Profile SFR-55

STELLA-2

Republic of KOREA

GENERAL INFORMATION NAME OF THE FACILITY STELLA-2 ACRONYM Sodium Integral Effect Test Loop for Safety Simulation and

Assessment: Phase 2 COOLANT(S) OF THE FACILITY

Liquid sodium

LOCATION (address): Fast Reactor Demonstration Division, Korea Atomic Energy Research Institute, 989-111 Daedeok-daero, Yuseong-gu, Daejeon, Korea

OPERATOR KAERI CONTACT PERSON (name, address, institute, function, telephone, email):

Jewhan Lee, 989-111 Daedeok-daero, Yuseong-gu, Daejeon, Korea, KAERI, Fast Reactor Demonstration Division, Tel. +82 42 868 2221, leej@kaeri.re.kr

STATUS OF THE FACILITY Under Design Start of operation (date): 2019

MAIN RESEARCH FIELD(S) ☐ Zero power facility for V&V and licensing purposes ☒ Design Basis Accidents (DBA) and Design Extended Conditions

(DEC) ☒ Thermal-hydraulics ☐ Coolant chemistry ☐ Materials ☒ Systems and components ☐ Instrumentation & ISI&R

TECHNICAL DESCRIPTION

Description of the facility STELLA-2 is a large-scale sodium integral effect test facil ity simulating a pool type sodium-cooled fast reactor system as the second step of the STELLA program. The main objectives of the facil ity are comprehensive review of key safety issues and database construction for the V&V of the safety analysis codes and thermal hydraulic design codes. It wil l be finally used to support the development of the Prototype Gen IV SFR in Korea.

In STELLA-2 facil ity, integral and transient responses of forced and natural circulation operation identified from the PIRT can be simulated to evaluate the plant dynamic behaviours for off-normal design conditions and to demonstrate decay heat removal performance. The STELLA-2 facil ity is capable of various transient analysis including LOF, LOHS, One Pump Seizure, Pump Discharge Pipe Break and etc. The multi-dimensional effect in a large sodium inventory of pool-type SFR can also be evaluated for flow characteristics.

The facil ity consists of the main test section and the auxil iary systems. The main test section includes the primary heat transport system (PHTS), the intermediate heat transport system (IHTS), and the decay heat removal system (DHRS), where all major components of reactor are also included. The PHTS mainly consists of a reactor vessel with the same (or similar) internal structures as close as that of PGSFR, an electric core simulator, four intermediate heat exchangers (IHX) and two primary pump paths. The IHTS consists of loop piping, an expansion tank, double IHXs and an ultimate heat exchanger (UHX) simulating steam generator heat sink. It simulates thermal inertia in intermediate sodium inventory during, for example, a loss of heat sink event. Two kinds of DHR system are installed. One is the passive DHR system and the other is the active one with motor-driven equipments, e.g. EM pump, air blowers, etc. Total four sodium-to-sodium decay heat exchangers (DHX) are installed inside the reactor vessel, and a helically-coiled sodium-to-air heat exchanger (AHX) and a finned-tube sodium-to-air heat exchanger (FHX) are connected to each DHX with loop piping, respectively. The auxil iary systems such as a sodium supply/purification system, a heat loss compensation system, a power supply system and a gas supply system are also included in the STELLA-2 facil ity to provide the various environments and boundary conditions for performing the experiments.

Parameters Scaling operators

Ratio (M/P)

