EVIDENCE OF DRAMATIC FISSION PRODUCT RELEASE EVIDENCE OF DRAMATIC - - PowerPoint PPT Presentation

EVIDENCE OF DRAMATIC FISSION PRODUCT RELEASE EVIDENCE OF DRAMATIC FISSION PRODUCT RELEASE FROM IRRADIATED NUCLEAR CERAMICS FROM IRRADIATED NUCLEAR CERAMICS

Lionel THOMÉ, Aurélie GENTILS, Frédérico GARRIDO

Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse, IN2P3-CNRS, Bât. 108, 91405 Orsay, France

Jacek JAGIELSKI

Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warszawa, Poland The Andrzej Soltan Institute for Nuclear Studies, 05-400 Swierk/Otwock, Poland

PURPOSE OF THE WORK

1 - To show the efficiency of ion beams for the evaluation of nuclear ceramics 2 - To present results concerning the diffusion and release of radiotoxic elements (fission products) in nuclear ceramics

USE OF ION BEAMS FOR THE USE OF ION BEAMS FOR THE EVALUATION OF NUCLEAR CERAMICS EVALUATION OF NUCLEAR CERAMICS

TOPICS STUDIED WITH ION BEAMS

• Radiation effects

Fission Fragments α α α α particles α α α α recoils

• Retention of radionuclides

Actinides Fission Products

• Helium behavior

Helium location and retention Effects of He on materials properties

α α α α recoils

(~100 keV)

α α α α particles

(~5 MeV)

FF (~100 MeV) µ µ µ µm

10

DOPING

stable elements radioactive elements

USE OF ION BEAMS

IRRADIATION

High-energy ions (100 MeV) Low-energy ions (100 keV)

MATERIAL

CHARACTERIZATION

RBS / ERDA / PIXE Nuclear reactions Channeling

Radiation effects Retention of radionuclides He behavior Radiation damage Atomic mobility

Penning ion source

Middleton ion source Penning ion source electron microscope

IRMA

clusters implantation characterization

CSNSM accelerator

Damage evolution in zirconia irradiated with 500 keV Ar ions

FLUENCE (1015cm-2) 2 4 6 8 10 ACCUMULATED DAMAGE (fD) 0.0 0.2 0.4 0.6 0.8 1.0

dpa

1 2 3 4

stage 3 stage 2 stage 1 RT 800°C

ZrO2

• Stage 1:

Small isolated defect clusters

• Stage 2:

Transition from defect clusters to the linking of extended lattice defects

• Stage 3:

Dislocations

RADIATION DAMAGE INDUCED BY ION IRRADIATION

RETENTION OF RADIONUCLIDES RETENTION OF RADIONUCLIDES

EXPERIMENTAL APPROACH

MATRIX IONS

HIGH TEMPERATURE ANNEALING

+

HIGH TEMPERATURE IRRADIATION

DEPTH (nm)

20 40 60 80 100 120 140

Cs ION DISTRIBUTION

TRIM

Cs ZrO2

(300 keV)

Incident Ions (100 keV–1 MeV) 300 K

ION IMPLANTATION

He (MeV) Ω Ω Ω Ω θ θ θ θ He (MeV) Ω Ω Ω Ω θ θ θ θ

Matrix Matrix

implanted ions

ANALYSIS OF THE DEPTH DISTRIBUTION OF IMPLANTED IONS WITH RUTHERFORD BACKSCATTERING (RBS) Counts Energy Counts Energy

RBS spectra on zirconia implanted with 300 keV Cs ions

CHANNEL 380 400 420 440 NORMALIZED YIELD 10 20 30

Cs Zr

DEPTH (nm) 50 100 150 Cs CONC. (at.%) 1 2

EFFECT OF THE FISSION PRODUCT CONCENTRATION ON THE DIFFUSION

Modification of the FP depth profile upon annealing for Cs ions implanted into zirconia at two concentrations

DEPTH (nm)

20 40 60 80 100 120 140

Cs CONCENTRATION (at.%)

1 2 3 4 5

• ann. 500°C
• ann. 650°C

virgin

low c high c

EFFECT OF IRRADIATION ON FISSION PRODUCT DIFFUSION

Modification of the FP profile upon annealing or irradiation for Cs ions implanted at high concentration into zirconia

DEPTH (nm)

20 40 60 80 100 120 140

Cs CONCENTRATION (at.%)

1 2 3 4 5

• ann. 500°C
• ann. 650°C

virgin

high c

• irr. 500°C

Modification of the FP concentration upon thermal treatments for Cs ions implanted into zirconia

TEMPERATURE (°C)

200 400 600 800

Cs CONCENTRATION (at.%)

2 4 6 8

critical Cs concentration Filled: ann. Open: irr.

• Diffusion of FP depends on

their atomic concentration

• Existence of a critical FP

concentration below which the system is stable at high T

• Irradiation enhances the FP

mobility

SUMMARY OF THERMAL TREATMENTS IN ZIRCONIA

• Similar effects were found

in other nuclear ceramics

CONCLUSIONS

• Ion beams are efficient and versatile tools for the

evaluation of nuclear ceramics Several issues can be addressed :

• Simulation of damage by ion irradiation
• Doping of the matrix with foreign species
• Characterization of the material via nuclear

microanalysis techniques

• Studies of the retention of fission products in

nuclear ceramics show that :

• Diffusion and release of FP depends on concentration
• At high concentration irradiation enhances the

FP mobility