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Szewczak K.,Central Laboratory for Radiological Protection | Jednorog S.,Poland Institute of Plasma Physics and Laser Microfusion
Physica Scripta | Year: 2014

The Institute of Plasma Physics and Laser Microfusion operates the biggest plasma focus device built so far in the world. It is identified as DPF-1000 U (Dense Plasma Focus Upgrade). The plasma produced by the described device constitutes a pulse of highly effective neutron source with the neutron yield ranging up to 1012 n per impulse. The precise composition of the stainless steel from which the vacuum chamber of the plasma focus device is made, was determined by neutron activation analysis. It was found that nuclear reactions that occur inside the stainless steel are mainly (n, γ), (n, p) and (n, α) reactions. Taking into consideration the neutron energy spectrum and the material composition, 63 nuclear reactions leading to vacuum chamber material activation were identified in total. It was observed that in the first hour after shut-down, the main activity comes from 59Fe and 59Ni isotopes. One year after the shut-down, the main contribution to the observed radioactivity of the experimental chamber material was related to the presence of 54Mn isotope, while after 10 years the only significant contribution to the activity will be made by molybdenum isotopes such as 93mMo and 99Mo. © 2014 The Royal Swedish Academy of Sciences.


Szewczak K.,Central Laboratory for Radiological Protection | Jednorog S.,Poland Institute of Plasma Physics and Laser Microfusion
Journal of Radioanalytical and Nuclear Chemistry | Year: 2016

This paper focuses on radiation exposures to researchers and technicians involved in fusion research. It is the second article in the series on this topic. It discusses immediate exposures to the ionizing radiation that is generated immediately during fusion research performed on the PF-1000, a dense magnetized plasma generator that is the world’s largest. © 2015, Akadémiai Kiadó, Budapest, Hungary.


Szewczak K.,Central Laboratory for Radiological Protection | Jednorog S.,Poland Institute of Plasma Physics and Laser Microfusion
Central European Journal of Physics | Year: 2014

Plasma research poses a radiation hazard. Due to the program of deuterium plasma research using the PF-1000 device, it is an intensive source of neutrons (up to 1011 n · pulse -1) with energy of 2,45 MeV and ionizing electromagnetic radiation with a broad energy spectrum. Both types of radiation are mostly emitted in ultra-short pulses (∼100 ns). The aim of this work was to test and calibrate the RSS-131 radiometer for its application in measurements of ultra-short electromagnetic radiation pulses with broad energy spectrum emitted during PF-1000 discharge. In addition, the results of raw measurements performed in the control room are presented. © 2014 Versita Warsaw and Springer-Verlag Wien.


Szewczak K.,Central Laboratory for Radiological Protection | Jednorog S.,Poland Institute of Plasma Physics and Laser Microfusion
Journal of Radioanalytical and Nuclear Chemistry | Year: 2016

Plasma experiments conducted on the PF-1000 device generate the release of neutrons and ionizing radiation that are the source of immediate exposure to personnel. Neutron activation of materials in the research device and the surroundings is a source of ongoing radiation exposure to the same personnel. Having reported on personnel exposure from ionizing radiation and neutron activation, we now aim to characterize exposure from direct neutron emission generated by the device, and describe the process of ensuring measurement accuracy. © 2016 The Author(s)


Sterlinski S.,Central Laboratory for Radiological Protection
Radiochimica Acta | Year: 2010

It is argued that in the recent papers by A. Vivier and J. Aupiais (Radiochim. Acta 95, 471 (2007) and 96, 385 (2008)) some relevant probability distributions are incorrectly composed. The argument is supported by applying the Feller and Markov formulae. © Oldenbourg Wissenschaftsverlag, München.


Krajewska G.,Central Laboratory for Radiological Protection | Pachocki K.A.,National Institute of Public Health National Institute of Hygiene
Medycyna Pracy | Year: 2013

Background: Due to its use of ionising radiation, the field of nuclear medicine is a unique and significant part of medical diagnostics and patient treatment. The aim of this study was to assess the internal exposure of nuclear medicine employees to radioiodine 131I and technetium 99mTc as well as to assess the external exposure doses. Material and Methods: The radioiodine 131I and technetium 99mTc contents in the thyroid of staff members (about 100 persons) dealing with these radionuclides have been measured in four departments of nuclear medicine. The measurements were conducted with a portable detection unit for in situ measurements of radioiodine and technetium. High sensitivity environmental thermoluminescent dosimeters (TLD) were used to measure the external exposure dose. Results: The average values and ranges of radioiodine 131I activity measured in the thyroids of all of the medical units' employees were: 83 Bq (range: 70-250 Bq), 280 Bq (range: 70-4000 Bq), 275 Bq (range: 70-1000 Bq) for technical staff, nuclear medicine staff and hospital services staff, respectively. The mean value of technetium 99mTc content in the thyroids of nuclear medicine staff was approximately 1500 Bq (range: 50--1800 Bq). External exposure dose rates were in the range of 0.5-10 μGy/h. Conclusions: The calculated average effective dose for particular person caused by the inhalation of radioiodine 131I is below 5% of 20 mSv/year (occupational exposure limit). © Instytut Medycyny Pracy im. prof. J. Nofera w Łodzi.


