Correlation relations for estimating the content of plutonium isotopes in fallout due to the Chernobyl accident

The possibility of determining the total α activity A(^239,240Pu) of ²³⁹Pu + ²⁴⁰Pu according to the γ radiation of ¹⁰³Ru and ¹⁰⁶Ru is examined. The statistical properties of the experimental ratios of the activities ρ = A(¹⁰⁶Ru)/A(¹⁰³Ru) are investigated. The distribution of the experimental ratios is similar to the theoretical ratios for fuel and close to a Gaussian distribution with average value 〈p〉 = 0.22 and standard deviation Δ ∼ 0.06. This ratio is used to obtain a relation for estimating A(^239,240Pu) from the γ activity A(¹⁰³Ru). A theoretical analysis is made of the experimental data for the southern raions of Gomel oblast. It is shown that given a good statistical sample of measurements of the γ activity of ¹⁰³Ru it is possible to estimate the average value of the γ activity A(^239,240Pu) and with probability 0.95 the interval of the possible values of this activity. __________ Translated from Atomnaya énergiya, Vol. 103, No. 4, pp. 255–259, October, 2007.     

European experiences of the proposed ASTM test method for crack arrest toughness of ferritic materials

The proposed ASTM test method for measuring the crack arrest toughness of ferritic materials using wedge-loaded, side-grooved, compact specimens was applied to three steels: A514 bridge steel tested at −30°C (CV30–50°C), A588 bridge steel tested at −30°C (CV30–65°C), and A533B pressure vessel steel tested at +10°C (CV30-12°C) and +24°C (CV30+2°C). Five sets of results from different laboratories are discussed here; in four cases FOX DUR 500 electrodes were used for notch preparation, in the remaining case HARDEX-N electrodes were used. In all cases, notches were prepared by spark erosion, although root radii varied from 0.1–1.5 mm. Although fast fractures were successfully initiated, arrest did not occur in a significant number of cases.The results showed no obvious dependence of crack arrest toughness, K_a, (determined by a static analysis) on crack initiation toughness, K₀. It was found that K_a decreases markedly with increasing crack jump distance, Δα/W. A limited amount of further work on smaller specimens of the A533B steel showed that lower K_a values tended to be recorded.It is concluded that a number of points relating to the proposed test method and notch preparation are worthy of further consideration. It is pointed out that the proposed validity criteria may screen out lower bound data. Nevertheless, for present practical purposes, K_a values may be regarded as useful in providing an estimate of arrest toughness — although not necessarily a conservative estimate.     

Wear and corrosion resistance of AZ31 magnesium alloy irradiated by high-intensity pulsed ion beam

The wear and corrosion resistance of AZ31 magnesium alloy irradiated by high-intensity pulsed ion beam (HIPIB) at an ion current density of 100–300 A/cm² with shot number of 1–10 are investigated by sliding wear test and potentiodynamic polarization measurement. The surface and cross-sectional morphologies, phase structure and surface microhardness of the irradiated AZ31 magnesium alloy samples are characterized by scanning electron microscopy (SEM), optical microscopy, X-ray diffraction (XRD) and Vickers tester, respectively. The HIPIB irradiation produces the hardened surface layers and improves abrasive wear resistance of all the samples. The wear volume of the irradiated samples at 200 A/cm² and 300 A/cm² with 10 shots as well as 100 A/cm² with 5 shots is about four times less than that of the original sample. The apparent increase in corrosion resistance is achieved for all the irradiated samples in 0.01 mol/l NaCl solution with a pH value of 12. The corrosion potential and pitting breakdown potential for the samples irradiated at 100 A/cm² with 5 shots are 560 and 630 mV higher than those of the original sample, −1560 mV and −1300 mV (SCE), respectively. It is found that the combined improvement in wear and corrosion resistance of AZ31 magnesium alloy is achieved by HIPIB irradiation, which is ascribed to the microstructural refinement and the chemical homogeneity of the irradiated magnesium alloy.     

Standard samples of radioactive contamination of objects (SORZO)

A. A. Bochvar All-Union Scientific Research Institute of Novel Materials. Translated from Atomnaya Énergiya, Vol. 72, No. 4, pp. 411–412, April, 1992.     

Choice of NaI(Tl) crystal thickness for the detection of weak short-duration photon fluxes

Academician A. A. Bochvar All-Union Scientific-Research Institute of Standardization in Mechanical Engineering. Translated from Atomnaya Énergiya, Vol. 71, No. 4, pp. 345–348, October, 1991.     

