Radioactivity Laboratory Research Articles

Occupational health and safety aspects in the handling of cryogenic materials in nuclear and radiological facilities

Cryogenic materials, widely used in industries and facilities associated with nuclear technology and science and radiological applications, pose occupational health and safety hazards owing to their unique properties. The major health hazards include cold burns, asphyxiation, hot burns, and major safety hazards are explosion, fire, and equipment failure. Risk assessment consistent with material safety data sheet and hazard analysis is essential to assess the potential dangers while using cryogenic materials. Safe handling of cryogenic materials in nuclear and radiological facilities requires special considerations to ensure the protection of personnel and the environment. Administrative measures such as access control, training, checklists, and engineering controls such as ventilation, gas detection systems, and purging techniques are applied to deal with cryogenic hazards. Many personal proactive equipments are available to protect users from cryogenic hazards. While some protective measures for cryogenic hazards could suffice for low radioactivity laboratories, additional personal protective equipments are required to protect workers from radiation exposure in workplaces with potentially significant radiation hazards. The formulation of preparedness plans for emergencies resulting from cryogenic hazards should essentially take into account the unique constraints and requirements of radiological facilities. Simultaneous occurrence of radiological and cryogenic emergencies presents complex challenges requiring special mitigative measures.

Dose rate assessment of 137Cs to mussels and pelagic fish from the combined use of field measurements, satellite data and the ERICA Assessment Tool

Cesium-137 (137Cs) is the most important indicator of radioactive pollution in the marine environment due to its half-life (Tph: 30.2 years), its high fission yield, its solubility (70% in ionic form) and its bioavailability (similar to potassium). Soluble radionuclides, like 137Cs, in the seawater are associated with physicogeochemical and biological parameters of the marine environment (e.g. temperature, water density, biota exchange processes, water mass translocation etc.). Considering this characteristic, we investigate the potential relation between 137Cs activity concentration and sea surface temperature (SST). The parameter of SST is selected, as the element of cesium in the seawater is conservative and its horizontal and vertical dispersion depends on the water mass translocation and water currents. Water mass translocation and water currents are processes that are both governed by the SST. SST also influences the uptake of 137Cs in some marine organisms as it makes it more bioavailable and affects the biological retention time and the elimination rate. The study area is the Gulf of Corinth (Greece). Cs-137 in the Gulf of Corinth originates from water runnoff from the land (Chernobyl fallout from 1986) and a small influence exists from the Ionian and Aegean Sea water currents. A total of 17 measurements spanning 2004-2005, of 137Cs activity concentrations were retrieved from the Environmental Radioactivity Laboratory (ERL) database of NCSR “D”. Furthermore, SST measurements issued from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS). Databases of 137Cs activity concentrations and SST are used for regression analysis and definition of a linear model. The estimated 137Cs activity concentrations obtained by the model are then compared with the newest measured values obtained by seawater samples from September and November 2018 (a total of 8 seawater samples). Estimated concentrations present a relative difference of about 9% to the measured values. In order to conduct the risk assessment analysis in the studied area, the dose rates are calculated for marine organisms. The selected marine organisms are mussels and pelagic fish that are abundant in the area and have significant commercial value, with mussels also being an important bioindicator of marine pollution. The total dose rates in these organisms (resulting by both the internal and external exposure) vary from 3.30 × 101 to 5.40 × 101 μGy/year for the mussels and from 2.97 × 10-1 to 4.86 × 10-1 μGy/year for pelagic fish, which are much lower that the intervention levels, indicating low impact due to the 137Cs exposure.

The 64Zn-based production route to 64Cu β ± emitter using accelerator-driven 14 MeV fusion neutrons

The development of personalized medicine is important to avoid unnecessary and expensive treatments. The theranostic approach is an established tool for specific molecular targeting, both for diagnostics and therapy. Radionuclides used for theranostic radiopharmaceuticals are typically produced in nuclear fission reactors or bio-medical cyclotrons. Here, an alternative route for producing an emerging theranostic radionuclide, namely 64Cu, is investigated by using 14 MeV fusion neutrons produced by the Frascati Neutron Generator (FNG) at the ENEA Frascati Research Centre. Samples of zinc (natural and 64Zn-enriched) were irradiated and characterized, in turn being measured at high-level metrological conditions, at the Radioactivity Laboratory of ENEA-INMRI located in Casaccia Research Centre. The results achieved in the experiments are presented and compared to those obtained by Monte Carlo simulations and previously published experimental data.

