Luận án Nghiên cứu hiện tượng chuyển pha trong vùng hoạt lò phản ứng
Phase change in the nuclear reactor core is related to safety criteria such as Departure of Nucleate Boiling (DNB) during normal and transient conditions. So that, a lot of computer codes with verification and validation against experiment are used to investigation of thermal hydraulics behavior of vertical boiling flow in core channel with system and component scales. Until now, even many studies on boiling flow are implemented in CFD scale codes, but their utilization to specific nuclear reactor is not yet applied. Thus, the utilization of many codes including CFD scale (Ansys CFX) to investigate void fraction in hot channel of VVER- 1000/V392 reactor core is studied in this work. Due to VVER-1000/V392 nuclear reactor is a candidate for Ninh Thuan 1 nuclear power project, so that the understanding of VVER’s reactor technologies including research works of this thesis is important to develop competence of nuclear safety in Vietnam.
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BỘ GIÁO DỤC VÀ ĐÀO TẠO
TRƯỜNG ĐẠI HỌC BÁCH KHOA HÀ NỘI
HOÀNG MINH GIANG
NGHIÊN CỨU HIỆN TƯỢNG CHUYỂN PHA TRONG VÙNG HOẠT
LÒ PHẢN ỨNG
LUẬN ÁN TIẾN SĨ CƠ HỌC
Hà Nội – 2016
2
LỜI CAM ĐOAN
Văn Hiền.
Các số liệu, những kết luận nghiên cứu được trình bày trong luận văn
này trung thực và chưa từng được công bố dưới bất cứ hình thức nào.
Tôi xin chịu trách nhiệm về nghiên cứu của mình.
GV Hướng dẫn Nghiên cứu sinh
Nguyễn Đông
BỘ GIÁO DỤC VÀ ĐÀO TẠO
TRƯỜNG ĐẠI HỌC BÁCH KHOA HÀ NỘI
HOÀNG MINH GIANG
NGHIÊN CỨU HIỆN TƯỢNG CHUYỂN PHA TRONG VÙNG HOẠT
LÒ PHẢN ỨNG
Chuyên ngành: CƠ HỌC CHẤT LỎNG
Mã số: 62440108
LUẬN ÁN TIẾN SĨ CƠ HỌC
NGƯỜI HƯỚNG DẪN KHOA HỌC:
1. PGS.TS NGUYỄN PHÚ KHÁNH
2. TS TRẦN CHÍ THÀNH
Hà Nội – 2016
3
LỜI CAM ĐOAN
Tôi xin cam đoan luận án là công trình nghiên cứu của bản thân tôi dưới
sự hướng dẫn của tập thể giáo viên hướng dẫn.
Các kết quả nêu trong luận án là trung thực, không sao chép của bất kỳ
công trình nào và chưa từng được công bố trong bất kỳ công trình nào khác.
Hà Nội, ngày 27 tháng 4 năm 2016
NGHIÊN CỨU SINH
HOÀNG MINH GIANG
Hướng dẫn 1
PGS. NGUYỄN PHÚ KHÁNH
Hướng dẫn 2
TS. TRẦN CHÍ THÀNH
4
LỜI CẢM ƠN
Trước hết, tôi xin bày tỏ lòng kính trọng và biết ơn tới: PGS Nguyễn Phú
Khánh và TS Trần Chí Thành, những người thày đã trực tiếp hướng dẫn, giúp đỡ
tôi trong quá trình học tập và thực hiện luận án.
Tôi xin chân thành cảm ơn các thày cô tại Bộ môn Kỹ thuật Hàng không
và Vũ trụ, Viện Cơ khí Động lực; cảm ơn TS Lê Văn Hồng, Viện Năng lượng
Nguyên tử Việt Nam, chủ nhiệm đề tài độc lập cấp nhà nước (mã số
ĐTĐL.2011-G/82) “Nghiên cứu, phân tích, đánh giá và so sánh hệ thống công
nghệ nhà máy điện hạt nhân dùng lò VVER-1000 giữa các loại AES-91, AES-
92 và AES-2006”, các đồng nghiệp Hoàng Tân Hưng, Trung tâm An toàn hạt
nhân, Nguyễn Hữu Tiệp, Trung tâm Năng lượng hạt nhân, Viện Khoa học và Kỹ
thuật hạt nhân đã giúp đỡ, tạo điều kiện để tôi có thể hoàn thành luận án này.
Tôi cũng xin trân trọng cảm ơn Ban lãnh đạo Viện Khoa học và Kỹ thuật
hạt nhân, Viện đào tạo Sau đại học của Trường Đại học Bách Khoa Hà Nội đã
cử tôi đi đào tạo cũng như tạo điều kiện thuận lợi trong quá trình thực hiện luận
án.
