Effect of External Gamma Irradiation on Dissolution of the UO2 Matrix

AbstractLeaching experiments were done on UO2 pellets doped with alpha-emitters (238/239Pu, 1500 - year batch), in the presence of an external gamma irradiation source (A60Co = 260 Ci, γ dose rate = 650 Gy h−1). The effects of α and γ radiation and the nature of the cover gas (air or Ar + 4% H2) on water radiolysis, and on oxidizing dissolution of the UO2 matrix, are quantified and discussed. The cover gas clearly has a major role in the effect of γ radiolysis. The dissolution rate in an aerated medium is 83 mg m−2 d−1 compared with only 6 mg m−2 d−1 in Ar + 4% H2. The rate drop is accompanied by a reduction of about four orders of magnitude in the hydrogen peroxide concentrations in the homogeneous solution. The UO2 alteration rate under gamma radiation in Ar + 4% H2 is comparable to the rate obtained in the presence of alpha radiolysis alone for the doped UO2 pellets with the highest alpha activities (4.75 × 108 Bq/g UO2, 15 - year batch).

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Effects of α and γ Radiolysis of Water on Alteration of the Spent UO2 Nuclear Fuel Matrix

MRS Proceedings ◽

10.1557/proc-807-385a ◽

2003 ◽

Vol 807 ◽

Author(s):

C. Jégou ◽

V. Broudic ◽

A. Poulesquen ◽

J. M. Bart

Keyword(s):

Gamma Irradiation ◽

Alpha Particle ◽

Particle Flux ◽

Water Radiolysis ◽

Reaction Interface ◽

Alpha Emitters ◽

Fuel Pellets ◽

Irradiation Field ◽

Leaching Experiments ◽

Alpha Irradiation

ABSTRACTAn experimental approach was developed to quantify the influence of α and γ radiolysis of water on the dissolution kinetics of the spent UO2 fuel matrix. Two types of experiments were carried out: leaching experiments in deaerated media with UO2 fuel pellets doped with alpha emitters (238Pu), and leaching experiments with UO2 fuel pellets (standard or doped with alpha emitters) submitted to γ irradiation. Leaching experiments on UO2 pellets doped with alpha-emitters in deionized water and in deaerated media showed a correlation between the alpha particle flux at the reaction interface and uranium release in solution. The higher the alpha particle flux at the reaction interface, the higher the uranium release rate (mean rates over 30 days at S/V = 3 m−1: 15-year batch, r = 2.5 mg·m−2d−1; 1500-year batch, r = 0.2 mg·m−2d−1; 40 000-year batch, r = 0.04 mg·m−2d−1). These results, obtained at low flux levels that are realistic on a disposal time scale, supplement existing data describing the effect of doping on UO2 alteration at higher flux levels. Leaching experiments with the 1500-year batch under gamma irradiation allowed us to quantify the impact of a gamma irradiation field on the UO2 release. At 650 Gy·h−1 the effects of alpha irradiation appear to be fully masked since the uranium release is 450 times higher than in the presence of the alpha irradiation field alone. The Chemsimul code was also used to model water radiolysis and uranium release into solution.

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Gamma irradiation used on adult Tetranychus urticae Koch as a quarantine treatment

Journal of Plant Protection Research ◽

10.2478/jppr-2014-0024 ◽

2014 ◽

Vol 54 (2) ◽

pp. 150-155 ◽

Cited By ~ 3

Author(s):

Shiva Osouli ◽

Karim Haddad Irani Nejad ◽

Farhoud Ziaie ◽

Mohammad Moghaddam

Keyword(s):

Gamma Radiation ◽

Gamma Irradiation ◽

Dose Rate ◽

Tetranychus Urticae ◽

Linear Trend ◽

Young Females ◽

Dose Rates ◽

Adult Females ◽

Tetranychus Urticae Koch ◽

Old Females

Abstract The effect of gamma radiation with 0, 200, 250, 300, 350, 400, and 450 Gy intensities on the longevity, total number of eggs, and the percent of hatched eggs laid by irradiated females of Tetranychus urticae Koch (Tetranychidae) was evaluated. Two different groups (0–24 h old and 48–72 h old) of adult females were irradiated. The results showed that 350 and 300 Gy doses significantly reduced the longevity of the 0–24 h old females and the 48–72 h old females. The younger females were more tolerant at lower dose rates than the older females. There was a quadratic relationship between dose rates and young females, while it was linear in older females. The total number of eggs laid by females of both ages was significantly reduced with a linear trend by 250 Gy irradiation. The eggs laid by females of both the 0–24 h olds and the 48–72 h olds lost their hatchability when the dose rate was 350 Gy. It was concluded, that applying a dose rate of 320 Gy on one of the mates (male or female) before mating, or a 300 Gy on both of them, would be sufficient to cause sterility in adult mites.

