35 research outputs found
Mitigation Techniques for Interior Radon in Refurbishment Work in High Radiation Areas of Galicia: An Experimental Model to Test Building Solutions
Radon is a naturally occurring radioactive gas, which tends to
accumulate inside built structures. It is therefore necessary to include
techniques to mitigate radon concentration during refurbishing work.
The aim of this study is to assess the effectiveness of a number of
mitigation techniques, under real conditions, to determine which is
most suitable, in each case, for use in rebuilding solutions. The
methodology consisted in performing four experimental tests on
mitigation strategies recommended by the Código Técnico de la
Edificación (Technical Building Code) (CTE-DB-HS6) and by the
Government of the Autonomous Community of Galicia, (Xunta de
Galicia, 2018). The concentration was measured with three different
systems: radon in soil at 80 cm, passive detectors to confirm mean
concentration, and continuous monitoring by devices calibrated at the
LaRUC Laboratory of the University of Cantabria, in order to compare
the results of the tests. The experiments were carried out in premises
located in a high radiation area in Arteixo (La Coruña, Spain). Four
experimental models were designed, corresponding to each of the
building solutions under study, and tested over a period of 16 days in
two repeated series of trials. The results obtained show that, of the
different strategies tested, pressurising the living space achieves an
efficient reduction of the radon concentration with a significant
simplicity of construction. This solution, compatible with the minimal
intervention and reversibility principles stablished in the charters of
Venice, Krakovia and Nara, is shown to be especially useful when
work is carried out on structures considered to be part of protected
heritage
Optimization of a portable liquid scintillation counting device for determining 222Rn in water
The new EU Council Directive 2013/51/Euratom of 22 October 2013 introduced limits for the content of 222Rn in drinking water. Radon analysis in water requires a lengthy task of collection, storage, transport and subsequent measurement in a laboratory. A portable liquid scintillation counting device allows rapid sampling with significant savings of time, space, and cost compared with the commonly used techniques of gamma spectrometry or methods based on the desorption of radon dissolved in water. In this study, we describe a calibration procedure for a portable liquid scintillation counting device that allows measurements of 222Rn in water by the direct method, and we also consider the case of 226Ra being present in the sample. The results obtained with this portable device are compared with those obtained by standard laboratory techniques (gamma spectrometry with a high-purity Ge detector, gamma spectrometry with a NaI detector, and desorption followed by ionization chamber detection)
Measurement and mitigation of radon concentration in a traditional dwelling in Galicia, Spain
Radon is a naturally occurring radioactive gas which tends to build up within structures. It is therefore necessary to include techniques to mitigate radon concentration when undertaking refurbishment. The goal of this study is to assess the effectiveness of a mitigation technique based on pressurizing the interior of a building, by testing a prototype of the mitigating device, developed by Siglo 21 Consultores and the LaRUC of the University of Cantabria, under real conditions, to determine its effectiveness during refurbishment. The methodology involved installing the proposed solution in a traditional country dwelling in an area characterized by high radon concentration, on the coast of Galicia, Spain. In order to measure the effectiveness of the solution, continuous measurement sensors, set in an ionization chamber, and properly calibrated by the LaRUC laboratory, were installed. The results obtained show that pressurizing the living quarters brings about an effective reduction in the radon concentration, with a relatively simple building solution. This solution, which is compatible with the principle of minimum intervention, is seen to be especially appropriate when work is undertaken in structures recognized as heritage
A new methodology for defining radon priority areas in spain
One of the requirements of EU-BSS (European Basic Safety Standards) is the design and implementation of a National Radon Action Plan in the member states. This should define, as accurately as possible, areas of risk for the presence of radon gas (222Rn) in homes and workplaces. The concept used by the Spanish Nuclear Safety Council (CSN), the body responsible for nuclear safety and radiation protection in Spain, to identify "radon priority areas" is that of radon potential. This paper establishes a different methodology from that used by the CSN, using the same study variables (indoor radon measurements, gamma radiation exposure data, and geological information) to prepare a radon potential map that improves the definition of the areas potentially exposed to radon in Spain. The main advantage of this methodology is that by using simple data processing the definition of these areas is improved. In addition, the application of this methodology can improve the delimitation of radon priority areas and can be applied within the cartographic system used by the European Commission-Joint Research Center (EC-JRC) in the representation of different environmental parameters
Knowledge based recursive non-linear partial least squares (RNPLS)
Producción CientíficaSoft sensors driven by data are very common in industrial plants to perform indirect measurements
of difficult to measure critical variables by using other variables that are relatively easier to obtain.
