RADIATION PROTECTION
Italy currently does not produce energy through nuclear fission processes and does not have active nuclear power plants; however, the protection of people and the environment from ionizing radiation remains a matter of considerable importance in our country, also with a view to a possible return to nuclear power. In fact, among the possible types of exposure are the presence of radioactive waste produced by previous nuclear energy production activities, of contaminated materials in the structures and technological systems of nuclear plants undergoing decommissioning, as well as the increasingly frequent use of sources of ionizing radiation in medicine, industry and research.
No exposure to ionizing radiation, however modest, can be considered risk-free, as is the case with any human activity; it is therefore essential to guarantee an appropriate protection system from such exposures.
The discipline that studies and offers tools for the protection of people and the environment against the risks deriving from exposure to ionizing radiation is called "radiation protection". It is based on three fundamental principles: justification, optimization and limitation of doses. In fact, exposure to ionizing radiation must always be justified, ensuring that it brings more benefits than disadvantages. Therefore, individual doses, the number of people exposed and the probability of exposure must be kept to the minimum reasonably achievable, considering the state of technical knowledge and economic and social factors. The doses to individuals, however, must not exceed the limits defined in current legislation.
The ISIN, in relation to radiation protection, carries out investigative activities, technical assessments and control and supervision activities both on nuclear installations and on the use of ionizing radiation sources (radionuclides and x-ray machines). The Inspectorate is called upon to express an opinion, preparatory to the issuance of the inter-ministerial decree authorizing category A practice, on activities which involve the use of sources of ionizing radiation of considerable magnitude (for example use of cyclotrons for the production of radiopharmaceuticals, large particle accelerators in research, use of large quantities of radioisotopes in medical diagnostics and therapy).
The Inspectorate therefore carries out investigations and issues to the competent ministries the opinions required by current legislation for the activities of use of ionizing radiation sources, with regards to radiation protection and the safe management of the sources themselves; carries out assessments of the radiological impact on workers and individuals of the population as well as accident scenarios, as part of the authorization procedures relating to nuclear installations, carrying out its supervision at nuclear installations and at all installations where subject activities are carried out to the legislative provisions on radiation protection. The main investigative activities on nuclear plants include those relating to radiological characterization plans and radiometric verification plans for the removal of materials, as well as the release of areas, buildings and rooms of nuclear plants and remediation activities.
The Inspectorate also carries out technical assessments and checks regarding the safety of the sources; develops and disseminates, through guides, also in relation to international standards, good technical standards regarding health protection, prepares and adopts technical positions and opinions requested by Public Administrations and private entities.
The Inspectorate provides technical and regulatory support to the Civil Protection Authorities as part of the interventions envisaged following radiological emergencies and specific situations of national importance, also participating in Prefectural Commissions established by the competent Prefectures, carrying out on-site inspections; carries out and adopts, from the point of view of radioprotection of workers and the population, technical investigations and opinions concerning the remediation and safety measures of sites contaminated by artificial and natural radionuclides.
ISIN also carries out checks on the monitoring of environmental radioactivity in the areas surrounding nuclear installations, by updating data relating to monitoring of discharges of radioactive effluents from nuclear sites in normal operating and emergency conditions, taking care of their systematic collection, evaluation and publication.
It carries out control and supervision activities regarding exposure, deriving from work activities, to particular natural sources of ionizing radiation subject to radiation protection legislative provisions.
The Inspectorate ensures the functions of national contact point regarding the international control system, provided for by the Code of Conduct of the International Atomic Energy Agency (IAEA) regarding safety and security on sources radioactive sources as well as on the system of controls on imports and exports of radioactive sources. It participates in the activities of international organizations and European Union institutions and provides technical support in the development of national and international standards on radiation protection.
Experts from the Inspectorate participate in the examination commissions for registration in the list of names of authorized radiation protection experts and doctors, for the expression of the suitability judgment for the technical operation of nuclear plants in accordance with Presidential Decree 1450/1970.
Environmental radioactivity
ISIN ensures the surveillance activities of environmental radioactivity required by current legislation. Unless there are nuclear accidents, radioactivity in the environment is mainly of natural origin and only a small part is of artificial origin.
Natural radioactivity is of terrestrial origin, due to primordial radionuclides present in the earth's crust, and of cosmic origin (cosmic rays).
The main source of exposure of the population to natural radioactivity of terrestrial origin is represented by the decay products of radon, a radioactive gas generated in soils and rocks which is concentrated in closed environments (homes, schools, work environments). A further source of exposure to natural radiation can derive from materials containing radionuclides of natural origin (Naturally Occurring Radioactive Material – NORM), which constitute the raw material, product or residue of the production cycle of particular processes and industrial activities, and may lead to a significant increase in the exposure of the population and workers.
