Authors:Zs. Révay, T. Belgya, L. Szentmiklósi, and Z. Kis
The PGAA facility at the Budapest Research Reactor has been continually upgraded and developed since its start-up in 1996,
as a result of which its performance has improved considerably. The installation of the cold neutron source, the partial change
to supermirror neutron guides and their realignment increased the flux by almost two orders of magnitude. The data acquisition
has been modernized as well; digital spectrometers were tested and implemented in novel forms of gamma-ray spectrum collection.
This year a higher-efficiency HPGe detector and a new data acquisition module were put into operation. Most recently all the
neutron guides were changed to supermirror-coated ones to further increase the neutron flux. The improved evaluation software
makes possible a more reliable elemental analysis of the samples. In this progress report these developments are critically
reviewed. The characteristics of the latest system are also described. It is the first time that a set of new partial gamma-ray
production cross sections are presented, which are based on the new intensity values of 14N(n,γ)15N calibration standard.
Authors:Khairedin Abdalla, Dimitrios Kaziolas, and Charalambos Baniotopoulos
The present paper deals with the study of the installation behavior of high-strength bolts under friction. For this purpose an experimental program was conducted to evaluate the energy of these bolts that is dissipated due to tightening and loosening. The total number of tested specimens was 100 bolts furnished to the requirements of AASHTO specification M253M. The turn-of-nut tightening method is applied experimentally to evaluate the pretension and the torque for tightening and loosening of bolts. It is mentioned that a number of 56 bolts has 76 mm length while the rest is of 152 mm. The experimental preloading and the lost torque that overcomes friction are compared with the respective analytical values. It is confirmed that the K-nut factor is affected by the type of lubricant and the length of the bolt. Additionally, most of torque is going to overcome friction. The percentage of tightening and loosening torque for both the analytical and the experimental cases is very close.
Due to a need for security screening instruments capable of detecting explosives and nuclear materials there is growing interest
in neutron generator systems suitable for field use for applications broadly referred to as active neutron interrogation (ANI).
Over the past two years Thermo Electron Corporation has developed a suite of different compact accelerator neutron generator
products specifically designed for ANI field work to meet this demand. These systems incorporate hermetically-sealed particle
accelerator tubes designed to produce fast neutrons using either the deuterium-deuterium (En = 2.5 MeV) or deuterium-tritium (En = 14.1 MeV) fusion reactions. Employing next-generation features including advanced sealed-tube accelerator designs, all-digital
control electronics and innovative housing configurations these systems are suitable for many different uses. A compact system
weighing less than 14 kg (MP 320) with a lifetime exceeding 1000 hours has been developed for portable applications. A system
for fixed installations (P 325) has been developed with an operating life exceeding 4500 hours that incorporates specific
serviceability features for permanent facilities with difficult-to-access shield blocks. For associated particle imaging (API)
investigations a second-generation system (API 120) with an operating life of greater than 1000 hours has been developed for
field use in which a high resolution fiber-optic imaging plate is specially configured to take advantage of a neutron point-source
spot size of ∼2 mm.
At the end of the 1991 Gulf War the U.N. Security Council Resolution called upon IAEA, assisted by the U.N. Special Commission, to carry out inspections of all Iraqi nuclear installations. The IAEA Action Team succeeded in implementing, on very short notice, a comprehensive system of inspection activities, including sampling and analysis at the Agency's Laboratories and other laboratories in Member States. The Agency's Laboratories developed and implemented an analytical strategy with the aim to rapidly and accurately obtain the information necessary for verifying the Iraqi declarations. The analyses ranged from screening for - and /-emitters to accurate determinations of the amounts and isotopic composition of the radionuclides and associated trace elements and compounds. The arsenal of methods included ultra-sensitive radiometric methods, mass spectrometry, neutron activation, X-ray fluorescence and inductively coupled plasma emission spectrometry. Selected results include the detection of uranium chloride compounds, special composition steels, and quantitative accounting of uranium and plutonium production. The selectivity, sensitivity and reliability of the applied analytical techniques in conjunction with validated sampling procedures are essential components of an analytical measurements system that can provide credible results.
Authors:P. Aarnio, J. Ala-Heikkilä, T. Hakulinen, and M. Nikkinen
Using gamma-spectrometry systems on mobile units with accurate position information is a convenient means for surveying large
areas for radioactive fallout or finding hot spots due to misplaced sources or releases from nuclear installations. Traditionally,
large (tens of litres) high efficiency NaI(T1) detectors have been used for the purpose. HPGe detectors, however, offer certain
advantages which can often compensate for their lower efficiency. This kind of remote sensing, regardless of detector type,
requires specialized software. In order to provide accurate position information, the integration times must be kept as short
as possible. This is especially true for fast air-borne measurements where counting periods below one second are desirable.
