W’s AP600 &AP1000
by
T. G. Theofanous
In-Vessel Retention
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Loviisa VVER-440 first (1979)
Westinghouse's AP-600 (1987) FRR’ 17
Korean KNGR and AP1400 (1994)
Westinghouse’s AP-1000 (2004)
NUPEC’s BWR’s (2000)
The AP-600 work took three years it involved ~10 FTE’s
and was finalized with 17 experts
AP-600 The final bounding state
Phenomena of In-Vessel Melt Retention
Framework for Addressing IVR
Thermal Regime
Framework for Addressing IVR
FCI Regime
Research to Support Assessment of
IVR Thermal Loads
The Basic Geometry and Nomenclature of In-vessel Retention in
the Long-term, Natural Convection-Dominated, Thermal Regime
Schematic of the Physical Model
Used to Quantify Emergency Energy Partition, and Thermal Loads in the
Long-term, Natural Convection Thermal Regime. Also Shown is the
Nomenclature used in the Formulation of the Mathematical Model.
Schematic of the ACOPO facility
Heat Sink
Expansion
Tank
Pump Rack
Venturi Rack
Test Vessel
flow rates
Windows
control to 15 pumps
temperature
difference
Internal
temperature
sensors
Data Acquisition & Control
System
thermocouple position
expansion
volume
72”
15
14
33.4”
30.5”
28.5”
24”
21.5
17”
13.5”
10.5”
7”
3.5”
0.75”
1
The ACOPO facility
outlet
1/4 inch
square copper
tubing
silicone insulation
thermistors
venturi
inlet
12
13
11
10
9
8
7
6
5
4
3
2
33.75”
Cooling
Unit #7
The heat flux distribution on the lower boundary of
a naturally convecting hemispherical pool
ACOPO
Nusselt number dependence on
external Rayleigh number
Heat Flux at the Pool Upper Corner
(Churchill-Chu, 1975)
ACOPO (1998)
The oxides pool Nusselt number, as a function of the
Rayleigh number and the “fill” fraction, H0=R
Nup;up/Nup as function of Ra0 and H0=R
Num/Nuup as function of Raq, Hm/R, and G
Lines within each Hm/R group
correspond to emissivity
(bottom to top) 0.45; 0.55;
0.65; 0.75
Hm/R = 0.1
Hm/R = 0.2
Hm/R = 0.3
Hm/R = 0.4
G is a new dimensionless group reflecting materials properties.
Research to Support Assessment of
IVR Heat Removal Capability
Schematic of the ULPU facility: Configuration III
The ULPU facility
A temperature transient (local microthermocouple
response) associated with boiling crisis
210
Temperature [ oC]
200
190
180
170
160
150
0
5
10
15
Time [s]
20
25
30
35
Critical heat flux as a function of angular position
on a large scale hemispherical surface
ULPU-2000
Schematic of the ULPU facility: Configuration IV
New Configuration IV CHF results (data points),
relative to curren (AP600) technology
ULPU-2000
Schematic of the mini-ULPU facility
The mini-ULPU Experiment
The mini-ULPU Experiment
Critical Heat Flux, kW/m2
The Critical Heat Flux Data Obtained in mini-ULPU
----□---- Copper

---- ---- Steel
Both Surfaces are
Well-Wetted
Contact Frequency, Hz
The BETA Experiment
High-speed
video
Film
100m
Flash X-Ray
(5 ns)
High-speed IR
2kHz (5kHz)
200m
100m
100 nm Ti
• Heater 20x40 mm
• Constant Flux, Verified Infinite Flat Plate Behavior
Seeing is believing
130m
Glass
The Critical Heat Flux Data Obtained in BETA
CHFK-Z =
1.2 MW/m2
Generalization
In-Vessel Retention for Larger Power Reactors
The Coolability Region of an AP600 reactor for
different cooling options and metal layer emissivity
Pool Boiling
 = 0.45
N/C Boiling
 = 0.45
N/C Boiling
 = 0.8
Lines in each group
correspond to fraction of
Zr taken to be oxidized
(0.2; 0.4; 0.6; 0.8)
The Coolability Region of an GE-BWR reactor for
different cooling options and metal layer emissivity
Pool Boiling
 = 0.45
GE-BWR
N/C Boiling
 = 0.45
N/C Boiling
 = 0.8
Lines in each group
correspond to fraction of
Zr taken to be oxidized
(0.2; 0.4; 0.6; 0.8)
The Coolability Region of an W-PWR reactor for
different cooling options and metal layer emissivity
Pool Boiling
 = 0.45
N/C Boiling
 = 0.8
W-PWR
N/C Boiling
 = 0.45
Lines in each group
correspond to fraction of
Zr taken to be oxidized
(0.2; 0.4; 0.6; 0.8)
The Coolability Region of an Evolutionary PWR reactor
for different cooling options and metal layer emissivity
N/C Boiling
 = 0.8
Pool Boiling
 = 0.45
E-PWR
N/C Boiling
 = 0.45
Lines in each group
correspond to fraction of
Zr taken to be oxidized
(0.2; 0.4; 0.6; 0.8)
Making the case for AP1000
AP1000 IVR Thermal Margin
Estimates based on AP600 Technology
Coolability Limit
(CHF)
Thermal Load
AP600
AP1000
ULPU-V as Simulation Tool of AP1000
• Full Length;
with Heat Flux Shaping we have Full Scale Simulation
• Complete Natural Circulation Path of AP1000 Represented
as 1/84-Slice and Matched Resistance (Flow Areas and
Geometry) as specified by Westinghouse designers
• Special Investigations on Surface Effects: Paints, Coatings,
Deposits (boric acid in water), etc.
ULPU-V: Three Baffle Configurations
AP1000 water inlet geometry
ULPU-V Steam Outlet
ULPU-2400
Configuration V
1152 heaters (power control)
Magnetic Flowmeter
72 thermocouples
7 pressure transducers
Flow visualization
ULPU-V Reference Data for AP1000 IVR Conditions