The effect of the orientations of pebble bed in Indian HCSB

Module

Paritosh Chaudhuri

Institute for Plasma ResearchGandhinagar, INDIA

CBBI-16, 8- 10 Sept. 2011, Portland, USA

1.) Introduction

2.) Helium Cooled Ceramic Breeder(HCCB) concept

3.) Radiation Heat Transfer Analysis using ANSYS

4.) Performance Analysis

5.) Summary, Conclusions and Future Work

Outline

Lead-Lithium cooled Ceramic Breeder (LLCB)

Tritium Breeder: Lithium Ceramic pebbles; PbLi Coolant: PbLi (multiplier and breeder); FW coolant: Helium Gas; Structural Material: Reduced Activation FMS Purge gas: Helium, used for T extraction from CB

(LLCB TBM in one half of ITER port)

Helium Cooled Ceramic Breeder (HCCB)

Tritium Breeder: Lithium Ceramic pebbles;

Multiplier : Beryllium Pebbles;

Coolant : helium gas;

Structural Material: Reduced Activation FMS Purge gas: Helium T extraction from CB

(to participate as TBM Partner)

Indian Blanket Concepts

Helium Cooled Ceramic Breeder(HCCB) concept

HCSB Concept (Toroidal-Radial Orientation)

Features: Similar to other solid breeder concepts. With slight variance in the Tritium Breeder and Neutron multiplier bed design (Radial increase in the breeder bed thickness)

Objective:-To increase the tritium breeding by accommodating more breeder material (with optimization of multiplier material volume)

- To minimize the radial temperature gradient in the pebble beds

HCSB TBM (Exploded View)

Inner Back-Plate

First-Wall

Bottom-Plate Assembly

Breeder Units

Grid-PlateAssembly

Pipes(inlets & outlet)

Flexible supports

Top-Plate Assembly

Outer Back-Plate

SupportsKeys

Input: Neutronic heat generation in HCSB TBM

Radial Distribution of Neutronic Heat Generation (TBM)

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

0 100 200 300 400

Radial Distance (mm)

Hea

t G

ener

atio

n (

MW

m^3

)

Ceramic Breeder (CB-1)

Berrylium (Be-1)

Poly. (Ceramic Breeder(CB-1))Poly. (Berrylium (Be-1))

Neutronic Heat load on Different FW Materials (TBM)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

Nu

tro

nic

Hea

t G

ener

atio

n (

MW

/m3)

Performance Analysis

Pebble Bed Arrangement (Toroidal-Radial)

Pebble will settle down at the bottom, keeping some void space between the pebbles and top cooling plate.

no gap

Temperature Distribution

gap with radiative HT gap, no radiation

Max. temp. 557 C Max. temp. 813 C Max. temp. 928 C

Temperature Distribution at different Locations

Temperature (C) at different locations of ceramic breeder

A B C D E F G H

No Gap (Conduction)

With RadEmissivity = 0.3

812.754 813.041 811.461 805.405 787.013 769.098

705.755 410.144

With Gap(without Rad)

928.931 928.982 926.120 917.600 888.983 958.006

761.643 410.198

Temperature Distribution in HCSB TBM

Radiation with different CB

Emissivities

Temperature (C) at different locations of ceramic breeder

A B C D E F G H

Emissivity = 0.3 812.754 813.041 811.461 805.405 787.013 769.098 705.755 410.144

Emissivity = 0.6 806.498 806.939 805.555 799.232 781.911 760.895 696.21 410.542

Emissivity = 0.9 766.836 767.136 765.755 759.994 745.375 728.303 673.137 410.432

Temperature Distribution (Analytical Analysis)

From Toroidal-Radial Poloidal-Radial orientation

Toroidal-Radial

Poloidal-Radial

Comparison between two different orientations

Poloidal-Radial

Toroidal-RadialSurface Area: 0.097 m2

Temperature Distribution in Poloidal-Radial pebble bed

Toroidal-Radial view

Toroidal-Poloidal view

Transient Thermal Analysis on HCSB TBM

CB Be FMS

Pol-Rad Conduction 767.688 527.305 427.995

Pol-Tor Conduction 780.707 511.098 429.158

Radiation 780.707 511.097 429.158

Empty 780.707 511.097 429.158

In Toroidal-Radial orientation of pebble bed, the area of the cooling plate (heat transfer area) attached to the pebble bed is very large.

