Boric Acid Solution
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Author(s):  
Md Rezouanul Kabir ◽  
Morozov A.V. ◽  
Md Saif Kabir

The mechanisms of boric acid mass transfer in a VVER-1200 reactor core are studied in this work in the event of a major circulatory pipeline rupture and loss of all AC power. The VVER-1200's passive core cooling technology is made up of two levels of hydro accumulators. They use boric acid solution with a concentration of 16 g H3BO3/kg H2O to control the reactivity. Because of the long duration of the accident process, the coolant with high boron content starts boiling and steam with low concentration of boric acid departs the core. So, conditions could arise in the reactor for possible accumulation and subsequent crystallization of boric acid, causing the core heat removal process to deteriorate. Calculations were carried out to estimate the likelihood of H3BO3 build-up and subsequent crystallization in the core of the VVER reactor. According to the calculations, during emergency the boric acid concentration in the reactor core is 0.153 kg/ kg and 0.158 kg/kg in both the events of solubility of steam and without solubility of steam respectively and it does not exceed the solubility limit which is about 0.415 kg/kg at water saturation temperature. No precipitation of boric acid occurs within this time during the whole emergency process. Therefore, findings of the study can be used to verify whether the process of decay heat removal is affected or not.


2021 ◽  
Vol 12 ◽  
Author(s):  
Qing Liu ◽  
Zhao Liu ◽  
Changlin Zhang ◽  
Yanyan Xu ◽  
Xiaojing Li ◽  
...  

To determine the effect of 3% boric acid solution on cutaneous infections with Candida albicans (CA) in mice and its effect on skin microflora. Female mice were divided into three groups, with 18 mice in each group. Two injection sites were randomly selected, and 0.1 mL of CA mycelium suspension was injected into the epidermis and dermis of the back of mice. Group N was treated with sterile water for injection (SWFI). We observed the clinical manifestations, fungal fluorescence microscopic examination and colony count. Group B were hydropathically compressed with 3% boric acid solution for 30 min every 12 h. Group M was treated with SWFI, and group N was not treated. One week later, each group was observed with naked eyes, and skin samples were collected. The effect of boric acid on skin microflora was measured using Internal Transcribed Spacer Identification (ITS) and 16S rRNA genes. There were no significant changes in group M. In group B, the degree of skin injury was alleviated, the wounds healed markedly, and the exudate amount decreased. The effective rate of group B (83%) was significantly higher than that of group M (25%) (P < 0.05). The relative average abundance of Candida (P < 0.0001) and CA (P < 0.05) in group B was significantly lower than that in group M. Compared with group M, the microbial richness of group B changed little, but the diversity decreased. The flora structure of group B was significantly different from that of group M, but like that of group N. In group B, the abundance of Proteobacteria (P < 0.001), Enterobacteriaceae (P < 0.001), and Escherichia-Shigella (P < 0.001) was significantly greater, and the abundance of Firmicutes (P < 0.001), Staphylococcaceae (P < 0.001), and Staphylococcus (P < 0.001) were significantly lower. The 3% boric acid solution significantly reduced the symptoms of skin infection with Candida albicans. It inhibited the growth of Candida albicans and CA, reduced the diversity of skin microorganisms, increased the abundance of Proteobacteria, Enterobacteriaceae, Escherichia-Shigella, and reduced the abundance of Firmicutes, Staphylococcaceae, Staphylococcus.


2021 ◽  
Vol 7 (2) ◽  
pp. 1-7
Author(s):  
Skala M. ◽  
Kůs P. ◽  
Kotowski J. ◽  
Kořenková H.

Drained primary coolant from nuclear power plants containing boric acid is currently treated in the system of evaporators and by ion exchangers. Reverse osmosis as an alternative process to evaporator was investigated. Using reverse osmosis, the feed primary coolant is separated into two output streams: retentate and permeate. Retentate stream consists of concentrated boric acid solution together with other components, while permeate stream consists of purified water. In the first phase ofthe project the reverse osmosis modules from several manufactures were tested on a batch laboratory apparatus. Certain modifications to the pH of the feed solution were needed to enable the tested membranes to concentrate the H3BO3 in the retentate stream, separate from the pure water in the permeate stream. Furthermore, the separation capability for other compounds present in primary coolant such as K, Li or NH3 were evaluated. In the final phase of the project the pilot-plant unit of reverse osmosis was tested in nuclear power plant Temelín. It was installed in the Special Purification System SVO-6 for the regeneration of boric acid. The aim of the tests performed in Temelín nuclear power plant was to verify possible use of reverse osmosis for the treatment of primary coolant.


2021 ◽  
Vol 1036 ◽  
pp. 395-401
Author(s):  
Xiao Li ◽  
Tong Wang

Adding sap particle, Portland cement foamed concrete was studied to manufacture a new type of planting material. The pH, porosity, permeable capacity, infiltration rate and water storage were tested for evaluating the performance of foamed concrete. Solid-liquid extraction method and image binaryzation were used to study the pH and porosity of foamed concrete. A kind of self-made permeable device was also used in this paper. It was found that the pH of foamed concrete could be decreased by sap particles absorbed the boric acid solution in 14 d. For the foaming effect of fresh concrete was disturbed by liquid from sap particles, the porosity of foamed concrete was increased and then decreased. Seepage channels could be formed in foamed concrete when sap particles shrunk for releasing liquid and they also would be block for sap particles expanding when water permeated into foamed concrete. The permeable capacity and infiltration rate were decreased with increasing sap particles. The water storage of foamed concrete was fluctuated with sap particles increasing but more than that without sap particles. The optimal dosage of sap particles was 0.3wt% of binder material in this study. At the dosage, the minimal pH of foamed concrete could be obtained and performance of that would be good to plant, such as permeable capacity, infiltration rate and water storage.