Hà nội ngày 27/4/2016
Nghiên cứu sinh
Hoàng Minh Giang
5
STUDY ON PHASE CHANGE IN THE CORE OF
NUCLEAR REACTOR
6
TABLE OF CONTENTS
Abbreviations and Nomenclature ............................................................................................................... 8
List of Tables .............................................................................................................................................. 12
List of Figures ............................................................................................................................................. 14
Overview .................................................................................................................................................... 17
Chapter 1. Introduction to research work ............................................................................................... 19
1.1 Status of nuclear power in the World and Vietnam ........................................................................... 19
1.2 Brief overview of nuclear safety ........................................................................................................ 20
1.3 Core thermal hydraulics safety analysis in transient condition .......................................................... 21
1.3.1 Role of void fraction in simulation of two phase flow ................................................................ 24
1.3.2 Experiment overview for bundle of sub channel analysis ........................................................... 25
1.3.3 Void fraction prediction study ..................................................................................................... 26
1.4 VVER technology understanding related to this study ...................................................................... 27
1.5 Thesis objectives ................................................................................................................................ 29
1.5.1 Studied object .............................................................................................................................. 30
1.5.2 Scope of study ............................................................................................................................. 30
1.6 Thesis outline ..................................................................................................................................... 31
Chapter 2. Overview of phase change models in code theories with different scales ........................... 33
2.1 Multi code and multi scales approach to PWR thermal hydraulic simulation ................................... 33
2.1.1 Neutron codes and thermal hydraulics codes .............................................................................. 33
2.1.2 Different scale of thermal hydraulic codes .................................................................................. 34
2.1.3 Different thermal hydraulic modeling approaches ...................................................................... 36
2.2 Phase change models in system code RELAP5 ................................................................................. 38
2.3 Phase change models in sub channel code CTF ................................................................................. 40
2.3.1 Evaporation and condensation induced by thermal phase change .............................................. 40
2.3.2 Evaporation and condensation induced by turbulent mixing and void drift................................ 42
2.4 Phase change models in meso scale code CFX .................................................................................. 42
2.4.1 Evaporation at the wall ................................................................................................................ 42
2.4.2 Condensation model in bulk of liquid ......................................................................................... 43
2.5 Conclusions ........................................................................................................................................ 44
Chapter 3. Phase change models verification and assessment by numerical simulation ..................... 45
3.1 Brief information of VVER-1000/V392 ............................................................................................ 45
3.2 Verification of RELAP5 simulation models for VVER-1000/V392 reactor with SAR ..................... 47
3.2.1 Nodalization scheme ................................................................................................................... 48
3.2.2 Verification of modeling through steady-state study .................................................................. 48
3.2.3 Verification through accident case study .................................................................................... 49
7
3.3 CTF models verification and assessment with BM ENTEK tests ...................................................... 51
3.3.1 ENTEK BM facility .................................................................................................................... 51
3.3.2 Modeling by CTF ........................................................................................................................ 53
3.3.3 Results and discussions ............................................................................................................... 53
3.4 Verification CFX models with PSBT sub channel tests ..................................................................... 59
3.4.1 PSBT test section for single sub channel .................................................................................... 60
3.4.2 Mesh generation study ................................................................................................................ 61
3.4.3 Solver convergence study ............................................................................................................ 63
3.4.4 Mesh refinement study ................................................................................................................ 64
3.4.5 Sensitivity study on physical models .......................................................................................... 68
3.4.6 Assessment of CFX and CTF modeling results in comparison with PSBT single channel ........ 79
3.4.7 Discussion on CTF and CFX void fraction predictions .............................................................. 82