If the pebbles are settle down at the bottom, creating a finite gap between the cooling plate and the top surface of the pebbles, the large heat transfer area can not involve in transferring heat from CB to coolant. This leads to increase in CB temperature.

In Toroidal-Radial orientation of pebble bed, settling down of pebbles would not effect the heat transfer between the CB and coolant.

Summary and Conclusions

• Effect of the He purge gas to be introduced in the Radiative heat transfer analysis.

• Simulation and experimental comparison between various packing arrangements.

• Safety analysis of Blanket Modules.

• Fabrication of small scale mock-ups to demonstrate structural and pebble bed integrity.

Future Work

Backup Slides

Schematic of HCCB module and breeder unit

HCSB Concept

2-D representation of radial-poloidal cross section of a breeder unit

HCSB Concept 3/3

HCSB TBM (Preliminary Design) 2/3

FW is cooled by two counter-flowing helium circuits. Circuit 1 of theHe flow channels have openings at the edge face of the FW andCircuit 2 has the channel openings on the inner face of the FW.

First Wall of HCCB Ceramic Breeder: Li4SiO4, Li2TiO3 (pebble form)

Multiplier: Beryllium / Beryllides

Structure: RAFMS

Coolant: Helium

Purge Gas: Helium + %H2

Helium cooling circuits for FW

In C-13

In C-7

Out C-9

Out C-5

In C-11

Out C-3

In C-14

In C-1

Out C-7

In C-3

In C-5

Out C-14

Out C-1

In C-9

Out C-16

In C-2

In C4-

In C-12

In C-6

In C-8

In C-15

In C-10

Out C-10

Out C-15

Out C-8

Out C-6

Out C-12

Out C-4

Out C-2

In C-16

FW Slot

FW Slot

- Total number of channels: 64 - Number of circuits: 2

- Number of passes per circuit: 8 - Number of channels per passes: 4

- Channel dimension: 20x20 mm - Pitch: 25.5 mm - Rib thickness: 5.5 mm

C 1 C 3 C 4 C 5 C 6 C 7 C 8 C 9 C 10 C 11 C 12 C 13 C 14 C 15 C 16C 2

BU 1 BU 2 BU 3 BU 4 BU 5 BU 6 BU 7 BU 8 BU 9 BU 10

Horz/VertGP

Horz/VertGP

FW

~~ Pump

He at 3000C

1.8 kg/s

1.8 kg/s

0.06 kg/s

0.06 kg/s

0.06 kg/s

0.06 kg/s

0.06 kg/s

0.06 kg/s

0.06 kg/s

0.06 kg/s

0.06 kg/s

0.06 kg/s

0.1 kg/s

0.1 kg/s

0.2 kg/s

0.1 kg/s

0.1 kg/s

0.1 kg/s

Heat Exchanger

FWSlot

0.1 kg/s

TopBottom

Plate

0.1 kg/s

0.1 kg/s

0.1 kg/s

0.1 kg/s

0.1 kg/s

0.1 kg/s

0.1 kg/s

0.1 kg/s

0.1 kg/s

0.1 kg/s

Helium Flow path in HCCB

Helium Flow Distribution in HCCB

Grid Plate Assembly (HCSB TBM)

Top Plate assembly for HCSB TBM

Inlet

Inlet

Outlet

Helium-flow path

First-Wall

Top-Plate Assembly

Top-Plate 4mm-thk

Bottom-Plate 4mm-thk

R30

424

538

Channels4mm-thk

101

83

83

83

83

85

62

60