Natural Circulation Salt Heat Transfer X. Sun, H.C. Lin, and S. - PowerPoint PPT Presentation

Molten Salt Reactor Workshop 2017 Key Technology and Safety Issues for MSRs October 3 - 4, 2017 Natural Circulation Salt Heat Transfer X. Sun, H.C. Lin, and S. Zhang Department of Nuclear Engineering and Radiological Sciences University of Michigan Session 7: Support for Salt Technologies 10/04/2017

Prandtl Number of Different Fluids • Liquid Salts - FLiBe - FLiNaK - KF-ZrF 4 - KCl-MgCl 2 - KNO 3 -NaNO 2 -NaNO 3 • Water • Dowtherm A • Air 2

� Natural/Forced Convection Heat Transfer Coefficient Correlations Natural Correlation Geometry Working Pr range Ra or Re Ref. Convection fluid range (NC)/Forced Convection (FC) Ra ≤ 10 /8 NC Vertical plate Sodium, 0.004 ≤ Pr ≤ 300 [1] Nu mercury, = 0.825 air, water, ⁄ 0.387Ra / 0 + oil 7 89 ⁄ ⁄ 6 /0 1 + 0.437 Pr 10 < ≤ Ra ⁄ NC Nu = 0.54Ra / ; Horizontal plate, Air Pr = 0.7 [2] ≤ 2×10 9 hot surface facing up ⁄ 3×10 < NC Nu = 0.27Ra / ; Horizontal plate, Air Pr = 0.7 hot surface ≤ Ra ≤ 10 /? facing down Nu = 0.474Ra ?.8< P𝑠 ?.?;9 3×10 8 NC Horizontal Air, water, 0.7 ≤ Pr ≤ 3090 [3] cylinder silicone ≤ Ra ≤ 2×10 9 oils 3

Natural/Forced Convection HTC Correlations (Cont’d) Natural Correlation Geometry Working Pr range Ra or Re Ref. Convection fluid range (NC)/Forced Convection (FC) Ra ≤ 10 // NC Nu Spheres air, water, oil Pr ≥ 0.7 [4] ⁄ 0.589Ra / ; = 2 + ; 6 ⁄ ⁄ 6 /0 1 + 0.469 Pr Re ≥ 10 ; FC Nu Pipe air, water, oil 0.7 ≤ Pr [5] = 0.027Re ?.7 Pr / E ⁄ ?./; ⁄ ≤ 16700 𝜈 𝜈 G FC Pipe air, water, oil 0.7 ≤ Pr Re [6] / E ⁄ 𝐸 ⁄ Pr / E Nu = 1.86Re / E ⁄ ≤ 16700 ≤ 2300 𝑀 ?./; ⁄ 𝜈 𝜈 G FC Nu Pipe air, water, oil 0.7 ≤ Pr ≤ 3 3500 [7] ⁄ ≤ Re = 0.116JRe 8 E ≤ 1.2 − 125LPr / E ⁄ ?./; ⁄ 𝜈 𝜈 G ×10 ; 4

Natural/Forced Convection HTC Correlations (Cont’d) Natural Correlation Geometry Working Pr range Ra or Re Ref. Convection fluid range (NC)/Forced Convection (FC) Nu = 0.023Re ?.7 P𝑠 M Re ≥ 10 ; FC Pipe air, water, 0.7 ≤ Pr ≤ 100 [8] 𝑜 = 0.4 if the fluid is heated oil 𝑜 = 0.3 if the fluid is cooled Re ≤ 7.6×10 ; FC Nu Sphere air, water, 0.7 ≤ Pr ≤ 380 [9] = 2 oil + J0.4Re ?.< ⁄ LPr ?.; + 0.06Re 8 E Re ≥ 10 ; Nu = 0.023Re ?.7 Pr / E ⁄ FC Pipe air, water, 0.7 ≤ Pr ≤ 100 [10] oil 5