Behavior of photocathodes on superficial modification by electrical breakdown

In this work, we present the experimental study and a theoretical approach of the photoemission of rough and smooth photocathodes. The cathode was made of pure yttrium while its surface was morphologically modified. The cathode surface was irradiated by a KrF excimer at normal incidence. The measurements were performed after electric breakdowns between anode and cathode. For the rough cathode the maximum output current was 10.5 A, with a maximum quantum efficiency value of 1.3 × 10⁻⁴. Instead, the smooth cathode provided an output current of 8.4 A with a maximum quantum efficiency value of 7.0 × 10⁻⁵. In this process, the plasma production and the Schottky effect play a fundamental role.     

Use of microwave energy in reprocessing of high-level waste

Scientific-Research Construction Institute of Mechanical Engineering. A. A. Bochvar All-Union Scientific-Research Institute on Normalization in Mechanical Engineering. Translated from Atomnaya Énergiya, Vol. 73, No. 3, pp. 210–215, September, 1992.     

Reagent-assisted decontamination of sandy soil by activation leaching at 80–140°C

A three-step processing scheme is proposed for decontaminating sandy soil: water-gravity separation of a fine fraction, reagent-assisted processing, and repeated water-gravity separation of a fine fraction. Reagent-assisted decontamination was conducted using 1–4 M sulfuric acid with liquid/solid phase ratio 1/1 over 7 h at 110–140°C in an autoclave. A sandy fraction, comprising 77.6 wt.%, was separated by water-gravity separation from the initial soil whose specific activity was ~1100 kBq/kg. Its reagent processing and repeated water-gravity separation made it possible to lower the specific activity of ¹³⁷Cs to 1.1 ± 0.2 kBq/kg.     

Selection of fuel-element parameters to increase reactor safety

A. A. Bochvar All-Union Scientific-Research Institute on Normalization in Mechanical Engineering. Translated from Atomnaya Énergiya, Vol. 73, No. 3, pp. 185–189, September, 1992.     

Pilot studies of an extraction process for reprocessing of spent fuel from fast reactors: Hardware and process details of extractor selection

FÉI. NIKIMT Scientific Production Association. VNIPIET Scientific Production Association. A. A. Bochvar VNIINM. Translated from Atomnaya Énergiya, Vol. 72, No. 5, pp. 481–491, May, 1992.     

Nondestructive nuclear-physical method of determining hydrogen in zirconium hydride

A. A. Bochvar All-Union Scientific-Research Institute of Inorganic Materials (VNIINM). Translated from Atomnaya Énergiya, Vol. 74, No. 5, pp. 448–450, May, 1993.     

Experience in operating the ÉP-500/1R ceramic melter for vitrification of liquid high-level wastes

A. A. Bochvar All-Union Scientific-Research Institute of Standardization in Machine Building. Industrial Association “Mayak.” Scientific-Research Institute of Chemical Machine Building, Ekaterinburg. Translated from Atomnaya énergiya, Vol. 76, No. 3, pp. 183–188, March, 1994.     

Spatially nonuniform nature of the development of porosity in the vicinity of grain boundaries in nickel during neutron irradiation

I. V. Kurchatov Institute of Atomic Energy. Academician A. A. Bochvar All-Union Scientific-Research Institute VNIINM. Translated from Atomnaya Énergiya, Vol. 70, No. 1, pp. 20–24, January, 1991.     

Modelling deuterium release during thermal desorption of D-irradiated tungsten

Thermal desorption profiles were modelled based on SIMS measurements of implantation profiles and using the multi-trap diffusion code TMAP7 [G.R. Longhurst, TMAP7: Tritium Migration Analysis Program, User Manual, Idaho National Laboratory, INEEL/EXT-04-02352 (2004)]. The thermal desorption profiles were the result of 500 eV/D⁺ irradiations on single crystal tungsten at 300 and 500 K to fluences of 10²²-10²⁴ D⁺/m². SIMS depth profiling was performed after irradiation to obtain the distribution of trapped D within the top 60 nm of the surface. Thermal desorption spectroscopy (TDS) was performed subsequently to obtain desorption profiles and to extract the total trapped D inventory. The SIMS profiles were calibrated to give D concentrations. To account for the total trapped D inventory measured by TDS, SIMS depth distributions were used in the near-surface (surface to 30 nm), NRA measurements [V.Kh. Alimov, J. Roth, M. Mayer, J. Nucl. Mater. 337-339 (2005) 619] were used in the range 1-7 μm, and a linear drop in the D distribution was assumed in the intermediate sub-surface region (∼30 nm to 1 μm). Traps were assumed to be saturated so that the D distribution also represented the trap distribution. Three trap energies, 1.07 ± 0.03, 1.34 ± 0.03 and 2.1 ± 0.05 eV were required to model the 520, 640 and 900 K desorption peaks, respectively. The 1.34 and 1.07 eV traps correspond to trapping of a first and second D atom at a vacancy, respectively, while the 2.1 eV trap corresponds to atomic D trapping at a void. A fourth trap energy of 0.65 eV was used to fit the 400 K desorption peak observed by Quastel et al. [A.D. Quastel, J.W. Davis, A.A. Haasz, R.G. Macaulay-Newcombe, J. Nucl. Mater. 359 (2006) 8].     