The NORMs have received positive discipline in the Legislative Decree. n. 101/2020 and subsequent amendments: the "industrial sectors" and the related "classes or types of practices or exposure scenarios" to be placed under surveillance have been identified, the exemption levels of materials and industrial residues with relative removal levels in relation to the intended use.
Artificial radioactivity is generated by anthropic activities linked to the production of nuclear energy, the use of radioactive sources in the medical-diagnostic, industrial and scientific research fields, and the production of war material. In the environment, artificial radioactivity is largely due to atomic tests in the atmosphere in the 1960s and nuclear accidents, in particular Chernobyl in 1986 (Figure 1).
Control of environmental radioactivity
In our country, the control of environmental radioactivity is regulated by Legislative Decree 101/2020 and subsequent amendments. The Ministry of the Environment and Energy Safety exercises control over environmental radioactivity, while the Ministry of Health exercises control over food and drinks for human and animal consumption.
The set of controls is divided into national and regional surveillance networks. The regional networks are managed by the individual Regions. The national networks are the national RADioactivity Surveillance NETWORK - RESORAD, the automatic networks with ISIN early warning functions (REMRAD and GAMMA) and the alarm network managed by the Ministry of the Interior. To these must be added the local surveillance networks of the environmental radioactivity of nuclear plants, managed by the operators of the plants themselves, on which the ISIN carries out the institutional control function.
RESORAD makes use of the radiometric surveys and measurements of the regional and provincial agencies for the protection of the environment (ARPA/APPA) and other suitably equipped bodies, institutes and bodies such as the Experimental Zooprophylactic Institutes.
ISIN carries out the technical coordination functions of RESORAD, collects and disseminates the results of the measurements carried out, manages the new SINRAD web portal (National Radioactivity Information System) within which there is a specific section containing data on radioactivity environmental products produced by RESORAD, which are annually transmitted to the European Commission in compliance with current legislation and the Euratom Treaty.
The main objective of the network is to monitor the space-time trend of radioactivity in the matrices of the various environmental and food sectors according to Guidelines that take into account the European Commission Recommendation 2000/473/Euratom.
In June 1998 the Italian national network was able to detect, through the recording of an anomalous presence of radioactivity in the air, an accident at the Spanish foundry of Algeciras, in which a source of Cesium-137 was melted. In March 2011, it was RESORAD that detected the first traces of radioactivity in the environment, Iodine-131 in atmospheric particulates, following the accident at the Fukushima nuclear power plant (Figure 2) and the only one, in terms of analytical sensitivity, in able to provide data in environmental and food matrices in the days following the event.
In order to ensure the homogeneity of the surveys, sampling and measurement methods, the RESORAD network Manual has been developed, which collects all the information on the structure, the sampling plans, the sampling and measurement methods and the flow of data from the network itself. In addition to the manual, further reference documents, results of investigations and guidelines relating to issues concerning the protection of the population from exposure to ionizing radiation are available.
The GAMMA network, currently undergoing renewal and technological updating, is made up of 64 stations for determining the environmental dose equivalent rate, located throughout the national territory. These stations continuously measure radioactivity in the air, providing a radiological value averaged over ten minutes and the hour, which is transmitted, displayed and saved in real time on the ISIN Control Center. About half of the stations have spectrometric as well as dosimetric capabilities, integrating an inorganic CeBr3 or LaBr3 type scintillator internally and reaching sensitivities lower than 10 nSv/h (Figure 3). Each station is equipped with a rain reading system, so as to correlate any radiometric anomalies with natural variations in the environmental background. The high sensitivity combined with the rapid response and radionuclide identification capabilities make these stations a valid tool to support decision-making choices in the first phase of any radiological and nuclear emergencies.
The data from the GAMMA network are also shared with the European Commission and sent to the EURDEP data exchange platform (European Union Radiological Data Exchange Platform).
The REMRAD network, also undergoing technological modernization, is made up of 6 stations installed in strategic points across the national territory and guarantees air monitoring through the deposition of airborne particulate matter which is sucked onto a large filter. The filter measurement is carried out in two different phases. The first phase consists of a measurement in "continuous" mode, during air sampling, by means of a scintillation detector and the second phase consists of a measurement in "delayed" mode after 24 h from the end of sampling, in order to to minimize the contribution of natural radionuclides, by means of a hyperpure germanium detector of the BEGe (Broad Energy Germanium) type. The very high sensitivity is guaranteed by the high sampling rate, approximately 500 m3 h-1, for a sampling time of 24 hours and allows us to report every minimal radiometric anomaly present within the air masses that pass through our Village.
These stations, taking up the configuration already used by the CTBTO (Comprehensive Nuclear-Test-Ban Treaty Organization) within its monitoring network, present an innovative feature consisting precisely of the measurement system in "continuous" mode which was designed on the basis of an industrial invention patent developed entirely within the ISIN.