3.4.8 Improvement of CFX void fraction prediction in saturated region ............................................. 84
3.5 Conclusions ........................................................................................................................................ 86
Chapter 4. Void fraction prediction in hot channel of VVER-1000/V392 ............................................ 88
4.1 Calculation Diagram .......................................................................................................................... 88
4.2 Power distribution calculation by MCNP5 code ................................................................................ 90
4.3 LOCAs simulation by RELAP5 code ................................................................................................ 93
4.4 Void fraction prediction in hot channel during transient by CTF code .............................................. 96
4.4.1 VVER-1000/V392 void fraction prediction by CTF ................................................................... 96
4.4.2 Discussion on RELAP5 and CTF void fraction predictions ....................................................... 98
4.5 Void fraction prediction in single channel by CFX code ................................................................. 100
4.5.1 Mesh refinement study .............................................................................................................. 101
4.5.2 Void fraction prediction calculated by CFX along sub channel ................................................ 102
4.6 Void fraction prediction in bundle of channel calculated by CFX code .......................................... 104
4.7 Conclusions ...................................................................................................................................... 107
Conclusions and proposals ...................................................................................................................... 108
Achievements and new findings given by the thesis .............................................................................. 108
Proposal of future work .......................................................................................................................... 110
References ................................................................................................................................................. 112
List of Author’ papers and report .......................................................................................................... 116
8
Abbreviations and Nomenclature
Abbreviations
VVER A Type of Pressurized Water Reactor developed by Russia
VVER-1200/V491 A type of Russia reactor with capability of 1200 MWe
VVER-1000/V392 A type of Russia reactor with capability of 1000 MWe
VINATOM Vietnam Atomic Energy Institute
TSO Technical Support Organization
DID Defend in depth policy in nuclear power plant design
PWR Pressurized Water Reactor
SAR Safety Analysis Report of nuclear power plant
NRA Nuclear Regulatory Authority
RIAs Reactivity insertion accident
LOFAs Loss of coolant flow
LOCAs Loss of coolant accident
DNB Departure of nucleate boiling
DNBR Departure of nucleate boiling ratio
Castellana The 4 x 4 square rod bundle test for fuel rod in Columbia University
(USA)
EPRI Electric Power Research Institute
BM ENTEK The BM Facility at the Research and Development Institute of Power
Engineering (RDIPE; a.k.a., ENTEK and NIKIET) models the forced
circulation circuit of RBMK type reactors
RBMK-1000 A type of Russia reactor of 1000 MWe with transliteration of Russian
characters for graphite-moderated boiling-water-cooled channel-type
reactor
PSBT OECD/NRC Benchmark based on Nuclear Power Engineering
Corporation (NUPEC, Japan) PWR sub channel and bundle tests
CTF A version of COBRA-TF improved by Pennsylvania State University
(USA)
RELAP5 System code developed by Information Systems Laboratories, Inc.
Rockville, Maryland Idaho Falls, Idaho
COBRA-TF Coolant-Boiling in Rod Arrays—Two Fluids (COBRA-TF) is a Thermal
Hydraulic (T/H) simulation code designed for Light Water Reactor (LWR)
vessel analysis developed by Pacific Northwest Laboratory
RELAP-3D Newest version of RELAP5 with coupling with COBRA-TF
MARS-3D Newest version of MARS with coupling with COBRA-TF
Belene A site for nuclear power plant project in Bulgaria
Ansys CFX A Computational Fluid Dynamics developed by Ansys
CFX Same as Ansys CFX
PARCS A code for neutron kinetic calculation
ITT interface tracking technique
0D, 1D, 2D Dimension of spatial averaging
CHF Critical Heat Flux
TH Thermal hydraulics
RANS Reynolds-averaged Navier–Stokes Simulation
9
LES Large Eddy Simulation
MSLB Main steam line break
PTS Pressurize Thermal shock
CFD Computational Fluid Dynamics
DI Deterministic Interface
FI Filtered Interface
SI Statistical Interface
U-RANS Unsteady flow
T-RANS Transient flow
meso scale The spatial scale with size around 1mm and less simulated with RANS
ECCS system Emergency Core Cooling System
LBLOCAs Large break for loss of coolant accident
SBO Station black out
SG Steam Generator
SG PHRS Passive Heat Removal through Steam Generator
HA-2 Secondary stage of Hydro accumulators
HA-1 First stage of Hydro accumulators
PCT Peaking temperature of cladding
DBA Design Base Accident
MCPL Main Coolant Pipe line
LOOP Loss of offsite power
DG Diesel Generator
SAR SG SG Active Heat Removal System
OECD/NRC BFBT UPEC BWR Full-size Fine-mesh Bundle Test (BFBT) Benchmark
αcrit Void fraction corresponding with critical heat flux correlation
10
Nomenclature
Sub-cooled vapor interfacial area per unit volume (m
-1
)
Super-heated liquid interfacial area per unit volume (m
-1
)
Super-heated vapor interfacial area per unit volume (m
-1
)
As Conductor surface area in mesh cell (m
2
)
Ax Mesh-cell area, X normal (m
2
)
Cpl Liquid specific heat, constant pressure (J/kg.K)
Cpv Vapor specific heat, constant pressure (J/kg.K)
̅ Mixing mass flux (kg/m
2
.s)
Vapor saturation enthalpy (J/kg)
Sub-cooled liquid interface heat transfer coefficient (W/m
2
.K)
Sub-cooled vapor interface heat transfer coefficient (W/m
2
.K)
Super-heated liquid interface heat transfer coefficient (W/m
2
.K)
Super-heated vapor interface heat transfer coefficient (W/m
2
.K)
hc Chen correlation heat transfer coefficient (W/m
2
.K)
hl
*
Liquid enthalpy (J/kg)
Liquid saturation enthalpy (J/kg)
hg Vapor enthalpy (J/kg)
Vapor interface heat transfer coefficient (W/m
3.
