Usages of Nanomaterials in the Treatment of Primary Coolant Water for Pressurized Water Reactor

Abstract

The application of nano silica extracted from kaolinite, bentonite and rice straw is proposed as treatment material for the purification of primary coolant water of pressurized water reactors. Three elements were used to simulate some radionuclides that can be released in the primary coolant water namely, strontium, nickel and cobalt. Various batch experiments were performed including selection of efficient sorption nanomaterial, optimum operational weight ratio (element/nano material), selectivity of the nano silica for elements used, determination of the equilibrium curve of sorption process, and desorption behavior of nanomaterial with pH and temperature variation. The samples were analyzed using the inductively coupled plasma emission spectrometer. Silica of kaolinite, bentonite and rice straw showed the same results in the efficiency/ capability removing the three elements used. Silica form of rice straw has been selected as nano-treated materials for economic and environmental reasons. The sorption process reached equilibrium after 30 min approximately. The experiments demonstrated that the sorption reaction of elements by the nano-silica is an irreversible reaction with the change of temperature and pH. The obtained results indicated that using the nano silica increased the safety margin of the treatment stage in the multi barrier concept.

The Analysis of Adsorption Phenomenon for Nano silica with Some Radionuclides Released in The Primary Coolant of PWR

“…In the presence of tiny diameter of nano particles (17-33 nm) as obtained from previous work [37], with respect to the particle diameter of the element, the sorption behavior is considered adsorption and not absorption. In the case of adsorption, the nano particle is the adsorbent and the elements are adsorbate.…”

“…It occurs at uniform rate. It is unaffected by temperature; it is an endothermic process [21]. In the other hand, adsorption is physical cohesion of binding ions and molecules on surface of another phase [22].…”

“…The type of adsorption process could be determined from the value of apparent adsorption energy E. If the value of E was lower than 8 kJ/ mol, the process was physical adsorption. If the value of E was higher than16 kJ / mol, the process of chemical adsorption was very strong [36][37][38]. The adsorption energy values of the process calculated from (DKR) equations were 316.23, 316.23 and 353.55KJ mol-1, respectively.…”