Two-phase modelling for fission gas sweeping in restructuring nuclear oxide fuel

In this work, we propose a modelling approach for the intra-granular fission gas behaviour in UO2 under restructuring process. Leveraging the definition of restructured volume fraction, we consider the fuel matrix transition from the non-restructured to the restructured phase, together with the evolution of the corresponding fission gas concentrations retained in the fuel matrix. Firstly, we derive a sweeping term that exchanges fission gas atoms from the non-restructured to the restructured fuel region. The sweeping term is then included in the conventional intra-granular fission gas diffusion problem. Secondly, the spectral diffusion algorithm is employed to solve two spatially-dimensionless problems, properly representing the non-restructured region with micrometric grains and the restructured region with sub-micrometric grains. The model developed is implemented in SCIANTIX, a 0D meso-scale code for physics-based modelling of fission gas behaviour in nuclear oxide fuel and compared with experimental data and semi-empirical models.LR

A reduced order model for fission gas diffusion in columnar grains

In fast reactors, restructuring of the fuel micro-structure driven by high temperature and high temperature gradient can cause the formation of columnar grains. The non-spheroidal shape and the non-uniform temperature field in such columnar grains implies that standard models for fission gas diffusion can not be applied. To tackle this issue, we present a reduced order model for the fission gas diffusion process which is applicable in different geometries and with non-uniform temperature fields, maintaining a computational requirement in line with its application in fuel performance codes. This innovative application of reduced order models as meso-scale tools within fuel performance codes represents a first-of-a-kind achievement that can be extended beyond fission gas behaviour.</p

A reduced order model for fission gas diffusion in columnar grains

In fast reactors, restructuring of the fuel micro-structure driven by high temperature and high temperature gradient can cause the formation of columnar grains. The non-spheroidal shape and the non-uniform temperature field in such columnar grains implies that standard models for fission gas diffusion can not be applied. To tackle this issue, we present a reduced order model for the fission gas diffusion process which is applicable in different geometries and with non-uniform temperature fields, maintaining a computational requirement in line with its application in fuel performance codes. This innovative application of reduced order models as meso-scale tools within fuel performance codes represents a first-of-a-kind achievement that can be extended beyond fission gas behaviour.</p

Estabilidad oxidativa del aceite de soja conteniendo aceite de rosa e irradiado con UV y rayos X

The effects of UV radiation and X-ray on the oxidative stability of soybean oil were investigated. Also, rose oil was incorporated into soybean oil and its antioxidant activity was compared with that of α-tocopherol during accelerated storage. Treating the samples with radiation (UV and X-ray) stimulated the oxidation process in soybean oil in comparison with samples that did not receive radiation. X-rayed samples had significantly higher amounts of oxidation products than UV irradiated samples. The X-ray caused more oxidation in the samples due to its higher energy content. Also, the antioxidant activity of rose oil was comparable with that of α-tocopherol.Se investigaron los efectos de la radiación UV y los rayos X sobre la estabilidad oxidativa del aceite de soja. Además, el aceite de rosa se incorporó al aceite de soja y su actividad antioxidante se comparó con la del α-tocoferol durante el almacenamiento acelerado. El tratamiento de las muestras con radiación (UV y rayos X) fomentó el proceso de oxidación del aceite de soja en comparación con las muestras que no recibieron radiación. Las muestras con rayos X tenían cantidades significativamente más altas de productos de oxidación que las muestras irradiadas con UV. Los rayos X causaron más oxidación en las muestras debido a su mayor contenido de energía. Además, la actividad antioxidante del aceite de rosa fue comparable con la del α-tocoferol

Acid-modified Biochar Effect on Some Physiological Indicators and Micronutrient Availability of Quinoa (cv. Gizavan) in a Calcareous Soil