.K)
Liquid interface heat transfer coefficient (W/m
3.
.K)
̇
Mass exchange due to drift model (kg/s)
̇
Mass exchange of phase k (kg/m
2
.s)
Ρl Density of liquid (kg/m
3
)
Qwf Wall heat transfer to liquid (W)
Wall heat transfer to liquid for convection (W)
Q
w
if, Qboil Wall heat transfer to liquid for vaporization (W)
Tg Vapor temperature (K)
T
S
Saturated temperature (K)
Tcrit Critical heat flux temperature (K)
Tl, Tf Liquid temperature (K)
rb Bubble diameter (m)
Void fraction of phase k induced by sub channel i
Equilibrium quality void fraction
Two phase turbulent mixing coefficient
Density of phase k in sub channel i (kg/m
3
)
Liquid density (kg/m
3
)
Vapor density (kg/m
3
)
̅ Mixing density (kg/m
3
)
Γ’’’ Volumetric mass flow rate (kg/m3.s)
Vapor generation from near wall (kg/m
3
.s)
Total Vapor Generation (kg/m
3
.s)
Mesh-cell axial height (m)
Surface tension (N/m)
Fluid viscosity (Pa.s)
Pressure (Pa)
11
Γ’’ Evaporation rate (kg/m2.s)
Tw Wall surface temperature (K)
Tchf ,Tcrit Critical heat flux temperature (K)
Re Reynolds number
Pr Prandtl number
Nu Nusselt number
n Wall nucleation site density (m
-2
)
kl , Liquid thermal conductivity (W/m.K)
hv Vapor enthalpy (J/kg)
hnb Nucleate-boiling heat transfer coefficient (W/m
2
.K)
hl Liquid enthalpy (J/kg)
hg Vapor saturation enthalpy (J/kg)
hfc Forced-convective heat transfer coefficient (W/m
2
.K
hf Liquid saturation enthalpy (J/kg)
hc Chen correlation heat transfer coefficient (W/m
2
.K)
g Gravitational acceleration (m/s
2
)
FChen Chen Reynolds number factor
f Bubble detachment frequency (s
-1
)
Dh Hydraulic diameter (m)
Cp Specific heat, constant pressure (J/kg.K)
Ax Mesh-cell area, X normal (m
2
)
As Conductor surface area in mesh cell (m
2
)
Mesh-cell axial height (m)
Inverse Martinelli factor
Liquid density (kg/m
3
)
Fo Fourier number
Vapor density (kg/m
3
)
̅ Mixing density (kg/m3)
, Void fraction
Volumetric heat transfer from the wall (W/m
3
)
Total wall heat flux (W/m
2
)
Quenching heat flux (W/m
2
)
Evaporative heat flux (W/m
2
)
Convective heat flux (W/m
2
)
Local mean bubble diameter (m)
Saturation temperature (K)
Liquid temperature (K)
Mesh-cell area of phase k (m
2
)
Chen suppression factor
Heat transfer per volumetric unit (W/m
3
)
̅ Mixing mass flux (kg/m
3
.s)
Area influence factors
12
List of Tables
Table 1.1 Multiple levels of protection from DID approach (source [45]) ............................................20
Table 1.2 Content of Safety Analysis Reports (source [45]) .................................................................21
Table 1.3 Castellana 4x4 test characteristics (source [29]) ....................................................................25
Table 1.4 EPRI 5x5 characteristics for test 74 and test 75(source [29]) ................................................25
Table 1.5 Geometry and power shape for Test Assembly B5, B6, and B7 (Source [1]) .......................25
Table 2.1 Main characteristics of codes with four different scales (source [11]) ..................................36
Table 2.2 Main characteristics modeling approaches for three main types of single-phase CFD .........37
Table 3.1 Main technical characteristics of VVER-1000/V392 (source[36]) ........................................46
Table 3.2 Comparison of steady-state of VVER-1000/V392 .................................................................48
Table 3.3 Boundary conditions for event number 3 (source [35]). ........................................................49
Table 3.4 Chronological sequence of Event 3 from SAR [35] and this study .......................................50
Table 3.5 Setting for base case and sensitivity cases according to test 01 and test 17 ...........................53
Table 3.6 Base case void fraction distribution calculations versus experiment for cases at 3MPa. ......54
Table 3.7 Base case void fraction distribution calculations versus experiment for cases at 7MPa. ......54
Table 3.8 Deviation of void fraction distribution calculation results versus experiment .......................55
Table 3.9 Deviation of void fraction distributions on inpu