2021 ◽  
Author(s):  
Tatiana Smirnova ◽  
Irina Temereva ◽  
Sergei Panov ◽  
Tatiana Stepanova

This article analyzes the results of four-year research which examined the effectiveness of pre-sowing treatment (soaking, spraying) of white cabbage seeds with trace element solutions of various concentrations. The research was conducted under laboratory conditions at the Agricultural Chemistry and Soil Science Department of Omsk State Agrarian University with a mid-season-ripening, medium-yielding and high-yielding variety of white cabbage (Sibiryachka 60) found in the Omsk region. 0.02%, 0.04% and 0.05% solutions of ZnSO4 ⋅ 7H2O and 0.01%, 0.02%, 0.03% and 0.05% solutions of H3BO3 were used in the experiment. The cabbage seeds were soaked in water (control) and in trace element solutions for 6-12-24 hours. The germination energy and germination capacity of the seeds, the zinc distribution, and the biometric indicators of the seedlings and of the cabbage transplant seedlings were determined. The optimal concentrations of the trace element solutions and the optimal duration of pre-sowing treatment were established, which stimulated the development of seedlings and increased seed germination by 5-9%. It was noted that, compared with the control, 2 times more plants reached the 6-leaf phase by the time of planting when transplant seedlings were treated with a boric acid solution in the optimal concentration, and 3.6 times more plants did when fertilized with zinc. Based on the results the following is recommended for implementation in production: soaking seeds in a 0.03% solution of Н3ВО3; soaking seeds in a 0.04% solution of ZnSO4; soaking time - 6 hours; a 1:2 ratio of seeds to the solution; and concentration of solutions per element for boron – 0.005% and zinc – 0.01%. Keywords: white cabbage, seeds, micro-fertilizers, pre-sowing treatment


Author(s):  
György Pátzay ◽  
József Dobor ◽  
Emil Csonka ◽  
Gábor Lozsi ◽  
Ferenc Feil

Borate ion exchange capacity of Purolite NRW600 strong base anion resin in hydroxide form and mixed bed NRW600+NRW100 ion exchange was investigated with static experiments. Anion exchange resin was saturated with 0.1–45 g/dm3 concentration boric acid solution in a static mixer at 20, 30, 40 and 50 °C at 150 rpm for 24 hours. Remaining borate content of saturation solutions was deter-mined with ion chromatography and ICP-OES. The amount of fixed borate as borate anions increased with the saturation borate concentration as well as in case of simple anion exchange as in case of mixed bed.Column sorption-elution study was carried out by using strong base anion exchange resins (Purolite NRW600 and Amberlite IRN78). Resins in hydroxide and in chloride forms were saturated in column with 5–40 g/dm3 boric acid solution in excess. The resin was then eluted with 200 cm3 salt free water with 5 cm3/min at 25 °C and then eluted by 1 mol/dm3 sodium-sulfate solution with 5 cm3/min. The effluent was collected and analyzed for borate content by titrimetric method. In chloride form the resin adsorbed and released much less borate. Effective borate and polyborate sorption needs hydroxide ions in resin phase.


2020 ◽  
pp. 14-19
Author(s):  
V. V. Potapov ◽  
V. A. Ilin

Assessment of the technical condition of the main systems and structures is one of the main stage tasks of technical diagnostics of NPP elements. One of the important elements of the hermetic volume of the protective shells of nuclear power plants is a storage pool (SP) of spent nuclear fuel (SNF). For provision of SNF storage the appropriate systems and structures are used: SNF handling system, SP cooling system and SP by itself. Pools are made of monolithic reinforced concrete with stainless steel lining intended to retain cooling water (boric acid solution) and protect the concrete from direct effect of aggressive environments. Emergency leaks may occur through the SP lining during operation of a nuclear power plant. Materials used for pool structures must be radiation resistant and resistant to a boric acid solution. The structure of the storage pool must be earthquake-proof, must allow monitoring of emergency leaks and maintain a controlled water level in case of leaks for the time period until the fuel will be discharged. Features of failures during operation, results of research and recommendations for extending the service life of storage pools at domestic nuclear power plants with VVER are considered. Assessment of the technical condition of the main structures of the SP provides for specialized research. Thus, the SP survey generally involves visual and instrumental examination of the bottom lining, internal lining, as well as concrete walls and bottom.


2020 ◽  
Vol 405 ◽  
pp. 193-198
Author(s):  
Daniela Marušáková ◽  
Pavel Kůs ◽  
Lorant Szatmary ◽  
Iveta Adéla Prokůpková

We tested stability of 43 selective sorbents, covering the widest range of functional groups, efficiency of sorption, method of production, and which are theoretically useful for sorption of cesium, strontium, cobalt, arsenic and actinoids. We present 3 of them: A = TiO2, B = Al2O3 and C = MxH(TiO)4(SiO4)3 . z H2O. In first testing, sorbents were exposed to the model solution of boric acid for 168 hours, in which they were mixed in a closed container with a rotator. After the exposure, sorbent solutions were filtered and analysed by spectroscopic techniques (Infrared Spectroscopy (IR), Raman Spectroscopy (RS) and newly by Scanning Electron Microscopy (SEM), combined with Energy Dispersive Spectroscopy (EDS)). Exposed spectra were compared with spectra of new, non-exposed sorbents. In second testing, sorbents were exposed to gamma radiation for 12 days with total dose 666 ± 43 kGy, produced by cobalt bomb and analysed by same techniques. The aim of our testing was to find out how sorbents behave in model boric acid solution and what effect has the gamma radiation on sorbent spectra and to analyse sorbents by SEM with EDX.


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