IMMOBILIZATION OF RADIOACTIVE IODINE IN IMMOBILIZATION OF RADIOACTIVE IODINE IN PHOSPHATE GLASSPHOSPHATE GLASS
T. Lemesle1,2, F.O. Méar1, L. Campayo2, O. Pinet2, L. Montagne1
1 Unité de Catalyse et Chimie du Solide - UMR-CNRS 8181 - Université Lille Nord de France, F-59652 Villeneuve d’Ascq, France
2DEN/DTCD/SECM/LDMC, CEA Marcoule, BP 17171, 30207 Bagnols sur Cèze, France
Tg variation as a function of the formulation
Unité de Catalyse et de Chimie du Solide - UMR CNRS 8181USTL - Bâtiment C3 - 59655 Villeneuve d’Ascq Cedex - France - +33 (0)3 20 43 49 11
Email : [email protected] - http://uccs.univ-lille1.fr
Many thanks to all the following organizations for their kind contribution to this work
References :[1] CAMPAYO ET AL., PROJET MATINEX [4] KAWAMURA ET AL., SOLID STATE IONICS, 2002[2] DARAB ET AL., MRS, 1999 [5] VAN WÜLLEN ET AL., SOLID STATE SCIENCES, 2005[3] MINAMI ET AL., J. ELECTROCHEM. SOC., 1977
Glass system: Glass system: AgAg22O – (1-x) PO – (1-x) P22OO5 5 -- AlAl22OO33 – x B – x B22OO33 – AgI – AgI
Density variation as a function of the formulation
Structural variations as a function of the formulation
A linear increase in density is observed.
Addition of AgI increases density whatever the glasses; however, the increase is more important in phosphate glasses than in boro-phosphate glasses.
An increase in the AgI amount leads to a decrease of Tg.
For AgI-bearing glasses, impact on the Tg is more important for glasses with boron substituted for a small amount of phosphate and having a low Ag/P ratio.
No more Tg variations are observed even with modified Ag/P ratios at nearly 1% of iodine content by volume.
Addition of Al2O3 moves the chemical shift to the left with a higher fraction of Qn-1 units (shorter phosphate chain than Qn).
Even with Al2O3, addition of AgI moves the spectra to the right.
(ppm)-35-30-25-20-15-10-505101520253035
AgI-AgPO3 (1% vol)
AgI-Ag4P2O7 (1% vol)
AgI-Ag5P3O10 (1% vol)
Ag5P3O10
AgPO3
Ag4P2O7
Q2Q1
(ppm)-30-25-20-15-10-50510152025303540455055606570
AgI-Ag4P2O7-5Al (1% vol)
Ag4P2O7-5Al
AgI-Ag5P3O10-5Al (1% vol)
Ag5P3O10-5Al
AgI-AgPO3-5Al (1% vol)
AgPO3-5Al
Al(4) Al(5) Al(6)
Al(PO3)3 [A]AlPO4
Tg increases with the addition of alumina
Addition of Al2O3 in AgI glasses having high Ag/P ratios is found to be more efficient
Substitution of P2O5 by B2O3 and then addition of Al2O3 cause a high increase of Tg
Increase in Ag/P decreases Tg
Al2O3 substitution for P2O5 has no significant effect on Tg
High density for silver phosphate glasses
Al2O3 substituted for P2O5 has more effect on the density than B2O3 substituted for P2O5.
An increase in the Ag/P ratio increases glass density.
Impact on density with the addition of Al2O3 is crucial on glasses having a high Ag/P.
With the incorporation of higher AgI amounts, broad peaks become narrower. Broad peaks correspond to different sites for silver cations [4].
The addition of Al2O3 changes the chemical shift values. It is explained by the increase in bond length of Ag-O [5].
(ppm)-30-25-20-15-10-50510152025303540455055606570
AgPO3 – 3Al
AgPO3 – 3Al + 5B (B sub. for P)
AgI-AgPO3-3Al (1% vol)
AgI - AgPO3 – 3Al + 5B (B sub. for P)
Al(5) Al(6)
Al(PO3)3 [A]
Lower tendencies to the crystallisation by addition of AgI in silver aluminophosphate glasses with substitution of B2O3 for P2O5
With AgI, aluminum changes from Al(6) to Al(5) plus Al(6).
0.00 0.25 0.50 0.75 1.00
0.00
0.25
0.50
0.75
1.00 0.0
0.2
0.4
0.6
0.8
1.0
Al2
O3
Ag2
O
P2O
5
AgPO3
+ x Al2
O3
Ag5P
3O
10 + x Al
2O
3
Ag4P
2O
7 + x Al
2O
3
Ag3
PO4
7% : Al2
O3
incorporation limit
ConclusionIn this study, B2O3 and Al2O3 were added and/or substituted for phosphate in iodine-bearing glasses. This was done to find a phosphate glass having a high iodine content, an intermediate Tg (> 180 °C) and no crystallisations. The results suggest that to meet the above-mentioned criteria, the glass has to have less than 5% of Al2O3 and a low Ag/P ratio. The formulation can even be improved by substituting B2O3 for P2O5. Finally, the finding suggest that the thermal and structural properties of glasses are highly influenced by the incorporation of AgI and this change will be deeply studied in further investigations.
