Nuclear reactors closed primary cooling systems

Reactors operating today all have closed primary cooling systems that do not allow for this type of contamination. Therefore, under normal conditions production of electricity from nuclear reactors does not create significant amounts of operational discharges of radionuclides. However, the 434 energy-producing nuclear plants of the world in 1998 created radioactive waste in the form of utilized fuel. Utilized fuel is either stored or reprocessed. 

The PWR has three main water circuits. The first is the primary circuit that carries heat energy from the nuclear reactor to the steam generators. The water is maintained at a pressure of sl50bar and an operating temperature of s573 K. Since the primary circuit is a closed loop, it is the only water circuit in the power station that contains radioactivity. The second water circuit is the water-steam cycle, and the final circuit is the water cooling system, which dissipates excess heat. 

The intense primary y radiation due to nuclear fission, the secondary y radiation emitted by the fission and activation products and the radiation from the fission products give rise to radiation-induced chemical reactions. The most important reaction is the radiation decomposition of water in water-cooled reactors, leading to the formation of H2, H2O2 and O2. Many substances dissolved in the water influence the formation of H2 (Fig. 11.18). In most closed coolant systems equipment for... 

---