• De ontwikkeling van Storybuilder : Achtergrond en verantwoording

      Sol V; Bellamy L; van Eijk V; Mud M; ABI; M&V (Rijksinstituut voor Volksgezondheid en Milieu RIVMWhite QueenRPS, 2014-03-04)
      Storybuilder is an instrument analysing underlying causes of occupational accidents. This analysis can help companies to choose preventive and protective measures. This is important as still 80 to 90 fatal accidents occur at work every year; that is almost 2 fatal accidents per week. The instrument is developed by RIVM and is available on rivm.nl. It is a database containing information on serious accidents coupled with a specific developed software program. This report describes the issues addressed in the development of Storybuilder, and the development choices made. The Storybuilder database is developed on the basis of information of the Labour Inspectorate on around 23,000 serious incidents investigated since 1998. Based on the information 36 accident hazard types are distinguished. The type of accident with the highest incidence is people falling from heights (ladder, roof, scaffold, etcetera), because of absence of edge protection or fall arrest or because of unsuccessful body control and balance. The second highest is people getting trapped in moving parts of machines, because of insufficient physical guarding. Each accident is represented in the software program via a graphical narrative, as a sequence of events, providing insight into the origin and progress of a specific type of accident and its consequences. What was the activity of the victim when the accident happened? What equipment, such as machines or scaffolds, was involved? What was the direct cause of the accident (where did it go wrong) and what were the underlying causes (how and why did it go wrong)? Reportable serious occupational accidents should be reported to the Labour Inspectorate. Subsequently, the Inspectorate investigates the causes of each accident and whether they are the result of a breach of the law. Storybuilder makes the information of the Inspectorate accessible in such a way that lessons can be learned from it. Storybuilder is unique due to the very detailed information and the description of accidents from a broad range of industrial sectors.
    • Radiologisch onderzoek bij kinderen : Inventarisatie van de Nederlandse praktijk met de focus op dosis-reducerende maatregelen

      Bijwaard H; Valk D; ABI; M&V (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2015-06-02)
      By order of the Health Inspectorate, the National Institute for Public Health and the Environment has investigated radiation protection in paediatric radiology. This research was motivated by recent scientific findings that indicate that the radiation hazards for children are higher than previously thought. A striking observation from this research are the large differences in practices between hospitals. Paediatric hospitals use special child protocols for radiological examinations, whereas general hospitals not always have these. Apart from that, radiation protection measures differ between hospitals. Furthermore, the number of high dose examinations has risen sharply over the past years. Examples are CT scans and fluoroscopic procedures, in which the patient is imaged in real time during an operation. Especially the rise in the number of CT scans by 80% with respect to 2005, is remarkable. This rise has also been observed for examinations of adults. Finally, in approximately half of the hospitals the applied doses are not compared to the so-called Diagnostic Reference Levels (DRLs) for children. This is probably due to the small number of children that is being examined: for this comparison a minimum of 20 children is needed. In hospitals that do compare to the DRLs, these are exceeded in one in five cases. DRLs are meant to give an indication of an acceptable dose, with which an appropriate radiological image can be obtained. For heavy patients and complex procedures DRLs can be exceeded. Radiology departments are not obliged to adhere to the DRLs. The reasons for the rise in paediatric examinations are unknown. It is important to clarify these. Apart from that, the small number of comparisons to the DRLs and their regular exceedance, deserve further attention. In addition, it is recommended to spread the knowledge of paediatric hospitals to the general hospitals in order to bring all hospitals up to date with the state of the art.
    • Radon, thoron en gammastraling op werkplekken en in publiek toegankelijke gebouwen in Nederland : Resultaten RIVM-meetcampagne 2016-2017

