Сorrosion and radiation resistance of potassium magnesium phosphate matrices
Corrosion and radiation resistances of potassium magnesium phosphate (PМP) matrices for hardening of liquid radioactive wastes of NPP were investigated. The high corrosion resistance of the PMP matrices to leaching of both basic components of matrix and cesium was shown. Results of performed wor...
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nasplib_isofts_kiev_ua-123456789-1477042025-02-09T21:59:15Z Сorrosion and radiation resistance of potassium magnesium phosphate matrices Корозійна та радіаційна стійкість калій-магній-фосфатних матриць Коррозионная и радиационная стойкость калий-магний-фосфатных матриц Sayenko, S.Y. Shkuropatenko, V.A. Zykova, A.V. Surkov, O.Y. Pylypenko, O.V. Ulybkina, К.А. Lobach, K.V. Физика радиационных повреждений и явлений в твердых телах Corrosion and radiation resistances of potassium magnesium phosphate (PМP) matrices for hardening of liquid radioactive wastes of NPP were investigated. The high corrosion resistance of the PMP matrices to leaching of both basic components of matrix and cesium was shown. Results of performed work showed stability of physics and mechanical properties, as well as phase composition and microstructure of PMP after simulated γ-irradiation up to the absorbed dose 10⁸ rad. It was determined that irradiation by high-energy electrons to the absorbed dose 10¹⁰ rad results in partial dehydration and amorphization of PMP. Досліджена корозійна та радіаційна стійкість калій-магній-фосфатних (КМФ) матриць для затвердіння рідких радіоактивних відходів АЕС. Показана висока корозійна стійкість КМФ-матриць до вилуговування як основних компонентів матриці, так і цезію. Результати виконаної роботи показали стійкість фізичних та механічних властивостей, а також фазового складу і мікроструктури КМФ після імітації γ-опроміненням до поглиненої дози 10⁸ рад. Було встановлено, що опромінення високоенергетичними електронами до поглиненої дози 10¹⁰ рад призводить до часткової дегідратації та аморфізації КМФ. Исследована коррозионная и радиационная стойкость калий-магний-фосфатных (КМФ) матриц для отверждения жидких радиоактивных отходов АЭС. Показана высокая коррозионная стойкость КМФ-матриц к выщелачиванию как основных компонентов матрицы, так и цезия. Результаты выполненной работы показали устойчивость физических и механических свойств, а также фазового состава и микроструктуры КМФ после имитации γ-облучением до поглощенной дозы 10⁸ рад. Было установлено, что облучение высокоэнергетическими электронами до поглощенной дозы 10¹⁰ рад приводит к частичной дегидратации и аморфизации КМФ. 2018 Article Сorrosion and radiation resistance of potassium magnesium phosphate matrices / S.Y. Sayenko, V.A. Shkuropatenko, A.V. Zykova, O.Y. Surkov, O.V. Pylypenko, К.А. Ulybkina, K.V. Lobach // Вопросы атомной науки и техники. — 2018. — № 5. — С. 75-81. — Бібліогр.: 17 назв. — англ. 1562-6016 PACS: 28.41.Kw https://nasplib.isofts.kiev.ua/handle/123456789/147704 en Вопросы атомной науки и техники application/pdf Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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Физика радиационных повреждений и явлений в твердых телах Физика радиационных повреждений и явлений в твердых телах |
| spellingShingle |
Физика радиационных повреждений и явлений в твердых телах Физика радиационных повреждений и явлений в твердых телах Sayenko, S.Y. Shkuropatenko, V.A. Zykova, A.V. Surkov, O.Y. Pylypenko, O.V. Ulybkina, К.А. Lobach, K.V. Сorrosion and radiation resistance of potassium magnesium phosphate matrices Вопросы атомной науки и техники |
| description |
Corrosion and radiation resistances of potassium magnesium phosphate (PМP) matrices for hardening of liquid
radioactive wastes of NPP were investigated. The high corrosion resistance of the PMP matrices to leaching of both
basic components of matrix and cesium was shown. Results of performed work showed stability of physics and
mechanical properties, as well as phase composition and microstructure of PMP after simulated γ-irradiation up to
the absorbed dose 10⁸
rad. It was determined that irradiation by high-energy electrons to the absorbed dose 10¹⁰ rad
results in partial dehydration and amorphization of PMP. |
| format |
Article |
| author |
Sayenko, S.Y. Shkuropatenko, V.A. Zykova, A.V. Surkov, O.Y. Pylypenko, O.V. Ulybkina, К.А. Lobach, K.V. |
