Magnesium-Potassium Phosphate Matrix for Immobilization of 14C

Dmitrieva, Anastasia; Kalenova, M. Yu.; Kulikova, Svetlana A.; Kuznetsov, I. V.; Koshcheev, A. M.; Винокуров, С. Е.

doi:10.1134/s107042721804016x

Cited by 10 publications

(4 citation statements)

References 9 publications

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“…All of the indicated values are in accordance with the regulatory requirements for a cement compound (no less than 4.9 MPa) [38]. Thus, the calcium carbonate present in the MPP_dolomite_720 sample plays the role of a reinforcing agent for the matrix, which leads to an increase in compressive strength, as we noted earlier [31]. On the other hand, the absence of this phase and the presence of the calcium hydroxide phase lead to a significant decrease in the strength of MPP_dolomite_750 samples.…”

Section: Study Of the Mpp Matrix Samplessupporting

confidence: 78%

“…At the same time, we have previously shown the possibility of including up to 50 wt% CaCO 3 into the MPP matrix in order to use it for conditioning RW containing 14 C and established its high-quality parameters (compressive strength, hydrolytic stability, etc.) and minimal carryover of CO 2 into the atmosphere during synthesis and exposure of compounds [31]. Thus, dolomite powder, calcined in accordance with the reaction (2) and thus containing MgO and CaCO 3 , is considered a promising raw material that serves as a source of magnesium.…”

Section: Introductionmentioning

confidence: 99%

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The Use of Dolomite to Produce a Magnesium Potassium Phosphate Matrix for Radioactive Waste Conditioning

et al. 2023

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Magnesium potassium phosphate (MPP) matrix MgKPO4 × 6H2O is a known material for radioactive waste (RW) conditioning; magnesium oxide MgO is used in the classical method of matrix synthesis. The aim of the work was to investigate the possibility of using the widely available natural mineral raw material dolomite, incorporating mixed magnesium and calcium carbonate, for the production of this matrix. To control the quality of the samples obtained, their phase and elemental compositions, microstructure, density, volumetric and apparent porosity, compressive strength, and hydrolytic stability were studied. As a result, it was found that using dolomite powder pre-calcined at 720 °C for 1.5 h, samples of matrix whose properties meet the regulatory requirements for solidified RW were obtained. Thus, a new, cost-effective method of synthesis of the MPP matrix has been demonstrated to solve the RW solidification problem.

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Section: Study Of the Mpp Matrix Samplessupporting

confidence: 78%

Section: Introductionmentioning

confidence: 99%

The Use of Dolomite to Produce a Magnesium Potassium Phosphate Matrix for Radioactive Waste Conditioning

et al. 2023

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“…From the data obtained, we calculated the effective diffusivity D (cm 2 /s), leachability index L for each leach interval, and average leachability index (L) av of 137 Cs in the MPP compounds in accordance with standard test ANSI/ANS-16.1 [42] by the Equations (7)- (9).…”

Section: Synthesis and Study Of The Mpp Compoundsmentioning

confidence: 99%

“…Previously, in a number of literary sources [2][3][4][5][6][7][8][9][10][11][12][13], it was shown that the compound based on the magnesium potassium phosphate (MPP) matrix MgKPO 4 × 6H 2 O, which is formed at room temperature and is an analogue of the natural mineral K-struvite [14], is a promising material for immobilization of various LRW types, including HLW. A key task during HLW immobilization is to ensure binding of mobile cesium isotopes in the MPP compound.…”

Section: Introductionmentioning

confidence: 99%

Optimization of the Solidification Method of High-Level Waste for Increasing the Thermal Stability of the Magnesium Potassium Phosphate Compound

et al. 2020

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The key task in the solidification of high-level waste (HLW) into a magnesium potassium phosphate (MPP) compound is the immobilization of mobile cesium isotopes, the activity of which provides the main contribution to the total HLW activity. In addition, the obtained compound containing heat-generating radionuclides can be significantly heated, which increases the necessity of its thermal stability. The current work is aimed at assessing the impact of various methodological approaches to HLW solidification on the thermal stability of the MPP compound, which is evaluated by the mechanical strength of the compound and its resistance to cesium leaching. High-salt surrogate HLW solution (S-HLW) used in the investigation was prepared for solidification by adding sorbents of various types binding at least 93% of 137Cs: ferrocyanide K-Ni (FKN), natural zeolite (NZ), synthetic zeolite Na-mordenite (MOR), and silicotungstic acid (STA). Prepared S-HLW was solidified into the MPP compound. Wollastonite (W) and NZ as fillers were added to the compound composition in the case of using FKN and STA, respectively. It was found that heat treatment up to 450 °C of the compound containing FKN and W (MPP-FKN-W) almost did not affect its compressive strength (about 12–19 МPa), and it led to a decrease of high compressive strength (40–50 MPa) of the compounds containing NZ, MOR, and STA (MPP-NZ, MPP-MOR, and MPP-STA-NZ, respectively) by an average of 2–3 times. It was shown that the differential leaching rate of 137Cs on the 28th day from MPP-FKN-W after heating to 250 °C was 5.3 × 10−6 g/(cm2∙day), however, at a higher temperature, it increased by 20 and more times. The differential leaching rate of 137Cs from MPP-NZ, MPP-MOR, and MPP-STA-NZ had values of (2.9–11) × 10−5 g/(cm2∙day), while the dependence on the heat treatment temperature of the compound was negligible.

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New Methods and Materials in Nuclear Fuel Fabrication and Spent Nuclear Fuel and Radioactive Waste Management

Винокуров

Kulikova²,

Frolova³

et al. 2023

Advances in Geochemistry, Analytical Chemistry, and Planetary Sciences

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Magnesium-Potassium Phosphate Matrix for Immobilization of 14C

Cited by 10 publications

References 9 publications

The Use of Dolomite to Produce a Magnesium Potassium Phosphate Matrix for Radioactive Waste Conditioning

The Use of Dolomite to Produce a Magnesium Potassium Phosphate Matrix for Radioactive Waste Conditioning

Optimization of the Solidification Method of High-Level Waste for Increasing the Thermal Stability of the Magnesium Potassium Phosphate Compound

New Methods and Materials in Nuclear Fuel Fabrication and Spent Nuclear Fuel and Radioactive Waste Management

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