      Goemans P; de Waard IR; Blaauboer RO; Smetsers RCGM; de Groot GM; ABI; VLH (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2018-10-04)
      Op vrijwel alle werkplekken en in openbare gebouwen zijn de gemeten radonconcentraties laag, gemiddeld 15,9 Bq/m3 (Becquerel per kubieke meter). Wereldwijd bedraagt de gemiddelde radonconcentratie in gebouwen ongeveer 40 Bq/m3. Slechts in enkele zeer specifieke gevallen in dit onderzoek zijn de radonconcentraties hoger dan 300 Bq/m3. Bijvoorbeeld bij enkele grondwater-zuiveringsstations bij drinkwaterbedrijven en ondergrondse ruimten zoals grotten. De radonconcentraties zijn, net als in woningen, iets hoger in Zuid-Limburg en het Rivierengebied dan in de rest van Nederland. Dit komt doordat er in deze gebieden van nature meer radon vrijkomt uit de bodem. Dit blijkt uit een meetcampagne die het RIVM in de periode 2016-2017 heeft uitgevoerd op enkele honderden werkplekken en openbare gebouwen in Nederland. De resultaten van de meetcampagne geven een beeld van de radonconcentraties in gebouwen in Nederland. Dit is onder andere nodig om Europese regelgeving te implementeren. Een van de Europese verplichtingen is om nationale referentieniveaus vast te stellen voor radon op werkplekken en voor radon in openbare gebouwen. Beide referentieniveaus zijn in Nederland sinds 6 februari 2018 in het Besluit basisveiligheidsnormen stralingsbescherming vastgesteld op 100 Bq/m3. Behalve naar radon is onderzoek gedaan naar zogeheten thorondochters en naar gammastraling. Deze dragen net als radon bij aan de blootstelling aan natuurlijke radioactiviteit in gebouwen. De thorondochterconcentraties die nu op Nederlandse werkplekken en in openbare gebouwen zijn gemeten, liggen in lijn met de waarden die volgens internationale organisaties in gebouwen verwacht kunnen worden. De resultaten van de metingen naar gammastraling zijn vergelijkbaar met die in eerder uitgevoerde onderzoeken in Nederland en zijn laag ten opzichte van het vastgestelde referentieniveau voor gammastraling uit bouwmaterialen. Radon en thoron zijn radioactieve edelgassen die van nature ontstaan in de bodem en in bouwmaterialen die daarvan worden gemaakt. Radon kan vanuit de bodem en bouwmaterialen in gebouwen terechtkomen. Thoron in gebouwen komt met name uit materialen waarmee de muren en plafonds zijn afgewerkt. De radioactieve stoffen die ontstaan als radon en thoron vervallen, vergroten het risico op het krijgen van longkanker, vooral bij rokers. Gammastraling in gebouwen komt uit bouwmaterialen en uit het buitenmilieu (al wordt de straling van buiten grotendeels weer door het gebouw afgeschermd) en draagt bij aan de blootstelling aan externe straling in gebouwen. Dit onderzoek is uitgevoerd in opdracht van het Ministerie van Sociale Zaken en Werkgelegenheid (SZW) en de Autoriteit Nucleaire Veiligheid en Stralingsbescherming (ANVS).
    • Recent developments in medical techniques involving ionising or non-ionising radiation : Update 2014

      de Waard-Schalkx I; Stam R; van der Schaaf M; Bijwaard H; ABI; M&V (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2015-12-17)
      The National Institute for Public Health and the Environment (RIVM) has investigated new medical techniques using radiation that are being developed, are at the experimental stage and are now in use. The techniques investigated are those that employ ionising radiation as well as those that employ non-ionising radiation. Both types of radiation are being used for diagnosis and treatment. These new techniques generally yield more information than existing techniques, which leads to more accurate diagnosis and more effective treatment. In addition, it is generally possible to produce better images with less radiation and therefore a lower patient dose. This report is an update of research carried out in 2011. It has been compiled by order of the Health Inspectorate. In addition to a literature search, experts have been interviewed to find out which techniques have already been implemented in Dutch clinical practice. Examples of medical techniques that use ionising radiation are X-ray radiography and computed tomography (CT), both used to image the interior of the human body. New developments involve the use of the wave characteristics of X-rays to extract more information from the data. In addition, techniques that reduce the radiation dose are increasingly being used. These encompass tube current modulation, a technique that adapts the radiation dose to the size of the body part that is being irradiated. The latest development in radiation therapy is imaging with MRI during irradiation. This combination leads to a more accurate irradiation of tumours that are not in a fixed position in the body. Proton therapy, which is also used to treat tumours more precisely, is also being developed and will be available in the Netherlands soon. Examples of techniques that employ non-ionising radiation are electromagnetic (MRI) and optical techniques. Apart from improvements in MRI, compact equipment is being developed to image the skin and blood vessels using weak electromagnetic fields in situations where traditional equipment is unsuitable. Another development is the increasing use of wireless techniques to guide cameras and manage (drug) implants. For optical imaging, infrared radiation and internal techniques are being used more widely.
    • Regelgeving in omringende landen over de invoer van NORM reststoffen

