Hydrolytic and thermal stability of magnesium potassium phosphate compound for immobilization of high level waste

Винокуров, С. Е.; Kulikova, Svetlana A.; Myasoedov, Β. F.

doi:10.1007/s10967-018-6181-x

Cited by 11 publications

(4 citation statements)

References 6 publications

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“…The influence of different HLW types on the properties of the MKP compound was studied, including 99 Tc waste solutions [5], Pu contaminated ash [6], surrogate denitrated HLW from the PUREX process [7], and HLW bottom sediment surrogates [8]. In our early works, we confirmed the premise of using the MKP compound for HLW solidification of various composition and origin, including historical waste from the implementation of military programs of the Soviet Union and the United States [9,10], as well as waste obtained after the reprocessing of SNF of a 1000 MW water–water energetic reactor (WWER-1000) [11,12,13].…”

Section: Introductionsupporting

confidence: 63%

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The Influence of Zeolite (Sokyrnytsya Deposit) on the Physical and Chemical Resistance of a Magnesium Potassium Phosphate Compound for the Immobilization of High-Level Waste

Kulikova

Винокуров

2019

Molecules

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The manuscript presents the results of the development of new material for high-level waste (HLW) management: the magnesium potassium phosphate (MKP) compound. The possibility of using zeolite (Sokyrnytsya deposit) to increase the mechanical, thermal, and hydrolytic resistance of this compound with immobilized HLW was studied. The main component of the used natural zeolite is a mineral of the clinoptilolite–heulandite series, and quartz, microcline, and clay minerals (illite, sepiolite, and smectite) are present as impurities. The compressive strength of the compound, containing at least 4.2 wt % zeolite, is about 25 MPa. Compound containing 28.6 wt % zeolite retains high compressive strength (at least 9.0 MPa), even after heat treatment at 450 °C. The adding of zeolite to the composition of the compound increases its hydrolytic stability, while the leaching rate of the mobile nuclides 137Cs and 90Sr decreases up to one order of values. Differential leaching rate of radionuclides from the compound containing 28.6 wt % zeolite is 2.6 × 10−7 for 137Cs, 2.9 × 10−6 for 90Sr, 1.7 × 10−9 for 239Pu, and 2.9 × 10−9 g/(cm2∙day) for 241Am. Thus, the properties of the resulting compound correspond to the requirements for solidified HLW in Russia.

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Section: Introductionsupporting

confidence: 63%

“…It was previously noted that increasing the temperature of the MKP compound may lead to a decrease of its stability [12,13]. Zeolite is a promising mineral modifier of the MKP compound.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Zeolite (Sokyrnytsya Deposit) on the Physical and Chemical Resistance of a Magnesium Potassium Phosphate Compound for the Immobilization of High-Level Waste

Kulikova

Винокуров

2019

Molecules

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“…The samples were prepared at the MgO:H 2 O (in prepared S-HLW):KH 2 PO 4 weight ratio of 1:2:3. A feature in the synthesis of the MPP compound with FKN was the use of wollastonite (W) (FW-200, Nordkalk, Pargas, Finland) in an amount of 23.3 wt % as a reinforcing additive to increase the mechanical strength of the compound (hereinafter, the sample was designated as MPP-FKN-W compound), as we showed earlier in [7,8,38].…”

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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Hydrolytic and thermal stability of magnesium potassium phosphate compound for immobilization of high level waste

Cited by 11 publications

References 6 publications

The Influence of Zeolite (Sokyrnytsya Deposit) on the Physical and Chemical Resistance of a Magnesium Potassium Phosphate Compound for the Immobilization of High-Level Waste

The Influence of Zeolite (Sokyrnytsya Deposit) on the Physical and Chemical Resistance of a Magnesium Potassium Phosphate Compound for the Immobilization of High-Level Waste

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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