Long term 7Be deposition in Romania

This study is based on monthly 7Be deposition data at 29 of the stations of Romania's National Environmental Radioactivity Surveillance Network (NERSN), with different geographical and climatological conditions, extending over periods up to 17 years (1979–1995). The 7Be activity in each monthly sample from each station was determined using high-resolution gamma-ray spectrometry performed at the Environmental Radioactivity Laboratory, Bucharest-Afumati.The annual dynamics of atmospheric deposition of 7Be at each NERSN station showed a strong seasonal trend, very similar to the precipitation regime, with the highest values being observed in spring/summer and the lowest in winter. But the annual 7Be deposition fluxes varied broadly from station to station and year to year, from a minimum of 164 Bq/m2/y (Bechet, 1989) to a maximum of 1388 Bq/m2/y (Baia Mare, 1988). This large space-time variability of deposition was mainly due to the variability of the precipitation regime.The analysis of experimental data confirms the strong correlation of 7Be deposition data with precipitation, air temperature and the number of sunspots.Wet and dry deposition data are presented and discussed for four stations where separate dry and wet 7Be deposition measurements were performed.

Determination and mapping of the spatial distribution of cesium-137 in the terrestrial environment of Greece, over a period of 28years (1998 to 2015).

In this study, we are applyingthe GIS techniques in order to record the data that have been collected for cesium-137, over the for the period 1998 to 2015, for the terrestrial environment in Greece. Following the Chernobyl Nuclear Power Plant (CNPP) accident in 1986, extended fieldwork was conducted for the determination of cesium-137 concentrations in the terrestrial environment. In 2011, in the light of the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident, new campaigns were organized in order to assess the variation in cesium-137 activity concentrations. The measured data, combined with data taken from the databases of the Environmental Radioactivity Laboratory (NCSR'Demokritos', inAthens, Greece), as well as, from the European Atlas of Cesium Deposition on Europe, are being used for the spatial distribution analysis of cesium-137 in the country. Furthermore, are used for the temporal analysis of this radionuclide in a long-term basis. Moreover, we are usingthe ERICA AssessmentTool for the calculation of the dose ratethat the studied organisms (plants of Poaceae spp. and mammals of Bovidae spp.) receive due to the exposure to cesium-137. All gathered information provides uswith thematic maps, designedthrough the GIS techniques, that allow for an appropriate representation of cesium-137 presence in the country nowadays. This study provides an insightful view of the behavior of this anthropogenic radionuclide that isuseful for future research in order to elucidate its behavior in long-term periods. The knowledge of the environmental fate of radionuclides is important because it contributes to the projection of long-term risks resulting from radionuclide releases, as well as, forthe selection of cost-effective remediation strategies. Furthermore, it provides the opportunity to conduct a comprehensiverisk assessmentin the region, as thestudied organisms were exposed to low-level ionizing radiation. But, as it was shown, on the level of ecosystem, no significant impact was estimated. However, regarding the future objectives, further consideration of the exposure levels should be considered while taking also into account the exposure to natural and background radiation and the exposure to spontaneous emission of anthropogenic radionuclides, especially if we want to consider the eventual effects of protracted low-level ionising radiation on the various levels of life's organization.

