Bezbednosni aspekti transporta nuklearnih materijala

Ovaj rad detaljno istražuje i analizira tehničke standarde bezbednosti transporta nuklearnog materijala, kao i metode i načine prevencije, detektovanja i pružanja odgovora na namerne i neovlašćene pokušaje pristupa i druga nezakonita dela usmerena ka nuklearnom i drugom radioaktivnom materijalu, povezanim objektima i aktivnostima. S obzirom da se se nuklearni materijali nalaze na meti raznih kriminalnih aktera zainteresovanih za dolazak u posed materijala koji kasnije mogu da upotebe u izradi oružja, od rane faze razvoja nuklearne energiji usmerene na bezbednost fisionog materijala pa sve do danas, ova oblast striktno je regulisana posredstvom međunarodnih pravnih okvira. Bezbedan transport između objekata je od kritičnog značaja za postizanje i očuvanje stabilne proizvodnje energije i zaštite ciklusa nuklearnog goriva. Pored zakonskih okvira koje pružaju multilateralne konvencije i međunarodni tehnički standardi, domaći zakoni i propisi su od ključnog značaja za manifest međunarodnog nuklearnog prava. Implementacija multilateralnih i bilateralnih sporazuma, tehničkih standarda i domaćih propisa među državama mogle bi da budu ključne komponente za sprečavanje razvoja međunarodnog nuklearnog oružja. Postoje jaki dokazi koji ukazuju da su stvarni rizici po čoveka i okolinu od radioaktivnih transportnih operacija mali, ne samo za teške scenarije nesreće, već i za zlonamerne radnje. Stoga je od vitalnog značaja da nastavimo naše napore da otklonimo iracionalne strahove i uverimo javnost da je pod trenutnim regulatornim režimom IAEA transport radioaktivnog materijala bezbedan

Influence of bentonite and zeolite on Cs+ and Co2+ cement matrix leaching phenomena

The probability of Cs+ and Co2+ ions retention by immobilization processes in the cement matrix was determinate as the subject of analyses: matrix design, water/cement ratio, and structure porosity. Comparison of experimental results was accomplished by Hespe standard leaching method. Diffusion and semi-empirical models were used for the assessment of the washing rate as a function of time. The higher value of cement matrix mechanical resistance corresponds to a lower value of Co2+ and Cs+ ions leaching. The Co2+ leaching level was more than two orders of magnitude less than the leaching level of Cs+. The influence of bentonite and zeolite on Co2+ leaching reduction was significantly smaller in comparison with Cs+, while zeolite had a higher Cs+ and Co2+ sorption ability than bentonite. Under static leaching conditions, the contribution of diffusion to the total transport of ions in the matrix porous medium was dominant. The contribution of matrix dissolution was insignificant concerning the dominant contribution of diffusion and surface washing. The semi-empirical model showed a better approximation of the Co2+ and Cs+ ions laboratory leaching process

Sektorski pristup u analizi bezbednosnih rizika upravljanja nuklearnim otpadom

U ovom radu izvršen je uporedni prikaz političkih, ekonomskih, društvenih i ekoloških aspekata u analizi bezbednosnih rizika koji potiču od različitih oblika ugrožavanja poput terorizma, krađa, pronevera, sabotaža i prevara u upravljanju nuklearnim otpadom. Na taj način, primenom sektorskog pristupa bezbednosti, formulisanog u okviru Kopenhaške škole studija bezbednosti, na celovit i sveobuhvatan način pristupa se predmetu ovog istraživanja primenom u teoriji proverenog analitičkog okvira. Nuklearni otpad je nusproizvod aktivnosti nuklearnih reaktora, postrojenja za preradu goriva, bolnica i istraživačkih objekata, a stvara se i prilikom zatvaranja i dekomisije nuklearnih postrojenja. U međunarodnoj politici upravljanje nuklearnim otpadom je kompleksno i osetljivo pitanje koje uključuje veliki broj državnih i komercijalnih aktera i posebno je regulisano kao deo nuklearne industrije, a usaglašeno sa uslovima tretiranja opasnog otpada. U odnosu na druge vrste otpada, prilikom upravljanja nuklernim otpadom izraženije su društveni aspekti bezbednosti, pre svega kompleksni bezbednosni rizici ali i briga, neizvesnost i perspektive za buduće generacije. Takođe, sa političkog i ekološkog aspekta, upravljanje i odlaganje nuklearnog otpada predstavlja najveći razlog mimoilaženja između nuklearnih pristalica i protivnika. Troškovi upravljanja i odlaganja otpada iz nuklearnih elektrana obično čini oko 5% ukupnih troškova generisane električne energije, a najveći udeo čine troškovi njegovog privremenog i trajnog odlaganja. Nuklearni otpad bi trebalo skladištiti u dubokim geološkim formacijama, jer rizici protokom vremena postaju niži od rizika skladištenja na površini. Upravljanje nuklearnim otpadom karakteriše visok nivo složenosti i interkompatibilnosti značajnih faktora: pitanja transporta, finansiranja prerade otpada i raspolaganja, kao i vođenja administrativnih evidencija. Određene tendencije u regulisanje industrije, za koje se tvrdi da su opravdane na bezbednosnim osnovama, smanjuju transparentnost i istinitost izveštavanja i tako otvaraju mogućnost za korupciju i druge oblike tzv. „kriminaliteta belog okovratnika“. Stvaranjem kulture nekažnjivosti ovih, uslovno rečeno blažih kriminalnih akata, ostvaraju se preduslovi za nastanak i ispoljavanje ozbiljnijih krivičnih dela, uključujući terorizam