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Radiation Induced Dissolution of UO2

MRS Proceedings ◽

10.1557/proc-212-213 ◽

1990 ◽

Vol 212 ◽

Cited By ~ 18

Author(s):

Hilbert Christensen

Keyword(s):

Corrosion Rate ◽

Gamma Radiation ◽

Ambient Temperature ◽

Dose Rate ◽

Oxidation Mechanism ◽

Sample Surface ◽

Oh Radicals ◽

Water Radiolysis ◽

Radiation Induced ◽

Polished Specimen

ABSTRACTIn order to be able to model the effect of water radiolysis on the dissolution of fuel in the disposal vault it is essential to study the oxidation mechanism. Radiolysis of water produces radicals and molecules, amongst them the oxidizing species H2O2 and OH radicals, and, in aerated solutions, O2- as well. These species are probably responsible for the oxidation and dissolution of UO2 observed in a number of experiments. In the present investigation the effect of the oxidizing species has been studied separately using suitable scavengers. A polished specimen of UO2 was immersed in water and irradiated at ambient temperature with Co-60 gamma radiation. After irradiation the amount of uranium which had dissolved, or deposited elsewhere than the sample surface, was measured, and the oxidation of the surface was determined, using ESCA and SIMS. In 50 mM H2O2 (without irradiation) the corrosion rate was 5±3 μg.cm−2d−1 after 6 d exposure at pH 8. Corresponding rates for oxidation by O2- and OH radicals were about 3 μg.cm−2d−1, (dose rate 600±90 Gy/h.)

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An improved method for the preparation of a stable noninfective western equine encephalomyelitis diagnostic antigen

Canadian Journal of Microbiology ◽

10.1139/m69-193 ◽

1969 ◽

Vol 15 (9) ◽

pp. 1091-1094 ◽

Cited By ~ 1

Author(s):

John R. Polley ◽

Muriel M. Guerin

Keyword(s):

Chick Embryo ◽

Gamma Radiation ◽

Gamma Irradiation ◽

Dose Rate ◽

Infected Mouse ◽

Allantoic Fluid ◽

Tissue Cultures ◽

Improved Method ◽

Diagnostic Antigen ◽

Embryo Tissue

The virus of western equine encephalomyelitis (W.E.E.) was propagated in chick embryo tissue cultures. The rates of inactivation of the infectivity and the specific antigenicity of the infected fluid by gamma irradiation were determined. It was found that it was possible to destroy the infectivity while still retaining most of the specific complement-fixing activity. No difference in the rate of inactivation of the W.E.E. virus was observed when the dose rate of gamma radiation was varied between 0.9 × 106 and 2.7 × 106 rads/hour, showing a considerable tolerance in the dose rate of the gamma cell used. The residual infectivity of incompletely irradiated samples did not undergo a significant change in titer if titrated immediately or 2 days after irradiation, so that titrations do not have to be carried out immediately after irradiation, if inconvenient. A routine noninfective W.E.E. diagnostic antigen can be prepared by this process and then concentrated if required, followed by lyophilization for stable storage. Such an antigen can be produced more readily in bulk than those prepared from infected mouse brains or allantoic fluid.

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THE EFFECT OF GAMMA STERILIZATION AND ITS EFFECT ON MICROSCOPIC STRUCTURE OF DEEP FROZEN DOG SKULL

Journal of Medicine and Pharmacy ◽

10.34071/jmp.2018.2.6 ◽

2018 ◽

pp. 37-40

Author(s):

Phuong Thao Tien Nguyen ◽

Anh Hung Tran ◽

Van Tam Le ◽

Huu Thao Phung ◽

Phan Quynh Anh Nguyen

Keyword(s):

