|
|
Fusion systems and their shielding
Roubal, Michal ; Katovský, Karel (referee) ; Král, Dušan (advisor)
This thesis is concerned with nuclear fusion and its use as a source of energy for humanity. In the first part of my thesis, I will briefly explore the research history of nuclear fusion. Next, I will investigate the various possible issues connected with achieving and sustaining nuclear fusion. I will briefly discuss the importance of mastering it. I will talk about existing and anticipated risks of radiation damage which can occur during nuclear fusion. Lastly, i will discuss the principles of tritium breeding.
|
|
|
Fusion systems and their shielding
Roubal, Michal ; Katovský, Karel (referee) ; Král, Dušan (advisor)
This thesis is concerned with nuclear fusion and its use as a source of energy for humanity. In the first part of my thesis, I will briefly explore the research history of nuclear fusion. Next, I will investigate the various possible issues connected with achieving and sustaining nuclear fusion. I will briefly discuss the importance of mastering it. I will talk about existing and anticipated risks of radiation damage which can occur during nuclear fusion. Lastly, i will discuss the principles of tritium breeding.
|
|
|
An assessment of interferences influence on tritium volume activities measurement in liquid discharges of Temelin NPP
ŘEHÁČEK, Martin
The aim of this bachelor thesis is to evaluate the importance of selected disturbance effects on the accuracy of tritium determination in wastewater by means of liquid scintillation spectrometry. The thesis studies three disturbance effects: the pH of the sample, the UV radiation illumination of the sample and increased background in sample measurement caused by samples containing beta and gamma radiation emitting radionuclides placed inside the analyzer. The TriCarb 2910TR measuring analyzer and Ultima Gold XR scintillation cocktail were used for the study. Four samples with the following tritium volume activity were prepared for the study: < 3,7 Bq/l, 199,1 +- 4.1 Bq/l, 20 298,2 +- 73,5 Bq/l and 2 659 078,8 +- 6555,2 Bq/l. Each sample was influenced by disturbance effects of increasing intensity. For the experiment with the pH effect, a set of 12 samples with a pH ranging from 1 to 12 was prepared. For the illumination of samples, a room illuminated with fluorescent lamps, which are also a source of UV radiation besides visible radiation, was used. To examine the effect of increased background, three samples containing isotopes of caesium 134Cs and 137Cs emitting beta and gamma rays were prepared. Each sample was gradually affected by these disturbance factors and measured ten times. The measured data were statistically processed and evaluated. The conducted experiment and the statistical processing of the results, taking into account the accuracy of the instrument, revealed that the disturbance effects of the increased background of beta and gamma radiation and UV light exposure only have a significant effect on samples with very low tritium activity. In samples with high tritium activity, this effect is insignificant. The examination of the effect of the pH confirmed that the scintillation cocktail used showed satisfactory stability of the efficiency of the conversion of beta radiation to photons in the pH range of 2-12.
|
|
|
Independent monitoring of Nuclear power plant Temelin environs by Regional centrum of SONS České Budějovice. Project of independent monitoring NPPTE in the case of Emergency incident.
ZEMAN, Karel
The State Office for Nuclear Safety (SONS) and the National Radiation Protection Institute (NRPI) are involved in independent monitoring of surrounding areas of nuclear power plants (NPPs), in accordance with the Czech legislative requirements (Decree No. 319/2002 Coll. on radiation monitoring network (RMS), as amended by Decree No. 27/2006 Coll.). The monitoring includes surveillance of environmental samples, in which radionuclides can be detected in case of emergency event, i.e. radioactivity release from the NPP. Another part of the monitoring is measurement of photon dose equivalent, continuously in the air (early detection network - SVZ) or using thermoluminescent dosimeters (TLD) placed in SONS monitoring points in the NPP vicinity. Environmental sampling and evaluation of photon dose equivalent in the air is carried out in regular intervals. The 137Cs and 131I activity is measured by gamaspectrometry method used with Gamat evaluation program, according to SONS internal procedure (VDMI). Tritium activity in surface water is measured by liquid scintillation spectrometer Beta TriCarb made by Canberra Packard Company, according to methodology CSN ISO 9698 (757635). Evaluation of dose equivalent rate is carried out continuously by LB 6360 proportional probe and LB 6500-3 Geiger-Muller tube located in RC Building in Ceske Budejovice. TLD evaluation is carried out by NRPI laboratory in Prague and the results are sent to SONS RC Ceske Budejovice. Goal of this work is to provide a set of results of the independent monitoring in surrounding areas of Temelin NPP (ETE) carried out between 1999 and 2009, by determination of volume, mass or surface activity of environmental samples (137Cs and 131I) and spot samples of water (3H) taken from SONS monitoring points near ETE . The set of such results should provide a baseline reference values for normal (pre-accident) situations. Additionally, based on the long term of the ETE surrounding surveillance, it can be shown that the ETE operation represents no threat to the health of the critical population group, and that the radiation situation in the ETE surrounding is stable. It can be also shown that the ETE operator meets requirements and conditions of authorized limits for discharging radionuclides into the environment. Procedures and method of independent environmental monitoring in the ETE surrounding during emergency events can be proposed on the basis of many years of experience with proven methodologies, experience with sampling locations, staffing and organization of measurement.