| author_facet |
Sayenko, S.Y. Shkuropatenko, V.A. Zykova, A.V. Surkov, O.Y. Pylypenko, O.V. Ulybkina, К.А. Lobach, K.V. |
| author_sort |
Sayenko, S.Y. |
| title |
Сorrosion and radiation resistance of potassium magnesium phosphate matrices |
| title_short |
Сorrosion and radiation resistance of potassium magnesium phosphate matrices |
| title_full |
Сorrosion and radiation resistance of potassium magnesium phosphate matrices |
| title_fullStr |
Сorrosion and radiation resistance of potassium magnesium phosphate matrices |
| title_full_unstemmed |
Сorrosion and radiation resistance of potassium magnesium phosphate matrices |
| title_sort |
сorrosion and radiation resistance of potassium magnesium phosphate matrices |
| publisher |
Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| publishDate |
2018 |
| topic_facet |
Физика радиационных повреждений и явлений в твердых телах |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/147704 |
| citation_txt |
Сorrosion and radiation resistance of potassium magnesium phosphate matrices / S.Y. Sayenko, V.A. Shkuropatenko, A.V. Zykova, O.Y. Surkov, O.V. Pylypenko, К.А. Ulybkina, K.V. Lobach // Вопросы атомной науки и техники. — 2018. — № 5. — С. 75-81. — Бібліогр.: 17 назв. — англ. |
| series |
Вопросы атомной науки и техники |
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| fulltext |
ISSN 1562-6016. ВАНТ. 2018. №5(117) 75
CORROSION AND RADIATION RESISTANCE
OF POTASSIUM MAGNESIUM PHOSPHATE MATRICES
S.Y. Sayenko, V.A. Shkuropatenko, A.V. Zykova, O.Y. Surkov, O.V. Pylypenko,
К.А. Ulybkina, K.V. Lobach
Institute of Solid State Physics, Material Science and Technology
National Science Center “Kharkov Institute of Physics and Technology”, Kharkov, Ukraine
E-mail: shkuropatenko@kipt.kharkov.ua
Corrosion and radiation resistances of potassium magnesium phosphate (PМP) matrices for hardening of liquid
radioactive wastes of NPP were investigated. The high corrosion resistance of the PMP matrices to leaching of both
basic components of matrix and cesium was shown. Results of performed work showed stability of physics and
mechanical properties, as well as phase composition and microstructure of PMP after simulated -irradiation up to
the absorbed dose 10
8
rad. It was determined that irradiation by high-energy electrons to the absorbed dose 10
10
rad
results in partial dehydration and amorphization of PMP.
PACS: 28.41.Kw
INTRODUCTION
At present, the problem of the radioactive waste safe
handling is very challenging for further scale and
dynamics of the nuclear power industry development
[1]. It is known that in the process of exploitation of
nuclear power plant, plenty of liquid radioactive wastes
(LRW) of low and middle activity appears, gathers and
kept. These radioactive wastes should not be used for
the direct disposal, according to existent Ukrainian
rules. One of the main methods of LRW solidification is
the waste hardening by the addition of various binding
components [2, 3]. The cementation is the simplest and
most accessible method of LBW hardening. The main
disadvantages of this method are low strength of the
cement matrices, low filling of salts, low solidification
speed, incomplete solidification of the liquid phase at a
high water-cement ratio [4]. In addition, the salts
included in LRW affect the basic processes of cement
hydration, which leads to the degradation of the cement
matrix over time [5].
As an alternative to the cement matrices, a
potassium magnesium phosphate (PMP) matrices has
been proposed for the immobilization of LRW [6]. The
PMP matrix consists of a monophasic crystalline
hexahydrate of magnesium and potassium double
orthophosphate (KMgPO4∙6H2O). The PMP is an analog
of natural phosphate minerals monazite and apatite,
which demonstrate high physic-chemical stability in the
geological environment. PMP is classified as ceramic
cement and has properties characteristic of both
ceramics and hydraulic cements due to the uniqueness
of its properties. The microstructure of PMP is similar
to ceramics, with a strongly pronounced crystalline
structure. However, in contrast to traditional ceramics,
PMP is formed at room temperature and uses water at
the beginning of chemical reactions, with subsequent
solidification of the material, similar to the production
of hydraulic concretes.
