Nitrogen solubility in water

When gas pressurizers are used, it is important to consider gas transport in the primary circuit. It is well known that solubility of nitrogen taken as a working medium in the pressurizer rises as temperature increases. Under 15 MPa nitrogen solubility in water reaches its maximum at temperature of -270° C. As a result, possible gas transport firom the pressurizer to the primary circuit, subsequent gas release and formation of gas bubbles in various regions of the circuit will cause certain difficulties as well as some changes in heat transfer conditions in the core and steam generator. 

When NSSS is in operation, temperature in the central cavity of the pressurizer is settled at 120° C, i.e. these are conditions of minimum nitrogen solubility in water. Besides, sequential connection of the reactor annulus and peripheral and central cavities allows to operate the pressurizer as hydraulic siphon gas being accumulated in the upper part of the reactor or in peripheral cavity of the pressurizer will flow under fluctuation of the primary temperature to the central cavity and adds to total mass of gas. 

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