Nuclear Radioactive Materials Research Articles

Study on Severe Accidents of the New Generation WWER-1200 Reactor

As the safety of new generation reactors regarding conditions of radioactive material leakage into the environment greatly attracted the attention of engineers and scientists in the nuclear industry, because if these nuclear radioactive materials enter the environment, they will leave irreversible influences on humans and the environment for years, hence, it is environmentally very essential to investigate the safety of nuclear reactors. The wwer-1200 reactor is a reactor under preparation, and many investigation has been performed on its safety, and all research has revealed that this reactor is safe during all accidents. In this research, numerous severe accidents were examined in this reactor. The results indicated that in only one case this reactor go beyond its design safety situations, which is the concurrent incidence of cooling-water loss and a fracture in the lower part of the reactor chamber without emergency cooling systems. And the results revealed the temperature of the fuel pellet and fuel sheath as the central safety layer

Novel electron microscopic staining method using traditional dye, hematoxylin

Uranyl acetate (UA) has been routinely used as a staining solution for ultrathin sections used in biological electron microscopy. As a radioactive nuclear material, UA is subject to strict international regulations. To develop an alternative and easy-to-use staining method for ultrathin sections, we examined various commercial light microscopic dyes. We found that Mayer’s hematoxylin followed by Reynold’s lead citrate solution showed staining results comparable to UA and Reynold’s lead citrate solution, and this method is therefore suggested as a reliable and promising alternative to UA staining.

Selection of elements of the detector unit of the system for measuring the coordinates of gamma radiation sources

The article considers the current problem of creating modern, effective and reliable systems for monitoring the radiation situation and the operational search for nuclear radioactive materials and radiation sources that have come out of regulated supervision. A promising method of non-destructive testing using semiconductor detectors of ionizing radiation is used for radiation-environmental monitoring, prevention of the consequences of nuclear smuggling and determination of coordinates of ionizing radiation sources. The method for determining the direction to pulsed and constant sources of gamma radiation uses the ratio of the number of signals coming from the detectors located in the absorbers of a special geometric shape. The purpose of the article is to select the elements of the detector unit for the tool, which uses the method of absorption to determine the coordinates of the source of gamma radiation. The main attention is paid to the search for optimal characteristics of the material of the radiation absorber and the choice of the detector. The article analyzes the parameters of nuclear radiation detectors from different semiconductor materials, highlights and describes their characteristics. Analysis of experimental data and theoretical calculations allows us to assert that in the case of coordinateometry of gamma-radiation sources, a wide-gap semiconductor CdZnTe should be chosen as a detector material. For detectors of this type, the energy range is from 20 to 3000 keV, the operating temperature range is from -40 to +50 0С, and the energy resolution is of the order of several percent.

Design of Energy Recovery Linac for a Source of High-Flux Gamma-ray by Laser Compton Scattering

We investigate the generations of a high-flux γ-ray beams by laser Compton scattering. We performed the design of an energy recovery linac that produces a γ-ray beam with the flux of ∼ 1013 photons/s. It is important to examine the effects on beam performances of the ERL in detail. Thus, we examined the effects of emittance growths on higher order modes in the superconducting linac and coherent synchrotron radiation in the designed lattice of the energy recovey linac. They were checked by performing the start-to-end simulation of multi-beam particle trackings in the designed 355 MeV ERL. It was shown that the energy recovery linacs by laser Compton scattering may provide monochromatic high-flux gamma-ray beams. It is shown through our design studies that goals of γ-ray beam parameters in the ERL facility are achievable. Such an energy-tunable γ-ray beams that are generated by laser Compton scattering may be applied to nuclear resonance fluorescence(NRF) measurements for the non-destructive detection of radioactive nuclear materials. The investigations show that our design studies provide a good optimized ERL parameters in terms of beam dynamics.

Identifying anomalous nuclear radioactive sources using Poisson kriging and mobile sensor networks.

Nuclear security is a critical concept for public health, counter-terrorism efforts, and national security. Nuclear radioactive materials should be monitored and secured in near real-time to reduce potential danger of malicious usage. However, several challenges have arose to detect the anomalous radioactive source in a large geographical area. Radiation naturally occurs in the environment. Therefore, a non-zero level of radiation will always exist with or without an anomalous radioactive source present. Additionally, radiation data contain high levels of uncertainty, meaning that the measured radiation value is significantly affected by the velocity of the detector and background noise. In this article, we propose an innovative approach to detect anomalous radiation source using mobile sensor networks combined with a Poisson kriging technique. We validate our results using several experiments with simulated radioactive sources. As results, the accuracy of the model is extremely high when the source intensity is high or the anomalous source is close enough to the detector.