Examples of the PMP matrices application for
solidification of Tc-containing wastes simulators,
incorporation of Pu, immobilization of cesium and
simulators of liquid high-salt HLW are well known
[710].
One of the main requirements for LRW
solidification matrices selection is the radiation and
corrosion resistance. The corrosion resistance of the
matrices with respect to leaching in the water is the
main criterion for their applicability for the
environmentally safe storage of radioactive waste. The
matrix with radioactive waste included will be subject to
the action of β-particles and γ-radiation due to the decay
contained in radionuclide waste. There can be changes
in volume, microstructure, mechanical properties and
resistance to leaching of solidified waste forms under
the irradiation process.
The aim of the study was research of the radiation
and corrosion resistance of PMP as promising materials
for the solidification of LRW at nuclear power plants.
MATERIALS AND METHODS
For the synthesis of PMP KMgPO4∙6H2O, the
following reactors were used:
– magnesium oxide MgO (grade h);
– potassium dihydrogen phosphate KH2PO4
(grade h);
– distilled water (pH = 5.5).
In the case of synthesizing cesium-containing PMP
samples, cesium chloride CsCl was used as a starting
reagent (grade hp).
Irradiation by electrons and bremsstrahlung
γ-radiation of PMP samples was carried out at the
KUT-1 accelerator of the NSC KIPT (electron energy
E = 10 MeV). PMP samples were irradiated by electrons
to a set of absorbed dose of 10
10
rad (10
8
Gy) and
bremsstrahlung γ-radiation – 10
8
rad (10
6
Gy).
The phase composition of the PMP materials was
investigated by X-ray diffraction analysis (DRON-4-07
in copper Cu-Kα-radiation using a Ni selectively
absorbing filter). To identify the phases, the JCPDS
diffraction data base was used. The density of the PMP
samples was determined by hydrostatic weighing.
https://www.kipt.kharkov.ua/kipt_sites/isspmst/main_site/ENGindex.html
76 ISSN 1562-6016. ВАНТ. 2018. №5(117)
Compression tests of PMP samples were carried out
on an electromechanical press of the brand “ZD 10/90”,
the maximum load – 10 tons.
To analyse the corrosion resistance of PMP
matrices, leaching tests were carried out at a
temperature of 90 °C for 7 days in accordance to the
PCT test [11]. The test was made according to the
procedure ASTM C1285 “Standard Test Methods for
Deter-Mineral Chemical Durability of Nuclear,
Hazardous, and Mixed Waste Glasses: The Product
Consistency Test (PCT)”.
Corrosion resistance of PMP matrices with respect
to cesium leaching as the main radionuclide of LRW
from NPP was determined in accordance to the ANS
16.1 test [12] in the long-term leaching of PMP samples
containing 10 wt.%CsCl and 15 wt.%CsCl in bidistilled
water at 25 °C. The concentration of K, Mg, P, Cs in the
leachate was determined by atomic-emission
spectroscopy with inductively coupled plasma ICP-AES
(Spectrometer Scan Advantage, manufactured by
Thermo Jarrell Ash, USA).
EXPERIMENTAL PART
PMP were obtained at room temperature as a result
of an acid-alkaline reaction between magnesium oxide
MgO and potassium dihydrogen phosphate KH2PO4 in
water [9]. The dry mixture of MgO and KH2PO4 was
thoroughly mixed, and then the required amount of
water was added to this mixture. Further, the resulting
mass was stirred for 20…30 min until a pasty state. The
paste was placed in a plastic mold. The temperature of
the paste rose to 45 °C within 10 min. To increase the
reaction time, 1…2 wt.% of boric acid H3BO3 were
added to the mixture. To increase the strength properties
of the PMP samples, 10 wt.% of wollastonite CaSiO3
was added to the mixture. After extraction from the
plastic form of PMP, the samples were held at a
temperature of 20 °C for 28 days. As a result, samples
of the compositions (KMgPO4∙6H2O),
(KMgPO4∙6H2O + 10 wt.%CaSiO3) and
(KMgPO4∙6H2O + 10…15 wt.%CsCl) were obtained in
the form of a cube with dimensions of 20x20x20 mm
and cylindrical samples with a diameter of 19 mm and a
height of 35 mm (Fig. 1,a).