Comparison of Colburn Correlation with Salt Forced Circulation Experiments (G. Yoder, 2014) 6

Comparison with Salt Forced Circulation Experiments +20% -20% Sieder Tate correlation for trubulent flow: ⁄ Nu = 0.027Re ?.7 Pr / E ⁄ ?./; 𝜈 𝜈 G Sieder Tate correlation for laminar flow: ⁄ / E 𝐸 ⁄ Pr / E ⁄ Nu = 1.86Re / E ?./; 𝜈 𝜈 G ⁄ 𝑀 Hausen correlation for transitional flow: ⁄ − 125 Pr / E Nu = 0.116 Re 8 E ⁄ ?./; 𝜈 𝜈 G ⁄ 7

Thermal Expansion Coefficient for Different Fluids • FLiBe • FLiNaK • KF-ZrF 4 • KCl-MgCl 2 • H 2 O (1 atm) ( ) g Δ h Δ p = ρ 0 β Δ T 8

Review of Natural/Forced Circulation Loops for MSRs/FHRs at max Organization NC/FC Experiment Objective Material Working fluid Max Max Ref. Modeling working temp. power temp. (K -1 ) (kW) ( o C) Oak Ridge NC Experiment Preparation for operation of the MSRE Hastelloy N LiF-BeF 2 -ZrF 4 -UF 4 , 784 -- 30,000 [11] National Single loop Laboratory, LiF-BeF 2 -ZrF 4 670 8.8 USA a) Determine if the experimental 0.00032 0.5 NC Experiment Nickel FLiNaK 700 [12] Fluent configuration provides sufficient salt crucible [13] velocity for collection of corrosion data; b) Quantify natural circulation salt velocities using a laser Doppler velocimeter; FC Experiment a) Develop a nonintrusive, inductive Inconel 200 heating technique 600 single b) Measure heat transfer characteristics loop 0.00061 2 The Ohio NC Experiment Examine the couplings among the SS 304 Water 76.5 [14] State Relap5 MOD 4.0 natural circulation/convection loops and coupled [15] University provide experience for high-temperature loops (University DRACS loop design of NC Experiment Investigate DRACS performance under SS 316 FLiNaK 722 0.00032 70 Michigan), steady-state and transient conditions, coupled USA including startup, pump trip test w/o IHX loops 9

Review of Natural/Forced Circulation Loops for MSRs/FHRs (Cont’d) at max Organization FC/NC Experiment Objective Material Working fluid Max Max Ref. Modeling working temp. power temp. (K -1 ) (kW) ( o C) University of NC/FC Experiment Provide experimental validation data for Stainless Dowtherm A 120 0.00075 10 [16] California, Relap5-3D system-level thermal hydraulic codes; steel/copper [17] Berkeley, modeling Serve as an advanced reactor test bed; USA University of NC/FC Experiment System code validation; Heat exchanger Stainless Dowtherm A -- -- 20 [18] New Mexico, testing steel USA single loop University of NC Experiment Research in natural circulation stability, -- FLiBe 800 0.00027 -- [19] Wisconsin, Fluent salt freezing, etc. USA FC Experiment Identify salt corrosion and heat transfer SS 316 KCl-MgCl 2 600 0.00029 4 [20] issues Single loop US Industry NC/FC Experiment Gaining operation experience with salts, Salts corrosion, component testing, instrumentation, etc. Ulsan NC Experiment Understand the thermal-hydraulic SS 304 Dowtherm RP 80 0.00071 0.3 [21] National MARS code characteristics of molten salts using Single loop Institute of modeling simulants Science and Technology, Korea 10

