regular verification of methods

Implementation Best Practices:

1. Start with risk assessment: Identify which standards apply based on your operations (e.g., routine monitoring, incident response, or advanced laboratory analysis).
2. Update SOPs: Incorporate the latest requirements and calculation methods into your Standard Operating Procedures.
3. Invest in training: Ensure measurement, calibration, and quality staff are trained in new procedures and software tools (e.g., UncertRadio).
4. Utilize software: Leverage recommended and open-source tools for complex calculations, particularly for Monte Carlo or unfolding methods.
5. Maintain thorough records: Document all calibration, measurement, and quality assurance activities to support traceability and audits.

Testing and Certification Considerations:

• Laboratories may pursue or renew accreditations (such as ISO/IEC 17025) highlighting adherence to these updated standards
• Regular participation in interlaboratory comparisons is encouraged, especially for trueness and precision benchmarking
• Validation of new methods (including advanced spectrometric or unfolding techniques) is essential before routine deployment

Conclusion / Next Steps

The December 2025 publication of these five metrology and measurement standards represents a major advance in the science and practice of radioactivity quantification, measurement precision, and uncertainty analysis. Organizations active in environmental surveillance, nuclear operations, waste management, or quality assurance should review these standards in detail and update all relevant practices.

Key Takeaways:

• Stay compliant by integrating the latest methods and statistical tools
• Enhance data quality, stakeholder trust, and global comparability
• Leverage new opportunities for innovation in radiation detection and measurement uncertainty analysis

Recommendation: Explore the full text of each standard through iTeh Standards, evaluate your current compliance posture, and take prompt action to align with these latest international requirements.

Stay at the forefront of metrology and radiation measurement best practices. Browse the full collection of standards at iTeh Standards.