Estimation of centerline temperature of the waste form for the rare earth waste generated from pyrochemical process

Choi, Jonghyun; Eun, Hee-Chul; Lee, Tae-Kyo; Lee, Ki-Rak; Han, Sang Do; Jeon, Min-Ku; Park, Hwan-Seo; Ahn, Do-Hee

doi:10.1016/j.jnucmat.2016.11.004

Cited by 11 publications

(7 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The choice of composition in the SiO [30,42]. This increases the T g value to 770-797 • C, which is significantly higher than the values for typical B-Si glass compositions for nuclear waste [35].…”

Section: General Patterns Of Crystallization Of Vitreous Matrices Con...mentioning

confidence: 94%

“…High short-lived radionuclide contents will cause heating of the matrix, which can change its properties. A few works [28][29][30][31] show that the temperatures of HLW matrices can reach several hundred degrees Celsius and persist for tens and hundreds of years. Due to the tendency of glass to crystallize at high temperatures, heating will have the greatest effect on vitreous matrices.…”

Section: Effect Of Radiogenic Heat On the Vitreous Matrix Of The Ree-...mentioning

confidence: 99%

“…After 5-10 years of SNF storage, heat release due to the decay of short-lived REE radionuclides drops tens and hundreds of times (Table 8), so their contribution to matrix heating in 10 years will decrease to several tens of degrees. The temperatures of a glass containing 50 wt.% REE from the pyrochemical processing of SNF were estimated [30]. Calculations were performed for a cylindrical block of glass with a diameter of 0.3-1.0 m; a residual amount of 0 to 20 rel.% of trans-uranium elements (TUEs) was allowed due to their incomplete extraction.…”

Section: Temperature Of the Ree-ma Fraction Matrix With Decaying Reementioning

confidence: 99%

“…To obtain large phase grains, heating is first carried out at 20-50 °C above Tg (Figure 4) to form crystallization centers (nucleation stage), and then the temperature is raised by 100-200 °C (growth stage of crystalline phases). The temperatures of a glass containing 50 wt.% REE from the pyrochemical processing of SNF were estimated [30]. Calculations were performed for a cylindrical block of glass with a diameter of 0.3-1.0 m; a residual amount of 0 to 20 rel.% of trans-uranium elements (TUEs) was allowed due to their incomplete extraction.…”

Section: General Patterns Of Crystallization Of Vitreous Matrices Con...mentioning

confidence: 99%

See 3 more Smart Citations

Thermal Effects and Glass Crystallization in Composite Matrices for Immobilization of the Rare-Earth Element–Minor Actinide Fraction of High-Level Radioactive Waste

Yudintsev,

Ojovan,

Malkovsky

2024

J. Compos. Sci.

View full text Add to dashboard Cite

The current policy of managing high-level waste (HLW) derived in the closed nuclear fuel cycle consists in their vitrification into B-Si or Al-P vitreous forms. These compounds have rather limited capacity with respect to the HLW (5–20 wt%), and their properties change over time due to devitrification of the glasses. Cardinal improvement in the management of HLW can be achieved by their separation onto groups of elements with similar properties, followed by their immobilization in robust waste forms (matrices) and emplacement in deep disposal facilities. One of the possible fractions contains trivalent rare-earth elements (REEs) and minor actinides (MAs = Am and Cm). REEs are the fission products of actinides, which are mainly represented by stable isotopes of elements from La to Gd as well as Y. This group also contains small amounts of short-lived radionuclides with half-lives (T1/2) from 284 days (144Ce) to 90 years (151Sm), including 147Pm (T1/2 = 2.6 years), 154Eu (T1/2 = 8.8 years), and 155Eu (T1/2 = 5 years). However, the main long-term environmental hazard of the REE–MA fraction is associated with Am and Cm, with half-lives from 18 years (244Cm) to 8500 years (245Cm), and their daughter products: 237Np (T1/2 = 2.14 × 106 years), 239Pu (T1/2 = 2.41 × 104 years), 240Pu (T1/2 = 6537 years), and 242Pu (T1/2 = 3.76 × 105 years), which should be immobilized into a durable waste form that prevents their release into the environment. Due to the heat generated by decaying radionuclides, the temperature of matrices with an REE–MA fraction will be increased by hundreds of centigrade above ambient. This process can be utilized by selecting a vitreous waste form that will crystallize to form durable crystalline phases with long-lived radionuclides. We estimated the thermal effects in a potential REE–MA glass composite material based on the size of the block, the content of waste, the time of storage before immobilization and after disposal, and showed that it is possible to select the waste loading, size of blocks, and storage time so that the temperature of the matrix during the first decades will reach 500–700 °C, which corresponds to the optimal range of glass crystallization. As a result, a glass–ceramic composite will be produced that contains monazite ((REE,MA)PO4) in phosphate glasses; britholite (Cax(REE,MA)10-x(SiO4)6O2) or zirconolite ((Ca,REE,MA)(Zr,REE,MA)(Ti,Al,Fe)2O7), in silicate systems. This possibility is confirmed by experimental data on the crystallization of glasses with REEs and actinides (Pu, Am). The prospect for the disposal of glasses with the REE–MA fraction in deep boreholes is briefly considered.

