Sung Ho Kim, J.H. Baek, J.H. Kim, C.B. Lee

Next Generation Fuel Development Division

Korea Atomic Energy Research Institute

Fabrication and Evaluation of

SFR Cladding Tubes

International Conference on Fast Reactors

and Related Fuel Cycles

2013, Paris, France

2

Outline

1. Introduction

2. Status of SFR Cladding Tube Development

• Advanced cladding materials development

• Cladding tube fabrication

• Evaluation of cladding tube

3. Future Works

4. Summary

3

FM Steels for SFR Cladding Tubes

Upper End Plug

Upper Gas Plenum

Fuel Slug

Lower End Plug and Shielding

Wire Wrap

Handling Socket

Duct

Nose Piece

Coolant Port

Fuel Pin

Ferritic/martensitic steels

– High thermal conductivities

– Low expansion coefficients

– Excellent irradiation resistance

to a void swelling

Cladding materials

– Development of FM steels

– Basic composition

• 9Cr-2W steel

4

Core Environment & Design Requirements

Core Environment

– Inlet temperature : 390oC

– Outlet temperature : 545oC

– Fuel temperature : > 650oC

– Fast neutron fluence : > 200 dpa

– Hoop stress (end of life) : 70MPa

– 3-4 cycles (1 cycle : 18 month) : 50,000 hrs

Design Requirements of Cladding Tube

– Thermal strain : < 1%

– Total strain : < 3%

– Swelling : < 5%

5

Target of SFR Cladding Tubes

Development of new cladding having higher creep

rupture strength

Development of cladding tube fabrication process

KALIMER 600 New Target

Max. allowable temp.

of cladding tube 630oC Above 650oC

Max. fluence of

cladding tube 200 dpa > 200 dpa

6

Strengthening mechanism of FM steels

V, Nb, Ta, B, C, N, … W, Mo, …

Solid Solution

Strengthening

Precipitation

Strengthening

Group 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

I II III IV V VI VII VIII

Period

hydrogen helium

1 2

H He

1.0079 4.0026

lithium beryllium boron carbon nitrogen oxygen fluorine neon

3 4 5 6 7 8 9 10

Li Be B C N O F Ne

6.94 9.01218 10.81 12.011 14.0067 15.999 18.998403 20.18

sodium magnesium aluminium silicon phosphorus sulfur chlorine argon

11 12 13 14 15 16 17 18

Na Mg Al Si P S Cl Ar

22.98977 24.305 26.98154 28.086 30.97376 32.07 35.453 39.948

potassium calcium scandium titanium vanadium chromium manganese iron cobalt nickel copper zinc gallium germanium arsenic selenium bromine krypton

19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36

K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

39.0983 40.08 44.95591 47.867 50.9415 51.996 54.93805 55.84 58.9332 58.693 63.55 65.4 69.723 72.6 74.9216 79 79.904 83.8

rubidium strontium yttrium zirconium niobium molybdenum technetium ruthenium rhodium palladium silver cadmium indium tin antimony tellurium iodine xenon

37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe

85.468 87.62 88.9058 91.22 92.9064 95.94 [97.9072] 101.1 102.9055 90 107.868 112.41 114.82 118.71 121.76 127.6 126.9045 131.3

caesium barium 57-71 hafnium tantalum tungsten rhenium osmium iridium platinum gold mercury thallium lead bismuth polonium astatine radon

55 56 * 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86

Cs Ba Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn

132.9054 137.33 178.5 180.9479 183.84 186.207 190.2 192.22 195.08 196.9666 200.6 204.383 207.2 208.9804 [208.9824] [209.9871] [222.0176]

francium radium 89-103rutherfordiu

mdubnium seaborgium bohrium hassium meitnerium

darmstadtiu

mroentgenium ununbium ununtrium

ununquadiu

mununpentium ununhexium ununseptium ununoctium

87 88 ** 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118

Fr Ra Rf Db Sg Bh Hs Mt Ds Rg Uub Uut Uuq Uup Uuh Uus Uuo

[223.0197] [226.0254] [263.1125] [262.1144] [266.1219] [264.1247] [269.1341] [268.1388] [272.1463] [272.1535] [277] [284] [289] [288] [292] [291]*** [294]***

