S. Deme

A new thermoluminescent dosimeter system for space research

A small, portable, vibration and shock resistant thermoluminescent dosimeter system was developed to measure cosmic radiation dose on board a spacecraft. The system consists of a small battery-operated reader and a special bulb dosimeter. Doses from 10 microGy up to 100 mGy can be measured. The electrical power consumption of the reader is about 5 W, its volume is about 1 dm3 and its mass is about 1 kg. Details are given for the construction and technical parameters of the dosimeter and reader.

Dose measurements in space by the Hungarian Pille TLD system

Exposure of crew, equipment, and experiments to the ambient space radiation environment in low Earth orbit poses one of the most significant problems to long-term space habitation. Accurate dose measurement has become increasingly important during the assembly (extravehicular activity (EVA)) and operation of space stations such as on Space Station Mir. Passive integrating detector systems such as thermoluminescent dosemeters (TLDs) are commonly used for dosimetry mapping and personal dosimetry on space vehicles. The well-known advantages of passive detector systems are their independence of power supply, small dimensions, high sensitivity, good stability, wide measuring range, resistance to environmental effects, and relatively low cost. Nevertheless, they have the general disadvantage that for evaluation purposes they need a laboratory or large--in mass and power consumption--terrestrial equipment, and consequently they cannot provide time-resolved dose data during long-term space flights. KFKI Atomic Energy Research Institute (KFKI AEKI) has developed and manufactured a series of thermoluminescent dosemeter systems for measuring cosmic radiation doses in the 10 microGy to 10 Gy range, consisting of a set of bulb dosemeters and a compact, self-contained, TLD reader suitable for on-board evaluation of the dosemeters. By means of such a system, highly accurate measurements were carried out on board the Salyut-6, -7 and Mir Space Stations as well as on the Space Shuttle. A detailed description of the system is given and the comprehensive results of these measurements are summarised.

Thermoluminescent dose measurements on-board Salyut type orbital stations.

A small, vibration- and shock-resistant thermoluminescent dosemeter /TLD/ system--named PILLE--was developed at the Health Physics Department of the Central Research Institute for Physics, Budapest, to measure the cosmic radiation dose on board orbital stations. The first on-board measurements with this system were performed /by B. Farkas, the Hungarian astronaut/, on the Salyut-6 space station in 1980. The same instrument was used by other crews in the following years. Doses measured at different sites in Salyut-6 are presented. The dose rates varied from 0.07 to 0.11 mGy.day-1. After the first cosmic measurements, the system was further developed. The minimum detectable dose of the new TLD system is 1 microGy, i.e. less by on order of magnitude than that of the former system. The self-irradiation dose rate of the TLD bulbs is also reduced--by more than one order of magnitude--to 10 nGy.h-1, by the use of potassium-free glass for the bulb envelope. This new type of PILLE TLD system is currently on-board Salyut-7. The dose rates /0.12-0.23 mGy.day-1/ measured in 1983 are presented in detail.

Twenty years of TLD measurements on board space vehicles by the Hungarian “Pille” system

Publisher Summary On-board personal dose measurements are mainly based on thermoluminescent dosimetry. Because of the large dimensions and big mass of the readers, the TLDs used in space activities are generally evaluated only after their return to the ground, in terrestrial laboratories. The disadvantage of on-ground evaluation is that it results in the dose accumulated since the last read-out, that is, the dose of the whole flight, whereas with the increased duration of space flights periodic and relatively frequent dose measurements would be needed. A small, portable, and space-qualified TLD reader suitable for reading out the TL dosimeters on board provides the possibility of overcoming the above-mentioned disadvantage. Such a system offers a solution for EVA dosimetry as well. KFKI Atomic Energy Research Institute (KFKI AEKI) has developed and manufactured a series of thermoluminescent dosimeter systems for measuring cosmic radiation doses in the 10 μGy to 10 Gy range, consisting of a set of bulb dosimeters and a small, compact, TLD reader suitable for on-board evaluation of the dosimeters. By means of such a system, highly accurate measurements were carried out on board the Salyut-6, -7 and Mir Space Stations as well as on the Space Shuttle and the International Space Station (ISS). A detailed description of the system is given and the comprehensive results of these measurements are summarized in this chapter.

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

Dosimetric complex for long-term manned space flights

Abstract A dosimetric complex is proposed for use in long-term manned space flight on the orbital station and for the planned Mars expedition. This complex includes thermoluminescence dosimeters with on-board readout, a channel for continuous monitoring of dose rate and a channel for continuous measurement of absorbed and equivalent doses, as well as measurement of the LET spectra. The last four parameters are measured by a tissue-equivalent proportional counter.