A Custom Low-Noise Silicon Photodiode Detector Designed for Use With X-Ray Capillary Optics

We present the first results of a custom low-noise silicon photodiode detector designed for use with X-ray capillary optics. This system is intended to perform as a smaller, lighter, and low-powered alternative to currently existing X-ray telescope technologies. The detector has an active area with a diameter of 100 μm, and its small size leads to a low capacitance of well under 1 pF and a leakage current of 1 pA or less at the depletion voltage. We tested the detector with both a discrete preamp and an ultralow-noise front-end application-specific integrated circuit (ASIC). The front-end ASIC, developed at Brookhaven National Laboratory, was designed for low-capacitance detectors but had not been previously tested with a detector. Here, we discuss the detector design, the experimental setup, and the resulting detector performance. Using radioactive laboratory sources, we measure a full-width at half-maximum (FWHM) of 211 ± 8 eV at 5.9 keV with the ASIC and are able to set the threshold as low as 0.6 keV.

On the Quality Control for the Determination of Ultratrace-Level 236U and 233U in Environmental Samples by Accelerator Mass Spectrometry.

Our recent attempt to determine ultratrace-level 236U and 233U in small-volume seawater samples was challenged by high and unstable procedure blanks in our environmental radioactivity laboratory, which used to be a spent fuel research facility. Through intercomparison experiments with different laboratories and background checks on the chemical reagents and laboratory dust, the resuspended U-bearing dust was identified as the dominating source of the 236U and 233U contamination. With the implementation of background control (especially dust control) measures, the procedure blanks and detection limits of 236U and 233U for the radiochemical separation procedure have been significantly improved by three orders of magnitudes. With well-controlled blanks, the analytical precision for 236U and 233U predominantly relies on the AMS counting statistics. Background check and dust control are strongly recommended before the analyses of environmental-level long-lived radionuclides (such as 236U and 233U) that are conducted in the former or active nuclear facilities, even if clearance of radioactivity relevant for radioprotection was achieved.

Air Quality and sick building syndrome symptoms in a public building in Athens, Greece

Air Quality and sick building syndrome symptoms in a public building in Athens, GreeceIoannis Nezis1, George Biskos2,3, Konstantinos Eleftheriadis4, Prodromos Fetfatzis4, Olga Popovicheva5, Nikolay Sitnikov6, Olga-Ioanna Kalantzi1*1 Department of Environment, University of the Aegean, Mytilene, 81100, Greece2 Climate and Atmosphere Research Center, The Cyprus Institute, Nicosia, Cyprus 3 Faculty of Civil Engineering and Geosciences, Delft University of Technology, Delft, The Netherlands 4 Environmental Radioactivity Laboratory, N.C.S.R. “Demokritos”, 15310 Ag. Paraskevi, Greece5 Institute of Nuclear Physics, Moscow State University, 119991, Moscow, Russia6 Central Aerological Observatory, Moscow region, 141700, RussiaBackground: The objective of this study was to investigate the concentrations of particulate matter (PM2.5) and Black Carbon (BC) and the prevalence of sick building syndrome (SBS) symptoms of civil servants working in a public building in the center of Athens, Greece.Methods: Continuous air measurements were carried out from March until May 2016 (24 hours, 7 days per week) in four different types of rooms, including an office, a printer room and two filing rooms, representing both high and low exposure environments. Data on SBS symptoms was collected from 73 employees.Results: Indoor PM2.5 and BC concentrations in the office ranged from 5.9 to 14.3 μg/m3 and 1.1 to 1.9 μg/m3, respectively. During working hours the indoor PM2.5 and BC to outdoor ratio (I/O) was higher than 1. The most commonly reported SBS symptoms were irritation of the eyes, a stuffy or runny nose, headache and drowsiness. These symptoms occurred “often” or “always” and subsequently disappeared after leaving the building. Female employees were more likely to report SBS symptoms than male employees (“Unusual tiredness or fatigue” OR = 5.4; “feeling depressed” OR = 4.1).Conclusions: PM2.5 and BC concentrations varied substantially between the different rooms depending on the ventilation, construction characteristics and indoor activities.

A Mixed-methods Approach for Improving Radiation Safety Culture in Open-source University Laboratories.