The fission products palladium and rhodium: Their state in solutions,their behavior in the regeneration of fuel of atomic power stations,and the search for selective extraction techniques

A. A. Bochvar All-Union Scientific-Research Institute of New Materials. Translated from Atomnaya Énergiya, Vol. 72, No. 5, pp. 462–473, May, 1992.     

Detection of trace quantities of10B in biosamples using track detectors

A new variant of a solid-state detector adapted for estimating the¹⁰B content in biological tissue was developed. A new polymeric composition based on oligoester acrylates was used as the detector. The number of tracks is a linear function of the boron content in the concentration range 0.5–200 μg¹⁰B/g inbiological sample samples with mass 100–500 μg. The detector can be recommended for deterning¹⁰B in biological tissues, mineralogy, and agrochemistry, 3 figures, 2 references. Translated from Atomnaya énergiya, Vol. 88, No. 3, pp. 194–197, March, 2000.     

Thermal hydraulic performance analysis of the printed circuit heat exchanger using a helium test facility and CFD simulations

The thermal-hydraulic performance of the PCHE was investigated using the KAIST helium test loop. Experiments were performed in the helium laminar region with 350 < Re < 1200. The hot/cold side inlet conditions were 25–550 °C/25–100 °C over the operating pressure of 1.5–1.9 MPa, respectively. Mass flow rates were controlled in the range of 40–100 kg/h. Pressure drop and temperature difference were measured at the inlet and outlet of the hot and cold sides. A global Fanning factor correlation and a global Nusselt number correlation were proposed using information only at the inlet and outlet of the hot and cold sides. A three-dimensional (3-D) numerical simulation was performed using FLUENT, a commercial computational fluid dynamics (CFD) code, to compare simulation results to the KAIST helium test data and to obtain the local Nusselt number in the PCHE. CFD predictions showed good agreement with experimental data. A local pitch-averaged Nusselt number correlation was proposed using local temperature, pressure, surface heat fluxes, and properties provided by CFD simulations. The system analysis code, GAMMA, was also utilized to identify which correlation was more applicable for system analysis. It turns out that the proposed local pitch-averaged Nusselt number correlation from CFD simulations is more appropriate than the global Nusselt number correlation developed from experimental data.     

A high charge state all-permanent magnet ECR ion source for the IMP 320 kV HV platform

A 320 kV high voltage (HV) platform has been constructed at Institute of Modern Physics (IMP) to satisfy the increasing requirements of experimental studies in some heavy ion associated directions. A high charge state all-permanent magnet ECRIS-LAPECR2 has been designed and fabricated to provide intense multiple charge state ion beams (such as 1000 eμA O⁶⁺, 16.7 eμA Ar¹⁴⁺, 24 eμA Xe²⁷⁺, etc.) for the HV platform. LAPECR2 has a dimension of ∅ 650 mm × 560 mm. The powerful 3D magnetic confinement to the ECR plasma and the optimum designed magnetic field for the operation at 14.5 GHz makes it possible to obtain very good performances from this source. After a brief introduction of the ECRIS and accelerator development at IMP, the conceptual design of LAPECR2 source is presented. The first test results of this all-permanent magnet ECRIS are given in this paper.     

The inhibiting effects of hydrogen on the corrosion of uranium dioxide under nuclear waste disposal conditions

A number of electrochemical experiments were employed to investigate the effects of hydrogen on the corrosion of UO₂ under nuclear waste disposal conditions. A combination of corrosion potential (E_CORR) measurements and cyclic voltammetry have indicated that dissolved hydrogen can polarize the UO₂ surface to reducing potentials; i.e., to E_CORR values more negative then those observed under anoxic (argon-purged) conditions. A comparison of the behaviours of SIMFUEL specimens with and without incorporated noble metal ε-particles indicates that these particles may act as catalytic electrodes for H₂ oxidation, H₂ ↔ 2e⁻ + 2H⁺. It is the galvanic coupling of these particles to the UO₂ matrix which suppresses the fuel corrosion potential.     

Iodine diffusion in the alpha phase of Zr-1% Nb alloy

Moscow Engineering Physics Institute (MIFI). A. A. Bochvar All-Union Scientific-Research Institute of Inorganic Materials (VNIINM). Translated from Atomnaya Énergiya, Vol. 75, No. 2, pp. 97–103, August, 1993.