Introduction Organic matter and alkaline pH are the main causes of nutrient deficiencies in calcareous soils of arid and semi-arid regions. The availability of some nutritional elements, including the micronutrients such as iron, zinc, copper, and manganese is very low in calcareous soils, although the total concentration of these elements may be relatively high.  Burning crop residues results in substantial loss of nutrients, and may lead to air pollution and human health problems. An alternative approach is to apply crop residues to soil in the form of biochar. The biochar modification with acid may increase the solubility of nutrients (P, Fe, Zn, Cu, Mn) present in biochar, thereby significant improvement in mineral nutrition of plants grown in calcareous soils. Therefore, the object of this study is to investigate the effect of acid-modified biochar from rice residues on the amount of chlorophyll and the micronutrient concentration of quinoa plant (Chenopodium quinoa) in a calcareous soil.   Methods and Materials The soil was air-dried and ground to pass through a 2-mm sieve then was analyzed to determine various soil physico-chemical properties using standard methods. To achieve the aim of this study the factorial experiment was carried out based on a completely randomized design in 4 replications. Factors include 3 types of biochar (unmodified, modified by pre-acidic method and modified by post-acidic method) and different levels of biochar (0, 2, and 5% by weight). Then 10 quinoa seeds were planted in each pot at 2-cm depth which after emergence, declined to 3 plants in each pot. The pots were randomly moved twice a week during the growth period to eliminate environmental effects. Irrigation and weeding operations were performed by hand. Determination of chlorophyll content (a, b, and ab) and carotenoids were measured precisely before harvesting in fresh plants using Arnon method.  Plants were harvested at 187 days after planting, washed with distilled water and dry with tissue paper. The samples were air-dried and then oven dried at 65˚C to a constant weight in a forced air-driven oven. Then the total micronutrient content of the plant was determined after dry ashing. The statistical results of the data were analyzed using SAS software (9.4) and LSD test (at 5% level) was used for comparing the mean values.   Results and Discussion Based on the variance analysis, all attributes responded positively to different types and levels of biochar and modified biochar (p<0.01). The comparison of the average effect of the studied treatments showed that with the increase in the levels of all three types of biochar, the amount of chlorophyll a, b, total, and carotenoid increased so the highest amount of chlorophyll a, b, total, and carotenoid respectively, with an average of 2.58 and 1.54, 4.13 and 1.36 mg g-1 were obtained from the treatment of 5% post-acidic biochar. The results showed that the highest amount of Fe concentration in shoots with an average of 229.48 mg kg-1 was obtained from the treatment of 5% post-acidic biochar, although there was no statistically significant difference with the treatment of 5% pre-acidic biochar with an average of 220.48 mg kg-1 and its lowest value with an average of 95.95 mg kg-1 was related to unmodified biochar. The highest amount of Zn concentration in shoots with an average of 13.42 mg kg-1 was related to the treatment of 5% post-acidic biochar which showed an increase of 13.24 and 33.26% compared to the treatment of 5% pre-acidic and unmodified biochar, respectively. Also, the highest concentrations of Cu and Mn in shoots were obtained with an average of 3.85 and 23.37 mg kg-1 respectively, from the treatment of 5% post-acidic biochar.   Conclusion Post-acidic biochar had better results in terms of physiological indices and the concentration of micronutrients (Fe, Zn, Cu, and Mn) than unmodified biochar in quinoa. The increase of nutrients in quinoa can be attributed to the dissolution of biochar nutrients after being modified with acid and the reduction of pH and the availability of these elements in the soil. Therefore, biochar modified with acid or biochar produced from sources that have acidic properties can be recommended as a suitable method for improving fertility and increasing micronutrients in calcareous soils affected by salt

Psychometrics properties of the Iranian version of fertility quality of life tool: a cross- sectional study

Background: Clinical measurement of quality of life for assessing reproductive problems should be considered as a standard investigation at the initial and continuing medical consultations with infertile people. Objective: The purpose of this study was comprehensive testing the psychometric properties of the Iranian version of fertility quality of life (FertiQol) as its use could be considerable due to the prevalence of infertility in Iran and the importance of evaluation of QoL in patients with infertility. Method and material: This was a psychometric properties study of 300 women referred to infertility clinic, Hormozgan, Iran. After linguistic validation of the Iranian version of MPCOSQ, a semi-structured interview was conducted to assess face validity. Consequently exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were performed to indicate the scale constructs. Discriminant validity was assessed using the known groups comparison. Convergent validity was evaluated by assessing the correlation between similar content on the 12-Item Short Form Health Survey, Hospital Anxiety and Depression Scale and FertiQol. In addition, reliability analysis was carried out with internal consistency. Results: The reliability of the Iranian version of the FertiQol questionnaire was satisfactory in all dimensions (Cronbach’s alpha ranging from 0.77 to 0.83 ). Six factors (emotional, mind/body, relational, social, environmental and tolerability) were extracted from the results of EFA with factor loading of the more than 0.3. Discrimination validity showed that FertiQol can differentiate between female patients with differing duration of infertility and number of children; this indicates favorable discrimination validity. Moreover, the results of convergent validity showed a favorable correlation between the related dimensions of 12-Item Short Form Health Survey (correlation ranging from 0.43 to 0.68 ), Hospital Anxiety and Depression Scale(correlation ranging from 0.47 to 0.52 ) and FertiQol. Conclusion: The Iranian version of FertiQol is valid and reliable for assessing infertility problems and the effects of treatment on quality of life of infertile patients referred for diagnosis and treatment at an Iranian infertility clinic. The clinical use of this measure is recommended for Iranian infertility clinics

