[en] On 2nd Apr. 2011, highly contaminated water which flowed into the cable trench of unit 2 brought ambient dose rate up to 1,000mSv/h at the cable pit near the sea water intake of the unit. This was the first sign of the leakage of contaminated water

[en] Every business suffers from excessive regulations, unpredictable changes in legislation, various kinds of the political rent, extorting practices like 'big business social responsibility' and more. The industries with long-term return-of-investment (ROI) are most vulnerable to political and legal risks. For the nuclear industry, long-lasted public perception of radiation as an imminent threat caused the present over-regulation look natural. Therefore ROI is above two decades, essentially precluding private entrepreneurship activity. While durable solution includes changing public perception and updating regulation, both are 'facts on the ground' and 'habits are hard to break'. Political alliances, appeal to public opinion and lobbying are legitimate methods for promoting industry's interests in a democratic state. However in case of the nuclear industry, bureaucratic and political interests seem too strong to be overpowered by regular lobbying activities. Durable solutions we are searching for should not only eliminate the present legal and political obstacles, but also prevent them in near- to middle-term future. Such solutions would mitigate risks and remove barriers in number of industries, including nuclear industry as well. Particularly, 'not in my backyard' (NIMBY) attitude to nuclear installations is often viewed as a formidable problem. However, this problem has pretty old and reliable solution via compensation for real estate devaluation, if such takes place. Such solution may preclude some projects, but makes others predictable and reliable (e.g. in sparsely populated or relatively poor areas)

[en] The most commonly used building materials in Hungary and in numerous country of the world are the bricks, which made from clays. Due to the congenial internal structure properties of the clays these raw materials can be mixed with other materials, provides great possibility to reuse industrial by-products as additive material. The production and inbuilt of new types of synthetic building materials based on NORM (naturally occurring radioactive materials) by-products is raising concerns among authorities, public and scientists. Several NORM residues produced in large quantity, such as: phospogypsum (phosphate industry), red mud (aluminium processing industry), fly ash, coal slag (coal burning and steelworks) and so on are presently under investigation. The aluminum manufacturing in Ajka (Hungary) started in 1943. As a result of the bauxite refining activities up to now approximately 30 Mt of red mud has been produced in Hungary, stored in reservoirs. The radionuclide content of the bauxite usually exceeds the world average in soils (WA), which entirely remains in the by-product during Bayer process. The exposure pathways in case of application of NORM residues have to be explored in order to reveal the potential risks of NORMs on residents. The gamma radiation originated from the primordial radionuclides (K-40; U-238; Th-232) and their daughter elements found in nature and in building materials as well increase the external dose of the human body. In the EU the Radiation Protection 112 (RP 112) guideline serves for classification of building material, wherein the gamma exposure is limited by I-index

[en] Tritium is produced primarily by interactions of cosmic rays with the atmosphere. However, nuclear installations may add significantly tritium to the surroundings, increasing its concentration. The main sources of tritium released by man are linked to the nuclear power cycle: nuclear power stations, nuclear fuel reprocessing plants or tritium production plants. Tritium is found in the environment mainly as tritiated water, in gaseous or liquid form (HTO, T2O), in the surrounding air and in soil. It accumulates in plants, which may use as a measure to the level of tritium concentration in the environment. The most common routes of tritium uptake from the environment in plants are from atmospheric humidity and by precipitation water which entered the soil. The fraction of tritium bound to the plant tissue is small compared to that present as tritiated water in the plant (from 0.06% to 0.3% for growing crops). The tritiated water uptake is through the roots, as tritiated water from the soil follows a pathway similar to that of ordinary water. As most tritium in plants consists of tritiated water, the measurements of only the tissue free water tritium concentration (as HTO or T2O) gives an accurate estimate of the tritium content in the plant. Analyzing free tritium in biological matrices usually requires using the freeze-drying method to extract the water from the sample, and then measure the water collected in a cold trap with a Liquid Scintillation Counter (LSC). The 'freeze-drying' occurs because of the sublimation of the frozen water inside the plant, that takes place when the temperature is beneath the triple point and the vapour pressure is low. In the temperature range of -5° to -10° C the mechanism that plants use to avoid freezing is drawing of water from the cell protoplasm into the intercellular spaces. Changes in cell membrane permeability allow water to leave the cell and enter the spaces between the cells where it freezes instead of freezing within the cell and causing its death. This process continues until the cells are almost totally dehydrated. In the temperature range of -20° to -60° C the intra-cellular water freeze forms 'sharp' ice crystals that cause the death of the cells. Water (H2O) and tritiated water (HTO) behave nearly identically in both liquid and vapour phases. The freeze-drying method, although relatively simple, requires the use of dedicated systems and is time consuming. When a plant is frozen in a closed bag, ice is accumulated on the exterior surface of the plant and in the plastic bag that contained the sample, producing a 'self-freeze drying' effect. This ice may be directly used for tritium evaluation if the tritium measurement results are compatible with the generally accepted freeze-drying (lyophilization) method. The present work presents a comparison of this simple Ice Extraction Method (IEM) for tritiated water analysis with the standard lyophilization method