Irradiation by electrons and bremsstrahlung
γ-radiation of PMP samples was carried out on the
accelerator KUT-1 up to a set of absorbed dose of
10
10
rad and bremsstrahlung γ-radiation – 10
8
rad. The
target, in which the samples were placed, exposed to
electrons, was cooled with water. Therefore, to prevent
the interaction of the PMP material with water samples
during electron irradiation, the samples were placed in
0.3 mm stainless steel capsules (see Fig. 1,b).
Containers with PMP samples were irradiated with
electrons along the axis of the cylindrical capsules. PMP
samples were irradiated with bremsstrahlung γ-radiation
in an aluminum foil. Samples were irradiated with
bremsstrahlung γ-radiation in air.
The amount of absorbed dose was chosen taking into
account the requirements for the materials of containers
for the packaging, transportation and storage of
radioactive waste (including spent nuclear fuel, low –
and high – active waste). According to the requirements,
the material of the container must have radiation
resistance of 10
8
rad or higher under irradiation
conditions, in the case of necessity. The radiation dose
of 10
8
rad is based on its equality to the total dose
received in more than 300 years by radioactive waste
containing
137
Cs or
90
Sr at a concentration of 10 Ci/ft
3
[13].
a b
c
Fig. 1. PMP samples: a – view; b – in capsules before electron irradiation; c – after electron irradiation
ISSN 1562-6016. ВАНТ. 2018. №5(117) 77
a b
Fig. 2. The appearance of the container with a sample for performing the leaching test:
a – PCT; b – ANS 16.1
Corrosion resistance to the leaching of the main
components of the PMP matrix (K, Mg, P) was
determined in accordance with the PCT test. To carry
out the corrosion resistance tests, a Teflon container was
used. The starting PMP samples were ground and then
sieved. The resulting powder was washed in distilled
water and acetone in an ultrasonic bath. Next, the dried
purified powder was milled in a Teflon container and
water was added according to the ASTM C1285
standard (Fig. 2,a). The container was placed in a
thermostat for 7 days at a temperature of (90±2) °C.
After the test, the resulting leach was filtered from the
powder particles. The concentration of elements in the
leachate was determined by ICP-AES.
The normalized leaching rate of the elements was
calculated by the formula:
),/( tSfVcR ii (1)
where R is the normalized leaching rate of the element,
g/(m
2
∙day); ci is the concentration of the i-th element in
the solution after leaching, g/l; V is the volume of the
leaching water, l; S is the specific surface area of the
milled sample, m
2
; fi is the content of the i-th element in
the matrix; t – leaching time, days.
Corrosion resistance of the resulting PMP matrices
with respect to cesium leaching was determined in
accordance with ANSI/ANS 16.1–1986 test
“Measurement of the leach-ability of a solid-state low-
level test procedure” (see Fig. 2,b). This test is usually
used to characterize such forms of solidified low-level
waste, such as bitumen, concrete and other cementing
materials. The ANS 16.1 test provides for the long-term
leaching of samples in water at 25 °C at the following
time intervals: 2, 5, 17 hour, four 24-hour intervals
followed by 14, 28, and 43-day intervals (total time 90
days). Determination of cesium content in the leach was
carried out with ICP-AES. The obtained values were
used to calculate the effective diffusion coefficient D
and leaching indexes Li:
,
)(
/
22
0
S
V
T
t
Aa
nD
n
n
(2)
where D is the effective diffusion coefficient, cm
2
/s;
V is the volume of the sample, cm
3
; S is the geometric
surface area of the sample, calculated from the
measured sample parameters, cm
2
; T is the average
leaching time, s; an – the amount of the element selected
from the sample for the n-th interval; Ao is the total
amount of element in the sample prior to leaching; Δtn is
the duration of the n-th interval
,log
10
1 10
1
n
i
i
D
L
(3)
where Li is the i-element leach index; β is a constant
(1.0 cm
2
/s); Di is the effective diffusion coefficient of
the i-element.