The use of soft sensors implies some challenges, such as the colinearity of the predictor variables,
the time-varying and possible non-linear nature of the industrial process. To deal with the first
challenge, the partial least square (PLS) regression has been employed in many applications to model
the linear relations between process variables, with noisy and highly correlated data. However, the
PLS model needs to deal with the other two issues: the non-linear and time-varying characteristics
of the processes. In this work, a new knowledge-based methodology for a recursive non-linear PLS
algorithm (RNPLS) is systematized to deal with these issues. Here, the non-linear PLS algorithm is set
up by carrying out the PLS regression over the augmented input matrix, which includes knowledge
based non-linear transformations of some of the variables. This transformation depends on the system’s
nature, and takes into account the available knowledge about the process, which is provided by expert
knowledge or emulated using software tools. Then, the recursive exponential weighted PLS is used to
modify and adapt the model according to the process changes. This RNPLS algorithm has been tested
using two case studies according to the available knowledge, a real industrial evaporation station of
the sugar industry, where the expert knowledge about the process permits the formulation of the
relationships, and a simulated wastewater treatment plant, where the necessary knowledge about the
process is obtained by a software tool. The results show that the methodology involving knowledge
regarding the process is able to adjust the process changes, providing highly accurate predictions.Este trabajo forma parte del proyecto de investigación: MINECO/FEDER: DPI2015-67341-C2-2-R
Radon concentration in caves as a proxy for tectonic activity in the cantabrian mountains (Spain)
Radon (Rn) constitutes a good geochemical tracer for neotectonic activity in faults since associated fracturing near the surface favours fluid escape to the atmosphere. In this contribution, we measured the Rn concentration in the air inside karst caves to constraints the recent fault activity in the Cantabrian Mountains (N Spain). Rock formations exhumed during the uplifting of the Cantabrian Mountains record a long history of fracturing, which has the potential to connect deeper sources of Rn with the surface. In this regional study, we correlate Rn measurements with cave survey data and geological structures using a Geographic Information Systems. Thirty-four Rn average concentration was recorded by CR-39 detectors during 8 integrated months. The method is applied to the central part of the Cantabrian Mountains that is built on sedimentary and low-grade metamorphic rocks relatively poor in U. Dominant tectonic structures and Rn concentration are examined in 28 cavities. The concentration of Rn values is higher than 0.5 kBq·m-3 in caves developed preferably following fractures with the direction N30oW, being the concentration greater than 0.8 kBq·m-3 in cavities located less than 200±50 m from subvertical faults with such orientation. Rn anomalies point to relative high connectivity along subvertical fault zones NW-trending, preserving fracture connectivity in the most recent structures in the Cantabrian Mountains. Finally, in the study area there is a low but significant radioactive hazard which is associated to fault zones in a fractured rock massif. It contrasts with other active tectonic settings where the radioactive hazard may come from fault movements
Two significant experiences related to radon in a high risk area in Spain
Número monográfico dedicado al "Proceedings of the International Conference Radon in Environment 2009”Radon is a natural radioactive gas and it is currently accepted as being responsible for lung cancer in some cases. One of the most important sources of indoor radon is from the soil. The radium content of soil is also a very important factor to be taken into account. The natural radiation map of Spain (MARNA) classifies the country into three regions with different levels of natural gamma radiation. There are some areas in Spain with high levels of natural radiation one of those is the province of Salamanca. Western part of this province presents a population of 20 000 inhabitants and 7% of the houses have an indoor radon concentration above 400 Bq•m–3. In this high risk area, the village of Villar de la Yegua is of special interest: 11% of the houses in this village have an indoor radon level below 400 Bq•m–3, 89% have above 400 Bq•m–3 and 71% of the houses have a radon concentration above 1000 Bq•m–3. An old uranium mine site close to this village has been selected for the construction of an experimental pilot house. It is a two
story house located in the place with a very high 226Ra concentration in soil. Radon in soil at 1 m depth has an average level of 250 kBq•m–3. We present in this work the characteristics of the experimental unit located in this high risk area and we describe the zone where one of the Spanish villages with the highest radon concentration is located. This is a very interesting place for further research on indoor radon concentration and it is a unique opportunity of testing radón monitors, radon passive detectors and remedial actions for the mitigation of radon in real conditions. It is common to carry out intercomparison exercises under laboratory conditions. Nonetheless, it is not so common to develop these exercises in real conditions as we have in the experimental unit we present here. We offer in this work the possibility for other research groups of testing their equipments in this unit and we also show the evolution of the works carried out in the locality of Villar de la Yegua
The radon gas. An air pollutant
