Effects of process-generated hydrogen on RPV walls

5. Hydrogen production in PWR

where T is the temperature in K and T c is the critical temperature of water, 647.3 K. This function is shown in Figure 5.1. Morris et al. [56] have shown that this equation agrees well with their own experimental values, measured at pressures between 4.2 and 15.5 MPa.

Figure 5.1: Henry constant for hydrogen gas in light water as a function of temperature expressed in GPa. [55, 56]

To simplify the calculations in the following steps, this Henry constant will be converted to the equivalent Henry constant expressed in mol/m 3 Pa. The following conversion equation allows to do so:

1 H H 2 [GPa]

ρ H 2 O M

3 Pa] = 10 − 9

H H 2 [mol/m

(5.2)

where ρ H 2 O is the density of water at the corresponding temperature in g/m 3 and M is the molar mass of water, equal to 18.01528 g/mol. The density of the water is temperature and pressure dependent. For a pressure of 150 bar, which is the typical pressure in a PWR, the temperature dependent density of water is shown in Figure 5.2. [50] The converted Henry constant given in mol/m 3 Pa is shown in Figure 5.3. 40