Irradiation of SFR metal fuel in HANARO and the

results of post irradiation examination

2013. 3. 6

Byoung Oon LEE

International Conference on Fast Reactors and Related Fuel

Cycles (FR13), Paris, France

2 2 FR13 13.03.06

OUTLINE

1 Introduction

2

3

4

PIE

Conclusions

HANARO Irradiation

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INTRODUCTION 1

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Metallic Fuel for SFR

Metallic Fuel Design Concept

• Fuel slug : U-Zr & U-TRU-Zr

• Fuel rod gap filled with sodium

• Cladding and duct : Ferritic martensitic steel

(HT9M) Fuel rodlet for HANARO

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SFR Metal Fuel Development Plan

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HANARO Irradiation Tests Plan

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HANARO Irradiation 2

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Irradiation in HANARO

Fuel

Na

Outer tube

Gap (He, 60m)

Coolant

Cladding

Fuel slug Cladding Sealing tube

OD, mm

Density, g/cc

Length, mm

OD, mm

ID, mm

Length, mm

OD, mm

ID, mm

Length, mm

3.7 15.8 50 5.5 4.6 193 8.62 5.62 233

2010. 11.15~2012.1.5 : 1st irradiation in

HANARO

Irradiation condition

• Fuel : U-10wt.%Zr-(5Ce)

• Cladding : T92 (FMS)

• Fast reactor condition

Thermal neutron filter : Hf

Fuel temp. control : He gap

Fuel/cladding gap bonding : Na

Fuel Slug Cross Section

Upper Part

Na

Fuel Slug Cross Section

Upper Part

Na

Mid-core

bottom top

Mid-core

bottom top

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Irradiation Capsule for HANARO

Characteristics of irradiation capsule

• 12 rodlets : 6 U-10Zr & 6 U-10Zr-5Ce

• Barrier : 20 μm thick Cr

• Cladding : ferritic-martensitic steel (T92)

• Sealing tube : 316L

• Capsule : total length 961 mm, diameter 56 mm, thickness 3 mm

• Hf tubes : upper(1.35 mm) & lower(1.58 mm) to limit fuel linear power

Lower fuel rodlet

Upper fuel rodlet

Coolant

Fuel slug

Hf tube

A-AB-B Neutral plane of core

Bottom view

No. Fuel slug Cladding Barrier

U

pp

er

1 U-10Zr T92

2 U-10Zr T92

3 U-10Zr T92 Cr

4 U-10Zr-5Ce T92

5 U-10Zr-5Ce T92

6 U-10Zr-5Ce T92 Cr

L

ow

er

1 U-10Zr T92

2 U-10Zr T92

3 U-10Zr T92 Cr

4 U-10Zr-5Ce T92

5 U-10Zr-5Ce T92

6 U-10Zr-5Ce T92 Cr

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Evaluation of Irradiation Capsule

Evaluation of Irradiation capsule Integrity

• Fuel integrity is maintained during irradiation : temperature, strain

Cladding inner temperature < 600 C

Conservative LHGR : 352 W/cm

• Out-of-pile tests : satisfied the requirements of the compatibility with the

HANARO

200

250

300

350

400

400

450

500

550

600

650

700

750

800

0 1 2 3 4 5

Lin

ea

r p

ow

er, W

/cm

Te

mp

era

ture

, C

Burnup, at%

Clad inner-wall temp

Centerline temp

LHGR, W/cm

Variation of fuel temperature with burnup

Hf tube

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HANARO Irradiation History

Irradiation began :‘10.11.15

• Burnup at 1st irradiation cycle (29EFPD) : 0.3 at.%

Average burnup (~2012.1.5) : 2.73at.%

As-run linear heat rate

• 240 W/cm at BOC

decreased to 220 W/cm at EOC

Initial Fuel & Capsule Test Conditions Irradiation history

0

5

10

15

20

25

30

0.000

5.000

10.000

15.000

20.000

25.000

30.000

0 20 40 60 80 100 120 140 160 180 200

upper part Linear (kW/m)

lowe part Linear (kW/m)

upper part burnup(GWD/MTU)

lower part burnup(GWD/MTU)

Linear Flu

x(kW/m

)