Length Ratio lR 1/5

Area Ratio aR (=d

R

2) 1/25

Volume Ratio aR l

R 1/125

Temperature Rise/Drop Ratio 1 1/1 Time Ratio l

R

1/2 1/2.24

Velocity Ratio lR

1/2 1/2.24

Gravity Acceleration Ratio 1 1/1 Core Power Density Ratio 1/l

R

1/2 2.24

Power Ratio aR l

R

1/2 1/55.9

Flow rate Ratio aR l

R

1/2 1/55.9

Pressure Drop Ratio lR 1/5

Aspect Ratio lR

/ aR

1/2 1.0

Parameters Reference (PGSFR) STELLA-2

Length scale - 1/5 Aspect ratio 1.0 1.0

Simulated core power (kWt) 3.922x105 ~ 500

RV height (m) ~ 15.0 ~ 3.18 RV diameter (m) ~ 8.8 ~ 1.80

Core simulator OD (m) ~ 2.8 ~ 0.56 RV Volume (m

3) ~ 630 ~ 5.03

Total Sodium mass (ton) - < 11.0

Acceptance of radioactive material No

Scheme/diagram

3D drawing/photo

I

UIS

Rx. core

EMP

damper

IHTS

Air Blower

cold air in

IHTS cold-leg

IHTS hot-leg

DHX DHX

UHX

hot air out

EMP

M

hot sodium in

cold sodium out

Expansion vessel

M

cold air in

Argon

Na

hot air out

AHXdamper

FHX

cold air in

hot air out

Argon

Na

IHX

Air BlowerAir BlowerFree intake air path

M

Free intake air path

EMP

M

M

Argon

Na

EMP

damper

damper

Hot pool sodium level

Cold pool sodium level

Electric Core Simulator

Reactor head Reactor head

Hot-leg

Cold-leg

FINa

V-39

TINa

TINa

HCS

Heater

TIs

Hot-leg

Cold-leg

FINa

V-40

TINa

TINa

HCS

Heater

TIs

1/4"-Ar

←

Cover gas

SodiumFHX

Hot-leg

Cold-leg

Expansion vessel

Argon TINa

TIs

TINa

TINa

TIs

FINa

V-42

TIgas

1/2"

-Na

PTNa

1/2"

-Na

PTNa

1/2"

-Na

PTNa

TIs

TIAir

TIAir

TINa

HCS

Heater

HCS

Heater

HCS

Heater

EM

P

TIAir

FIAir

TIAir

1/2"

-Gas

PTAir

1/2"-GasPTAir

TIS

1/2"-GasPTAir

1/2"

-Gas

PTAir

TINa

TINa

LINa

HCS

Heater

TIs

HCS

Heater

Damper

Damper

Air intake

Blower

FIAir

PTgas

1/2"

-Gas

1/4"-Ar←

DHX

TINa

HCS

Heater

TIs

FINa

TINa

1/2"

-Na

PTNa

Active tube length

1/2"-Na

PTNa

TINaTI

Na

TINa

FINa

1/2"-NaPTNa

TINa

1/2"-NaPTNa

1/4"-Ar

←

Cover gas

Sodium FHX

Hot-leg

Cold-leg

Expansion vessel

ArgonTINa

TIs

TINa

TINa

TIs

FINa

V-35

TIgas

1/2"-Na

PTNa

1/2"-Na

PTNa

1/2"-Na

PTNa

TIs

TIAir

TIAir

TINa

HCS

Heater

HCS

Heater

HCS

Heater

EM

P

TIAir

FIAir

TIAir

1/2"-Gas

PTAir

1/2"-Gas PTAir

TIS

1/2"-Gas PTAir

1/2"-Gas

PTAir

TINa

TINa

LINa

HCS

Heater

TIs

HCS

Heater

Damper

Damper

Air intake

Blower

FIAir

PTgas

1/2"-Gas

1/4"-Ar←

DHX

TINa

HCS

Heater

TIs

FINa

TINa

1/2"-Na

PTNa

Act

ive

tube

leng

th

1/2"-Na

PTNa

TINa TI

Na

TINa

FINa

1/2"-Na PTNa

TINa

1/2"-Na PTNa

Hot-leg

Cold-leg

FINa

V-37

TINa

TINa

HCS

Heater

TIs

Hot-leg

Cold-leg

FINa

V-43

TINa

TINa

HCS

Heater

TIs

Sodium

Cover gasArgon

TIs

TINa

HCS

TIgas

LINa

PTgas

1/2"

-Gas

Dump valves

Gas supply system

Ar Ar Ar Ar

PCV1

PCV2

←

Sodium storage tank

←

1/4"-Ar

←

←

1/4"-Ar

Dump valves

TI

FI

LI

PT

s

gas

Na

Air

HCS

: Level

: Flow

: Temperature

: Pressure

: Heater controller

: Surface

: Gas

: Sodium

: Air

LEGEND

: Main sodium line

: Auxliary sodium line

: Gas (Argon) line

DHX

FINa

TINa

1/2"

-Na

PTNa

Active tube length

1/2"-Na

PTNa

TINaTI

Na

TINa

FINa

1/2"-NaPTNa

TINa

1/2"-NaPTNa

IHX

FINa

TINa

1/2"