First-principles prediction of universal relation between exchange current density and adsorption energy of rare-earth elements in a molten salt

Using first-principles calculations we developed, for the first time, atomistic-level kinetics model to identify a key descriptor controlling electrochemical behaviors of various rare-earth ions solvated in molten salt electrolyte depositing on a solid electrode. We identified that the thermodynamic adsorption energies of rare-earth elements in the metallic electrode have a universal relation with exchange current densities. Our studies can be very useful guide to separate high-level radioactive nuclear materials and industrially valuable rare-earth materials, which can substantially relieve the environmental protection issues in nuclear waste disposal.

Dynamic modeling of TENORM exposure risk during drilling and production

Exposure to Technologically Enhanced Naturally Occurring Nuclear Radioactive Material (TENORM) from oil and gas drilling and production activities can have effects on both the environment and workers involved in the industry. There is a significant lack of available information regarding dynamic modeling and risk assessment of TENORM occupational exposure in the oil and gas industry, and available studies show that workers in the field are at risk of being exposed to varying levels of radiation. This paper presents a methodology to bridge this knowledge gap by modeling workforce TENORM radiation exposure at different oil and gas operation stages. This was achieved by integrating SHIPP (System Hazard Identification, Prediction and Prevention) Methodology And Rational Theory (SMART approach). The SMART approach was applied to develop an integrated framework for TENORM occupational exposure risk assessment. Application of the proposed approach is illustrated with a scenario, and outcomes from modeling this scenario explain how system degraded as a function of safety barrier performance.

Nuclear Forensics:What, Why and How?

Nuclear forensics is a relatively young branch of science in nuclear science and technology. It is a multidisciplinary field with an aim to answer questions regarding any interjected or smuggled material. The main objectives of these studies are to find out the origin/source of the material, date and place of production, age of the material, i.e. the date when it was last chemically processed or purified and if possible, the intended use of the material. Different analytical techniques, both non-destructive and destructive, e.g. gamma spectrometry, mass spectrometry, Raman spectroscopy, Fourier-transform infra red spectroscopy, scanning electron microscopy, transmission electron microscopy and laser-induced breakdown spectroscopy are employed to obtain the maximum possible information about the radioactive nuclear material. Information about structure and morphology of signatures, isotopic composition of the element, total amount, associated cations and anions, and isotope data on other elements, e.g. sulphur, Sr, Nd and Pb as to arrive at definite conclusions for material attribution.

Scenario-based risk assessment of TENORM waste disposal options in oil and gas industry

Technologically Enhanced Naturally Occurring Nuclear Radioactive Materials (TENORM) waste in the petroleum industry has become a serious concern as a potential source of radiation. The risk of being exposed to TENORM waste must be identified and controlled to protect workers, the general public and the environment. This paper presents an analysis of TENORM waste disposal options and risk assessment methods commonly used in the oil and gas industry. To assess their effectiveness, the paper utilizes an integrated fate and transport methodology and exposure pathways. The paper also studies plausible scenarios in which the contaminants can migrate through the geosphere and biosphere, reaching the environment, animals and humans. A real case scenario of TENORM waste disposed in an evaporation pond is simulated using RESRAD (version 6.5) where real data used as input parameters to evaluate the potential radiological doses and increased carcinogenic risk. To both understand and validate the simulated results, the findings of the real case scenario are compared with results obtained using a similar simulated scenario constructed from a literature review.

SU‐E‐I‐23: Design and Clinical Application of External Marking Body in Multi‐ Mode Medical Images Registration and Fusion

Purpose:To design an external marking body (EMB) that could be visible on computed tomography (CT), magnetic resonance (MR), positron emission tomography (PET) and single‐photon emission computed tomography (SPECT) images and to investigate the use of the EMB for multiple medical images registration and fusion in the clinic.Methods:We generated a solution containing paramagnetic metal ions and iodide ions (CT' MR dual‐visible solution) that could be viewed on CT and MR images and multi‐mode image visible solution (MIVS) that could be obtained by mixing radioactive nuclear material. A globular plastic theca (diameter: 3–6 mm) that mothball the MIVS and the EMB was brought by filling MIVS. The EMBs were fixed on the patient surface and CT, MR, PET and SPECT scans were obtained. The feasibility of clinical application and the display and registration error of EMB among different image modalities were investigated.Results:The dual‐visible solution was highly dense on CT images (HU>700). A high signal was also found in all MR scanning (T1, T2, STIR and FLAIR) images, and the signal was higher than subcutaneous fat. EMB with radioactive nuclear material caused a radionuclide concentration area on PET and SPECT images, and the signal of EMB was similar to or higher than tumor signals. The theca with MIVS was clearly visible on all the images without artifact, and the shape was round or oval with a sharp edge. The maximum diameter display error was 0.3 ± 0.2mm on CT and MRI images, and 1.0 ± 0.3mm on PET and SPECT images. In addition, the registration accuracy of the theca center among multi‐mode images was less than 1mm.Conclusion:The application of EMB with MIVS improves the registration and fusion accuracy of multi‐mode medical images. Furthermore, it has the potential to ameliorate disease diagnosis and treatment outcome.

