RIKEN Accelerator-driven compact neutron source, RANS, has been operational since 2013. There are two major goals of RANS research and development. One is to establish a new compact low energy neutron non-destructive evaluation system on-site of floor-standing type for industrial use. Another goal is to invent a novel transportable compact neutron system for the preventive maintenance of large scale construction such as a bridge. For the realization of the preventive maintenance usage with neutron methods for non-destructive test of large scale structures on-site, “Standardization”, such as inclusion in manuals and inspection procedures, is essential. Technology research association for the infrastructure preventive maintenance standardization is established. RANS and RANS-II are in operation, and RANS-III, and RANS-μ, neutron salt-meter, are under development.