RESULTS AND DISCUSSION
IRRADIATION OF PMP SAMPLES BY
BREMSSTRAHLUNG γ-RADIATION
AND ELECTRONS
After irradiation of the PMP samples with
bremsstrahlung γ-radiation up to a set of absorbed dose
of 10
8
rad, no chemical, phase and noticeable
microstructural changes have been detected. Fig. 3,a,b
show the diffraction patterns of the sample composition
(KMgPO4∙6H2O + 10 wt.%CaSiO3) before and after
γ-irradiation. Comparison of the diffractograms shows
the complete coincidence of the main X-ray lines of
potassium-magnesium phosphate before and after
γ-irradiation.
In addition, according to IR spectroscopy, irradiation
with bremsstrahlung γ-radiation with a maximum
energy of 13.5 MeV to a dose of 1.35∙10
5
Gy does not
lead to a change in the main phase composition of the
PMP samples material, since the number and position of
all bands of the spectrum remains unchanged. Changes
in the intensity of bands in the IR spectrum are
associated with an increase in the degree of crystallinity
of the material of the PMP sample after γ-irradiation
[14].
78 ISSN 1562-6016. ВАНТ. 2018. №5(117)
Fig. 3. XRD patterns of KMgPO4∙6H2O + 10 wt.% CaSiO3: a – before γ-irradiation; b – after γ-irradiation
In contrast to γ-irradiation, not only the
KMgPO4∙6H2O and wollastonite CaSiO3 materials but
also the anhydrous phosphate KMgPO4 X-ray lines
against the halo background at the angles of 20º–2θ–40º
were observed on the diffractogram of the sample
composition (KMgPO4∙6H2O + 10 wt.%CaSiO3) after
electron irradiation with a set of absorbed dose of
10
10
rad (Fig. 4). This fact indicates that after electron
irradiation with high energies (10 MeV), partial
dehydration and amorphization of the PMP samples
took place. As it is known from the DTA/TG analysis
[9] that the maximum endothermic peak, which
corresponds to the intense dehydration of potassium-
magnesium phosphate, is observed at a
temperature of 120 °C (Fig. 5). It was shown in [15] that
when KMgPO4∙6H2O is heated to a temperature of
200 °C, it completely dehydrates and forms amorphous
KMgPO4, which crystallizes at higher temperatures. The
obtained results show that irradiation of PMP samples
with high-energy electrons leads not only to partial
amorphization of potassium magnesium phosphate, but
also causes crystallization of amorphous KMgPO4 at
temperatures below 100 °C.
Externally, PMP samples with wollastonite
irradiated by γ-radiation and electrons did not differ
from unirradiated samples. Any volume changes and
visible damage of the samples were not observed (see
Fig. 1,c). No changes in the microstructure of the PMP
samples (KMgPO4∙6H2O + 10 wt.%CaSiO3) before and
after the electron irradiation were detected by the SEM-
method (Fig. 6). In both photographs, the well-bound
microstructure of the samples KMgPO4∙6H2O +
+10 wt.%CaSiO3, and elongated particles of
wollastonite CaSiO3 are seen.
However, irradiation with both electrons and γ-
radiation leads to a slight change in the density and
compression strength of PMP samples with
wollastonite. Thus, a slight decrease in the density and
compressive strength of KMgPO4∙6H2O + 10 wt.%
CaSiO3 samples after γ-radiation is observed (Tabl. 1).
Table 1
Density and compressive strength of the samples
KMgPO4∙6H2O + 10 wt.% CaSiO3 before
and after electron and -irradiation
Conditions Density, g/cm
3
Compressive
strength, MPa
Before irradiation 1.67 12.7
After -irradiation 1.58 11.3
After electron
irradiation
1.62 14.4
The decrease in the density and compressive
strength after γ-irradiation can be explained on the basis
that the energy of radiation can drive away part of the
bound water from the samples and, thus, increase the
porosity and reduce the strength. In the case of electron
irradiation, a less noticeable decrease in the density of
the KMgPO4∙6H2O + 10 wt.%CaSiO3 sample is
observed. The increase in porosity of the PMP sample
surface layer occurs under the radiative action, due to
the small penetrating ability of electrons. The increase
in the compressive strength of the test samples after
irradiation with high-power electrons may be due to the
formation of hardening calcium-phosphate inclusions in
the process of irradiation.