show abstract

Section: General Patterns Of Crystallization Of Vitreous Matrices Con...mentioning

confidence: 94%

Section: Effect Of Radiogenic Heat On the Vitreous Matrix Of The Ree-...mentioning

confidence: 99%

Section: Temperature Of the Ree-ma Fraction Matrix With Decaying Reementioning

confidence: 99%

Section: General Patterns Of Crystallization Of Vitreous Matrices Con...mentioning

confidence: 99%

See 2 more Smart Citations

Thermal Effects and Glass Crystallization in Composite Matrices for Immobilization of the Rare-Earth Element–Minor Actinide Fraction of High-Level Radioactive Waste

Yudintsev,

Ojovan,

Malkovsky

2024

J. Compos. Sci.

View full text Add to dashboard Cite

show abstract

“…e Sr waste form is expected to exhibit a high heat generation rate; therefore, the centerline temperature of the waste form can be increased based on the waste loading, which may adversely affect the thermal durability. Consequently, the aforementioned results can be applied to estimate the centerline temperature in conjunction with the experimentally obtained thermal conductivity data of the waste form [16]. If the estimated thermal integrity is not to be within the range of the durability limit, the waste loading must be limited.…”

Section: Characterization Of Srmentioning

confidence: 99%

Characterization of Waste Generated from Nuclide Management Process in Waste Burden Minimization Technology for Spent Nuclear Fuel

Choi

Lee

et al. 2022

Science and Technology of Nuclear Installations

Self Cite

View full text Add to dashboard Cite

To reduce the environmental burden caused by the disposal of spent nuclear fuel, waste burden minimization technology is currently being developed at the Korea Atomic Energy Research Institute. The technology includes a nuclide management process that can maximize disposal efficiency by selectively separating and collecting major nuclides in spent nuclear fuel. To manufacture a waste form of high durability, the characteristics of the waste generated during the process should be evaluated. In this study, the physical, radiological, and thermal characteristics of the waste and waste forms for major nuclides (Cs, Sr, I, transuranic/rare earth, and Tc/Se) generated in the nuclide management process were analyzed. In the case of Cs nuclides, characterization was conducted according to the capture rate of the adsorbent in the high-temperature heat treatment process; meanwhile, in the case of Sr nuclides, characterization was performed by considering the ratio of similar nuclides in the chlorination process. For I nuclide, analysis was performed based on the available waste form, and for TRU/RE and Tc/Se nuclides, analysis was performed by considering chlorination and mid-temperature heat treatment. The radioactivity and heat generation rate of each waste and waste form were evaluated over a period of 1,000 years. The results of this study could be used to derive the centerline temperature for the thermal stability evaluation of waste forms and for the feasibility evaluation of each disposal system considered in the waste burden minimization technology.

show abstract

Leaching of Degraded Preservative Matrices, Based on Sodium Aluminophosphate Glasses, for High-Level Wastes

et al. 2018

View full text Add to dashboard Cite

Estimation of centerline temperature of the waste form for the rare earth waste generated from pyrochemical process

Cited by 11 publications

References 14 publications

Thermal Effects and Glass Crystallization in Composite Matrices for Immobilization of the Rare-Earth Element–Minor Actinide Fraction of High-Level Radioactive Waste

Thermal Effects and Glass Crystallization in Composite Matrices for Immobilization of the Rare-Earth Element–Minor Actinide Fraction of High-Level Radioactive Waste

Characterization of Waste Generated from Nuclide Management Process in Waste Burden Minimization Technology for Spent Nuclear Fuel

Leaching of Degraded Preservative Matrices, Based on Sodium Aluminophosphate Glasses, for High-Level Wastes

Contact Info

Product

Resources

About