13) V, Nb, Ta, Ti

5) C, N

1) Cr

2) Mo, W, Re

5) B

3

4

5

6

7

6) Si, Mn

7) Ni, Cu, Co

8) Al, P, S

2

7

Alloy Design

1. B201 (1 alloy) : reference alloy

• 9Cr-0.5Mo2W-VNbTa-00

2. B202~B203 (2 alloys) : Ta effect

• 9Cr-0.5Mo2W-VNbTa-N1

• 9Cr-0.5Mo2W-VNbTa-N2

3. B204~B205 (2 alloys) : V effect

• 9Cr-0.5Mo2W-VNbTa-V1

• 9Cr-0.5Mo2W-VNbTa-V2

4. B206~B208 (3 alloys) : W, N, B, V effect

• 9Cr-0.5Mo3W-VNbTa-00

• 9Cr-0.5Mo2W-VNbTa-B1

• 9Cr-0.5Mo2W-VNbTa-VB1

5. B209~B210 (2 alloys) : P effect

• 9Cr-0.5Mo2W-VNbTa-P1

• 9Cr-0.5Mo2W-VNbTa-P2

6. B211~B213 (3 alloys) : Zr, Pt, Ge, Cu effect

• 9Cr-0.5Mo2W-VNbTa-Zr

• 9Cr-0.5Mo2W-VNbTa-Pt

• 9Cr-0.5Mo2W-VNbTa-GeCu

7. B214~B215A (3 alloys) : Nb, Ta, N effect

• 9Cr-0.5Mo2.2W-3VNb

• 9Cr-0.5Mo2.2W-3VNbTa

• 9Cr-0.5Mo2.2W-3VNbTaN

1. B001(1종):기준합금• 9Cr-2W00

2. B002~B003(3종):B 첨가영향

• 9Cr-2WB1• 9Cr-2WB2

3. B004~B005(2종):C최적화• 9Cr-2WC1• 9Cr-2WC2

4. B006~B008(3종):V/Nb 최적화• 9Cr-2WVNb1• 9Cr-2WVNb2

• 9Cr-2WVNb35. B009~B010(2종):Ta첨가영향

• 9Cr-2WVNbTa1• 9Cr-2WVNbTa2

1. B101(1종):기준합금 9Cr-2WVNbTaB1

2. B102~B104(4종):V, Nb, Ta 함량최적화 9Cr-2WVNbTaB2 9Cr-2WVNbTaB3 9Cr-2WVNbTaB4

3. B105 (1종):C, N 최적화 9Cr-2WVNbTaB5

4. B106~B110(5종): Ti, Zr, Pd, Pt, Nd 영향평가 9Cr-2WVNbTiB 9Cr-2WVNbZrB 9Cr-2WVNbPdB 9Cr-2WVNbPtB 9Cr-2WVNbNdB

Batch 0 Batch 1 Batch 2

B001 (1 alloy) : Ref. alloy

B002, 3 (2 alloys) : B

B004~5 (2 alloys) : C

B006~8 (3 alloys) : V, Nb

B009~10 (2 alloys) : Ta

B101 (1 alloy) : Ref. alloy

2. B102~4 (4 alloys) : V, Nb, Ta

B105 (1 alloy) : C, N

B106~10 (5 alloys) :

Ti, Zr, Pd, Pt, Nd

8

Advanced Cladding Materials Development

Alloy design and manufacturing

– 38 alloys in 3 batches

– Vacuum induction melting (30kg)

– Hot rolling (thickness : 15mm)

– Heat treatment (normalizing at 1050oC,

tempering at 750oC)

Performance tests

– Microstructure examination

– Sodium compatibility tests

– Creep/tensile tests

• CRS of new alloy improved by more than 35 %

from HT9

• 9Cr-2W-0.05Ta-0.08N-0.006B

• 9Cr-2W-0.05Ta-0.02N-0.15B

100 1000 10000100

120

140

160

180

650 oC

Str

es

s (

MP

a)

Time to Rupture (hr)

HT9

T92

PNC-FMS

KAERI

9

피복관 예비시제품 제조

Hot extrusion

Heat treatment

Fabrication of HT9 Cladding Tube

Hollow billet

– VIM (1 ton ingot)

– Hot forging at 1200oC

– Machining (OD 180mm)

Mother tube fabrication

– Hot extrusion (OD 54mm)

– Pilgering & Drawing

– Intermediate HT (OD 19mm)

Tube fabrication

– Drawing (4 times)

– Intermediate heat treatment

– Final heat treatment

– Cladding tube

(OD 7.4mm, T 0.56mm)

Drawing

Intermediate tube Cladding tube

1 ton ingot

10

Microstructure of HT9 Cladding tube

Dimension

- Outer diameter : 7.427 + 0.05 mm

- Inner diameter : 6.318 + 0.05 mm

- Thickness : 0.549 mm

Microstructure

– Martensite + Delta ferrite

Surface roughness

- Outside : 0.441 ㎛

- Inside : 0.111 ㎛

Straightness

– < 10 ㎛

11

Tensile Test of Cladding Tubes

Test temperature : RT ~ 700oC

Gr.92 tube had higher yield and ultimate tensile strength than HT9 tube.

Total elongation of Gr.92 tube was a little lower than that of HT9 tube.

HT9 cladding tube had tensile properties similar to the data in the literature.

