Not In My Back Yard (NIMBY) issues indicated that a facility should be sited at only one location. However, locating facilities in multiple sites is worth considering from the perspective of reducing inequity. The protected values are known as the blocking factor of public acceptance, which contains the feature of insensitivity to quantity. We hypothesized that multiple locations could mitigate the protected values and lead to public acceptance as a result of reducing inequity, not because of the reduction in burden. To examine the hypothesis, this study conducted a hypothetical scenario experiment using the siting of geological disposal of high-level radioactive waste (HLW). We manipulated the number of sites and the amount of HLW, and measured inequity, protected values, and acceptance. The results revealed that the participants who read the scenario with multiple sites showed less inequity and greater acceptance than those who read the single site scenario. On the other hand, the amount of HLW had no significant effect. Furthermore, the results of mediation analysis indicated that the number of sites reduced inequity, which mitigated the protected values leading to acceptance.