Another peculiarity of these stations is that in the event of an emergency it is possible to remotely change the configuration of the measurement procedure to obtain rapid results which are essential for directing decision-making choices in the first moments of the emergency situation.
ISIN publishes an annual report on the national networks for monitoring environmental radioactivity.
Radon
See the statistics of the SINRAD radon section
Radon, in the absence of accidental events, represents the main source of exposure to radioactivity of natural origin for the population. The World Health Organization, through the International Agency for Research on Cancer (IARC), has evaluated the carcinogenicity of radon since 1988 and has included it in Group 1 of human carcinogens. Estimates consolidated for decades worldwide attribute to radon the second cause of lung cancer after tobacco smoking with a risk proportional to the concentration. Radon is a radioactive gas produced by the decay of uranium, naturally present in soils and rocks with different concentrations depending on their composition. The radon emitted from the soil, in a diversified manner depending on the geology of the area, is present everywhere in the air we breathe but, while it disperses outdoors without reaching high concentrations, in closed places (indoors - homes, schools, work environments , buildings in general) accumulates, reaching, in some cases, concentrations that pose a non-negligible risk to health. Some building materials and water are secondary sources of radon. Further causes, such as the methods of construction of buildings, with particular reference to contact with the ground, and the lifestyle habits of the occupants, can affect the presence of radon. The set of these factors, all very variable, contributes to a highly diversified spatial distribution of indoor radon concentration across the territory, mainly governed by local geolithology. Even between individual buildings that are similar and close to each other, it is possible to find a strong difference in radon concentration.
The Legislative Decree of 31 July 2020 n. 101 and subsequent amendments, transposing Directive 2013/59/EURATOM of the European Council, introduced important innovations, also for radon, regarding prevention and protection from ionizing radiation, adapting national legislation to what is provided for at European level.
For the first time, residential environments (homes) are included in the regulation as part of protection from exposure to radon, classified as existing exposure situations like workplaces. The maximum reference levels, in terms of the average annual value of the concentration of radon activity in the air, are set at 300 Bq m-3 for workplaces and existing homes, and at 200 Bq m-3 for homes built after 31 December 2024. A reference level in terms of annual effective dose of 6 mSv is also set for workplaces.
The provisions relating to exposure to radon in the workplace apply to underground workplaces, semi-underground workplaces or workplaces located on the ground floor within priority areas (in which it is estimated that the average annual concentration of radon activities radon in the air exceeds the reference level in a significant number of buildings), in specific types of workplaces identified by the National Radon Action Plan, and in spas.
In these workplaces, the operator is required to measure radon using recognized dosimetry services and, if the aforementioned reference level is exceeded, to implement corrective measures to reduce the concentration to the lowest level. as low as reasonably achievable. In this context, Legislative Decree no. 101/2020 and subsequent amendments. introduces for the first time the professional figure of the expert in radon remediation interventions, who must possess specific requirements on the subject. If, despite the application of corrective measures, the radon concentration remains higher than the reference level, the operator must carry out an assessment of the effective annual doses with the help of a radiation protection expert. In the event that the results of the assessments are higher than the reference level in terms of effective dose equal to 6 mSv/year, the operator is required to apply certain measures provided for by Title XI of Legislative Decree no. 101/2020 “Exposure of workers”.
The renewed regulatory framework provided for the implementation of the National Radon Action Plan, within which to identify the strategies, criteria and methods of intervention to prevent and reduce long-term risks due to exposure to radon . The National Radon Action Plan 2023-2032 was adopted with the Prime Ministerial Decree of 11 January 2024, published in the Official Journal no. 43 of 02.21.2024 - SO n. 10. ISIN ensures support to the competent Ministries within the scope of this Plan.
Among the functions that the new decree attributes to ISIN regarding radon, there are the collection and recording of data produced at a national level by the regional and provincial agencies for environmental protection (ARPA/APPA) and by the dosimetry services, within the RADON section in the new SINRAD web portal (National Information System on Radioactivity). ISIN also carries out indoor radon gas monitoring and control activities through its own measurement investigations.
In the 90s the ISIN, then ENEA-DISP, and the Istituto Superiore di Sanità (ISS), in collaboration with the regional health departments and with the Regional Reference Centers for the Control of Environmental Radioactivity, now merged into the ARPA /APPA, carried out a national survey on the concentration of radon in approximately 5,000 homes, from which the national average concentration of radon was estimated at 70 Bq m-3, a value higher than the European average of approximately 55 Bq m-3 and the global one equal to approximately 40 Bq m-3. The average concentrations measured by the Regions and autonomous Provinces showed values ranging from approximately 25 Bq m-3 to approximately 120 Bq m-3. At a national level it is estimated that in approximately 2% of homes the average annual radon concentration is greater than 300 Bq m-3.
