[en] A simple method non-solid multi monitor HAV-1 for the systematic evaluation of reactor neutron flux parameters for K_o neutron activation analysis is presented. Solution of Au, Zr, Co, Zn, Sn, U and Th (deposited in filter paper) are used to study the parameters alpha and f. Dissolved Lu is used to neutron temperature (Tn) determination, according to the Wescott's formalism. A multipurpose multi monitor HAV-1 preparation, certification and evaluations presented

[en] The use of the reactor Triga Mark III of the Nulcear Center of Mexico after shut-off as an intense gamma source is presented. Doses higher than 1 Mrad in 10 minutes irradiation time were obtained as determined by the aqueous oxalic acid dosimeter. A comparison made of the experimental values with the theoretical ones based on the attenuated gamma flux due to the fission products were in acceptable agreement. Also the requirements needed to obtain reliable results are discussed. (author)

No abstract available

[en] The k₀ standardization for instrumental neutron activation analysis is a relatively new nuclear analytical technique. It is extended i n more than 20 countries of the world with reactor facilities, including some from Latin America. The great advantages of this technique (low uncertainties, fast and massive analysis, no standard necessity) with respect to relative, absolute and radiochemical activation analysis, are the reason of it fast introduction in Geology, Medicine, Agriculture and other fields of applications. But for the k₀ instrumental neutron activation analysis implementation, the good knowledge of some reactor neutron flux and isotopes characteristics is necessary. The non ideality of the epithermal neutron flux temperature (T_n) and the k₀ factors for more than 20 isotopes were determinate in the 3 typical irradiation positions of the TRIGA Mark III reactor of the National Nuclear Research Institute, Salazar, Mexico, using different experimental methods with conventional and non-conventional monitors

[en] The non ideality of the epithermal neutron flux distribution at a reactor site parameter (made, using Chloramine-T method. Radiochemical purity and stability of the labelled product were determined by radiochromatography. The labelled Melagenine-II showed two radioactive fractions thermal-to-epithermal neutron ratio (f) were determined in the 3 typical irradiations positions of the TRIGA Mark III reactor of the National Nuclear Research Institute, Salazar, Mexico, using the Cd-ratio for multi monitor and bare bi-isotopic monitor methods respectively. This characterization is of use in the K_o- method of neutron activation analysis, recently introduced at the Institute

[en] Published in summary form only

[en] Published in summary form only

[en] The isothermic calorimeters, one containing graphite and the other aluminum, were used to measure ionizing radiation doses received in three experimental positions of a TRIGA Mark III reactor core. The dose rates in the positions studied were found to be the following: Central Thimble (CT): (12.8+-0.3) x 10⁵ Gy/h, 64% γ: 36% nsub(f); In-Core Isotope Production Facility (I-CIPF): (5.0+-0.1) x 10⁵ Gy/h, 76%: 24% nsub(f); In-Pool Isotope Production Facility (I-PIPF): (2.0+-0.1) x 10⁵ Gy/h, 80% γ: 20% nsub(f). The solid oxalic acid dosimetric technique was also utilized. Radiolytic decomposition constant (a) values observed in the experimental positions were the following: asub(CT)=17.64+-0.01 MGy; asub(I-CIPF)=17.4+-0.4 MGy; asub(I-PIPF)=17.6+-0.4 MGy. (author)

[en] In the framework of the Technical Cooperation Regional Project for Latin America RLA/4/018 for the biennium 2001-2002, one of the activities identified is the characterization of spent fuel. Of these activities an important one is not doubt the physical condition of spent fuel because an appropriate identification of the fuel status will prevent problems of fuel leaks, corrosion problems etc. As part of the activities of the project was decided that countries no having visual inspection and sipping systems should be very desirable to have them as a result of this project. The Triga reactor of Mexico does not have both of them, therefore, it was decided the need of having both system. The paper describe first the way we designed and constructed a remote Visual Inspection System and example of how is operated. Along the experience and problems we have had with the system. Also we will present the design of the Sipping system were two option were considered. First to take a sample of water after a convenient period of time passing through a circuit to a multichannel analyzer and to identify leakage by way of measuring Caesium-137. Second, exists the possibility that the Stainless Steel sleeve of the fuel has only very small failures, so it is going to be very difficult to have leakages unless the fuel is hot. Therefore we are evaluating the possibility of using heaters to increase the temperature of the fuel and succeed on detecting leakages. The results - we hope - will be ready to be presented at the meeting. (author)

[en] The contention developed a leak that was found on March 15th 1985 in a routine inspection to the exposure room. The maximum water leak reached almost 5 liters per hour, it started to diminish until it disappeared completely two months later. It is believed that the holes were blocked by particles in suspension that were introduced to the primary system during the leaking tests. Immediately after the finding of the leak an inspection, testing and repair program was established. Hydrostatic tests to the primary cooling system and cooling system of the exposure room piping showed that the problem was the aluminum liner and not the piping. In order to have the possibility of inspecting the walls of the tank, the pool was drained from its 7.49 m of water down to 3.6 m of depth. At this point the reactor operation stopped and the inspection work started. Previously gamma radiation doses were evaluated using TLD crystals and was determined that 3.6 m of water column gave 0.1 mR/hr of gamma radiation doses at the surface. (orig./HP)