Structural Change ◽

Gamma Radiation ◽

Gamma Irradiation ◽

Key Words ◽

Bone Matrix ◽

Infected Tissue ◽

Microscopic Structure ◽

Bacteriological Examination ◽

Microscopic Scale

Objective: To evaluate the effect of gamma sterilization and its effect on microscopic structure of deeply frozen dog skull. Subjects and methods: 50 pairs of dog skull fragments have the same size,which were taken symmetrically through the midline of the skull, were divided into two lots. Evident lot consisting of 50 pieces are just deeply frozen, not irradicated. Experimental lot which was composed of 50 pieces were deeply frozen and exposed to 25kGy of gamma radiation. Afterwards, to evaluate the effect of gamma sterilization and compare the alter of bone matrix between lot groups. Results: After gamma irradiation, all dog skull fragments were negative with bacteriological examination. In microscopic scale, no difference was found between the two lots and there was no structural change in the irradiated fragments of all dog skull. Conclusion: Gamma irradiation with 25 kGy: (i) It has the ability to kill bacteria completely in the type of bacteria commonly infected tissue. (ii) It does not alter the structure of dog skull in microstructures. Key words: dog skull, gamma, sterilize

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Decomposition of hydrogen peroxide on nickel(II) oxide irradiated by γ-radiation and by neutrons

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19762159 ◽

1976 ◽

Vol 41 (8) ◽

pp. 2159-2163 ◽

Cited By ~ 22

Author(s):

V. Múčka

Keyword(s):

Hydrogen Peroxide ◽

Γ Radiation

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Facile preparation of new polystyrene leucomalachite green thick films and study of their radiochromic behavior for low doses of gamma radiation

International Journal of Advanced Chemistry ◽

10.14419/ijac.v5i2.8136 ◽

2017 ◽

Vol 5 (2) ◽

pp. 80

Author(s):

Anuradha Bera ◽

Shatrughan Malav ◽

Bajrang Lal Tiwari ◽

Shyam Govind Vaijapurkar

Keyword(s):

Film Thickness ◽

Gamma Radiation ◽

Thick Films ◽

Radiation Processing ◽

Γ Radiation ◽

Dye Loading ◽

Leucomalachite Green ◽

Colour Development ◽

Green Coloration ◽

Potential Use

Colourless polystyrene-leucomalachite green (PS-LMG) thick films containing a suitable chloroalkane were prepared by a fast and facile casting method, and were investigated for their radio chromic response behavior under the influence of 1.25 MeV γ-radiation. Their gamma response was studied in the 0.05 kGy to 10 kGy range to evaluate their suitability for potential use as the dosimeter in the radiation processing industries. The films were found to undergo a visibly distinct green coloration in the studied range, with the colour intensity increasing with an increase in the total dose. The radiochromic response of these films when investigated as a function of film thickness showed that the colour development as well as the linearity of the response was markedly affected by the thickness of the films. The effect of dye loading and the chloroalkane concentration on the radiochromic response of these films were also investigated. Depending upon the film thickness and reactant concentrations, the films were found to be capable of visually detecting gamma radiation doses as low as few tens of grays.

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Mass Treatment of Flooded Archival Materials by Gamma Radiation

Restaurator International Journal for the Preservation of Library and Archival Material ◽

10.1515/res-2021-0007 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Matteo Montanari ◽

Sara Pipponzi ◽

Pietro Livi ◽

Antonio Prodi

Keyword(s):

Gamma Radiation ◽

Gamma Irradiation ◽

Culture Method ◽

Test Species ◽

Atp Assay ◽

Recovery Processes ◽

Mycelia Growth ◽

Thermal Drying ◽

Radiation Treatments ◽

Main Components

Abstract This work describes mass recovery processes of flooded archival materials at industrial scale. The presence of fungi on paper represents a threat to the integrity of the document because they degrade cellulose, one of the main components of paper. Gamma radiation treatments are investigated as mass disinfection agents for their high penetrating power, speed of treatment, and absence of risk due to chemical residuals. We compared two different recovery processes: thermal drying followed by gamma irradiation and gamma irradiation followed by thermal drying. Both these processes were conducted simultaneously on naturally contaminated archival items and on paper specimens artificially contaminated with species test. Efficacy was assessed by culture method and ATP assay, right after the treatments and after four years of storage at room temperature. Coupling gamma irradiation with a drying step with dry heat at 55–60 °C reduces the fungal loads on natural items up to levels close to the detection limits, and the reduction is maintained after four years. On artificial specimens, spore germination is completely inhibited, mycelia growth is also highly affected, but the melanised test species appear to be more resistant. A synergistic effect between gamma irradiation, water content, and thermal drying is highlighted in this paper.

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