The estimates of average radon concentrations in the Regions and Autonomous Provinces and the average value estimated for Italy from the 1990s survey still represent a national reference. Many other investigations were subsequently carried out not only by ISIN, but also by the Regions, through ARPA/APPA, not only in homes, but also in schools and workplaces, carrying out tens of thousands of measurements of the average annual concentration of radon. Taking homes as a reference, it should however be noted that the percentage of homes measured is rather small compared to the total homes present on the national territory.
The regional investigations were carried out using different methods and criteria which, although valid for the purposes of classifying territorial areas, make a direct comparison complicated. In order to undertake a process of data harmonization at national level, also with the aim of representing the spatial variability of radon concentration in a more homogeneous way between the Regions and autonomous Provinces and of making the information usable, the ISIN has started a collection of estimates of average radon concentrations in Italian municipalities developed by ARPA/APPA and by ISIN itself.
From the information received up to 2019, data on average radon concentrations are available for 4,241 Municipalities, with a territorial coverage corresponding to 53% of Italian Municipalities, but are fragmented and more concentrated in the regions of northern and central Italy. Furthermore, their examination shows some differences in the methods of carrying out radon measurement investigations essentially attributable to two main types of approaches in carrying out measurements in homes: the first for those located exclusively or mainly on the ground floor; the second for those located on different floors. The estimates of the average municipal concentrations obtained from measurements carried out exclusively or mainly on the ground floor concern over 80% of the municipalities subject to evaluation and over 40% of all Italian municipalities. On the basis of this information relating to the time interval from 1989 to 2019, ISIN developed a thematic map of average municipal radon concentrations. The values reported in the thematic map must be consulted taking into account the information returned from the spatial query of the municipal units regarding the type of data used or estimates made. It is also important to remember that the high variability of the radon concentration between different homes, even in the same municipality, does not allow the value of the municipal average to be used as a reliable indicator of the value of the radon concentration in a specific home located in the same municipality. . The only way to have a reliable estimate of the radon concentration in a specific home is to carry out a direct measurement, which costs approximately, excluding any on-site inspections, a few tens of euros.
Radiometric laboratories
The radiometric laboratories of the ISIN carry out measurement and investigation activities in support of the tasks and institutional activities of the Inspectorate in the field of environmental radioactivity control.
The laboratories are equipped to carry out investigations aimed at the radiometric characterization of specific sites of interest, the determination of the state of the environment, through measurements performed on environmental samples and on specific materials that may represent a source of contamination. The laboratory facility is built and authorized to receive and process samples with low activity concentrations.
The main activities are addressed:
· To technical-scientific support in the field of surveillance of nuclear installations, carried out through investigations around nuclear sites and control measures on effluents;
· To the characterization of industrial materials containing radionuclides of natural origin (NORM), with particular regard to the Reclamation Sites of National Interest (SIN) in which there are disused plants and landfills containing massive quantities of NORM;
· Technical-scientific support in cases of radiological emergencies, for the purpose of assessing the state of the environment and the health protection of the population and workers.
The laboratories also provide support to public administrations and judicial authorities in the field of radioactivity in the environment and in food and in the preparation of remediation and intervention plans in the context of contaminated sites with the presence of radioactive materials. To carry out the tasks described, the laboratories are able to perform gamma spectrometry and radiochemistry measurements (alpha spectrometry and beta counts) for non-gamma emitting radionuclides.
The Inspectorate is also equipped with a laboratory dedicated to measuring the concentration of radon gas in the air, which is mainly used for indoor investigations in places of public interest (schools, workplaces, etc.) or in private homes.
ISIN also manages the Laboratory for measuring radioactivity in atmospheric particulate matter, called ITL10, of the International Monitoring System (IMS), on behalf of the Ministry of Foreign Affairs and International Cooperation, in compliance with the Treaty on total ban of the United Nations Nuclear Experiments (CTBT).
The Treaty provides for a ban on all nuclear tests and for its entry into force it must be signed and ratified by at least 44 main member states of the 196 total. Currently, several states have not yet signed or ratified the treaty.
The International Monitoring System consists of a set of detection networks: seismic, infrasonic, hydroacoustic and radioactivity in the atmosphere.
The ITL10 laboratory is one of 16 laboratories strategically distributed on all continents capable of carrying out highly specialized and sensitive measurements of radioactivity in atmospheric particulate matter and which represent the highest technology for this type of measurement. The analyzes are able to detect and characterize traces of radionuclides in the air due to a nuclear event, wherever in the world it may occur, also estimating the date of occurrence. The additional information available to the International Monitoring System also makes it possible to establish its origin. The ITL10 laboratory was officially certified on 14 December 2016.