Research Article

Analysis of Control Rod Drop Accidents for the Canadian SCWR Using Coupled 3-Dimensional Neutron Kinetics and Thermal Hydraulics

Table 1

Fuel lattice cell specifications.

ComponentDimensionMaterialComposition [wt%]Density [g⋅cm−3]

Centre tube coolant4.6 cm radiusLight water100% H2OVariable

Centre flow tube4.60 cm inner radius; 0.1 cm thickZr-modified 310 stainless steelC: 0.034; Si: 0.51; Mn: 0.74; P: 0.016; S: 0.002; Ni: 20.82; Cr: 25.04; Fe: 51.738; Mo: 0.51; Zr: 0.597.9

Inner fuel pins (24)0.415 cm radius; 5.4 cm pitch radius0–3 m ∣ 12.8 wt% PuO2 in ThO2Pu: 11.293; Th: 76.632; O: 12.0759.91
3-4 m ∣ 12.3 wt% PuO2 in ThO2Pu: 10.851; Th: 77.072; O: 12.077
4-5 m ∣ 11.5 wt% PuO2 in ThO2Pu: 10.146; Th: 77.775; O: 12.079

Outer fuel pins (24)0.44 cm radius; 6.575 cm pitch radius0–3 m ∣ 10.24 wt% PuO2 in ThO2Pu: 9.034; Th: 78.882; O: 12.0849.87
3-4 m ∣ 9.84 wt% PuO2 in ThO2Pu: 8.682; Th: 79.233; O: 12.085
4-5 m ∣ 9.20 wt% PuO2 in ThO2Pu: 8.117; Th: 79.796; O: 12.087

Inner fuel pins with burnable absorber (8)0.415 cm radius; 5.4 cm pitch radius (evenly spaced, π/8 angular offset) 0–3 m ∣ 12.8 wt% PuO2 in ThO2; 3 wt% Gd2O3 in PuO2/ThO2Pu: 10.954; Th: 74.333; O: 12.11; Gd: 2.6039.82
3-4 m ∣ 12.3 wt% PuO2 in ThO2; 2 wt% Gd2O3 in PuO2/ThO2Pu: 10.635; Th: 75.53; O: 12.10; Gd: 1.7359.85
4-5 m ∣ 11.5 wt% PuO2 in ThO2; 2 wt% Gd2O3 in PuO2/ThO2Pu: 9.943; Th: 76.219; O: 12.103; Gd: 1.7359.85

Outer fuel pins with burnable absorber (8) 0.44 cm radius; 6.575 cm pitch radius (evenly spaced, no angular offset) 0–3 m ∣ 10.24 wt% PuO2 in ThO2; 3 wt% Gd2O3 in PuO2/ThO2Pu: 8.764; Th: 76.515; O: 12.118; Gd: 2.6039.79
3-4 m ∣ 9.84 wt% PuO2 in ThO2; 2 wt% Gd2O3 in PuO2/ThO2Pu: 8.508; Th: 77.649; O: 12.108; Gd: 1.7359.81
4-5 m ∣ 9.20 wt% PuO2 in ThO2; 2 wt% Gd2O3 in PuO2/ThO2Pu: 7.955; Th: 78.20; O: 12.11; Gd: 1.7359.81

Cladding0.06 cm thickZr-modified 310 stainless steelAs above7.9

CoolantLight water100% H2OVariable

Liner tube7.2 cm inner radius; 0.05 cm thickZr-modified 310 stainless steelAs above7.9

Insulator7.25 cm inner radius; 0.55 cm thickYttria stabilized ZirconiaZr: 66.63; Y: 7.87; O: 25.55.37

Outer liner tube7.8 cm inner radius; 0.05 cm thickExcel aloySn: 3.5; Mo: 0.8; Nb: 0.8; Zr 94.96.52

Pressure tube7.85 cm inner radius; 1.2 cm thickExcel alloySn: 3.5; Mo: 0.8; Nb: 0.8; Zr 94.96.52

Moderator25 cm square lattice pitchHeavy water99.833 D2O; 0.167 H2O1.0851

Plutonium isotopicsReactor grade plutoniumPu238: 2.75; Pu239: 51.96; Pu240: 22.96; Pu241: 15.23; Pu242: 7.10

Control blade bodySpan 48.4 cm; thickness 1 cm;Excel alloySn: 3.5; Mo: 0.8; Nb: 0.8; Zr: 94.96.52

Control blade absorberPosition on the blade’s arm: 16–24 cm; thickness 0.8 cmStainless steel 3047.94