Tamás Pázmándi

Methods, results and dose consequences of 106Ru detection in the environment in Budapest, Hungary

From late September to early October of 2017, the majority of European networks involved in environmental radiological monitoring - including the environmental monitoring system of the KFKI Campus in Budapest - detected 106Ru isotope of artificial origin in the atmosphere. The reported values higher than the minimum detectable activity (MDA) concentrations were in the range of 0.8 μBq/m3 - 145 mBq/m3. Based on the results of environmental measurements and the available meteorological data, assessments were made to analyze concentration levels of 106Ru activity and to help understand the behavior of radioruthenium in various environmental media. Evaluation of the daily variation of activity levels indicated a maximum of 4 day-long residence time of 106Ru contamination presence in ground level air in Budapest. An average 106Ru activity concentration of 25.6 ± 1.4 mBq/m3 have been observed for the estimated residence time of 106Ru in the air. Deposition of 106Ru was dominantly influenced by rainfall, the major contributor wet deposition which led to an average of 11.3 ± 1.3 Bq/m2 deposition on the ground surface prior to plume passage.

The revision of the current radioactive fallout measurements at the KFKI campus in Budapest, Hungary

The permanent improvement of the nuclear environmental monitoring systems and the involved procedures is essential in order to fulfill the regulations in a continually changing regulatory environment, in terms of the recent technical requirements and newest monitoring methods. Considering the necessity of optimization, a holistic examination was started to revise the operation of the environmental monitoring system at the KFKI Campus and configure a reliable system that is able to ensure optimal functioning.

CALIBRATION OF A WHOLE BODY COUNTER FOR 241Am WITH THE LLNL CHEST PHANTOM.

An occupational incorporation event occurred at the Radioactive Waste Treatment and Disposal Facility in December 2013 at Püspökszilágy, Hungary. Internal contamination due to (241)Am was discovered by a regular routine whole body counting measurement at the Centre for Energy Research, Hungarian Academy of Sciences. After that, a whole body counter was calibrated for an organ counting geometry. For preliminary calibration, a home-made MIX-D chest phantom was applied simulating uniform lung activity distribution by (241)Am point sources located in different positions within the lung volume of the phantom. In order to carry out a more precise calibration, a Lawrence Livermore National Laboratory (LLNL) chest phantom was provided by the International Atomic Energy Agency. For counting efficiency over the lungs, values of 0.46±0.19 and 0.55±0.07 cps kBq(-1) were obtained for the MIX-D and the LLNL phantom, respectively; thus, the results are in good agreement.

A New Simulation Code for Analyzing Loss of Coolant Accidents in VVER-440/213 Reactors Concerning Activity Transport

In the Atomic Energy Research Institute, Budapest, Hungary a computer code for modelling the in-containment fission product related processes of a design basis LOCA in VVER-440/213 type nuclear reactors is under development. The model is based on the lumped-parameter approach (the total volume of the simulated containment is divided into distinct, connected sub-volumes in which the parameters are assumed to be homogenous). The structural and functional models of the adequate reactor units are implemented in the code. The main considered physical processes of the fission product elements are radioactive decay, transport by gas flows, removal from the containment atmosphere by adsorption to wall surfaces and wash-out. In order to test the abilities of the code we performed sample calculations for the units of the Paks Nuclear Power Plant, Hungary. In this study the discussion of the first results is presented following a summary of the basics of the physical models implemented in the code.Copyright