General Prevention of Radioactive Materials Illicit Trafficking

Broj pretnji od kriminalnih ili neovlašćenih radnji koje uključuju nuklearne i druge radioaktivne materijale značajno je porastao u poslednjih 30 godina. Različiti nedržavni akteri poput terorističkih organizacija i organizovanih kriminalnih grupa pokušavaju da dođu do ovog materijala u okviru permenentnih pokušaja da proizvedu oružje za masovno uništenje. Nezakonita trgovina radioaktvinim materijalima podrazumeva namerno, ilegalno kretanje radioaktivnih materijala, uključujući nuklearni materijal, radi terorističkog, političkog ili nezakonitog profita. S tim u vezi, fokus bezbednosnih napora je na sprečavanju nedozvoljene trgovine nuklearnim i drugim radioaktivnim materijalima. Borba protiv ilegalne trgovine radioaktivnim materijalima putem opšte prevencije je odgovornost svake države. Države realizuju čitav spektar bezbednosnih mera kao odgovor na pokušaje ilegalne trgovine i nenamernih kretanja radioaktivnih materijala kao deo nacionalnih aranžmana države. Otkrivanje radioaktivnih materijala na granicama predstavlja ključnu komponentu ukupne strategije kako bi se osiguralo da takvi materijali ne dođu u ruke terorističkih grupa i drugih kriminalnih organizacija.Studies have shown that threats of criminal or unauthorized acts involving nuclear and other radioactive materials have increased significantly in the last 30 years. Numerous non-state actors as terrorist groups have permanently tried to acquire this material as a part of their attempts to produce a weapon of mass destruction. Deliberate, illegal movements of radioactive materials, including nuclear material, for terrorist, political, or illegal profit is generally understood to be illicit trafficking. In this regard, the focus of security efforts is on the prevention of illicit trafficking of nuclear and other radioactive materials. Combating illicit trafficking of radioactive materials through general prevention is the responsibility of each State. There are a number of response measures to the illicit trafficking and inadvertent movements as part of a State’s national arrangements. Detection of radioactive materials at borders is an essential component of an overall strategy to ensure that such materials do not fall into the hands of terrorist groups and other criminal organizations that could supply them.XXXII Simpozijum Društva za zaštitu od zračenja Srbije i Crne Gore, 4-6. oktobar 2023; Budva, Crna GoraProceedings: [https://vinar.vin.bg.ac.rs/handle/123456789/11602

Relationships Between Bone Treatment Conditions and Co2+ Sorption Capacities

Co-60 is an important radionuclide in spent nuclear fuel and liquid radioactive wastes. For the purification of water containing Co2+, ions sorption on hydroxyapatite (Ca-10(PO4)(6)(OH)(2)) can be applied. The process is particularly cost-effective if biological apatite from animal bones is utilized. In this study, dependence between bovine bone treatment conditions and Co2+, sorption was investigated as a function of initial metal concentration. Eight sorbents were previously prepared using fractional factorial design, by simultaneous variations of five process variables between two levels: factor A-the type of the chemical reagent (H2O2 or NaOH), factor B-reagent concentration (0.1 mol/L or 2 mol/L), factor C-reaction temperature (20(o)C or 60(o)C), factor D-contact time (1h or 3h) and factor E-sample annealing (without or at 400(o)C). At this point, the effects of treatment factors on Co2+, sorption efficiency were evaluated using statistical analysis. Amounts of Co2+ sorbed, amounts of released Ca2+ ions and final pH values were considered as system responses. The results showed that the impact of various treatment factors was different for different starting concentrations of Co2+. Consequently, no statistically important relations could be established between treatment conditions and Co2+, sorption from 10(-4) and 5*10(-4) mol/L solutions, whereas thermal treatment at 400(o)C was the only statistically significant factor influencing sorption from the most concentrated solution (5*10(-3) mol/L). Depending on initial Co2+, concentration, various factors had statistically significant effect on equilibrium pH values, whereas no relation was found between bone treatment conditions and the amounts of Ca2+, released during the sorption.3rd International Conference on Radiation and Applications in Various Fields of Research (RAD), Jun 08-12, 2015, Budva, Montenegr

