Nearly all decommissioning and dismantling (D&D) projects are steered by the characterisation of the plant being dismantled. This radiological characterisation is a complex process that is updated and modified during the course of the D&D. One of the tools for carrying out this characterisation is the performance of in-situ measurements.

There is a wide variety of equipment and methodologies used to carry out on-site measurements, depending on the environment in which they are to be carried out and also on the specific objectives of the measurements and the financial and personnel resources available. The extent to which measurements carried out with different types of equipment or methodologies providing comparable results can be crucial in view of the D&D strategy development and the decision-making process.

This paper concerns an on-site benchmarking exercise carried out at the activated biological shield of Belgian Reactor 3 (BR3). This activity allows comparison and validation of characterisation methodologies and different equipment used as well as future interpretation of final results in terms of uncertainties and sensitivities. This paper describes the measurements and results from the analysis of this exercise. Other aspects of this exercise will be reported in separate papers. This paper provides an overview of the on-site benchmarking exercise, outlines the participating organisations and the measurement equipment used for total gamma, dose rate and gamma spectrometry measurements and finally, results obtained and their interpretations are discussed for each type of measurement as a function of detector type.

Regarding the dose measurements, results obtained by using a large variety of equipment are very consistent. In view of mapping the inner surface of the biological shield the most appropriate equipment tested might be the organic scintillator, the BGO or even the ionisation chamber. In addition, for mapping this surface, the most appropriate total gamma equipment tested might be the LaBr₃(Ce), the thick organic scintillator or the BGO. These measurements can only be used as a secondary parameter in a relative way. Results for the gamma spectrometry are very consistent for all the equipment used and the main parameters to be determined.

几乎所有的退役和拆除（D＆D）项目都是由要拆除的工厂的特性决定的。这种放射学表征是一个复杂的过程，在D＆D过程中会进行更新和修改。进行此表征的工具之一是进行原位测量。

有多种设备和方法可用于进行现场测量，这取决于要进行测量的环境以及测量的特定目标以及可用的财务和人力资源。考虑到D＆D战略的发展和决策过程，使用不同类型的设备或方法进行测量以提供可比较的结果的程度可能至关重要。

本文涉及在比利时反应堆3（BR3）的活化生物防护罩上进行的现场基准测试。这项活动允许比较和验证表征方法和所使用的不同设备，以及就不确定性和敏感性而言对最终结果的未来解释。本文介绍了此练习的分析结果和测量结果。此练习的其他方面将在单独的论文中进行报告。本文概述了现场基准测试活动，概述了参与组织和用于总伽马，剂量率和伽马光谱测量的测量设备，最后，针对每种测量类型的函数讨论了获得的结果及其解释。探测器类型。

关于剂量测量，通过使用多种设备获得的结果非常一致。考虑到绘制生物屏蔽的内表面，测试的最合适的设备可能是有机闪烁体，BGO甚至电离室。另外，要绘制此表面的地图，测试过的最合适的总伽马设备可能是LaBr ₃（Ce），厚有机闪烁体或BGO。这些测量只能以相对方式用作辅助参数。伽马光谱法的结果对于所有使用的设备和要确定的主要参数非常一致。