Requirements of a system are gathered from various stakeholders, but especially in safety critical application domains, such as the nuclear energy domain, public authorities also impose requirements. Major parts of requirements are often written in natural language. Despite being widely applied and a convenient means, natural language requirements have deficiencies such as impreciseness and vagueness. One approach to improve especially existing requirements is to rewrite the requirements applying structured natural language templates such as Easy Approach to Requirements Syntax (EARS). In this paper, we describe results of an initial quasi-experimental study of applying EARS to nuclear energy domain requirements. The initial results were assessed by stakeholders from public authorities and power companies, and show improvement and utility of applying EARS. Finally, we describe our planned future work to apply EARS to parts of Finnish public authority guidelines for nuclear safety (YVL), which are currently undergoing major rework.