[en] Current ³He tubes utilized in neutron coincidence counting use different quench gas admixtures to shorten the avalanche process. In addition amplifier modules with different shaping characteristics are used to process detector signals. Both of these aspects affect the detector response. In the current paper, ³He tubes with several quench gas admixtures (CO₂, N₂, Ar+CH₄ and CF₄) and amplifier modules (PDT, AMPTEK, BOT) are compared. The plateau characteristics, gamma-sensitivity and deadtime of individual counters in combination with the listed amplifier modules are compared to determine optimum amplifier module/counter performance for the spent fuel applications.

[en] The Uranium is a chemical element very important in nuclear fuel cycle. The uranium concentrated is used as fuel in nuclear power reactors and research reactors. The manufacture of nuclear fuel comprises chemical, physical and metallurgical process which requires careful process control to obtain a final product of quality. In the preparation process can add certain impurities that can damage fuel efficiency by delivering low power reactor, thereby surpassing international standards. The studies of trace elements with a high percentage presence of one specific metal present problems because the emission interferes with the spectral lines of every analito longwave read by the high-resolution spectrometry inductive plasma source measurements, ICP- OES. For this reason, the objective of this work is to separate uranium from uranium concentrated matrix by ion exchange method, this consist in separate a specific ion for another ion previously chosen. These will in use of ion exchange resins in columns, it is a small polystyrene bed having a mobile ion in its chain, which is to be exchanged by complex ions of uranium forms and/ or elements planned. The methodology developed is to separate trace elements in stages depending on selectivity complex having formed with the reagents are circulated through the column in the early and trace elements are obtained in last stage get uranium. Five anions exchange resins were studied, these are Dowex M- 43, Dowex 21K-XLT, Dowex 21K (16/30), Dowex BSR- 1 and Lewatit MP 62. Two glass columns for each resin were used, and the recovery process is divided into five stages, the first stage is circulated by 4M HCl column one, in the second stage is passed 0.4M HCl, and in the third 2M HNO_3 stage by the same column. The fourth step to the second glass column is used and circulated recovery of the second stage, but redissolved in 0.05M H_2SO_4. Then in the fifth and final stage 0.5M HNO_3 is passed through the second column, which makes it completely elute the uranium from the resin. The behavior of seventeen elements was analyzed, between of them is Aluminium, Cadmium, Cobalt, Nickel, Vanadium, Iron, Molybdenum, Tin, Cupper, Lithium, Titanium, Zinc, Manganese, Calcium, Tungsten, Zirconium and Phosphorus. About these five resins analyzed, Dowex M- 43 was selected for certified samples, U_3O_8 124-1 New Brunswick Laboratory, because as it is best shown in behavioral recovery of uranium and its impurities. Eight elements were determined with a precision over eighty percent of recuperation, these were Cadmium, Cobalt, Nickel, Vanadium, Lithium, Titanium, Manganese and Zirconium (author)

[en] 3D laser scanning is an established verification technology in nuclear safeguards, applied inter alia for Design Information/ Basic Technical Characteristics Verification (DIV/BTC) and change monitoring in nuclear facilities. Current systems are based on high-accuracy, high-resolution 3D laser scanners which require one minute or more to acquire a single scan. Therefore, the scanners need to be immobile during data acquisition. In order to cover the complete scene, several scans are acquired in a so-called ‘stop-and-go’ mode, which are then registered into a single coordinate frame in an offline post-processing phase. Recently, new 3D laser scanners with a significantly increased acquisition speed have emerged. They acquire 3D scans at a frame rate of 10Hz and more - at the cost of reduced accuracy and resolution – and thus enable the scanner to be mobile during acquisition, i.e. the data can be acquired while walking or driving. Mobile laser scanning can significantly increase the efficiency of existing safeguards applications for 3D laser scanning, i.e. DIV/BTC and change monitoring. Furthermore, by registering each scan with a reference model (which can either be generated a priori or while scanning), it is possible to compute the current position and track the movement of the scanner. Hence, mobile laser scanning with real-time data processing provides indoor positioning capability to nuclear inspectors during their field work. It enables all observations and measurements to be connected with their respective location and time stamps and to retrieve location-based information as required. The paper presents the Mobile Laser Scanning Platform (MLSP) developed at the JRC, which consists of a commercial mobile scanner, the processing unit and the proprietary software for real-time processing and visualization. The system will be illustrated using two test cases: a DIV/BTC scenario for the future Finnish underground repository (ONKALO) and indoor localization.