-Na

PTNa

1/2"-Na PTNa

TINa

FINa

TINa

1/2"-Na

PTNa

1/2"-NaPTNa

TINa

DHX

FINa

TINa

1/2"-Na

PTNa

Act

ive

tube

leng

th

1/2"-Na

PTNa

TINa TI

Na

TINa

FINa

1/2"-Na PTNa

TINa

1/2"-Na PTNa

Rx.core

EMP FINa

V-41

TINa

EMPFINa

V-36

TINa

V-38

FINaEMP

1/4"-Ar

←

Cover gas

Sodium AHXExpansion

vessel

ArgonTINa

TIs

TINa

TINa

TIs

TIgas

1/2"-Na

PTNa

1/2"-Na

PTNa

1/2"-Na

PTNa

TIs

TIAir

TIAir

HCS

Heater

HCS

Heater

HCS

Heater

TIAir

FIAir

TIAir

1/2"-Gas

PTAir

1/2"-Gas PTAir

TIS

1/2"-Gas PTAir

1/2"-Gas

PTAir

TINa

TINa

LINa

HCS

Heater

TIs

HCS

Heater

Damper

Air intakeFIAir

PTgas

1/2"-Gas

1/4"-Ar←

EM

P

Damper

Blower

1/4"-Ar

←

Cover gas

SodiumAHXExpansion

vessel

Argon TINa

TIs

TINa

TINa

TIs

TIgas

1/2"

-Na

PTNa

1/2"

-Na

PTNa

1/2"

-Na

PTNa

TIs

TIAir

TIAir

HCS

Heater

HCS

Heater

HCS

Heater

TIAir

FIAir

TIAir

1/2"

-Gas

PTAir

1/2"-GasPTAir

TIS

1/2"-GasPTAir

1/2"

-Gas

PTAir

TINa

TINa

LINa

HCS

Heater

TIs

HCS

Heater

Damper

Air intakeFIAir

PTgas

1/2"

-Gas

1/4"-Ar←

EM

P

Damper

Blower

1/4"-Ar

←

Cover gas

Sodium UHXExpansion

vessel

ArgonTINa

TIs

TINa

TINa

TIs

TIgas

1/2"-Na

PTNa

1/2"-Na

PTNa

1/2"-Na

PTNa

TIs

TIAir

TIAir

HCS

Heater

HCS

Heater

HCS

Heater

EM

P

TIAir

FIAir

TIAir

1/2"-Gas

PTAir

1/2"-Gas PTAir

TIS

1/2"-Gas PTAir

1/2"-Gas

PTAir

TINa

TINa

LINa

HCS

Heater

TIs

HCS

Heater

Damper

Damper

Air intake

Blower

FIAir

PTgas

1/2"-Gas

1/4"-Ar←

1/4"-Ar

←

Cover gas

Sodium

Expansion vessel

Argon TINa

TIs

TINa

TINa

TIs

TIgas

1/2"

-Na

PTNa

1/2"

-Na

PTNa

1/2"

-Na

PTNa

TIs

TIAir

TIAir

HCS

Heater

HCS

Heater

HCS

Heater

EM

P

TIAir

1/2"

-Gas

PTAir

1/2"-GasPTAir

1/2"

-Gas

PTAir

TINa

TINa

LINa

HCS

Heater

TIs

HCS

Heater

Damper

Air intake

Blower

FIAir

PTgas

1/2"

-Gas

1/4"-Ar←

UHX

FIAir

TIAir

1/2"-Gas

TIS

1/2"-GasPTAir

Damper

TINa

1/2"-Na

PTNa

TINa 1/

2"-N

a

PTNa

IHX

TINa 1/

2"-N

a

PTNa

TINa

1/2"-Na

PTNa

Parameters table

Coolant inventory Less than 10 ton Power MW

TS (Reactor vessel)

Characteristic dimensions 2.2 m (diameter), 4.0 m (height) Static/dynamic experiment Dynamic Temperature range in the test section (Delta T) 390 ~ 550 ℃ (Core in/out) Operating pressure and design pressure Operating Pressure: 1~2 bar Design pressure: 5 bar Flow range (mass, velocity, etc.) 0 ~ 25 kg/s

TS (IHX)

Characteristic dimensions 342 mm (diameter), ~4 m (height) Static/dynamic experiment Dynamic Temperature range in the test section (Delta T) 390 ~ 550 ℃ (in/out) Operating pressure and design pressure Operating Pressure: 1~2 bar Design pressure: 5 bar Flow range (mass, velocity, etc.)