Cooperativity‐Driven Reactivity of a Dinuclear Copper Dimethylglyoxime Complex

In this report, we present the dinuclear copper(II) dimethylglyoxime (H$_2$dmg) complex [Cu$_2$(H$_2$dmg)(Hdmg)(dmg)]$^+$ (1), which, in contrast to its mononuclear analogue [Cu(Hdmg)$_2$] (2), is subject to a cooperativity-driven hydrolysis. The combined Lewis acidity of both copper centers increases the electrophilicity of the carbon atom in the bridging μ$_2$-O−N=C-group of H$_2$dmg and thus, facilitates the nucleophilic attack of H2O. This hydrolysis yields butane-2,3-dione monoxime (3) and NH$_2$OH that, depending on the solvent, is then either oxidized or reduced. In ethanol, NH$_2$OH is reduced to NH$_4$$^+$, yielding acetaldehyde as the oxidation product. In contrast, in CH$_3$CN, NH$_2$OH is oxidized by Cu$^{II}$ to form N$_2$O and [Cu(CH$_3$CN)4]$^+$. Herein are presented the combined synthetic, theoretical, spectroscopic and spectrometric methods that indicate and establish the reaction pathway of this solvent-dependent reaction

Helium solubility in oxide nuclear fuel: Derivation of new correlations for Henry’s constant

Helium plays an important role in determining nuclear fuel performance both in-pile (especially for MOX fuels and those at high burnup) and in storage conditions. Predictive models of helium behaviour are therefore a fundamental element in fuel performance codes. These models are based on the accurate knowledge of helium diffusivity (addressed in a previous paper, Luzzi et al. (2018)) and of helium solubility in oxide nuclear fuel. Based on all the experimental data available in the literature and after verification of the validity of Henry’s law we propose two correlations for Henry’s constant, kH (at m-3 MPa-1 ): kH = 1. 8·10^25·exp(-0.41/kT) for powders and kH = 4.1·10^24·exp(-0.65/kT) for single crystals, with the Boltzmann factor 1/kT in (eV-1). The correlation for Henry’s constant in powder samples is of interest for the analysis of helium behaviour in the fuel after the pulverization occurring during LOCA-like temperature transients, while the correlation for Henry’s constant in single-crystals is usable in meso-scale models describing helium behaviour at the level of fuel grains. The current lack of data for this fundamental property, especially for poly-crystalline samples, calls for new experiments

Numerical and mathematical approaches for computation time reduction

This work, coordinated by UNIPI, was done with a direct contribution of all the Task 6.1 partners. This document provides first a review and a detailed analysis of existing models for Pellet-Cladding Mechanical Interaction (PCMI), the Fission Gas Behaviour (FGB) and Fuel Overfragmentation (FO) phenomena in industrial type fuel performance codes, such as TRANSURANUS, FINIX and CYRANO3, for which an improvement is expected by the substitution of an empirical formulation by machine-learning, surrogate modelling, or data-driven approaches. In a second part of the document a review is proposed for an identification and a presentation of the most powerful computation time reduction methods. The latter are decomposed in two categories with Machine Learning Methods (MLM) and surrogate models. In the last part of document some existing preliminary application of computation time reduction method for PCMI and FGB are discussed with more details. At the end of this review, we can conclude that the integration of MLM and surrogate models will bring significant progress in reducing computation time for the complex simulations needed for the fuel performance studies expected in the WP7 of the OperaHPC project. The implementation of the computation time reduction methods, specified in this document for PCMI, FGB and FO, can now start in the framework of the Tasks 6.2 and 6.3 of the WP6

Assessment of INSPYRE-extended fuel performance codes against the SUPERFACT-1 fast reactor irradiation experiment

Design and safety assessment of fuel pins for application in innovative Generation IV fast reactors calls for a dedicated nuclear fuel modelling and for the extension of the fuel performance code capabilities to the envisaged materials and irradiation conditions. In the INSPYRE Project, comprehensive and physics- based models for the thermal-mechanical properties of UePu mixed-oxide (MOX) fuels and for fission gas behaviour were developed and implemented in the European fuel performance codes GERMINAL, MACROS and TRANSURANUS. As a follow-up to the assessment of the reference code versions (“pre- INSPYRE”, NET 53 (2021) 3367e3378), this work presents the integral validation and benchmark of the code versions extended in INSPYRE (“post-INSPYRE”) against two pins from the SUPERFACT-1 fast reactor irradiation experiment. The post-INSPYRE simulation results are compared to the available integral and local data from post-irradiation examinations, and benchmarked on the evolution during irradiation of quantities of engineering interest (e.g., fuel central temperature, fission gas release). The comparison with the pre-INSPYRE results is reported to evaluate the impact of the novel models on the predicted pin performance. The outcome represents a step forward towards the description of fuel behaviour in fast reactor irradiation conditions, and allows the identification of the main remaining gaps