Fuzzy-Logic Radioisotope Identifier for Gamma Spectroscopy in Source Search

Detection and identification of radioactive nuclear materials in urban searches can be fully performed with a portable gamma ray detector-spectrometer. Due to limited acquisition time and, as a consequence, low signal to noise ratio (SNR), development of fast and accurate real-time radioisotope identifier (RIID) algorithms is essential for automated source detection. In this paper, we evaluate the performance of fuzzy logic real-time radioisotope identification (FL-RIID) in several urban search scenarios. FL-RIID performance is tested on a database of searches consisting of injections of synthetic sources into experimental nuclear background spectra, acquired in one-second time intervals with a moving sodium iodide (NaI) gamma radiation detector-spectrometer. Performance of FL-RIID is benchmarked against that of maximum-likelihood (ML) fitting method. Demonstrated advantages of FL-RIID over ML in search applications include lower false alarm rate and faster execution time.

Analysis of a radiation attribute from uranium in storage

Storage of radioactive nuclear material necessitates the measurement of gamma and X-ray count rate to discourage tampering. However, in long-term, unattended storage scenarios, it is vital that the analysis of this count rate account for perturbations in the count rate caused by drifting equipment response, and changes in natural (radon levels, for example) or man-made background. In this paper, we report the long-term behavior of 420 silicon P–I–N diodes used as radiation detectors. Data were obtained over the course of 16–20 months at both 1-h and 1-min intervals, and, in addition to perfectly stable count rates, effects attributable to equipment failure, long-term gain drift, short-term gain drift, and software failures were observed. The results of statistical analyses of the time series will be given as well as a description of an event classification algorithm.

Unconventional nuclear weapons

Of the countless scenarios of terrorist mayhem, none quickens the pulse quite like the menace of a nuclear bomb. In light of the low-tech but catastrophic attacks on the World Trade Centre, building a nuclear bomb suddenly seems an unnecessarily difficult and risky proposition. Why build a bomb when there are far cheaper and simpler ways of waging nuclear terror? Analysts have accordingly turned their attention to two other possibilities that, for all their comparative simplicity, would deliver much of the bang of a bomb. Flying a fully fueled jumbo jet into a nuclear reactor is one. The other is using radioactive nuclear materials to kill or sicken people or render tracts of land uninhabitable by, for example, scattering the materials with a conventional explosion. This paper briefly discusses the likelihood of these two types of terrorist attack and the need to protect nuclear power stations and spent fuel from theft by terrorists.

A Nuclear Initiative of the President of Russia (Attempt at Analysis and Detailing)

The material contained in the speech of V. V. Putin, President of the Russian Federation, at the Millenium Summit is analyzed and explained in detail. This speech proposes initiatives for improving nuclear power by working within an international project. The concept examined introduces into nuclear power a higher degree of safety and at the same time precludes accidents requiring the evacuation of the population. It introduces a new technology for handling nuclear radioactive materials for solving ecological problems and a general solution for the problem of nonproliferation by eliminating the separation of plutonium in pure form, 233,235U, and so on. 5 references.

Development of creep curves from hot indentation hardness data

Indentation creep is defined as time dependent motion of a hard indenter into a solid under constant load and temperature. This technique is particularly advantageous for health hazardous radioactive nuclear materials since small samples are required for this test and a large number of data could be generated on the same sample. The only requirement for evaluation of indentation hardness and creep is a metallographically polished specimen surface. Several investigators have correlated hot hardness with creep and have estimated activation energy for creep and stress exponent for steady state creep rate. The aim of the present work is to evaluate hot hardness and in turn creep behavior of U-Zr alloy fuels containing 5, 10 and 15 wt.% of Zr and fuel cladding materials namely stainless steel (type 316) and zircaloy-2.

A multiple detector approach to radiological hot cell nuclear and chemical remote measurements

A remote measurement system has been constructed for in-situ gamma and beta isotopic characterization of highly radioactive nuclear material in hostile environments. A small, collimated, planar CdZnTe detector is used for gamma-ray spectroscopy. Spectral resolution of 2% full-width-at-half-maximum at 662 keV has been obtained remotely using risetime compensation and limited pulse shape discrimination (PSD). Isotopic measurement of high-energy beta emitters was accomplished with a ruggedly made, deeply depleted, surface barrier silicon detector. The primary function of the remote nuclear screening system is to provide fast qualitative and quantitative isotopic assessment of high-level radioactive material.

The development of a zoom macroscope for radioactive nuclear materials

SUMMARYThe macroscopic examination of irradiated reactor materials presents special problems in handling due to the necessity of shielding the instrument from the worker with a thick lead wall. The lack of availability of a suitable instrument has prompted the design of a special inverted stage macroscope equipped for remote operation. As the size of lens prevents turret mounting, a commercial 35 mm camera telephoto lens has been adapted in a special focusing mount. This permits the illuminator and stage assembly to be made non‐adjustable, simplifying the problems of remote working. An electronic drive is fitted to each stage movement, both of which are provided with remote position indicators.