Fig. 4. XRD patterns of KMgPO4∙6H2O + 10 wt.% CaSiO3
after electron irradiation process Fig. 5. DTA/TG analysis of PMP samples
a b
ISSN 1562-6016. ВАНТ. 2018. №5(117) 79
а b
Fig. 6. Microstructure of the samples KMgPO4∙6H2O + 10 wt.% CaSiO3:
a – before electron irradiation; b – after electron irradiation
Earlier, the authors of [16] noted the increase in
compressive strength simultaneously with a decrease in
the density of PMP samples with ash additives. Such
samples behavior was explained by the formation of
calcium-phosphate inclusions in the material, which leads
to the strengthening of the material. The rate of such
particles formation increases with increasing temperature
of PMP material synthesis. In our case, the formation of
such hardening calcium-phosphate inclusions can occur
due to local heating of the PMP samples with wollastonite
CaSiO3 during irradiation with high-energy electrons.
Obtained results shown that phase and structural changes
in potassium-magnesium-phosphate materials after -
irradiation were not detected. The density and
compressive strength values of PMP materials before and
after the -irradiation were practically not changed. This
fact indicates the resistance of the PMP matrices to the
radiation effect.
In addition, the behavior of the PMP samples obtained
under the conditions of irradiation by high-energy
electrons up to absorbed doses exceeding the doses that a
protective matrix can collect in a real situation of long-
term storage of radioactive waste was investigated.
After electron irradiation up to an absorbed dose of
10
10
rad, any destruction of the PMP samples was not
observed. The electron irradiation was not lead to
significant changes in the physic-mechanical
characteristics of the PMP materials.
LEACHING OF PMP SAMPLES WITH CESIUM
CHLORIDE ADDITIONS
Corrosion properties of PMP matrices were
determined by leaching in water samples of the
compositions (KMgPO4∙6H2O + 10…15 wt.%CsCl), in
accordance with the requirements of the PCT and ANS
16.1 tests [11, 12]. After conducting the PCT test using
ICP-AES, the content of potassium, magnesium,
phosphorus and cesium in the solution after leaching was
determined. The values were used to calculate the
leaching rates of these elements (Tabl. 2). Comparison of
the reduced rates of leaching shows that an increase in the
concentration of cesium does not lead to a significant
change in the values. Low leaching rates at a temperature
of 90 °C of the basic elements of the PMP matrix and
cesium indicate a high hydrothermal resistance of the
PMP matrices.
Table 2
Leaching rate of basic elements of PMP matrix
and cesium (PCT)
Element
Normalized Elemental Leach Rates,
g/(m
2
·day)
KMgPO4∙6H2O +
10 wt.% CsCl
KMgPO4∙6H2O +
15 wt.% CsCl
K 2.13·10
-3
2.88·10
-3
Mg 1.62·10
-6
5.20·10
-6
P 4.69·10
-4
4.25·10
-4
Cs 3.46·10
-5
3.04·10
-5
The results of the ANS 16.1 test are presented in
Tabl. 3. For cesium, despite the high content in the PMP
matrix (10 wt.% CsCl and 15 wt.% CsCl), high values of
the leaching indices L (11.5, 11.7), low values of the
effective diffusion coefficients D (8.23∙10
-14
, 1.19∙10
-13
cm
2
/s),
and the rate of leaching R (2.66∙10
-5
, 1.16∙10
-5
g/(cm
2
∙day))
with long-term (90 day) leaching at 25 °C is
characteristic. It is known that the rates of cesium
leaching from various types of glass used for radioactive
waste solidification are 10
-4
…10
-6
g/(cm
2
∙day), the rate of
cesium leaching from cemented forms is ≤ 10
-3
g/(cm
2
∙day),
and from the ceramic Synroc ~ 10
-5
g/(cm
2
∙day) [17].
Thus, according to the level of corrosion resistance with
respect to cesium leaching, potassium magnesium
phosphates are not inferior to other matrices in use at
present.
