Diagnostics of the Structure of a Nuclear Power Plant Unit Using Muonography

In 2022, a hybrid muon hodoscope with a sensitive area of $$3\times 3$$ m $${}^{2}$$ for studying the internal structure of large-scale objects using the muonography method was created at MEPhI. The hodoscope’s detecting system has a hybrid structure. It consists of a scintillation strip detector and a drift tube detector and is designed to record tracks of charged particles. The muonography method is based on the use of cosmic ray muons as penetrating radiation for ‘‘translucence’’ (analogous to radiography) of large-scale objects. Experimental studies of the internal structure of the Kalinin NPP power unit using the muonography method were carried out in 2022–2023. The paper presents a brief description of the design of a hybrid muon hodoscope, as well as the results of an experiment on diagnostics of the power unit structure using this method, which was carried out during the scheduled power unit’s maintenance. The purpose of the experiment was to develop a method for real-time detection of changes in the structure of a reactor unit during its maintenance.