Control rod strategy for long-term small rod-controlled pressurized water reactors

Fig. 2. Partitioning of radial (a) and axial (b) burnup zones

Fig. 3. Flow chart of critical rod position-search burnup code

Fig. 4. Variation of k_eff with burnup

Fig. 5. Variation of control rod value with burnup

Fig. 6. Variation of FU with burnup

Fig. 7. Variations of AO and the critical rod position of control rods with burnup

Fig. 8. Comparison of thermal-flux distribution between ARO (a) mode and control rod operation (b) mode at 2 d

Fig. 9. Comparison of thermal-flux distribution between ARO mode (a) and control rod operation mode (b) at 290 d

Fig. 10. Comparison of thermal-flux distribution between ARO mode (a) and control rod operation mode (b) at 590 d

Fig. 11. Comparison of FU distribution between ARO mode (a) and control rod operation mode (b) at 290 d

Fig. 12. Comparison of FU distribution between ARO mode (a) and control rod operation mode (b) at 590 d

Fig. 13. Variation of the critical rod position of control rods with burnup under different strategies

Fig. 14. Variations of FU and its axial inhomogeneity (DFUUL) with burnup under different strategies

Fig. 15. Variations of AO with burnup under different strategies

Fig. 16. Variation of R-PPF with burnup under different strategies

Fig. 17. Variations of AO and R-PPF with burnup under the value-equivalent scheme

Fig. 18. Variations of the critical rod position of control rods with burnup under the value-equivalent scheme

Table 1. Core parameters

Table 1. Core parameters

参数Parameter	数值Value
功率Power	100 MWt (for 1/4 core is 25 MWt)
燃料组成/密度Fuel component/ density	90wt% U+10wt% Zr/4.95 g·cm^-3
可燃毒物组成/密度Burnable poison component/ density	22.92wt% Gd₂O₃+77.08wt% Zr/6.83 g·cm^-3
燃料装载量Fuel load	805.14 kg (for 1/4 core is 201.285 kg)
燃料棒/可燃毒物/控制棒内径 Fuel rod/ Burnable rod/ control rod inner radius	0.23 cm/0.23 cm/0.26 cm
燃料棒/可燃毒物/控制棒包壳厚度 Fuel rod/ Burnable rod/ control rod cladding thickness	0.06 cm/0.06 cm/0.03 cm
燃料棒/可燃毒物/控制棒包壳材料 Fuel rod/ Burnable rod/ control rod cladding materials	Zr/Zr/06Cr18Ni10Ti
燃料棒外径/栅距Fuel rod outer radius/ pitch	0.58 cm/0.7 cm
组件外径/组件中心距Assembly outer radius/ pitch	6 cm/7.2 cm
组件包壳材料/厚度Assembly cladding materials/ thickness	Zr/0.15 cm
慢化剂Moderator	H₂O
堆芯活性区高度Core active height	1 m
堆芯半径Core radius	0.606 m
慢化剂温度Moderator temperature	295 ℃

Table 2. Typical macro neutron-absorption cross sections of control rod materials (E=0.025 3 eV)

Table 2. Typical macro neutron-absorption cross sections of control rod materials (E=0.025 3 eV)

材料 Material 、	宏观热中子吸收截面 Macro thermal neutron-absorption cross section / cm^-1 、
钛酸镝 Dy₂TiO₅	35.25
硼化铪（20%富集度¹⁰B） HfB₂ (20wo ¹⁰B)	54.91
氧化铕 Eu₂O₃	116.54
碳化硼 B₄C	202.67
硼化铪（80%富集度¹⁰B） HfB₂ (80wo ¹⁰B)	210.05

Table 3. Reactivity and initial value of the control rod

Table 3. Reactivity and initial value of the control rod

参数 Parameter 、	反应性或价值 Reactivity or value / 10^-5 、
初始剩余反应性 Initial excess reactivity	33 146
初始反应性 (ARO) Initial reactivity (ARO)	15 810
钛酸镝价值Value of the Dy₂TiO₅	17 037
硼化铪（20%富集度 ¹⁰B）价值 Value of the HfB₂ (20wo-¹⁰B)	19 796
氧化铕价值Value of the Eu₂O₃	20 463
碳化硼价值Value of the B₄C	22 945
硼化铪（80%富集度 ¹⁰B）价值 Value of the HfB₂ (80wo-¹⁰B)	23 277

Table 4. Initial integral value of maximum value groups

Table 4. Initial integral value of maximum value groups

材料 Material 、	最大价值棒组 Maximum value group / 10^-5 、
钛酸镝 Dy₂TiO₅	R2/1 887
硼化铪（20%富集度 ¹⁰B） HfB₂ (20wo ¹⁰B)	R2/2 063
氧化铕 Eu₂O₃	R2/2 132
碳化硼 B₄C	R2/2 323
硼化铪（80%富集度 ¹⁰B） HfB₂ (80wo ¹⁰B)	R2/2 328

Table 5. Move-in/out strategy and material selection