application of comsol pipe flow module to develop a high ...€¦ · application of comsol pipe...

Application of COMSOL

Pipe Flow Module To

Develop a High Flux

Isotope Reactor (HFIR)

System Loop Model

Dean Wang

Prashant K. Jain

James D. Freels

COMSOL Conference 2013

October 10, 2013

2 Managed by UT-Battelle for the U.S. Department of Energy

HFIR is a Multi-Purpose High-Performance

Research Reactor

• Operated since 1966 with one of the world’s highest thermal neutron fluxes ~2.5x1015 neutrons/(cm2-s )

• Involute-shaped fuel plates, beryllium reflected, light water-cooled and –moderated, pressurized, flux-trap type research reactor

• Highly enriched uranium (~93% 235U/U) fuel embedded in aluminum-6061 clad

• Cold and thermal neutron scattering, materials irradiation, isotope production, neutron activation analysis


Sixties’ Historical Photos of HFIR

HFIR pressure vessel as being lowered into the pool cavity


HFIR Primary Coolant System

HFIR Primary Coolant System


Schematics of HFIR System Components

Heat Exchanger Cells and Pool Structure

Heat Exchanger Flow Path

Vessel/Core Cross-section


HFIR COMSOL System Model Based

on the RELAP5 Model • Three primary loops modeled

• Reactor pressure vessel

– Inner fuel region

– Outer fuel regions

– Target region

– Reflector

• Primary coolant pumps

– Modeled with COMSOL Pump component

– Limited modeling capability: fixed flow, pressure increase, downstream pressure

– Pump curves needed for flow transient

• Heat Exchanger

– Modeled with COMSOL heat transfer component

– Currently, the component cannot define effective heat transfer area

TDJ

92-1

90

91-1

8180-4 80-1 79 77

50-2

52-1 75-4

175-1

173

170

152-4

157

Heat

Exchanger

C

51 53 54 55

64

65687271

TDV

TDJ 84

Reactor

Vessel

Main

Pressurizer

Pump

66

69

551

561

Standby

Pressurizer

Pump

Flow control

valve

Flow control

valve

550

560

Auxiliary

Pressurizer

Pump

TDV

Primary Coolant

Head Tank

TDV

20 Inch Cold Leg in Pipe Tunnel

18 Inch Hot Leg in Pipe Tunnel

check

valve174

Primary

Coolant Pump

75-1

73

70

52-4

57

Heat

Exchanger

D

60-3

60-2

60-1

62-1

74check

valve

Primary

Coolant Pump

Letdown

Valve 63

Letdown

Valve 163

275-1

273

270

260-3

260-2

260-1

252-4

257

Heat

Exchanger

A

274check

valve

Primary

Coolant Pump

Letdown

Valve 263

160-3

160-2

160-1

47

67-5

67-4

67-3

67-2

67-1

92-2

92-3

91-2

91-3

50-1

80-280-3

89

88

50-3

52-2

52-3

75-3

75-2

62-2

152-1

152-2

152-3

175-4

175-3

175-2

162-1

162-2

352-1

352-2

352-3

252-1 252-2

252-3

262-1

262-2

375-3

375-2

375-1

275-5 275-4

275-2

275-3

512

Break 6

513

508

Break 4

509

506

Break 3

507

504

Break 2

505

502

Break 1

503

510

Break 5

511

48

check valve

49

59

check valve

56

571

574

577

PU-1D (70)

Suction

PU-1C (170)

Suction

PU-1A (270)

Suction

83 leakage

76

801

relief valve

802

276 176

803-1 805804

check valve

Cell 110 Cell 111 Cell 113

578

575

572

Reactor Pool

803-2

venturi

HX

Vessel/Core

Pump HL

CL Check Valve


Vessel/Core Modeling

• Vessel/Core Components

– Fuel element

– Target

– Control cylinders,

– Reflector

– Core bypass

– Upper and lower plenum

– Outlet

• Inner and outer hot fuel elements

• Core heat loads: 86MW

– Distributed in fuel, target, cylinders, reflectors

– Axial power shape

• Core heat structures needed for transients


Heat Exchanger Modeling

• HX bundle consists of 1200 SS tubes

– Average tube length: 710.52 in.

– Tube ID/OD: 0.555/0.625 in.

• The secondary side flow pattern is much more complicated.

– HTC has to be estimated

• COMSOL lumped all tubes into one hydraulic pipe

– User defined primary side Nu = f(Re, Pr)


Extra-Vessel Piping

• Lengths and elevations of the piping throughout the primary side were obtained from the RELAP5 deck/document

• Values of Hydraulic Diameter and K-loss were obtained from the RELAP5 model. Modifications were made when necessary.

HL

CL


COMSOL vs. RELAP5 – Steady State Run

COMSOL RELAP5

Reactor power (MW) 86.6

Total Loop flow rate (kg/s) 327.4x3

RPV Inlet cold leg temperature (K) 325.56 325.48

RPV Exit Hot leg temperature (K) 346.8 347.2

RPV Inlet coolant pressure (MPa) 2.92 2.91

RPV exit coolant pressure (MPa) 2.31 2.20

Outer core hot fuel outlet coolant temperature (K)

385.08 386.2

Inner core hot fuel outlet coolant temperature (K)

380.1 381.1


Temperature Pressure

COMSOL Results – Steady State Run

1D-3D CFD Coupling (under investigation)


Advantages of COMSOL-based System

Model of HFIR

• Coupling with same, higher or lower order physics, as needed

– 1D-1D, 1D-2D, 1D-3D, 2D-3D…

– “system-CFD-multiphysics” coupling

• Independent capability for reviewing calculations within the limited scope

• Enhanced interaction between transient and steady state analyses for different applications

• Easily tractable and portable (ease of user management)

• Modern user-interface (ease of model input management)

• More solver options/features (convergence, stability)

• Ease of handling for nonlinear (T,P)-dependent material properties

• Parametric and functional inputs (mathematical dependencies) could be easily implemented


Thank you

for your attention.

This presentation has been authored by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the US Department of Energy. The US government retains and the publisher, by accepting the presentation for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this presentation, or allow others to do so, for US government purposes.

application of comsol pipe flow module to develop a high ...€¦ · application of comsol pipe...

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