Total Operation Day

Bu

rnu

p(G

WD

/MTU

)

Linear Flu

x(kW/m

)

Total Operation Day

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PIE 3

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PIE milestone for 1st HANARO Irradiation

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PIE (Post-irradiation examination) items

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IMEF and PIEF Plan View

1st floor plan view in IMEF 1st floor plan view in PIEF

3 pool, 4 concrete cell, 2 lead cells

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PIE Status in 1st Year

Status • Completion of Irradiation

(‘10.11.15~‘12.1.5) • Capsule transfer & dismantling

‘12.4.5

HANARO →IMEF (Irradiated Materials

Examination Facility)

Dismantling at hot cell in IMEF

• γ- scanning Completion of 12 rodlets

• Fission gas release measurement 4 rodlets

• Fuel rod cutting & Destructive test OM : 3 rodlets

SEM : 2 rodlets

PIE Status Irradiation Capsule Transfer

from HANARO to IMEF Capsule

Dismantling γ- scanning

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γ- scanning

Completion of 12 rodlets

• Cs-137, Nb-95, Rh-106m, Ru-103, Zr-95 analyzed Cs-137 : rise rapidly in the region of 55mm from the bottom of fuel slug Nb95/Zr95 &Zr-95

nearly constant along the fuel rod, and then drop rapidly

No. 9 (U-Zr, Cr barrier) No. 8 (U-Zr)

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Evaluation of γ- scanning

Irradiation Growth • U-Zr fuel slug : 10-12% • U-Zr-Ce : 6-8% • Similar or slight higher results than expected

Continuous evaluation will be carried out

Axial burnup • Similar burnup along axial direction of fuel rodlets

Irradiation Growth Cross section of irradiation capsule

Top view

1

2

3

6

5

4 0

2

4

6

8

10

12

14

0 1 2 3 4

Fue

l axi

al g

row

th, %

Burnup, %

U-10Zr

U-10Zr-5Ce

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FGR Measurement

Laser puncturing system for SFR metal fuel was prepared - Fuel rodlets were punctured in the plenum at room temperature

Fission gas release measurement - FGR : 66 ~90 % - The rodlet gas samples will be analyzed for elemental and isotopic composition in the

Chemical Laboratory

FGR measurement system Laser puncturing system

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OM (Optical Microscope)

Fuel swelling - unirradiated fuel : gap between fuel slug

and cladding - irradiated fuel : significant radial

swelling and contact with the cladding

micrographs of the U-Zr - containing a high density of small pores

Cr barrier - micrographs of the U-Zr with Cr barrier

cladding at the interface regions The circumferential difference of

plating thickness was observed in all parts of the Cr layer

no evidence of fuel-cladding chemical interaction,.

some crack has developed in the thin thickness regions

Cross-sectional metallography of the unirrdiated U-Zr and the irrdiated U-Zr specimen

Micrograph of the U-Zr with Cr barrier cladding

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SEM (U-Zr and Cr barrier)

Microstructure • Unirradiated fuel : Zr precipitate & Laminar structure in U-Zr matrix • Irradiated fuel

U & Zr distributed homogeneously Porosity developed along the fuel

Unirradiated fuel (U-Zr)

Irradiated fuel Transverse section between center and outer region

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Image Mapping (U-Zr-Ce and Cr Barrier)

Ce exited along Cr barrier • Ce diffused to outer region • Cr barrier prevent inter-diffusion

between Ce and cladding

Image Mapping for Cr Barrier and Ce

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CONCLUSIONS 4

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Metallic fuel development for SFR started in 2007

1st HANARO Irradiation : 2010.11 ~2012.1

PIE is being carried out in IMEF from 2012.4

• Gamma scans for twelve metallic fuel rodlets were completed

• The cross-sectional metalography of the irradiated U-Zr specimen shows

significant radial swelling

• Cr barrier cladding at the interface regions show there are no macroscopic

reaction between fuel and cladding

• PIE for 1st HANARO irradiation will be completed in 2014.02

Continuous experimental tests needed

• for the establishment of performance evaluation tools and design data bases

• 2nd HANARO Irradiation : 2014 ~

Conclusions