[en] This report gives a brief but comprehensive overview of operations at Mayak PA. Information has been gathered from a variety of sources which have been cross-checked where possible to ensure accuracy. Mayak PA is currently the only facility in Russia involved in large scale reprocessing of spent nuclear fuel (SNF). Gaining increased knowledge about the current status at Mayak PA and future plans for this facility is therefore very important. Such information may also be useful to give an insight into the environmental consequences of the day to day operations at Mayak PA. (author)

[en] The Nuclear Safety Commission of Japan issued the report 'Clearance level of uranium handling facilities' in October 2009. Practical application of uranium clearance measurement will be executed after a while. However, clearance of uranium is very important issue because many operators have shored the uranium waste in their radioactive waste storage facilities. Measurement technologies of low radioactivity levels in waste from nuclear power plants are now established because of γ nuclides in waste. However the clearance of uranium waste including α nuclides is now developing in constitutional system and technical aspect. Taking into account the above situation, present status and future development of uranium clearance inspection technology are briefly discussed by studying the past reports about the uranium measurement technology in the low radioactivity level. (author)

[en] Radiation safety analysis of the 3 facilities in the nuclear fuel element center (NFEC) for assessing possible implementation of the ICRP-60 standard has been done. The analysis has covered the radiation dose received by workers, dose rate in the working area, surface contamination level, air contamination level and the level of radioactive gas release to the environment. The analysis has been based on BATAN regulation and ICRP-60 standard. The result of the analysis has showed that the highest radiation dose received has been found to be only around 15% of the set value in the ICRP-60 standard and only 6% of the set value in the BATAN regulation. Thus the ICRP-60 as radiation safety standard could be implemented without changing the laboratory design

No abstract available

[en] The Digital Cherenkov Viewing Device (DCVD) is one of the tools available to an inspector performing verification of the irradiated nuclear fuel inventory in wet storages at a nuclear facility. For gross defect verification, the presence of Cherenkov light and its qualitative properties are sufficient to verify the presence of an irradiated fuel assembly. For partial defect verification, the measured Cherenkov light intensity is quantitatively related to the intensity that is expected from the assembly under investigation, given the operator declarations for that assembly. While the currently used method for predicting the Cherenkov light emission intensity has performed well, data have also shown that enhanced methods incorporating more details may improve the prediction capabilities even further, in particular for short-cooled fuel assemblies. Fuel parameters such as initial enrichment, burnup, cooling time, as well as the fuel irradiation history and fuel type affect the total emitted Cherenkov light intensity, and should be taken into account in the prediction process. Furthermore, a larger number of fuel types and geometries need to be incorporated into the methods to take geometric effects into account. This paper describes a new and fast method to predict the Cherenkov light intensity of an irradiated fuel assembly, taking the fuel irradiation history and fuel geometry into account. The proposed method takes advantage of pre-computed Monte Carlo simulations of the Cherenkov light generated by a fuel, and is fast enough to be used in the field. The improved prediction method will also allow for more stringent detection limits, which may improve the partial defect detection capabilities of the DCVD.

[en] The current work was made in Conversion laboratory belonging to Chilean Nuclear Energy Commission, CCHEN. This is constituted by the development of three hydrometallurgical processes, belonging to the recovery of uranium from fuel plates based on uranium silicide (U_3Si_2) process, for nuclear research reactors MTR (Material Testing Reactor) type, those that come from the Fuel Elements Manufacture Plant, PEC. In the manufacturing process some of these plates are subjected to destructive tests by quality requirement or others are rejected for non-compliance with technical specifications, such as: lack of homogenization of the dispersion of uraniferous compound in the meat, as well as the appearance of the defects, such as blisters, so-called "dog bone", "fish tail", "remote islands", among others. Because the uranium used is enriched in 19.75% U_2_3_5 isotope, which explains the high value in the market, it must be recovered for reuse, returning to the production line of fuel elements. The uranium silicide, contained in the plates, is dispersed in an aluminum matrix and covered with plates and frames of ASTM 6061 Aluminum, as a sandwich coating, commonly referred to as 'meat' (sandwich meat). As aluminum is the main impurity, the process begins with this metal dissolution, present in meat and plates, by NaOH reaction, followed by a vacuum filtration, washing and drying, obtaining a powder of uranium silicide, with a small impurities percentage. Then, the crude uranium silicide reacts with a solution of hydrofluoric acid, dissolving the silicon and simultaneously precipitating UF_4 by reaction with HNO_3, obtaining an impure UO_2(NO_3)_2 solution. The experimental work was developed and implemented at laboratory scale for the three stages pertaining to the uranium recovery process, determining for each one the optimum operation conditions: temperature, molarity or concentration, reagent excess, among others (author)

No abstract available