Zalewska T.,National Water Research Institute | Suplinska M.,Central Laboratory for Radiological Protection
Oceanological and Hydrobiological Studies | Year: 2012

Assessing the impact of ionizing radiation on the marine environment requires a well-defined methodology, which includes, among other elements, the analysis of exposure and effects. One of the most important components of the assessment system is the choice of reference organisms specific for the assessed area that fulfill requirements such as radioecological sensitivity, widespread distribution, and amenability to research and monitoring. The following species specific to the southern Baltic Sea that represent diversified ecological niches were proposed as reference organisms. Polysiphonia fucoides was proposed as a representative of macroalgae. Pelagic and benthic fauna were represented by Crangon crangon (crustacean), Saduria entomon (crustacean), Hediste diversicolor (polychaete), and Mytilus trossulus (mollusc). Fish were represented by Clupea harengus (pelagic planctotrophic fish), Gadus morhua (pelagic carnivorous fish), and Platichthys flesus (benthic fish). Activity concentrations of 137Cs were determined in reference biota as well as in seawater, as required for the total dose-rate evaluation, and relevant concentration factors were calculated. Copyright ©of Institute of Oceanography, University of Gdansk, Poland.


Jaworowski Z.,Central Laboratory for Radiological Protection
Human and Experimental Toxicology | Year: 2010

Personal reflections on radiation hormesis for the past 50 years are presented. The causes of ignoring and rejections of this phenomenon by international and national bodies and by radiation protection establishment are analyzed. The opposition against nuclear weapons and preparations for nuclear war was probably the main factor in inducing the concern for adverse effects of low doses of ionizing radiation, a byproduct of activism against the nuclear weapon tests. UNSCEAR was deeply involved in preparation of the scientific basis for cessation of nuclear test, and contributed to elaboration of the LNT assumption, which is in contradiction with the hormetic phenomenon. However, this authoritative body recognized also the existence of radiation hormesis, termed as 'adaptive response.' The political and vested interests behind exclusion of hormesis from the current risk assessment methodology are discussed.


Zalewska T.,National Water Research Institute | Suplinska M.,Central Laboratory for Radiological Protection
Chemosphere | Year: 2013

This paper presents the results of a study on changes in 137Cs activity concentrations in three fish species from the southern Baltic Sea: cod (Gadus morhua), herring (Clupea harengus) and flounder (Platichtys flesus), in the period 2000-2010. During the study period a marked decline in cesium activity concentration in fish muscle tissue was observed, which reflected changes in radionuclide activity concentration in seawater. No statistically significant temporal trends were determined in changes of concentration factors (CFfish/seawater) calculated for the examined fish species. The analysis of 137Cs activity as a function of ichthyological parameters revealed the lack of a relationship between radionuclide activity concentrations in herring muscle tissue and the fish age in an narrow age range (2-4years). However, a reverse proportionality of total fish mass, as well as body length, against 137Cs activity concentrations in muscles was well documented. The latter observation can be the direct result of the dilution effect related to the increase of fish body weight. 137Cs activity concentration in muscle tissue of the five fish species forms a declining sequence: Gadus morhua, Platichthys flesus, Clupea harengus, Perca fluviatilis and Neogobius melanostomus. © 2012 Elsevier Ltd.


Zalewska T.,National Water Research Institute | Suplinska M.,Central Laboratory for Radiological Protection
Oceanologia | Year: 2013

The radioisotopes of caesium (137Cs) and strontium (90Sr) make the greatest contribution to the radioactivity level due to artificial radionuclides in the Baltic Sea, where the level of 137Cs contamination is higher than in any other part of the world ocean. The main sources of man-made radionuclides are the Chernobyl accident in 1986 and the nuclear weapons tests carried out in the 1950s and 1960s. This study discusses the distribution patterns and trends in activity concentrations of 137Cs and 90Sr recorded in various compartments of the marine environment of the southern Baltic Sea. It is based on an investigation of radioactive substances as part of the Polish National Environmental Monitoring Programme. In 2010 the average concentration of 137Cs in the southern Baltic was 35 Bq m-3, while the level of 90Sr in these waters has remained at much the same level in recent years (ca 8 Bq m-3). The distribution of isotopes in the bottom sediments reflect historical events that can be identified in sediment profiles. The activity concentrations of the caesium isotope are the highest in sediments from the Gulf of Gdańsk, whereas the least polluted sediments are found in the Bornholm Basin, in the western part of the southern Baltic. The highest concentrations of 137Cs in benthic plants were measured in the red alga Polysiphonia fucoides: 22.3 Bq kg-1 d.w. in June and 40.4 Bq kg-1 in September. These levels were much higher than those found in the bivalve Mytilus trossulus (7.3 Bq kg-1 d.w.). 137Cs concentrations in fish have decreased in time, reflecting the trends recorded in seawater. In 2010 the respective 137Cs activities in Clupea harengus, Platichthys flesus and Gadus morhua were 4.7, 4.9 and 6.6 Bq kg-1 w.w. © by Polish Academy of Sciences, Institute of Oceanology, 2013.

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