Emergency management implies making decisions under uncertainty. Though this is a truism, uncertainties faced by different actors during radiological emergencies have not been investigated as intensively as other emergencies and lack a systematic analysis during realistic conditions. Hence, the goal of this study is to identify and analyse the uncertainties that may appear during radiological emergencies. Furthermore, this research explores among which actors and at which stages of decision-making process these uncertainties appear.

For this purpose, non-participatory observation has been used during 11 nuclear or radiological emergency exercises in the period of 2017–2018 at 29 observation points in 6 countries and 1 international exercise. The observers recorded actual behavior of different actors (participants of the observed exercises) under live conditions.

Results provide valuable insights into the complex decision-making process related to actions taken for the protection of individuals and society at large during realistic exercises of a radiological emergency. Most uncertainties synthesized from our observations are related to the practical implementation of emergency actions, e.g. the potential for unexpected failure of communication tools or channels, or the inadequacy of emergency plans to cope with the real situation. A high number of uncertainties were also associated to knowledge gaps, e.g. related to the consistency of radiological assessments or the insufficient familiarity of emergency actors with the rules and procedures. The findings of this study can inspire emergency planners and other stakeholders to strengthen radiological emergency management, advance emergency response practices, and improve communication and collaboration between different actors in emergency situations.

紧急管理意味着在不确定的情况下做出决策。尽管这是不言而喻的，但放射线紧急情况下不同行为者面临的不确定性并未像其他紧急情况那样得到深入研究，并且在现实情况下缺乏系统的分析。因此，本研究的目的是识别和分析在放射紧急情况下可能出现的不确定性。此外，本研究探讨了哪些不确定因素出现在哪些参与者以及决策过程的哪个阶段。

为此，在2017-2018年期间，在6个国家的29个观测点和1次国际演习中，进行了11次核或放射应急演习中使用了非参与性观察。观察者记录了在现场条件下不同演员（观察到的参与者）的实际行为。

结果为复杂的决策过程提供了宝贵的见解，这些决策过程与在放射紧急情况的实际演习中为保护个人和整个社会而采取的行动有关。从我们的观察中得出的大多数不确定性与应急措施的实际执行有关，例如，通信工具或渠道发生意外故障的可能性，或应急计划不足以应对实际情况。大量的不确定性也与知识差距有关，例如，与放射学评估的一致性或紧急行动者对规则和程序的不充分了解有关。这项研究的结果可以激发应急计划人员和其他利益相关者加强放射线应急管理，推进应急响应实践，