Número monográfico dedicado a la 19ª Jornada Técnica SESA sobre Radiaciones Ionizantes y Salud.[ES]En este trabajo se abordan distintos aspectos acerca de la problemática del radón en viviendas. Este gas de origen natural se encuentra prácticamente en la totalidad de los suelos de la corteza terrestre debido a la presencia de uranio y radio en la composición de los mismos. En función de factores arquitectónicos y de hábitos de ocupación de la vivienda pueden alcanzarse concentraciones elevadas del gas en interiores. En estas situaciones existe un incremento cuantificable del riesgo de desarrollar cáncer de pulmón en los habitantes de la vivienda. En los últimos años, las mejoras metodológicas en la realización de estudios epidemiológicos han conducido a la obtención de evidencias científicas de la relación entre la presencia de radón en interiores y el riesgo de cáncer de pulmón. Esta relación, encontrada hace años en trabajadores de minas de uranio, ha sido corroborada en el caso del radón residencial a la luz de los metaanálisis realizados recientemente a partir de estudios epidemiológicos agrupados. Durante los últimos 25 años se han realizado más de 6.000 medidas de radón en interiores. Se presentan los principales resultados de las mayores campañas de medida llevadas a cabo, así como los criterios recientemente establecidos por el Consejo de Seguridad Nuclear acerca de los niveles de intervención en viviendas y lugares de trabajo.[EN]In this work different aspects about the problem of the radon in dwellings are approached. This gas of natural origin is virtually present in all the soils in the earth’s crust due to the presence of uranium and radium in the composition of them. Depending on architectural factors and of occupancy habits of the house, high concentrations of this gas can be reached indoors. In these situations, there is a quantifiable increment of the risk of developing lung cancer in the inhabitants of the housing. In the last years the methodological improvements in the realization of epidemiologic studies have led to the obtaining of scientific evidences about the relationship between the presence of indoor radon and the risk of lung cancer. This relationship, found years ago in workers of uranium mines, has been corroborated in the case of the residential radon by the light of several recent meta-analysis performed on groups of epidemiologic studies. More than 6.000 radon measurements have been carried out in Spain during the last 25 years. A summary of the results obtained from the main national radon surveys are also presented, as well as the criteria recently established by the Spanish Nuclear Safety Council concerning radon action levels in dwellings and workplaces
El gas radón como contaminante atmosférico
In this work different aspects about the problem of the radon in dwellings are approached. This gas of natural origin is virtually present in all the soils in the earth’s crust due to the presence of uranium and radium in the composition of them. Depending on architectural factors and of occupancy habits of the house, high concentrations of this gas can be reached indoors. In these situations, there is a quantifiable increment of the risk of developing lung cancer in the inhabitants of the housing. In the last years the methodological improvements in the realization of epidemiologic studies have led to the obtaining of scientific evidences about the relationship between the presence of indoor radon and the risk of lung cancer. This relationship, found years ago in workers of uranium mines, has been corroborated in the case of the residential radon by the light of several recent meta-analysis performed on groups of epidemiologic studies. More than 6.000 radon measurements have been carried out in Spain during the last 25 years. A summary of the results obtained from the main national radon surveys are also presented, as well as the criteria recently established by the Spanish Nuclear Safety Council concerning radon action levels in dwellings and workplaces.En este trabajo se abordan distintos aspectos acerca de la problemática del radón en viviendas. Este gas de origen natural se encuentra prácticamente en la totalidad de los suelos de la corteza terrestre debido a la presencia de uranio y radio en la composición de los mismos. En función de factores arquitectónicos y de hábitos de ocupación de la vivienda pueden alcanzarse concentraciones elevadas del gas en interiores. En estas situaciones existe un incremento cuantificable del riesgo de desarrollar cáncer de pulmón en los habitantes de la vivienda. En los últimos años, las mejoras metodológicas en la realización de estudios epidemiológicos han conducido a la obtención de evidencias científicas de la relación entre la presencia de radón en interiores y el riesgo de cáncer de pulmón. Esta relación, encontrada hace años en trabajadores de minas de uranio, ha sido corroborada en el caso del radón residencial a la luz de los metaanálisis realizados recientemente a partir de estudios epidemiológicos agrupados. Durante los últimos 25 años se han realizado más de 6.000 medidas de radón en interiores. Se presentan los principales resultados de las mayores campañas de medida llevadas a cabo, así como los criterios recientemente establecidos por el Consejo de Seguridad Nuclear acerca de los niveles de intervención en viviendas y lugares de trabajo
Continuous monitoring of radon gas as a tool to understand air dynamics in the cave of Altamira (Cantabria, Spain)
The use of radon as an atmospheric tracer in the Altamira Cave over the past 30 years has provided relevant information about gaseous exchanges between the Polychromes Room, the adjoining Chambers inside the cave, and the outside atmosphere. The relatively simple physico-chemical behaviour of radon gas provides a marked advantage over other tracer gases that are usually present in high concentrations in hypogeous environments, such as CO2. Two types of continuous radon measurement were undertaken. The first involves active detectors located in the Hall and Polychromes Room, which provide radon concentration values at 1-hour intervals. In addition, nuclear solid track etched detectors (CR-39) are used in every chamber of the cave over 14-day exposure periods, providing average radon concentrations. In this paper we show some of the specific degassing and recharge events identified by anomalous variations in the concentration of radon gas in the Polychromes Room. In addition, we update knowledge regarding the degree of connection between chambers inside the cave and with the outside atmosphere. We verify that the connection between the Polychromes Room and the rest of the cave has been drastically reduced by the installation of the second closure in 2008. Except for point exchanges with the Crossing zone generated by a negative temperature gradient in that direction, the atmosphere of the Polychromes Room remains stable, or else it exchanges matter with the outside atmosphere through the karst interface. The role of radon as a tracer is demonstrated to be valid both to reflect seasonal cycles of degassing and recharge, and to analyse shorter (daily) period fluctuations.This research was funded by the Project “Estudios analíticos para una propuesta de accesibilidad pública de la Cueva de Altamira” funded by the Ministry of Education, Culture and Sports, Spain (MECD)