CONCLUSIONS
As a result of the acid-base reaction at room
temperature, PMP KMgPO4∙6H2O with the addition of
wollastonite CaSiO3 (10 wt.%) and cesium chloride CsCl
(10 and 15 wt.%) were obtained at room temperature.
Simulated irradiation with electrons (E – 10 MeV) and
bremsstrahlung γ-radiation of PMP samples to a set of
absorbed dose of 10
10
and 10
8
rad, respectively, was
carried out. The absence of phase and structural changes
in the material of the PMP samples after irradiation
processes was established, and also the value of the
density and compressive strength was not practically
changed. Irradiation with high-energy electrons of PMP
samples leads to partial dehydration and amorphization of
KMgPO4∙6H2O, as well as crystallization of amorphous
KMgPO4.
80 ISSN 1562-6016. ВАНТ. 2018. №5(117)
Table 3
Effective Diffusion Coefficient, Leachability Index and Stabilized Leaching Rate of Cs (ANS 16.1)
Corrosion properties of PMP matrices were
determined by leaching in water samples of the
compositions (KMgPO4∙6H2O + 10…15 wt.% CsCl), in
accordance with the requirements of the PCT and ANS
16.1 tests. Low leaching rates of the basic elements of the
PMP matrix and cesium indicate the high hydrothermal
stability of the PMP matrices (PCT). Based on the results
of the ANS 16.1 test, the values of cesium leaching rates
from PMP matrices are obtained that are at the level of
the leaching rates from glasses and ceramics of Synroc.
The results of the studies of the radiation and
corrosion resistance of the obtained PMP matrices
indicate the prospects of potassium-magnesium-phosphate
materials application for the solidification of LRW at
nuclear power plants.
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Статья поступила в редакцию 02.08.2018 г.
Parameter
Sample
KMgPO4∙6H2O +10 wt.% CsCl KMgPO4∙6H2O +15 wt.% CsCl
Effective Diffusion Coefficient D, cm
2
/s
Leachability Index L
Stabilized Leaching Rate R, g/(cm
2
·day)
8.23·10
-14
11.5
2.66·10
-5
1.19·10
-13
11.7
1.16·10
-5
ISSN 1562-6016. ВАНТ. 2018. №5(117) 81
КОРРОЗИОННАЯ И РАДИАЦИОННАЯ СТОЙКОСТЬ
КАЛИЙ-МАГНИЙ-ФОСФАТНЫХ МАТРИЦ
С.Ю. Саенко, В.A. Шкуропатенко, A.В. Зыкова, А.Е. Сурков, А.В. Пилипенко,
Е.А. Улыбкина, K.В. Лобач
Исследована коррозионная и радиационная стойкость калий-магний-фосфатных (КМФ) матриц для
отверждения жидких радиоактивных отходов АЭС. Показана высокая коррозионная стойкость КМФ-матриц к
выщелачиванию как основных компонентов матрицы, так и цезия. Результаты выполненной работы показали
устойчивость физических и механических свойств, а также фазового состава и микроструктуры КМФ после
имитации -облучением до поглощенной дозы 10
8
рад. Было установлено, что облучение
высокоэнергетическими электронами до поглощенной дозы 10
10
рад приводит к частичной дегидратации и
аморфизации КМФ.
КОРОЗІЙНА ТА РАДІАЦІЙНА СТІЙКІСТЬ
КАЛІЙ-МАГНІЙ-ФОСФАТНИХ МАТРИЦЬ
С.Ю. Саєнко, В.A. Шкуропатенко, А.В. Зикова, О.Є. Сурков, О.В. Пилипенко,
К.А. Улибкіна, K.В. Лобач
Досліджена корозійна та радіаційна стійкість калій-магній-фосфатних (КМФ) матриць для затвердіння
рідких радіоактивних відходів АЕС. Показана висока корозійна стійкість КМФ-матриць до вилуговування як
основних компонентів матриці, так і цезію. Результати виконаної роботи показали стійкість фізичних та
механічних властивостей, а також фазового складу і мікроструктури КМФ після імітації -опроміненням до
поглиненої дози 10
8
рад. Було встановлено, що опромінення високоенергетичними електронами до поглиненої
дози 10
10
рад призводить до часткової дегідратації та аморфізації КМФ.
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