|
|
|
3H monitoring in the river Vltava in the surroundings of NPP Temelín
ZEMAN, Karel
The State Office for Nuclear Safety (SÚJB) and the National Radiation Protection Institute (SÚRO) are involved in independent monitoring of the surroundings of nuclear power plants (NPPs) as stipulated by Czech legislation (Decree No. 319/2002 on Czech Radiation Monitoring Network, as amended by Decree No. 27/2006). This monitoring includes examination of samples from the hydrosphere, where any unusual presence of radionuclides can indicate radioactivity leaks from the NPP. Samples are taken weekly (2 sampling sites on the Vltava [Moldau] river downstream of the Temelín waste duct, viz. at Kořensko (downstream of the dam) and at Újezd) and monthly (from 5 sampling sites on the Vltava river {--} 2 upstream of the mouth of the duct and 3 downstream of the mouth of the duct {--} and 1 sampling site at the Býšov precipitation retention basin). A CANBERRA PACKARD TriCarb liquid scintillation beta spectrometer serves to measure the activity of tritium in surface waters in compliance with ČSN ISO 9698 (757635) standard. The aim of this work was to determine volume activity of point samples from the SÚJB monitoring sites in the Vltava river (with focus on Kořensko) and to examine tritium kinetics in dependence on factors such as the times of release from the NPP, flow rate through the Kořensko dam, Orlík basin level height, etc. The feasibility of back-tracing of the activity levels and times of release from the Temelín plant, which could serve SÚJB as a tool to check the data provided by the plant management, is discussed. The data of volume activity of tritium in watercourses in the vicinity of the NPP are in accordance with SÚJB{--}Temelín NPP interlaboratory comparisons. Linked to the known release times and amounts of effluents from the Temelín plant, the results of the measurements allow the propagation of tritium through the watercourse of the Vltava river to be assessed both in the time horizon and with respect to a quantitative estimate of dilution of the radioactivities in dependence on the flow rates. Owing to the fact that radioactivity in the surroundings of the NPP has been monitored for many years now, convincing evidence can be provided demonstrating that the operation of the plant does not endanger the health of the critical group of population living near the plant, that the radiological situation is stable, and that the requirements and conditions of authorized limits regarding the introduction of radionuclides into the environment are complied with.
|
|
|
Comparison of the gaseous and liquid releases of the Czech and world nuclear power plants
DOBEŠ, Petr
In this work, which deals with problematics of releases from nuclear power plants, I tried to make an overview of various types of nuclear power plants and radioizotopes which are released through liquid and gasseous effluents. As a part of this comparison evaluation of czech and world nuclear power plants gaseous and liquid releases was made. Introductory part of this work contains information about different types of nuclear power plants and radioizotopes, which are produced in their reactors. It continues with today{\crq}s legislative and information about releasing levels and methods and systems used for measurement of radioactive gaseous and liquid effluents from nuclear power plants. Second part of this work describes the aim of this work and hypothesis. Third part explains the methods, which were used for completing of this work. Fourth part contains results in the form of tables and graphs. Fifth part represents discussion of the results. Last part is a summarization of the results.
|
|
|
Methods of detection of ionizing radiation egress of nuclear power station
ŠŤASTNÁ, Milena
The approaches to the draining measurements and to the surroundings of nuclear power stations as well as the nuclear machinery changed depending on the development and the availability of measurement hardware as well as the development of models of radionuclide diffusion in the atmosphere and biosphere. In general, it is demanded to monitor systematically the draining of the radionuclides from nuclear reactors. Monitoring of the draining serves for the inspection of permited draining observance and for detection and estimation of possible evasions and their impact on the inhabitants in the workplace neighbourhood and on the environment. I aimed my study at tritium. Tritium is determined by using a liquid scintillation spectrometry. It is a very effective method of detection and spectrometry of ionizing particles. The liquid scintillation spectometry is aimed at low energetic beta emitters and this method can be also used when measuring alpha emitters. Tritium in the drainings to the drainage channels is measured by the same type of measuring equipment both in the Nuclear power station Dukovany and in the Nuclear power station Temelín. Setting of tritium in these nuclear power stations differentiates in sample preparations for measuring and consequently the measured values are not fully comparable.
|
|
|
Estimation of Tritium Activity in the River Vltavawith Respect to the Liquid Wastes from the Nuclear Power Plant Temelin.
ŠKOPEK, Petr
The main goal of this Thesis was to measure tritium activity in the Vltava River and in the vicinity of Temelín Nuclear Power Plant (hereinafter referred to as JETE) with the following objectives: Possibility to use the outlet of waste water damping unit (hereinafter referred to as VTOOV) as a control alerting system for nonstandard events in JETE, furthermore, monitoring of possible correlations between volume activity of tritium measured in VTOOV and activity above the limit value of the first quality class in selected sections of the Vltava River as well as comparison of the measured values with the results of other authors, and, finally, assessment of the relevance of the water quality estimated by the volume activity of tritium to the water quality according to other ingredients, i.e., stable isotopes of some metals and risk elements as well as general physical and chemical indicators. Theoretical part of the Thesis deals with radioactivity in general, activity of tritium, with regard to operation of nuclear plants, over the world and, especially, in the Czech Republic. The actual work consisted of collection of samples at predetermined places, preparation of these samples for measurement and measurement of tritium activity using scintillation spectrometer with liquid scintillator. Furthermore, basic chemical and physical properties of water, concentration of selected elements and also some anions were determined. The collected data were used for classification of waters from individual collection places into quality classes according to ČSN 75 7221. In all analyzed cases no activities were found which exceeded the limit values of liquid outlets from Temelín Nuclear Power Plant, given by regulations issued on waters by the District Health Office in Ceske Budejovice according to §8 of Act No. 138/73 Coll., in compliance with SÚJB requirements. This Thesis could be beneficial for possible utilization of VTOOV as a control alerting system for nonstandard events in JETE and also for assessment of impact of wastewaters from JETE on waters of the Vltava River.
|
|
| |
|
| |
guest ::