Ref.) W.L. Bell, et al., GE, Proc. of Topical Conf. on Ferritic

Alloys for use in Nucl. Energy Technologies (1983)

Ref.) W.L. Bell, et al., GE, Proc. of

Topical Conf. on Ferritic Alloys for use

in Nucl. Energy Technologies (1983)

12

Burst Test of Cladding Tubes

Test conditions

– Burst test was performed by pumping gas up to burst.

Test results

– Ultimate hoop stress

• HT9 : 1135MPa (R.T), 488MPa (658oC)

• Gr.92 tube had a lower UHS than HT9 tube at

elevated temperature. RT

452℃

562℃

614℃

658℃

13

Creep Test of HT9 Cladding Tube

Test conditions

– Test temperature : 650oC

– Applied hoop stress : 120MPa to 216MPa

Test results

–Time to rupture of HT9 tube

• 4hrs (216MPa), 9hrs (194MPa)

36hrs (162MPa), 173hrs (140MPa),

524hrs (120MPa)

– HT9 cladding tube had creep rupture

strength similar to the data

in the literature.

– Creep test of Gr.92 cladding tube is

on-going

10 100 1000 10000

60

80

100

120

140

160

180

200

220

240

Ho

op

str

ess (

MP

a)

Rupture time (hr)

HT9 (KAERI)1)

HT9 (KAERI-Round bar)2)

HT9 (EP0287710A2)3)

HT9 (EP0287710A2)4)

HT9 (EP0287710A2)5)

1) 1038C, 5min → 760C, 30min

2) 1050C, 30min → 750C, 2hr

3) 1100C, 5min → 760C, 30min

4) 1040C, 5min → 650C, 2hr

5) 1040C, 5min → 704C, 2hr

14 AR HT9 : 239.11

Final Heat Treatment

Heat treatment conditions

– Normalizing : 950 ~ 1100oC x 30min

– Tempering : 700 ~ 800oC x 1hr

Tensile test results

–Tensile test : 650oC

Future works

– Creep test 740 750 760 770 780

160

180

200

220

240

260

65

0C

YS

(M

Pa

)

Tempering temp. (oC)

950C

1000C

1050C

1100C

HT9 (AR)

740 750 760 770 780

160

180

200

220

240

260

280

65

0C

UT

S (

MP

a)

Tempering temp. (oC)

950C

1000C

1050C

1100C

15

Core Components Development Plan

Cladding tube

Duct

Wire

Cold working

process

Heat treatment

conditions

Wire design

Fabri. duct Out-of-pile test of duct (tensile, creep, impact etc.)

Fast reactor irradiation test

Out-of-pile test of wire (tensile, creep, impact etc.)

Fast reactor irradiation test of duct

Fast reactor irradiation test and PIE

Duct design

Fabri. Assembly

parts

Out-of-pile test (creep, tensile, impact, fracture toughness)

Fabri. wire

Out-of-pile test

Design of assembly parts

Design of

Irra. test

rig

Fabr. of

rig

Fabr. of rig

연구내용 차기단계 (표준설계)

(’12-’16) 2단계 (실증로 개념설계)

Item 2012 - 2014

2nd phase (2015-2016)

1st phase 차기단계 (표준설계)

(’12-’16) 3rd phase (2017-2020)

Assembly

parts Assembly parts fabrication

process

Duct fabri.

process

Fabri.

cladding

tube

PIE (swelling, creep etc.)

PIE (impact, fracture toughness etc.)

Fabr. of

rig

16

Irradiation Test Plan of Cladding Tube

Irradiation test : Oct. 2014

Specimens

– HT9M1 : 9Cr-2W-V-Nb-B (cladding)

– HT9M2 : 9Cr-2W-V-Nb-N (cladding)

– T91 : Modified 9Cr-1Mo (duct)

– HT9 (cladding & duct)

Irradiation temperature : 390oC, 545oC, 650oC

Fluence : 20dpa, 80dpa, 160dpa, 200dpa

17

Post Irradiation Test Plan of Cladding Tube

PIE items

– Nondestructive tests

• Visual inspection

• Irradiation swelling

• Irradiation creep (pressurized cladding tube)

– Destructive tests (4 set)

• Mechanical test (Tension, Charpy impact, fracture toughness, Compact

tension)

• Microstructure (dislocation, precipitation, void)

18

Summary

Development of advanced FM steels

– 9Cr-2W-TaVNbB

Fabrication and evaluation of cladding tubes

– HT9 and Gr.92 cladding tube fabrication

– Creep, tensile, burst, and microstructure

– HT9 cladding tube fabricated in Korea showed similar mechanical

properties with the data in the literature.

Future works

– Fabrication of cladding tubes with new alloys

– Performance of out-of-pile test

– Fast neutron irradiation test

19

Thank you for your attention!