Review of Natural/Forced Circulation Loops for MSR/FHR (Cont’d) at max Organization NC/FC Experiment Objective Material Working fluid Max Max Ref. Modeling working temp. power temp. (K -1 ) (kW) ( o C) Shanghai NC Experiment Gather experience on design and SS 316 KNO 3 -NaNO 2 - 450 0.00075 -- [22] Institute of validation of passive decay heat removal Single loop NaNO 3 Applied system for FHRs Physics, FC Experiment Validate system design; Develop Hastelloy FLiNaK 650 0.00032 150 China principle prototypes of molten salt C276 pump, valves, HX, etc. Single loop Beijing NC Experiment Investigate natural circulation heat SS 316 Ca(NO 3 ) 2 - KNO 3 - 250 -- 0.3 [23] University of transfer of molten salt in a single energy tank NaNO 3 -LiNO 3 Technology, storage tank China Bhabha NC Experiment Investigate thermal hydraulics, Inconel 625 KNO 3 -NaNO 3 - 580 0.0006 2 [24] Atomic In-house instrument development, and material Single loop LiNO 3 Research developed related issues relevant to high- Centre, India code temperature reactor, such as MSBR LeBENC Experiments: NC Experiment Hastelloy N LiF-ThF 4 750 0.00049 1 [25] a) Steady-state at different power levels; OpenFOAM Single loop b) Startup transient; c) Loss of heat sink; d) Heater trip; d) Step change in heater power. 11

Review of Natural/Forced Circulation Loops for MSR/FHR (Cont’d) at max Organization NC/FC Experiment Objective Material Working fluid Max Max Ref. Modeling working temp. power temp. (K -1 ) (kW) ( o C) EU project FC Experiment Preparation for MSFR -- FLiNaK 700 0.00032 -- [26] SAMOFAR FFFFER: Forced Fluoride Flow for [27] Experimental Research FC Experiment Study the solidification phenomena of a molten salt Czech FC Experiment Experimental program in MSR physics -- FLiBe -- -- -- [28] Republic and corrosion flow loop 12

Bhabha Atomic Research Centre’s NC Experiments • Startup Startup of natural circulation at 1200 W (A.K. Srivastava, et al., 2016) (A.K. Srivastava, et al., 2016) 13

Heat Transfer Correlations (HTC) in RELAP5 • Define the geometry of heat structure • For single phase liquid, RELAP5 calculate three heat transfer coefficients - find the maximum heat transfer coefficient - ℎ = 𝑛𝑏𝑦 ℎ defgMeh , ℎ jkhlkdmMj , ℎ Mejkhed User defined geometries Laminar Turbulent Natural Standard Dittus-Boelter Churchill-Chu or McAdams Horizontal annuli, flow in plate Dittus-Boelter McAdams and single tube Parallel flow in vertical bundle Dittus-Boelter- Churchill-Chu or McAdams Nu with in-line and staggered rods Inayatov = 4.36 Crossflow in vertical bundle with Dittus-Boelter Churchill-Chu or McAdams in-line and staggered rods Inayatov-Shah Parallel flow and crossflow in horizontal bundle Dittus-Boelter Churchill-Chu with in-line and staggered rods 14

HTC for Flow in Circular Tubes in RELAP5 (Cont’d) • Laminar forced convection (Sallers) - 𝑂𝑣 = 4.36 • Turbulent forced convection (Dittus-Boelter) - 𝑂𝑣 = 0.023𝑆𝑓 ?.7 𝑄𝑠 ?.; • Natural convection (Churchill-Chu) 8 t ?.E79se u - 𝑂𝑣 = 0.825 + } y z~ /v w.xyz tu {| - 𝑆𝑏 = 𝐻𝑠 € Pr 𝐻𝑠 = • z ‚ƒ „ … †„ ‡ ˆ ‰ Š z • Natural convection (McAdams) - 𝑂𝑣 = 0.27𝑆𝑏 ?.8< 15

HTC in TRACE • For single-phase liquid , also take maximum values among laminar and turbulent forced convection and natural convection (NC). - ℎ = 𝑛𝑏𝑦 ℎ defgMeh , ℎ jkhlkdmMj , ℎ defgMeh ‹Œ , ℎ jkhlkdmMj ‹Œ • Geometries - Tube - Rod bundle - Helical Coil - Cross Flow 16