Computational-Experimental Investigation of the Wigner Energy and the Physical Properties of Plunger Graphite in the Safety and Control System of an RBMK Reactor

The total amount of stored energy (Wigner energy) and the physical-mechanical properties of the graphite plunger, which exhausted its total service life (6 yr), in the No. 2 unit of the Kursk nuclear power plant were estimated experimentally. The results showed that the total accumulated energy was 180–220 cal/g ((8–10)·105 J/ kg). The real tempearture of the graphite plunger was found to be much lower – 70–80°C compared with the computed value 180–200°C. The energy was nonuniformly distributed over the cross section and azimuth of the plunger.