We have constructed a special version of SAMPO software which controls data acquisition and runs real-time gamma-spectrum
analysis including peak determination, nuclide identification, activity calculations, and reporting. The measurement/analysis
cycle can be reduced down to 0.5 seconds on a standard Pentium-based PC. The analysis results are combined with accurate co-ordinates
from a differential GPS system on a color coded map. The system is also able to give alarms based on different criteria. We
have already measured and analyzed more than 500 000 spectra in field applications using jets, helicopters, cars, and also
Authors:R. Keyser, W. Hensley, T. Twomey, and D. Upp
The necessity to monitor international commercial transportation for illicit nuclear materials resulted in the installation
of many nuclear radiation detection systems in Portal Monitors. To overcome the difficulty of innocent alarms due to a large
content of natural radioactivity or medical nuclides, Department of Homeland Security (DHS) supported the writing of the ANSI
N42.38 standard (Performance Criteria for Spectroscopy-Based Portal Monitors used for Homeland Security) to define the performance
of a portal monitor with nuclide identification capabilities, called a Spectroscopy Portal Monitor. To accomplish the necessary
performance, several different HPGe detector configurations were modeled using MCNP for the horizontal field of view (FOV)
and vertical linearity of response over the detection zone of 5 meters by 4.5 meters for 661 keV as representative of the
expected nuclides of interest. The configuration with the best result was built and tested. The results for the FOV as a function
of energy and the linearity show good agreement with the model and performance exceeding the requirements of N42.38.
South Africa signed and ratified the Comprehensive Nuclear Test-Ban-Treaty (CTBT) and accordingly made commitments to the Organization (CTBTO). Of the obligations are the establishment of a Radionuclide Laboratory, the design, installation and operation and maintenance of a radionuclide particulate and noble-gas monitoring station and the nomination of one radionuclide specialist South African to serve on an international team for On-Site Inspection (OSI). The last to provide expertise when the worldwide monitoring network provides strong indications that an illegal nuclear test has been performed at the territory of a State Party. The inspection team will be equipped with amongst others radiation monitors and nuclide specific measuring equipment limited to report on specific radionuclides agreed upon by all State Parties. In real-time operational circumstances one may assume that all members of the team will not be registered radiation workers and accordingly be regarded as members of the public when radiation hazard is to be evaluated. In this paper we try to categorize the radionuclides of interest and evaluate the radiological risk to the OSI-team due to inhalation of airborne radioactive particulate matter during the survey at the site of an anticipated nuclear test. From this study recommendations will be made to the CTBTO for possible implementation of portable sampling and analysis equipment to allow on-site evaluation of the potential internal exposure of OSI-team members.
In conjunction with its 30th anniversary in 2009 the Sóstó Museum Village examined the question of how to move forward. The best solution appears to be to take two directions: on the one hand, strengthening of the professional standard can bring renewal by transferring to the museum types of buildings or installations that have a curiosity value arousing the public’s interest (brandy distillery, soda-water plant, photographic studio, etc.), and on the other hand, strengthening our educational efforts, providing attractions for the public. We had thought that with the implementation of our building transfer plan the construction of the museum village could be regarded as completed, but we found that this was a mistake: there is no such thing as a completed museum, we are constantly faced with new challenges and we can only meet the expectations of the public by strengthening education and entertainment, expanding themes and complex services, and it is only in this way that we can provide a greater feeling of comfort for visitors. But in achieving this we must take care to avoid the danger of commercialisation and the “Disneyland“ effect. The article is about the attainment of this goal.
Colloids play a major role in the transport of trace metals as well as radionuclides in natural waters. These species are of importance for passive take in biota.Radionuclides may form colloids and pseudocolloids during hydrolysis or through interaction with other components present in the water phase, such as clay minerals or humic substances. Furthermore, aggregation and dispersion and other transformation processes, will influence the colloidal fraction, for instance during storage of samples. Fractionation of radionuclides associated with colloids in natural waters should, therefore, take place in situ or shortly after sampling.Different analytical techniques are useful for the fractionation of colloids, pseudocolloids, and particles. In the present paper, the application of hollow fiber ultrafiltration and dialysis is demonstrated for radionuclides in waste waters from the Oscarshamn nuclear installation in Sweden.The results illustrate that hollow fiber ultrafiltration is a more powerful technique than dialysis. The fractionation is rapid, sorption is of minor significance, the pore size distribution is rather narrow, and the filtering capacity is high.
Authors:H. Biggin, N. Chen, K. Ettinger, J. Fremlin, W. Morgan, R. Nowotny, M. Chamberlain, and T. Harvey
On peut déterminer la présence de cadmium chez l'homme à l'aide de technique de l'analyse par activation neutronique in vivo.
La capture des neutrons thermiques par113Cd conduit à une émission γ prompt qui peut être détectée au moyen d'un semi-conducteur convenable. On a réalisé une installation
à l'Université de Birmingham pour produire au moyen d'un cyclotron un faisceau de neutrons pulsés. Une série d'expérience
a été faites sur des cadavres; ces expériences ont prouvé qu'il est possible de détecter le cadmium à une concentration de
2,0 ppm dans le volume d'un foie humain pour une dose de 1 rem. On discute des résultats et des applications possibles de