## 4 Discussion
### Specific Safety Culture Traits of SNPPs  
The comparative analysis based on the three study variables (company, location, and contractual relationship) shows an interesting paradox: the existence of a uniform safety culture amongst the organizations, but also the coexistence of significant differentiating traits relating to location and contractual relationship. In general terms, these data suggest that there is strong cultural homogeneity amongst the three nuclear organizations included within this study. In all three, the same resulting pattern is obtained, with high scores for safety (scale and BARS), anticipative capacity (subscale of resilience), level of formalization (BARS), and, to a lesser extent, the processes of resources allocation and establishment of objectives (BARS). However, it is important to point out that within the scope of formalization there are significant differences between two out of the three organizations. Concerning differentiation, the analysis reveals that the variables \"place of work\" and \"contractual relationship\" may potentially lead to the creation of subcultures and to conform a safety culture with unique traits. This differentiation is present both in terms of the entire sector and within each of the organization's part of this study. As for \"location\", results show that personnel working at the facility score higher than personnel at the headquarters in the hazard scale. This is in fact the most statistically significant difference of the entire study. This finding is coherent with previous studies [72], which show that individual perceptions on hazard levels at the workplace in a nuclear organization seem to be associated to proximity to the technological element. That means workers within the group directly linked to plant operations, i.e., facility personnel, score higher in risk perception. Differentiated grades are also observed in all BARS. Headquarters personnel have a more favorable vision than facility personnel of the importance given by the organization to safety (BARS attention to safety), quality of standards, and procedures (BARS formalization) and allocation of resources (BARS resources allocation). The difference in this last BARS is quite significant, revealing that headquarters personnel have a much more positive view of resources allocation processes (82% vs. 46%). In short, it can be concluded that the safety culture of facility personnel differs from global safety culture mainly in their risk awareness, and also in a less categorical resolution of the safety-production dilemma (less clearly positioned towards safety), and a more critical vision of the processes for resources allocation and establishment of objectives. The analysis based on \"contractual relationship\" shows the level of variability in relation to overall safety culture traits. Contractors score lower than personnel in all measurement instruments used to describe the purpose of this study (the safety culture of SNPPs). On the one hand, contractors are less categorical when it comes to the priority of safety, level of formalization, and adequacy of resources allocation. Their score is also more aligned to safety culture at the facility. On the other hand, there are also significant differences in the perception of both a blame-free environment (SCWE scale) and the organization's capacity to respond to crises (resilience subscale). Contractors point to a lower level of freedom to express concerns and seem to be more concerned about the consequences of dissenting. They also assign a lower score to the organization's capacity to plan, respond to, and recover from crisis. Considering these results and an increasing number of contractors in nuclear power plants (exceeding the number of own staff), it is necessary to consider the impact these cultural differences may have on the overall safety of Spanish nuclear power plants.