Plutonium reactive transport in fractured granite: Multi-species experiments and simulations

Zhang, Xiaoying; Wang, Zheng; Reimus, Paul W.; Ma, Funing; Soltanian, Mohamad Reza; Xing, Baoshan; Zang, Jianzheng; Wang, Yu; Dai, Zhenxue

doi:10.1016/j.watres.2022.119068

Cited by 57 publications

(14 citation statements)

References 34 publications

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“…Some amount of 238 Pu in a small crack can be also explained by contamination during the sawing, since no Pu penetration along grain boundaries was noted. This observation is in a good agreement with previously published data [32], showing that Pu transport in low-porosity granitic rocks from the Beishan site is mostly determined by migration along the fractures (especially in form of colloids [33]) but not by diffusion in granite matrix.…”

Section: Bentonite and Granite Alterationsupporting

confidence: 93%

Long-Term Chemical Alteration of 238Pu-Doped Borosilicate Glass in a Simulated Geological Environment with Bentonite Buffer

et al. 2023

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Chemical degradation of borosilicate glass doped with 238Pu was modelled in conditions of a failed underground radwaste repository in granite host rock with bentonite buffer material after penetration of aqueous solutions at temperature of 90 °C. The total duration of the experiment exceeded two years. It is shown that wet bentonite preserved its barrier function and prevents migration of plutonium to the solution. The total amount of plutonium adsorbed on bentonite clay during the experiment did not exceed 0.02% of the initial amount of plutonium in the glass sample. Estimated accumulated dose of self-irradiation of the glass sample after the experiment varies from 3.16 × 1015 to 3.39 × 1015 α-decays per gram, which is equivalent to more than 1000 years storage of 239Pu doped sample with the same Pu content. Beishan granite remained intact, with no evidence of Pu penetration into the granite matrix along mineral grain boundaries.

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Section: Bentonite and Granite Alterationsupporting

confidence: 93%

Long-Term Chemical Alteration of 238Pu-Doped Borosilicate Glass in a Simulated Geological Environment with Bentonite Buffer

et al. 2023

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“…Plutonium has rich and unusual aqueous chemistry with oxidation states ranging from +3 to +7, and coordination numbers spanning from 6 to 12 . Its ability to equilibrate four oxidation states simultaneously (+3 to +6) in aqueous media is unparalleled, and this cycling of oxidation states at contaminated nuclear sites affects plutonium transport in the environment. , These basic aspects of plutonium chemistry also impact a broad range of applications that include civilian nuclear energy, space exploration, disposal of radioactive waste, and environmental remediation. − Despite the worldwide importance of this element, the ability to control oxidation states, coordination numbers, specific coordination geometries, and reactivity lags behind that of thorium and uranium because of the need for specialized research facilities for the safe handling of this element, the lack of isotope availability, and the inherent instability of plutonium coordination complexes owing to rapid radiolytic degradation. , Lastly, Pu III compounds and complexes can be air-sensitive and this can make chemical manipulations more challenging …”

Section: Introductionmentioning

confidence: 99%

Transformation of Mononuclear Plutonium(III) Tetrazolate Complexes into Dinuclear Complexes in the Solid State

Bai,

Scheibe,

Sperling

et al. 2024

Inorg. Chem.

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The salt metathesis reaction of Na(pmtz)•H 2 O [pmtz − = 5-(pyrimidyl)tetrazolate] and PuBr 3 •nH 2 O in an aqueous media leads to the formation of the mononuclear compound [Pu(pmtz) 3 (H 2 O) 3 ]•(3 + n) H 2 O (Pu1, n = ∼8) that is isotypic with the lanthanide compounds [Ln(pmtz) 3 (H 2 O) 3 ]•(3 + n) H 2 O (Ln = Ce−Nd). Dissolution and recrystallization of Pu1 in water yields the dinuclear compound {[Pu(pmtz) 2 (H 2 O) 3 ] 2 (μ-pmtz)} 2 (pmtz) 2 •14H 2 O (Pu2), which is isotypic with the lanthanide compounds {[Ln(pmtz) 2 (H 2 O) 3 ] 2 (μ-pmtz)} 2 (pmtz) 2 •14H 2 O (Ln = Nd and Sm). Like their nine-coordinate ionic radii, the M−O and M−N bond lengths in Pu1/Pu2 and Nd1/Nd2, respectively, are within error of one another. The Laporte-forbidden 4f → 4f and 5f → 5f transitions are also assigned in the UV−vis−NIR spectra for these f-element tetrazolate coordination compounds.

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“…Rock bursting occurs in deep mines and in quartz-rich rocks [43,44]. Stress release, cracks and fractures, faults and earthquakes are also involved in the escalation of this phenomenon [45][46][47]. Because the depth of these mines is less than 45 meters, and the overburden stress is negligible.…”

Section: Geo-mechanical Properties Of Samplesmentioning

confidence: 99%

Prediction of Rock Tensile Strength Using Soft Computing and Statistical Methods

Zheng

Shen

Motahari

et al. 2023

Period. Polytech. Civil Eng.

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The tensile strength of the rocks is one of the effective factors in the rupture of structure foundations and underground spaces, the stability of rocky slopes, and the ability to drill and explode in rocks. This research was conducted to estimate tensile strength using methods such as simple regression (SR), multivariate linear regression (MVLR), support vector regression (SVR) with radial basis kernel function, multilayer feed-forward artificial neural network (MFF-ANN), Gaussian process regression (GPR) using squared exponential kernel (SEK) function, and adaptive neuro-fuzzy inference system (ANFIS) based on Gaussian membership function. For this purpose, petrography, and engineering features of the limestone, sandstone, and argillaceous limestone samples in the south of Iran, were assessed. The results obtained from this study were compared with those of previous research, revealing a strong correlation (R2=0.95 to 1.00) between our findings and the published works. To estimate Brazilian tensile strength (BTS), the index properties including water absorption by weight, point load index (PLI), porosity%, P-wave velocity (Vp), and density were considered as inputs. Methods were compared using various criteria. The SVR precision (R=0.96) was higher than MFF-ANN (R=0.92), ANFIS (R=0.95), GPR (R=0.945), and MVLR (R=0.89) to estimate the tensile strength. The average BTS measured in the laboratory and predicted by all 5 methods is 6.62 and 6.71 MPa, respectively, which shows the very high precision of the investigated methods. Analysis of model criteria using statistical analysis for developed relationships revealed that there is sufficient accuracy to use the empirical equations.

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Plutonium reactive transport in fractured granite: Multi-species experiments and simulations

Cited by 57 publications

References 34 publications

Long-Term Chemical Alteration of 238Pu-Doped Borosilicate Glass in a Simulated Geological Environment with Bentonite Buffer

Long-Term Chemical Alteration of 238Pu-Doped Borosilicate Glass in a Simulated Geological Environment with Bentonite Buffer

Transformation of Mononuclear Plutonium(III) Tetrazolate Complexes into Dinuclear Complexes in the Solid State

Prediction of Rock Tensile Strength Using Soft Computing and Statistical Methods

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