CO₂ corrosion of IG-110 nuclear graphite studied by gas chromatography

Figures & data

Table 1. Impurity contents in the primary helium coolant in HTR-PM under normal operation conditions.

Impurity	H2O	H2	CO	O2	N2	CO2	CH4
Content (μg/g)	1.5	10	10	<1	1.4	2–3	1

Table 2. Main properties of IG-110 nuclear graphite.

Material	IG-110
Bulk density (g/cm^3)	1.75
Young's modulus (GPa)	9.6
Compressive strength (MPa)	70.5
Rockwell hardness (MPa)	74.2
Fracture toughness (MPa)	0.82
Thermal conductivity (W/mK)	116
Impurities (ppm)	<20

Figure 1. Gas flow route of the experimental setup.

Figure 2. Curve of lnQ against 1000/T from 745 to 1095 °C for an initial CO₂ concentration of 17%.

Figure 3. Outlet gas concentration ratio of CO to CO₂ from 745 to 1095 °C for an initial CO₂ concentration of 17%.

Figure 4. Curves of lnQ against 1000/T from 745 to 1095 °C for three initial CO₂ concentration of 10%, 14% and 17%.

Figure 5. SEM micrograph of the surface of IG-110 corroded to weight loss degrees of 0%, 10.4%, 25.0% and 41.7% at 1145 °C.

Table 3. Some parameters of the specimens corroded to different weight loss degrees at 1145 °C.

Sample	Weight before	Weight after	Weight loss	Volume after	Volume loss	Bulk density after	Bulk density
no.	corrosion (g)	corrosion (g)	degree	corrosion (mm^3)	degree	corrosion (g/cm^3)	loss degree
1	2.76	2.56	7.3%	1535	3.2%	1.667	4.2%
2	2.78	2.49	10.4%	1547	3.2%	1.610	7.5%
3	2.78	2.38	14.4%	1543	3.4%	1.543	11.3%
4	2.76	2.07	25.0%	1526	3.8%	1.357	22.0%

Figure 6. Q value and CO₂/CO concentration as a function of corrosion time at 1145 °C.