National Repository of Grey Literature 46 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Potential Radioactive Hot Spots Induced by Radiation Accident Being Underway of Atypical Low Wind Meteorological Episodes
Pecha, Petr ; Tichý, Ondřej ; Pechová, E.
Hypothetical radioactivity release with potentially high variability of the source strength is examined. The interactions of the radioactive cloud with surface and atmospheric precipitation are studied and possible adverse consequences on the environment are estimated. The worst-case scenario is devised in two stages starting with a calm meteorological situation succeeded by wind. At the first stage, the discharges of radionuclides into the motionless ambient atmosphere are assumed. During several hours of this calm meteorological situation, a relatively significant level of radioactivity can be accumulated around the source. At the second stage, the calm is assumed to terminate and convective movement of the air immediately starts. The pack of accumulated radioactivity in the form of multiple Gaussian puffs is drifted by wind and pollution is disseminated over the terrain. The results demonstrate the significant transport of radioactivity even behind the protective zone of a nuclear facility (up to between 15 and 20 km). In the case of rain, the aerosols are heavily washed out and dangerous hot spots of the deposited radioactivity can surprisingly emerge even far from the original source of the pollution.
Adaptation of SW for estimation of radiologic impact of incidental releases of radionuclides\nfrom spent fuel storages.
Pecha, Petr ; Pechová, E.
Analysis of implicit group of radionuclides and its extension included nuclides with long half-llive of decay. Selection from spent fuel inventories. Selection from fision products, transurans an actinide group. Estimation of possible uncertainties. Comparison analysis is done betřween HARP and European COSYMA codes.
Simulation of potential occurrence of hot-spots in the case of radioactivity releases during atypical meteorological episodes
Pecha, Petr ; Tichý, Ondřej
Simulation of accidental releases of radioactiity during calm meteorological situations in relations with planned nuclear spent fuel storages. Approximation of discrete Gaussian puffs is introduced. After some time the stationary calm field is assumed to be scattered by wind flow. In the 3dr hour of the wind-flow phase under rain commencement some surprised hot spots of CS137 on terrain have occurred in rather far distances from the source of discharges.
An assessment of radiological consequences of accidental radioactive releases from repositories of spent nuclear fuel
Pecha, Petr
The investigation of potential accidental releases o radionuclides from spent fuel repositories is resumed. Short-term life of radionuclides are assumed to be subsided and decisive role in radiological impact assessment have lradionuclides with long half-lives. Further decrease of radioactivity is then very slow. Comparable analysis of the results acquired by HARP code developed in ÚTIA with results of European code COSYMA is presented.
Research on advanced methods of detection, assessment and subsequent management of radioactive contamination
Kuča, P. ; Pecha, Petr
Summary Report containing the desired information and handover protocol concerning the Contract of expert support in modeling research of modern detection methods with a focus on assessing the impact of simulation radiological events on nuclear facilities.
Validation of the deterministic kernel HAVAR-DET of the HARP system and its applications in the field of radiological impact assessment
Pecha, Petr ; Pechová, E.
Validation of deterministic kernel of the HAVAR-DET systém designed for description of the radioactivity propagation through the living environment. Illustration of applications for various scenarios of the discharges of radioactivity into the atmosphere.
Progress of deterministic code HARP and its probabilistic extension
Pecha, Petr ; Hofman, Radek ; Pechová, E.
Development of environmental code HARP for analysis of radioactivity propagetion through the living environment. Assessment of health consequences of accidental discharges of activity.
Data assimilation methods used in the ASIM module
Šmídl, Václav ; Hofman, Radek ; Pecha, Petr
Comprehensive review of data assimilation methods for improvement of the model predictions of consequences of a radiation accident. The methods of the numerical optimization techniques and sequential Monte Carlo techniques are implemented. Applications in the field of consequence assessments are presented.
Variability and uncertainty in the estimates of ingestion benefits
Pecha, Petr ; Pechová, E. ; Hofman, Radek
V příspěvku zmiňujeme některé ak- tivity týkající se rozvoje ingesč- ního modulu softwarového produktu HARP (HAzardous Radioactivity Pro- pagation) vyvíjeného pro predikci ší- ření radioaktivního znečistění v život- ním prostředí.
Modelling the impact of a hypothetical release of radionuclides from a nuclear facility applications ESTE and HARP
Kuča, P. ; Prouza, Z. ; Češpírová, I. ; Marešová, B. ; Pecha, Petr ; Hofman, Radek
Příspěvek prezentuje výsledky modelování dopadů hypotetického úniku radionuklidů z jaderného zařízení do ovzduší aplikacemi ESTE ETE (ABmerit) a HARP (ÚTIA) implementovaných v SÚRO.

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