L. Sajo-Bohus

The case for the thorium molten salt reactor

Shortcomings of current PWR and BWR, solid uranium-fuel, nuclear power reactors are summarized. It is shown how the Molten Salt Reactor (MSR) created and operated at Oak Ridge National Laboratory (ORNL), USA (1960s–1970s) and developed as FUJI reactor by Furukawa and collaborators (1980s–1990s), addresses all of these shortcomings. Relevant properties of the MSR regarding to simplicity, its impact on capital and operating costs, safety, waste product production, waste reprocessing, power efficiency and non proliferation properties are reviewed. The Thorium MSR within the THORIMS-NES fuel cycle system is described concluding that the superior properties of the MSR make this the technology of choice to provide the required future energy in the South American region.

Quality Control of Pavements and Tarmacs Using (137Cs) γ Compton Scattering

The γ Compton scattering over a volume of concrete has been studied in order to design an instrument for density measurements. It will be used for the quality control in road construction, where large surfaces must be monitored. The experimental results and Monte Carlo simulations of the γ Compton scattering over homogeneous and inhomogeneous volumes of concrete are shown. MC simulations have been useful to optimize the values of several parameters to improve the experimental set up and to estimate the extension of the explored volume.

Search of Explosives in Vehicles by Using Tagged Neutrons

The search for explosives hidden in vehicles is one of the tasks of counterterrorism application. This task requires the detection of explosive material in car or truck bombs as well as illicit transport of such items. Liquid explosives, especially home made (HME) ones, have been used in terrorist attacks and are thus of great importance in this field. The detection of HME liquid explosives in trucks by using a neutron-in/gamma-out system as the EURITRACK portal is discussed. Moreover the possibility of material recognition by transmission measurements with a tagged 252Cf source is also presented. The latter system might find application in car inspections or in small parcel scanning systems.

Radon Exhalation from Industrial Residues as Suitable Additives for Building Materials

Radon exhalation from phosphogypsum (PG) and red mud (RM) samples are of environmental concern. The study is oriented to evaluate by different nuclear techniques, industrial materials cumulated in sites at Morón (PG) and Puerto Ordaz (RM) in Venezuela. RM samples and industrial by products are assessed for its potential use as additives in building materials regarding its radiological health risk. Radioactive matter concentration in RM is up to 11.6 kBq.kg-1. Radon concentration range for RM dry powder is between DL and 2.5 kBq.m-3 and for PG is between 105-340 Bq.m-3. Results indicate that industrial by product before it can be used as additive; require remedial actions to lower the environmental impact. Experimental values are compared with locally available cement, bricks and gypsum building materials.

Target Design for a Thorium Accelerator-Driven Molten Salt Reactor (AD-MSR)

Th–FLiBe fluid target design is proposed for a 1 GeV, 1 mA proton accelerator-driven molten salt reactor (AD-MSR). Simulations are carried out by FLUKA. The core of the system is an assembly with EURISOL target geometry. Results are presented for the geometrical distribution of neutron fluencies, the energy produced and fission density distribution, as well as neutron spectra in fuel, graphite moderator, reflector and concrete shielding. It is forecast to produce 10 MWth power, neutron fluence of 1022 n/cm2/GeV/mA produced by the spallation source and induced fission in FLiBe fuel.

Multiphase Monitoring by Annihilation Radiation Coincidence Mode

A multiphase monitoring system employing nuclear techniques is reported, which is aimed to provide a rapid - decision tool in oilfield applications. Liquid phase time variation is monitored employing two large volume BaF2 detectors. The radioisotope source of 22 Na is a positron emitter, therefore two antiparallel gammas are produced per decay, and phase flow in pipes is related to the count rate of gamma pulses in coincidence providing information on transient liquid phase during transport. Oil, gas, water fraction measurements were performed at a specialized test station assembled in our laboratory to model a wide range of field operating conditions. The time dependence of the mixed substances is monitored with the two most relevant hydrodynamic parameters, the density (type of the fluid) and the flow rate, in a LabView® environment. Performance of the monitoring system; its limitations and the possibility for further improvements are also provided.

Five Years of Cyclotron Radioisotope Production Experiences at the First PET‐CT in Venezuela

Five years operation of a compact cyclotron installed at PET‐CT facility in Caracas, Venezuela is given. Production rate of 18F labeled FDG, operation and radiation monitoring experience are included. We conclude that 18FDG CT‐PET is the most effective technique for patient diagnosis.

k0‐INAA of Archaeological and Industrial Venezuelan Samples

Archaeological and industrial Venezuelan samples were analyzed by k0‐INAA to provide new data on the provenance study of the figurines found in Los Roques Archipelago and on recycling of industrial by‐products. Los Roques and Valencia Lake Basin figurines are similar. Bottom Oil Ashes have 10 times the concentration of V, Mg, Ni, Fe, Na compared to ICP‐AES and TXRF results. Red Mud samples have Thnat and Unat from four to ten times higher concentrations than those recommended for building materials.