safety-critical system are systems in which failures may affect the environment of the system and cause injury or death to the people in that environment. The principal concern of safety specification is to identify requirements that will minimize the probability that system failures will occur. Safety requirements are primarily protection requirements and are concerned with normal system operation. They may specify that the system should be shut down so that safety is maintained in deriving safety requirements. You, therefore, need to find an acceptable balance between safety and functionality and avoid overprotection. There is a unit in banking a very safe system if it does not operate in a cost-effective way. Safety specification is usually focused on the hazards that may arise in a given situation, and the events that can lead to these hazards. The activities in the general risk-based identification process map onto the safety specification process as follows.
- （Risk identification）.In safety specification, this is the hazard identification process that identifies hazards that may threaten the system.
- （Risk analysis）.This is a process of hazard assessment to decide which hazards are the most dangerous and or the most likely to occur. These should be prioritized when deriving safety requirements.
- （Risk specification）.This process is concerned with discovering the events that can lead to the occurrence of a hazard. In safety specification, the process is known as hazard analysis.
- （Risk decomposition）.This process is based on the outcome of （hazard assessment） and leads to identification of safety requirements. These may be concerned with ensuring that a hazard does not arise or lead to an accident or that if an accident does occur, the associated damage is minimized.
安全关键系统指失效会影响周边环境、造成人员伤亡的系统，其安全需求规范的核心是在安全保障、系统功能与成本效益间找到平衡，避免过度防护导致系统失去经济实用性，比如银行系统若因过度安全丧失运行效率则不具备实际价值。在这类系统的安全需求构建中，风险导向的识别流程与安全规范环节存在明确对应关系：风险识别环节对应危险识别，需先全面排查系统面临的各类潜在危险；风险分析对应危险评估，要对已识别的危险开展严重性、发生概率的评估并进行优先级排序，以此确定安全需求的重点关注对象；风险规格化对应危险分析，核心是挖掘并明确可能触发危险的各类事件及相关条件；风险分解则是基于危险评估的结果，将风险拆解为具体可落地的安全需求，这些需求既要覆盖阻止危险发生、避免事故的场景，也要包含事故发生后降低损害程度的防护要求。整体流程以风险管理为框架，通过系统化的步骤将抽象的安全目标转化为具体的安全需求，为安全关键系统的安全性提供可执行的规范依据。
本题考察的是安全关键系统（safety-critical system）的安全需求规范过程与风险管理过程的映射。
语境定位：原句为 “____ In safety specification, this is the hazard identification process that identifies hazards that may threaten the system.”。空后 In safety specification this is the 是判断本空的关键。
答案判断：从语法看，这里需要名词或名词短语；从语义看，应填“风险识别，找出可能导致危害的风险源”。因此应选 Risk identification。
选项辨析：
A. Risk decomposition：这是将风险进一步分解为可管理的部分，不是识别风险的过程，错误。
B. Risk analysis：分析风险的严重性和可能性，不是最初的识别环节，错误。
C. Risk reduction：是风险控制或降低的措施阶段，不符合题干描述，错误。
D. Risk identification：是风险管理的第一步，目的是识别可能影响系统的潜在风险，对应 hazard identification，符合语境。
因此，选项 D 正确。