Influence of thermal neutron scattering effect of FLiBe molten salt on neutronic performance of molten salt reactors

Zhicheng ZHANG; Jifeng HU; Jingen CHEN; Xiangzhou CAI

doi:10.11889/j.0253-3219.2023.hjs.46.070605

Journals >NUCLEAR TECHNIQUES >Volume 46 >Issue 7 >Page 070605 > Article

NUCLEAR TECHNIQUES
Vol. 46, Issue 7, 070605 (2023)

Influence of thermal neutron scattering effect of FLiBe molten salt on neutronic performance of molten salt reactors

Zhicheng ZHANG^1、2、3, Jifeng HU^1、3、*, Jingen CHEN^1、2、3, and Xiangzhou CAI^{1、2、3、**}

Author Affiliations

¹Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China

²University of Chinese Academy of Sciences, Beijing 100049, China

³CAS Innovative Academy in TMSR Energy System, Chinese Academy of Sciences, Shanghai 201800, China

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DOI: 10.11889/j.0253-3219.2023.hjs.46.070605 Cite this Article

Zhicheng ZHANG, Jifeng HU, Jingen CHEN, Xiangzhou CAI. Influence of thermal neutron scattering effect of FLiBe molten salt on neutronic performance of molten salt reactors[J]. NUCLEAR TECHNIQUES, 2023, 46(7): 070605 Copy Citation Text

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Fig. 1. Structural diagram of calculation model for the reactor core

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Fig. 2. Influence of FLiBe thermal scattering on the neutron spectrum

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Fig. 3. Influence of FLiBe thermal scattering on the neutron spectrum in the ranges of 0.05⁓0.08 eV (a) and 0.2⁓0.4 eV (b)

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Fig. 4. Fitting of the fuel temperature reactivity coefficient

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$Variation of the core energy spectrum with the molten salt volume fraction$

Fig. 5. Variation of the core energy spectrum with the molten salt volume fraction

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$Variation of the reaction rate with the volume fraction of molten salt$

Fig. 6. Variation of the reaction rate with the volume fraction of molten salt

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$Influence of thermal scattering on keff as a function of the volume fraction$

Fig. 7. Influence of thermal scattering on k_eff as a function of the volume fraction

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主要参数 Main paramenters	数值 Values
燃料盐成分 Composition of fuel salt / mol%	65.31%LiF-28.67%BeF₂-4.78%ZrF₄-1.24%UF₄
熔盐密度（900 K）Density of fuel salt (900 K) / g∙cm^-3	2.311
⁷Li丰度 ⁷Li abundance / %	99.95
²³⁵U富集度 ²³⁵U enrichment / %	19.75
石墨密度 The density of graphite / g∙cm^-3	1.785
活性区高度/直径 Height/diameter of active region / cm	252/252
燃料通道半径 Radius of fuel channel / cm	3
石墨组件对边距 Graphite assembly pitch / cm	14

Table 1. Main parameters of the reactor core

反应道 Neutron activities	自由气体模型计算结果 Calculation result of free gas model / collisions·cm^-3·s^-1	热中子散射计算结果 Calculation result of TSL / collisions·cm^-3·s^-1	差值 Difference / 10^-5 collisions·cm^-3·s^-1
²³⁵U俘获 ²³⁵U capture rate	0.107 70	0.107 75	5
²³⁸U俘获 ²³⁸U capture rate	0.076 92	0.076 93	1
熔盐吸收 Molten salt absorption rate	0.150 39	0.150 40	1
²³⁵U裂变 ²³⁵U fission rate	0.522 68	0.522 29	-39
²³⁸U裂变 ²³⁸U fission rate	0.000 57	0.000 57	0

Table 2. Changes in neutron activity in the MSR

自由气体模型计算结果

Calculation result of free gas

model / 10^-5 K^-1

热中子散射计算结果

Calculation result of TSL

/ 10^-5 K^-1

差值

Difference

/ 10^-5 K^-1

密度系数 Density coefficient

-0.97

-0.99

-0.02

多普勒系数 Doppler coefficient

-3.23

-3.52

-0.28

燃料总温度系数 Fuel temperature coefficient

-4.25

-4.50

-0.25

Table 3. Fitted results for the fuel temperature reactivity coefficient

体积份额 Volume fraction / %	自由气体模型 Free gas model	热中子散射 TSL	差值 Difference / 10^-5
16.6	1.245 95(0.000 05)	1.245 03(0.000 05)	-92
20.4	1.217 62(0.000 05)	1.216 87(0.000 05)	-75
24.9	1.185 86(0.000 05)	1.185 18(0.000 05)	-68
30.6	1.143 35(0.000 05)	1.142 79(0.000 05)	-56
35.7	1.099 65(0.000 05)	1.099 30(0.000 05)	-35
45.7	1.026 62(0.000 05)	1.026 42(0.000 05)	-20

Table 4. Effect of FLiBe thermal neutron scattering on k_eff

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