Variation of TVariation of Tgg as a function of iodine content as a function of iodine content
Variation Variation of Tg as a function of the O/P ratio in the glass of Tg as a function of the O/P ratio in the glass systemsystem
AgAg22O – (1-x) PO – (1-x) P22OO5 5 -- AlAl22OO33 – x B – x B22OO33 – AgI – AgI
100
120
140
160
180
200
220
240
260
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Tg (
C)
% vol of iodine
AgI-AgPO3-3Al
AgI-Ag5P3O10-3Al
AgI-Ag4P2O7-3Al
AgI-AgPO3-3Al-5B
°
Variation Variation of density as a function of the O/P ratio in the glass of density as a function of the O/P ratio in the glass systemsystem
AgAg22O – (1-x) PO – (1-x) P22OO5 5 -- AlAl22OO33 – x B – x B22OO33 – AgI – AgI
4.4
4.6
4.8
5
5.2
5.4
5.6
5.8
6
6.2
6.4
2.90 3.00 3.10 3.20 3.30 3.40 3.50 3.60 3.70 3.80 3.90 4.00
Den
sity
O/ P
substitutionB for P
+ xAl2O3
(x=0 ; 3 ou 5)
+ x% vol iodine (x=0->1)
increase of Ag/P
substitutionAl for P
AgI-AgPO3
(1% vol I)
AgI-Ag3PO4
(1% vol I)
AgI-Ag4P2O7
(1% vol I)
AgI-Ag5P3O10
(1% vol I)
AgPO3
Ag5P3O10
AgPO3 -5B2O3
(B sub. for P)
Ag4P2O7
Ag3PO4
4.4
4.6
4.8
5
5.2
5.4
5.6
5.8
6
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
Gla
ss d
ensi
ty
% vol of iodine
AgI-AgPO3-3Al
AgI-Ag5P3O10-3Al
AgI-Ag4P2O7-3Al
AgI-AgP-3Al-5B
75
100
125
150
175
200
225
250
275
300
2.90 3.00 3.10 3.20 3.30 3.40 3.50 3.60 3.70 3.80 3.90 4.00
Tg (
C)
O/ P
AgI-AgPO3
(1% vol I)
AgI-Ag3PO4
(1% vol I)
AgI-Ag4P2O7
(1% vol I)
AgI-Ag5P3O10
(1% vol I)
AgPO3
Ag5P3O10
AgPO3 -5B2O3
(B sub. for P)
substitutionB for P
+ xAl2O3
(x=0;3 ou 5)
+ x% vol iodine (x=0->1)
increase of Ag/P
substitutionAl for P
°
Variation of density as a function of iodineVariation of density as a function of iodine
Influence of the incorporation of AgI on the structure as a function of Ag/P by Influence of the incorporation of AgI on the structure as a function of Ag/P by 3131P NMR P NMR
Addition of AgI for different ratios of Ag/P changes the chemical shift. The chemical shift is shifted towards the highest Qn.
Influence of the incorporation of AlInfluence of the incorporation of Al22OO3 3 and and AgI on the structure by AgI on the structure by 3131P and P and 2727Al NMR Al NMR
(ppm)-50-45-40-35-30-25-20-15-10-505101520253035404550
AgI-Ag4P2O7-5Al (1% vol)
Ag4P2O7-5Al
Ag4P2O7
AgI-Ag5P3O10-5Al (1% vol)
Ag5P3O10-5Al
Ag5P3O10
AgI-AgPO3-5Al (1% vol)
AgPO3-5Al
AgPO3
Q2Q1Q0
Al(PO3)3 [A]AlPO4
Without AgI, aluminum is in an octahedral form, Al(6), except for Ag/P < 2.
With addition of AgI, for Ag/P >1, aluminium exhibits two environments: Al(5) and Al(6), respectively.
Crystallisation of aluminum occurs in AgI-AgPO3-5Al: narrow peaks for Al(PO3)3 and AlPO4.
Influence of the incorporation of AgI and substitution in silver metaphosphate Influence of the incorporation of AgI and substitution in silver metaphosphate glasses glasses
by by 109109Ag, Ag, 3131P and P and 2727Al NMRAl NMR
Substitution of B2O3 for P2O5 has an effect (chemical shift moved to the left) even with 5%mol
(ppm)-50-45-40-35-30-25-20-15-10-505101520253035
AgPO3+ 5B (B sub. for P)
AgPO3
AgPO3 – 3Al
AgPO3 – 3Al + 5B(B sub. for P)
AgI-AgPO3-3Al (1% vol)
AgI - AgPO3 – 3Al + 5B (B sub. for P)
Q1 Q2
Al(PO3)3 [A]
P-O-Al zone
P-O-B zone
Analysis of incorporation of AgI and AlAnalysis of incorporation of AgI and Al22OO33 by by 109109Ag NMRAg NMR
Analysis of substitution of BAnalysis of substitution of B22OO33 for P for P22OO55 by by 3131P and P and 2727Al NMRAl NMR
(ppm)-400-350-300-250-200-150-100-50050100150200250300350400450500550600650700750
AgPO3
AgI-AgPO3 (1% vol)
AgPO3-3Al
AgI –AgPO3-3Al (1% vol)
AgI –AgPO3-5Al (1% vol)
AgPO3430 ppm
24 ppm
ratioratio
amount
Iodine-129, extracted during the reprocessing of spent nuclear fuel, is considered as a long-lived isotope (half-life: 15.7 million years). It is characterized by a high mobility in geologic environment as well as by its strong tendency to volatilization. Its management within the framework of a safe disposal in a deep geological repository requires the definition of a conditioning matrix.Two main types of conditioning matrices, mentioned in the available literature, seem particularly interesting: the ceramic matrices belonging to the system of lead-bearing vanadates [1 ] and the glassy matrices like borosilicate glasses [2] or phosphate glasses [3]. It is on the latter system that this PhD work is focused (127I is used as an analogue for 129I).
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