ODS cladding fuel pins irradiation tests using the BOR-60 reactor

Figures & data

Table 1 Irradiation condition of ODS cladding fuel pins in BOR-60 irradiation tests

	VS423E		VS424E
	Target value	Actual value^*2	Target value	Actual value^*2
Linear heat rate (W/cm)^*1	400–450	387–440	400–450	390–442
Burn up (at%)^*1	10	10.5	15	11.9
Neutron dose (dpa)^*1	50	45	75	51
Cladding mid-wall temperature (°C)^*1	650–700	660–700	650–700	650–700

Table 2 Chemical compositions of ODS claddings used for BOR-60 irradiation tests. (wt%)

	Analytical value													Calculated value
	C	Si	Mn	P	S	Ni	Cr	W	Ti	Y	O	N	Ar	Y2O3 ^*1	Ex.O^*2
9Cr-ODS martensitic steel (Mm14)	0.13	0.009	<0.01	<0.005	0.003	<0.01	8.8	2.0	0.20	0.28	0.17	0.012	0.0054	0.35	0.10
12Cr-ODS ferritic steel (F13)	0.03	0.045	0.07	0.005	0.003	0.03	11.5	1.9	0.27	0.18	0.12	0.0094	0.0055	0.23	0.07

Figure 1 Manufacturing process of ODS claddings used for BOR-60 irradiation tests

Table 3 Main technical characteristics of ODS cladding fuel pins in BOR-60 irradiation tests

	9Cr-ODS fuel pin	12Cr-ODS fuel pin
Fuel pin length (mm)	1050	←
Cladding outer diameter (mm)	6.9	←
Cladding wall thickness (mm)	0.4	←
Cladding material	9Cr-ODS martensitic steel	12Cr-ODS ferritic steel
End-plug material Upper	Same as cladding	←
Lower	05Cr12Ni2Mo	←
Wrapping wire material	ChS-68	←
Fuel column material	Vibro-packed MOX fuel with U metal  getter particles (5–7 wt%)	←
Pu content (wt%)	15	←
Fuel column length (mm)	300	450
Fuel column mass (g)	78	118
Smear density of fuel column (g/cm^3)	9.0	←

Figure 2 Schematic drawings of ODS cladding fuel pin and experimental fuel assembly

Table 4 Irradiation history of experimental fuel assemblies in BOR-60 irradiation tests

		VS423E			VS424E
				Cladding		Linear	Cladding
	EFPD^*1	Loading	Linear heat	mid-wall^*2	Loading	heat rate^*2	mid-wall^*2
Run	(days)	position	rate^*2 (W/cm)	temperature (°C)	position	(W/cm)	temperature (°C)
81A	51.8	5th row (D23)	410	700	—	—	—
83	51.9	4th row (E22)	427	675	4th row (B22)	431	680
83A	44.5	←	425	670	←	430	675
83B	72.0	←	415	665	←	431	670
84	31.6	←	405	675	←	423	680
84A	39.5	←	412	695	←	421	700
84B	51.0	←	411	680	←	427	690
85	45.6	←	395	670	←	405	670
85A	70.9	←	387	660	←	394	660
86	40.8	2nd row (E39)	440	695	←	390	650
86A	65.8	←	436	690	←	398	650
87	42.0	—	—	—	2nd row (E39)	442	685
87A	40.0	—	—	—	←	433	680
87B	48.0	—	—	—	←	408	665

Figure 3 Fuel pin configurations in experimental fuel assemblies

Figure 4 Diameter measurement results of ODS cladding fuel pins irradiated in VS424E

Figure 5 Optical micrographs of 9Cr-ODS cladding fuel pin (X46) irradiated in VS424E (top of fuel column; distance from core center = 213 mm)

Figure 6 Result of EPMA line analysis of 9Cr-ODS cladding fuel pin (X46) irradiated in VS424E (top of fuel column; distance from core center = 205 mm)

Figure 7 Optical micrographs of 12Cr-ODS cladding fuel pin (X36) irradiated in VS424E (top of fuel column; distance from core center = 215 mm)

Figure 8 FCCI of the irradiated ODS claddings compared with the FCCI of the modified 316 stainless steel (PNC316) and conventional ferritic steel (PNC-FMS) claddings

Figure 9 Optical micrographs of 9Cr-ODS cladding fuel pin (X46) irradiated in VS424E (vicinity of the welded section of upper end-plug by PRW method)

Figure 10 Photographs of the failure position of 9Cr-ODS cladding fuel pin (X42) irradiated in VS423E (distance from core center = 175–205 mm)

Figure 11 Optical micrographs of modified 316 stainless steel temperature monitors

Figure 12 Result of EPMA line analysis of 9Cr-ODS cladding fuel pin (X43) irradiated in VS423E (top of fuel column; distance from core center = 211 mm)

Figure 13 Optical micrographs of ChS-68 cladding fuel pins (A155 and A158) (top of fuel column; distance from core center = 213 mm)

Figure 14 Optical micrographs of 9Cr-ODS cladding fuel pin (X44) irradiated in VS423E (top of fuel column; distance from core center = 213 mm)

Figure 15 Material defect estimated to be metallic inclusion observed in 9Cr-ODS cladding fuel pin (X46)