Clearance measurement should be performed as a conformity assessment of the evaluated contamination values to the regulatory limit, considering the measurement’s uncertainty, including the uncertainty of the ratio of the activity concentration of the difficult to measure nuclide to that of the key nuclide. The key issues for the treatment of these uncertainty were summarized.

NRA Secretariat experts developed an empirical method for estimating source vicinity ground-motion levels on hard bedrock and annual exceedance probabilities for inland crustal earthquakes with sources difficult to identify in advance.

NRA conducted tube burst tests and post-test analyses on high-burnup spent nuclear fuel claddings to investigate the condition for the occurrence of macroscopic hydrogen-induced ductile-brittle transition at operational temperatures with quantitative consideration of precipitated Zr hydrides' morphology.

We have developed a debris bed formation prediction method that takes into account accident scenarios and physical properties by providing THERMOS with the analysis results in MELCOR.

Uranium is an important nuclear material and contaminant with respect to the sites of uranium mining and whole nuclear facilities.

A new risk-informed and performance-based inspection program will be enacted from April 2020. A part of this program builds on the information obtained from a probabilistic risk assessment (PRA).

The seawall is one of the main coastal protection structures against tsunamis. Estimating tsunami wave pressures on a structure is quite important when designing seawalls.

The regulatory guide for reviewing the licensee's technical report for the extension of the operating period of commercial power reactors, enacted in November 2013, requires evaluation of the proof stress of the concrete structures of nuclear power plants operated for more than 40 years if the neutron fluence exceeds or may exceed a certain limit where neutron irradiation affects the concrete strength.