Matematičko modelovanje fenomena transporta Cs+ iz solidifikovane istrošene jonoizmenjivačke smole

The aim of the study was to assess Cs+ ions transport phenomena from solidified spent ion exchange resin by mathematical modeling. The experimental results comparison was obtained by Hespe's Standard Leaching Method. For the leaching prediction rate as a function of time, diffusion and semi-empirical models were used. Due to the presence of spent ion exchange resin, the cement matrix absorbed a larger amount of water, swelled, and degraded. This phenomenon caused a significantly lower value of mechanical resistance to pressure. Also, through the increase of bentonite and zeolite content, the cement matrix decreased its mechanical resistance. The retention of cesium ions in the cement matrix was low and they were leached during the early phase of the investigation. The diffusion coefficient, De, decreased by three orders of magnitude with the addition of zeolite and bentonite in the cement matrix. Linear regression of experimental Cs+ leaching results, under static conditions, displayed that the semi-empirical parameter K3 than the absolute values of the parameters K2 and K1. Therefore, the contribution of matrix dissolution to the total radionuclides transport was irrelevant to the prevailing share of diffusion and surface washing processes

Ispitivanje uticaja fizičko-hemijskih svojstava sorbenata koštanog porekla na imobilizaciju jona Co2+ i Sr2+

Cilj istraživanja predstavlja ispitivanje mogućnosti imobilizacije jona Co2+ i Sr2+ sirovim i tretiranim životinjskim kostima kao biosorbentom. Određivan je uticaj različitih tretmana (hemijske degradacije, degradacije na povišenim temperaturama) na fizičko-hemijska svojstva životinjskih kostiju. Za karakterizaciju uzoraka životinjskih kostiju korištene su standardne metode: termička analiza (TG-DTG-DTA), infracrvena spektroskopska analiza (IC), rendgenska difrakciona analiza (XRD), BET metoda određivanja specifične površine, određivanje tačke nultog naelektrisanja metodom uravnotežavanja, dok je atomska apsorpciona spektrometrija - AAS korištena za merenje koncentracije jona metala. Na osnovu fizičko-hemijskih analiza biosorbenata, kao i poređenja kapaciteta i mehanizama imobilizacije jona Co2+ i Sr2+, uspostavljene su korelacije između različitih tretmana, strukture i sorpcionih svojstava

The evaluation of radionuclides removal using clinoptilolite, hydroxyapatite and their mixtures

The sorption properties of clinoptilolite and hydroxyapatite towards Cs1+, Co2+, and Sr2+ ions were compared, under the same experimental conditions. Cs1+ was preferably sorbed by natural clinoptilolite. Conversely, synthetic hydroxyapatite exhibited higher sorption capacities for Co2+ and Sr2+, while the sorption of Cs1+ was negligible. It was shown that, as a consequence of different affinity towards investigated cations, application of mixed clinoptilolite/hydroxyapatite sorbent represents a good strategy for the purification of effluents containing a mixture of Cs1+, Co2+ and Sr2+.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200

Influence of Silica Fume on SCC Concrete Properties

The use of recycled materials or waste increases sustainability in the construction sector. Likewise, the self-compacting concrete (SCC) has shown improvement in mechanical properties, when made with some waste pozzolanic materials. The differences in the compressive strength of the SCC concrete sample in the case of 5% by mass share of silica fume compared to samples with 7% were explored. The results shown that optimal replacement of Ordinary Portland Cement by silica fume is 5%, under applied experimental conditions

E-Waste Glass in Radionuclide Immobilization

Comprehensive needs for environmental protection are imposed by the prerogative of preserving natural resources, i.e. efficient usage of materials and energy. Therefore, there is an urgent need for different waste materials recycling or reusing. However, advances in new technologies in the electronics industry are leading to the problem of disposing of different types of E-waste, often discarded even before its usual time. This research represents an overview of E-waste glass utilization, like cathode ray tubes (CRT) from old computer monitors and TV screens, in mortar matrices for radionuclide immobilization. Due to its properties, mortar is used for liquid radioactive waste (LRW) solidification. Large quantities of cement, aggregates, and water are used annually for mortar and concrete manufacture. Also, cement production requires the consumption of large amounts of energy, i.e. the use of non-renewable fossil fuels. Nevertheless, mixing waste materials with mortar effectively reduces the amount of cement consumption. Aspects of this paper relate to a review of recent developments regarding the use of E-waste in cementitious materials. Emphasis was placed on their physico-mechanical properties to evaluate the possibility of CRT usage in mortar matrix for LRW immobilization