Investigation of radiation-induced surface activation effect in austenitic stainless steel under ultraviolet and γ-ray irradiations

Figures & data

Table 1. Chemical compositions of PNC1520 and SS304 (wt.%)

	C	Si	Mn	P	S	Ni	Cr	Ti	Mo	Nb
SS304	<0.08	<1.0	<2.0	<0.05	<0.03	8.00 −10.50	18.0 −20.0	-	-	-
PNC1520	0.058	-	1.75	0.028	-	19.88	15.11	0.23	2.51	0.1

Figure 1. The irradiation damage dependency of the contact angle of the water droplet in PNC1520 and SS304 specimens under (a) UV and (b) γ-ray irradiation. The dotted lines are guides.

Figure 2. The contact angle of the water droplet plotted as a function of holding time in PNC1520 and SS304 specimens after (a) UV and (b) γ-ray irradiation. Note that the specimens of 277.2 ks irradiated under UV irradiation were employed in the recovery behavior measurements, and the 710 kGy in KUR and 685 kGy in QST irradiated specimens were, respectively, used in this measurement. The dotted lines are guides.

Figure 3. An example to show the fitting results of the related parameters in the UV-irradiated PNC1520 (43.2 ks oxidization) specimen.

Table 2. The characteristics for the wettability improving factor in PNC1520 and SS304 specimen under UV irradiation. The k_b denotes the lifetime of wettability control factor

	Oxidation time (ks)	kb (μs^−1)
PNC1520	43.2	0.83
	86.4	1.11
	172.8	0.85
SS304	43.2	0.86
	86.4	0.96
	172.8	1.05

Figure 4. The numerical analysis results of PNC1520 specimens before and after UV irradiation. Specimens exposed to UV irradiation were kept in darkness after irradiation for various holding time.

Table 3. The characteristics for the wettability improving factor in KUR-irradiated PNC1520 and SS304 specimens under γ-ray irradiation. The k_b and g denote the lifetime of wettability control factor and abundance ratio, respectively

			s = 1		s = 2
	Contact angle (deg.)		kb1 (μs^−1)	g1　(%)	kb2 (μs^−1)	g2(%)
PNC1520	θ1	23	0.83	70	18.65	30
	θ2	15	0.98	99	18.94	1
	θ3	9	1.05	46	18.72	54
SS304	θ1	12	0.83	69	13.89	31
	θ2	14	0.99	59	18.52	41
	θ3	34	1.11	33	19.02	67

Figure 5. The numerical analysis results of the recovery behavior of wettability in the 710 kGy irradiation SS304 specimen in KUR.

Figure 6. The numerical analysis results of PNC1520 specimens after γ-ray irradiation at KUR and after dark place holding experiment.

Figure 7. Laser microscope photographs of oxidized and non-oxidized SS304 specimens. The photographs of oxidized specimens were taken after re-polishing the oxidized layer.

Figure 8. Raman spectra of 24 h oxidized PNC1520 and SS304 specimens. The Fe-oxide, Fe-hydroxide, and Cr-oxide Raman bands are indicated in this figure as reference data.