The radiation safety culture of those working in university open-source radioactive material laboratories was assessed by conducting both surveys and behavioral observations. Baseline results (n = 82, 89% response rate) of assessed safety culture categories indicated safety practices and safety compliance were the most in need of improvement. Specific training based on these results was provided to laboratory members at Princeton University, with creative signage and a safety newsletter posted in and around laboratories for reinforcement, in a targeted effort to improve the radiation safety culture. Signage posted utilized pop cultural memes and other engaging graphics designed to raise awareness of appropriate safety practices and the minimum laboratory attire expected while working in radioactive material laboratories. Postintervention results (n = 38, 43% response rate) indicated improvement in 4 out of the 10 safety culture indicators considered as well as fewer instances of improper safety practices. Collaborative techniques and increased communication between researchers and radiation safety staff appear to have initiated an improvement in the radiation safety culture in open-source radioactive material laboratories at Princeton University.

Gamma spectrometry and LabSOCS-calculated efficiency in the radiological characterisation of quadrangular and cubic specimens of hardened portland cement paste

Pursuant to European Directive 2013/59, materials additioned with NORM waste must be characterised radiologically to determine their acceptability for use in construction. The radionuclides studied to judge that acceptability, 232Th, 226Ra and 40K, are normally measured with gamma spectrometry. Gamma detectors are calibrated by using standards as similar as possible in dimensions and chemical composition as the matrix in the samples to be measured. In light of the broad spectrum of chemical and physical characteristics of NORM samples, experimental calibration is often beyond the means of gamma spectrometry laboratories. As a result, Monte Carlo-based methods are deployed to simulate the experimental setup consisting in detector and sample, both geometrically and chemically. Canberra Industries’ LabSOCS (Laboratory Sourceless Calibration Software) is one of the tools available for such calculations. This study verified the accuracy and precision of the counting efficiency delivered by LabSOCS, both with the standard powder geometry and a new geometry consisting in a 5 cm cubic specimen of Portland cement paste. The findings showed that in both geometries the accuracy and precision of LabSOCS-calculated efficiency (by specimen height and activity), across an energy range from 45.64 keV (210Pb) to 1460.82 keV (40K) met the acceptability criteria routinely applied in environmental radioactivity laboratories. The geometry proposed yielded activity values for the end construction material closer to the true indices than the conventional method consisting in summing the partial activities of the unreacted components.

Efficiency calibration of a well-type HPGe detector using experimental and Monte Carlo simulation techniques

Well-type high-purity germanium detectors are well suited for the analysis of small samples, as they combine high detection efficiency with low background radiation. The well geometry however makes efficiency calibration more difficult than that of ordinary HPGe detectors, due to intense true coincidence and possibly random summing effects. Such a detector has been installed at the Environmental Radioactivity Laboratory of the National Centre for Scientific Research "Demokritos". For the calibration of this detector, experimental and Monte Carlo simulation techniques were applied. To this end, calibration sources were produced from the radionuclides available at the Environmental Radioactivity Laboratory. Starting from the geometrical characteristics of the detector as provided by the manufacturer, using the calibration sources and applying Monte Carlo simulation techniques, the detector was characterized and peak efficiency, as well as total-to-peak calibration curves were produced. The results of the calibration finally obtained by simulation are found to be in good agreement with the respective experimental calibration results.

Activities and prospects of the Radioactive Materials Management Laboratory at the NCSR “Demokritos”

The Radioactive Materials Management Laboratory (RMML) was established in July 2013. The RMML is the sole laboratory in the country that holds the know-how in all the fields of radioactive waste management and decommissioning of nuclear facilities.The challenge for the Laboratory is the prospect of development of the Centralized Infrastructure of the country for Radioactive Waste at the NCSR D.