[en] The SARAF radio-frequency quadrupole (RFQ) is a crucial element in the SARAF proton/deuteron accelerator complex - it makes acceleration of high intensity ion beams possible. The RFQ electrodes consist of 4 four-meter long rods, with adjacent rods at opposite polarity and diagonal rods at same polarity, with the polarity oscillating sinusoidally at 176 MHz, thereby providing the element with very strong transverse focusing capabilities. In addition, properly designed longitudinal modulations on the electrode surfaces enable both acceleration and longitudinal focusing, and thereby the ability to bunch the beam. Bunching is a necessary feature for continuation of the acceleration with the superconducting half-wave resonators

[en] Research for developing a cold neutron detector for Chromatic Analysis Neutron Diffractometer Or Reflectometer (CANDOR) is underway at the NIST center for neutron research. The neutron detector is based on 6LiF:ZnS(Ag) scintillation material. The development required optimization of the detector design by simulating the nuclear interactions, light yield for different 6LiF:ZnS:Binder mixture ratios and the grain sizes effect on the light production. This optimization goal was achieved by using Geant4, a Monte Carlo based simulation software. The software enables the investigation of the Neutron interaction with the detector, the ionization process and the light transfer process following the nuclear process. Two neutron sensor configuration were evaluated, one with a mixture ratio of: 1:2:0.3 (6LiF:ZnS:Binder) and the other with ratio of 1:3:0.3. The simulation included the captured process of a cold neutron (mean value of 3.62 meV) by the 6Li in the scintillator and the production of an Alpha and a Triton particles. The particles ionize the ZnS(Ag), and blue light photons are created. Because the ionizing particles lose their energy to all of the compound components the number of light photons produced per neutron interaction can vary and a proper design can increase the energy transfer to the ZnS(Ag). Key words: 6LiF:ZnS(Ag), GEANT4, Neutron Detector

[en] Among the newest emerging technologies that are used in the design of personal gamma radiation detection instruments, the silicon photomultiplier (SiPM) light sensor is playing an important role. This type of photo sensor is characterized by low power consumption, small dimensions and high gain. These special characteristics present applicable alternatives for the replacement of traditional gamma sensors based on scintillator coupled to Photomultiplier tubes (PMT) or on Geiger-Muller(G.M.) sensors. For health physics applications, flat energy response is required for a wide range of radio-nuclides emitting gamma rays of different energies. Scintillation based radiation instrumentation provides count rate and amplitude of the measured pulses. These pulses can be split in different bins corresponding to the energy of the measured isotopes and their intensity. The count rate and the energy of the measured events are related to the dose rate. The conversion algorithm applys a different calibration factor for each energy bin in order to provide an accurate dose rate response for a wide range of gamma energies. This work describes the utilization of an innovative approach for dose rate conversion by using the abilities of newest 32-bit microcontroller based ARM core architecture

[en] The physical properties of binary actinides and transition metal alloys are of great importance for the safety assessment of nuclear fuels. Since transition metals are major components of the cladding material of fuel rods (stainless steel, HT-9 etc.), the physical properties of those compounds formed by accidental fuelcladding interactions could have limiting factors on the fabrication, life time operation and disposal of nuclear fuels. Binary compound of the form ReT5 (Re = rare earth, T = Transition metal) has been in the focus of interest mainly because of their magnetic properties (small Re to T stoichiometric ratio, large spontaneous magnetization and high Curie temperature) and their ability to store large amount of hydrogen per formula unit (f. u.)

[en] While seeking a remedy for the crisis of radiation fear in Japan, the author reread a recent article on radiation hormesis. It describes the motivation for creating this fear and mentions the evidence, in the first UNSCEAR report, of a factor of 3 reduction in leukemia incidence of the Hiroshima atom-bomb survivors in the low dose zone. Drawing a graph of the data reveals a hormetic J-curve, not a straight line as reported. UNSCEAR data on the lifespan reduction of mice and Guinea pigs exposed continuously to radium gamma rays indicate a threshold at about 2 gray per year. This contradicts the conceptual basis for radiation protection and risk determination that was established in 1956-58. In this paper, beneficial effects and thresholds for harmful effects are discussed, and the biological mechanism is explained. The key point: the rate of spontaneous DNA damage (double-strand breaks) is more than 1000 times the rate caused by background radiation. It is the effect of radiation on an organism's very powerful adaptive protection systems that determines the dose-response characteristic. Low radiation up-regulates the adaptive protection systems, while high radiation impairs these systems. The remedy for radiation fear is to expose and discard the politicized science

[en] The fact that two radioactive isotopes of the noble gas xenon, 131mXe and 133Xe, were identified provided reliable information on the nuclear fission nature of the source. A release from the DPRK test site was found to be consistent with the possible source region results from the ATM. The ATM also showed that the detections in Takasaki are consistent with a release activity of 1012 Bq, early in the morning of 7 April 2013, i.e. 54 days after the explosion. Any actions possibly performed at the DPRK test site (and their timing) are unknown. However, according to American estimations, based on UNE at the Nevada Test Site (NTS), 1-10 % of the noble gases total activity could be released to the atmosphere. Based on the above, the nuclear yield of the explosion is in the range of 1-10 kilotons TNT equivalent. This estimation is in agreement with the estimated yield in another study based on the CTBT international monitoring system