0 ~ 6 kg/s (Shell-side), 0 ~ 4 kg/s (Tube-side)

TS (DHX)

Characteristic dimensions 130 mm (diameter), ~3 m (height) Static/dynamic experiment Dynamic Temperature range in the test section (Delta T) 390 ~ 450 ℃ (in/out) Operating pressure and design pressure Operating Pressure: 1~2 bar Design pressure: 5 bar Flow range (mass, velocity, etc.) 0 ~ 0.4 kg/s (for both Shell-side and Tube-side)

TS (AHX)

Characteristic dimensions 595 mm (diameter), ~9 m (height) Static/dynamic experiment Dynamic Temperature range in the test section (Delta T) 400 ~ 450 ℃ (in/out) Operating pressure and design pressure Operating Pressure: 1~2 bar Design pressure: 5 bar Flow range (mass, velocity, etc.) 0 ~ 0.25 kg/s (Shell-side, Air), 0 ~ 0.4 kg/s (Tube-side, Na)

TS (FHX)

Characteristic dimensions 1.5 x 0.8 x ~10 m Static/dynamic experiment Dynamic Temperature range in the test section (Delta T) 400 ~ 450 ℃ (Core in/out) Operating pressure and design pressure Operating Pressure: 1~2 bar Design pressure: 5 bar Flow range (mass, velocity, etc.) 0 ~ 0.25 kg/s (Shell-side, Air), 0 ~ 0.4 kg/s (Tube-side, Na)

TS (UHX)

Characteristic dimensions 535 mm (diameter), ~5 m (height) Static/dynamic experiment Dynamic Temperature range in the test section (Delta T) 320 ~ 530 ℃ (Core in/out) Operating pressure and design pressure Operating Pressure: 1~2 bar Design pressure: 5 bar Flow range (mass, velocity, etc.) 0 ~ 2 kg/s (Shell-side, Air), 0 ~ 2 kg/s (Tube-side, Na)

Coolant chemistry measurement and control (active or not,

For impurities control, a separate purification loop is installed with the plugging meter sub-system. The plugging meter measures the plugging temperature to obtain the impurity concentration in liquid sodium and it is operated on-line with the cold trap.

measured parameters) Instrumentation Thermocouples, Electro-Magnetic Flowmeter, pressure transducer, leak

detector, smoke detector, inductive level meter

COMPLETED EXPERIMENTAL CAMPAIGNS: MAIN RESULTS AND ACHIEVEMENTS

PLANNED EXPERIMENTS (including time schedule) The following categories of experiments are planned after the STELLA-2 facility construction in 2019. (1) PHTS total loss of flow accident (LOF), (2) Loss of F/W accident or SG failure (LOHS), (3) PHTS pump discharge line break (pipe break), (4) a part of severe accident area (e.g. a total loss of decay heat removal and consequential in-vessel retention with external vessel cooling mechanism).

TRAINING ACTIVITIES Training activities can be arranged under the KAERI supervision.

REFERENCES (specification of availability and language) • Eoh, J., et al., “Computer Codes V&V Tests with a Large-scale Sodium Thermal-Hydraulic Test

Facility (STELLA). In: American Nuclear Society 2016 Annual Meeting, New Orleans, US, June 12-16, 2016

• Lee, J. et al, “Design Evaluation of large-scale sodium integral effect test facility (STELLA-2) using MARS-LMR”, Annals of Nuclear Energy, Vol. 120, pp. 845-856, 2018

• Eoh, J., et al., “Test Requirements for the Integral Effect Test to Simulate a Sodium-cooled Fast Reactor,” KAERI/TR-4424/2011, Korea Atomic Energy Research Institute (Kr)

• Jeong, J.H., Hwang, S.W., Choi, K.S., “Local flow distribution analysis inside the reactor pools of KALIMER-600 and PDRC performance test facility,” Korea Atomic Energy Research Institute, KAERI/CM-1276/2009 (Kr)

• Hahn, D. et al., “KALIMER-600 Conceptual Design Report,” Korea Atomic Energy Research Institute, KAERI/TR-3381/2007 (Kr))