Knowledge Against Cancer: The Second Step

Background and context: The Institute of Oncology and Radiology of Serbia (IORS), supported by the Ministry of Health, launched the project Knowledge Against Cancer in 2015, whose aim was to prepare educational material for cancer patients. Thirteen brochures were presented on WCC in Paris in 2016. The IORS conducted a survey among oncology patients in January 2017 for them to evaluate the distributed brochures and suggest the topics for new educational material. Aim: This paper aims at evaluation of brochures for cancer patients which were created during the project and its primary goal is to define new topics for future educational material. Strategy/Tactics: The study includes 348 respondents (92% women, 8% men) with average age of 54.77 ± 13.26 and predominantly highly educated (45.4%). 90% of the respondents has evaluated this kind of educational material as significant. The study has also examined the choice and relevance of topics and the quantity and usage potential of new data. The analysis has shown that most patients are interested in including psychological aspects of cancer treatment as a new topic (76%) and in including topics concerning healthy lifestyles (69%). As the majority of the respondents are women, the significant interest has been shown for topics concerning lifedem and tumor radiation of female genital organs (over 85% of female respondents). Based on the results obtained through survey and consultations and interviews with patient support group and patients associations the educational brochures were created. Program/Policy process: In 2017, nine new topics were prepared by multidisciplinary teams from IORS: Brochure: psychological support for oncology patients, the manual for family and friends, the manuals for patients on radiation of tumors on female genital organs, for head and neck tumors, lymphoedema - prevention and treatment, treatment of thyroid gland cancer with radioactive iodine, tumor markers and laboratory diagnostic, prevention of malign illnesses and quitting smoking. Outcomes: Brochures are currently available both in paper and on the Web site free of charge. The design of mobile phone application is planned for the future. The educational material is not only presented and distributed to cancer families and the public but also to health professionals and medical workers. What was learned: The research has shown that this educational material is very important for cancer patients and that with adequate information and data such patients can improve life quality predominantly through the reduction of fears and anxiety, development of coping mechanisms to deal with the cancer diagnosis and treatment and encouraging them to take active part in cancer treatment.

Laboratory Radioactive Protection and Safety Management

In order to strengthen the safety management of radioactive laboratories, ensure the safety of laboratory radioactive protection and management, This paper, according to the relevant national laws and regulations, combined with the characteristics and commitment of radioactive laboratories, analyzed the existing hazards, the protection and management measures that should be taken during radioactivity laboratories or in radioactive practice. Adhere to the principle of ″prevention in the first place and integrating prevention with control″ to ensure radiation safety, and environmental pollution.

Intercomparison of full energy peak efficiency curves for an HPGe detector using MCNP6 and GEANT4

This work is focused on studying the capabilities of different Monte Carlo tools to complement the Full Energy Peak Efficiency (FEPE) calibration procedures of the Environmental Radioactivity Laboratory of the Universitat Politècnica de València, UPV. In this frame, detailed models of a High Purity Germanium detector have been implemented using MCNP6 and GEANT4. Accordingly, an inter-comparison with experimental values ensures the model validation and improves the analysis of the physics phenomena involved. The validation of the models is determined by a quantitative comparison between the simulated and the measured efficiencies over the energy range under study (59.54–1836.01 keV). The results show discrepancies between both Monte Carlo tools for 139Ce, 88Y and 60Co as GEANT4 is able to simulate the coincidence summing effect of these radionuclides.

14 MeV neutrons for medical application: a scientific case for 99Mo/99Tcm production

99Tcm is a widely used radionuclide for SPECT (Single Photon Emission Computed Tomography) diagnostics thanks to its short half-life (about 6h) and the low-energy gamma ray emission (140 keV) well suited for diagnostic devices. The specific method for producing 99Tcm via 100Mo(n,2n)99Mo reaction, as it was investigated in ENEA, is discussed in detail in this paper. The 99Mo activity achieved by means of 14 MeV neutron irradiation on natural Molybdenum sample irradiated at the Frascati Neutron Generator (FNG) facility, at the Research Centre of ENEA-Frascati, was accurately assessed, by tracing it to the activity standards provided by the Italian National Institute of Ionizing Radiation Metrology (INMRI), located at the Research Centre of ENEA-Casaccia. The whole experiment carried out in ENEA was supported by simulations performed with the Fluka Monte Carlo code, whose predictions have been benchmarked against the experimental data collected at ENEA-FNG, relying on the traceability to the activity standards developed and maintained at the ENEA-INMRI Radioactivity laboratories.

Preliminary assessment, by means of Radon exhalation rate measurements, of the bio-sustainability of microwave treatment to eliminate biodeteriogens infesting stone walls of monumental historical buildings.

The main purpose of the work described in this paper has been to establish the protocol for a new non-disruptive technique of intervention, based on microwave treatment, for cleaning operations on monumental historical buildings, to eliminate biodeteriogens infesting stones. Non-destructive methods in the cleaning operations, should not only preserve the physical integrity, the chemical-mineralogical and structural identity of materials, but, when the exhalation of pollutant agents (like for example Radon gas) from building materials is considered, also, make the indoor air quality (IAQ) levels healthy. Therefore, one of the main steps of the protocol proposed in this paper is concerned with the assessment of the Radon exhalation rate in order to verify that microwave treatments do not increase the Radon naturally exhalated by building materials. In this paper, the preliminary results of the Radon measurements performed on two different type of tuff samples (grey tuff and yellow tuff), typical of the Italian traditional construction heritage, with the E-PERM passive technique at the Environmental Radioactivity Laboratory (Amb.Ra.), University of Salerno, Italy, ISO 9001:2008 certified, are summarized.

Radon measurement laboratories. An educational experience based on school and university cooperation

There is a growing interest in engaging students and the general public about the meaning and objectives of doing science. When it is possible students can learn by actively engaging in the practices of science, conducting investigations, sharing ideas with their peers, teachers and scientists, learning to work with measuring apparatuses, to acquire and process data and use models so as to interpret phenomena. This is a process that requires a gradual collective growth. Schools and universities can both benefit from this cooperation. This paper presents activities of a project focusing on the radon survey in high schools. The ENVIRAD (environmental radioactivity) educational project involved about 2500 students and some tens of teachers in measurements while using solid state nuclear track detectors. This experience began about 15 years ago and is still carried out by various national projects managed by the same research group. The measurements and data analysis have been done in school laboratories and in the university radioactivity laboratory. Several hundred students were also involved in the transduction and signal processing. In some cases, pupils have also been involved in citizen awareness and the dissemination of this experience has kicked off a follow-up project explicitly addressed to citizens. The project has led to the opportunity to learn science through a real physics experiment. The students’ enthusiasm allowed the collection of a relevant amount of data which benefitted both the regional survey on radon and the improvement of nuclear physics teaching at school. Through the project activities it was possible to recognize the interdisciplinary connections among different scientific disciplines connected to radioactivity.

Simulation of Gamma Rays Attenuation Through Matters Using the Monte Carlo Program

This research focuses on simulation of the radiation attenuation using a Monte Carlo program called GEANT4. In the simulation, properties and geometries of the shielding system including thickness and element of the shielding material can be varied. The radiation in gamma rays regime is considered to be emitted from a Cs-137 radioactive source. The number of gamma photons at specific energy of 661.7 keV is calculated to compare the ability of radiation attenuation for different shielding materials with variable thickness. In addition, the experimental investigation was performed for three materials, which are lead, aluminum and iron, by using a NaI(Tl) scintillation detector. Then, the XCOM database were calculated to compare the results with the simulation. Both XCOM and simulation data as well as the experimental results are agreed well to the theoretical suggestion. Consequently, the results from Monte Carlo simulation with program GEANT4 can be used to design the radiation shielding system for radioactive laboratories, particle accelerator institutes, radiotherapy area in hospitals, nuclear power plants, etc.

Radon Mitigation Approach in a Laboratory Measurement Room.

Radon gas is the second leading cause of lung cancer, causing thousands of deaths annually. It can be a problem for people or animals in houses, workplaces, schools or any building. Therefore, its mitigation has become essential to avoid health problems and to prevent radon from interfering in radioactive measurements. This study describes the implementation of radon mitigation systems at a radioactivity laboratory in order to reduce interferences in the different works carried out. A large set of radon concentration samples is obtained from measurements at the laboratory. While several mitigation methods were taken into account, the final applied solution is explained in detail, obtaining thus very good results by reducing the radon concentration by 76%.