      Goemans P; Folkertsma E; ABI; VLH (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2018-01-16)
      In binnen- en buitenland hebben verschillende niet-nucleaire industriële sectoren, zoals de olie- en gasindustrie, te maken met materialen die van nature radioactiviteit bevatten ('NORM'). Als gevolg van de productieprocessen kunnen reststoffen ontstaan die van nature radioactiviteit bevatten ('NORM reststoffen'). 'Reststoffen' zijn in dit onderzoek gedefinieerd als materialen die nog verder verwerkt kunnen worden voor (gedeeltelijk) hergebruik. Bij de verwerking van deze reststoffen kunnen afvalstoffen ontstaan die van nature radioactiviteit bevatten ('NORM afvalstoffen'). Deze afvalstoffen kunnen niet meer worden hergebruikt en moeten als radioactieve afvalstoffen worden afgevoerd voor opslag of stort. In het buitenland worden ook NORM reststoffen ingevoerd voor verdere verwerking. Het RIVM heeft daarom het beleid en de wet- en regelgeving van België, Duitsland, het Verenigd Koninkrijk en Noorwegen voor de invoer van NORM reststoffen in kaart gebracht. In het algemeen is het in deze landen niet toegestaan om NORM reststoffen in te voeren en vervolgens direct als afval af te voeren. Onder voorwaarden is het toegestaan om NORM reststoffen verder te verwerken, bijvoorbeeld als hierdoor materialen kunnen worden hergebruikt. Dit onderzoek is op verzoek van de Autoriteit Nucleaire Veiligheid en Stralingsbescherming (ANVS) uitgevoerd. Op basis hiervan is op hoofdlijnen een advies geformuleerd over welke criteria Nederland zou kunnen gebruiken om een aanvraag voor de invoer van NORM reststoffen te beoordelen. Deze criteria zouden kunnen worden toegepast in te ontwikkelen regelgeving op dit gebied.
    • Risico-inventarisatie gevaarlijke stofgroepen : Samenvatting

      Zweers PGPC; de Groot GM; Bakker J; ABI; M&V (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2015-02-11)
      RIVM has inventoried a broad spectrum of groups of substances that pose the greatest risk to the environment, consumers and workers. The risk inventory is intended to help the Dutch Human Environment and Transport Inspectorate (ILT) set priorities for the supervision of hazardous substances. This inventory describes the method used for selecting substances from the 55 groups of substances, the criteria applied to assess their related risks, and the decision rules used for ranking the groups of substances. For the risk inventory, 4 to 8 substances were selected to represent each group of substances. Subsequently, these substances were assessed for their hazardous properties, such as the degree to which they are flammable, explosive or poisonous, as well as the likelihood of human or environmental exposure to them. Finally, using decision rules, the groups of substances were categorised in various risk classes, depending on the protection objective (environment, workers or consumers). Other decision rules or risk criteria may deliver different results. The risk inventory was conducted in collaboration with TNO-Triskelion, by order of the ILT. As a follow-up to the inventory, for a number of high scoring groups of substances, the economic sectors that produce, import, distribute and/or process them also were investigated.
    • Risk inventory of groups of hazardous substances : Summary

      Zweers PGPC; de Groot GM; Bakker J; ABI; M&V (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2015-02-11)
      RIVM has inventoried a broad spectrum of groups of substances that pose the greatest risk to the environment, consumers and workers. The risk inventory is intended to help the Dutch Human Environment and Transport Inspectorate (ILT) set priorities for the supervision of hazardous substances. This inventory describes the method used for selecting substances from the 55 groups of substances, the criteria applied to assess their related risks, and the decision rules used for ranking the groups of substances. For the risk inventory, 4 to 8 substances were selected to represent each group of substances. Subsequently, these substances were assessed for their hazardous properties, such as the degree to which they are flammable, explosive or poisonous, as well as the likelihood of human or environmental exposure to them. Finally, using decision rules, the groups of substances were categorised in various risk classes, depending on the protection objective (environment, workers or consumers). Other decision rules or risk criteria may deliver different results. The risk inventory was conducted in collaboration with TNO-Triskelion, by order of the ILT. As a follow-up to the inventory, for a number of high scoring groups of substances, the economic sectors that produce, import, distribute and/or process them also were investigated.
    • Stralingsniveaumetingen aan het terrein van de EPZ kerncentrale Borssele in 2017

      Tanzi CP; ABI; VLH (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2018-11-01)
      Het gammastralingsniveau aan de terreingrens van kerncentrale Borssele lag in 2017 onder het toegestane maximum van 10 microsievert per jaar. De hoogste vastgestelde dosis is 1,04 microsievert. Dit blijkt uit controlemetingen van het RIVM. Het RIVM rapporteert jaarlijks in opdracht van de Autoriteit Nucleaire Veiligheid en Stralingsbescherming (ANVS) of de kerncentrale aan de vergunningseis voldoet. De kerncentrale moet ervoor zorgen dat de blootstelling van personen buiten de terreingrens maximaal 10 microsievert per jaar is. Dat is in de revisie van de kernenergiewetvergunning van 2016 vastgelegd. Om de maximale effectieve dosis te berekenen wordt op de terreingrens het gammastralingsniveau gemeten. Dit gebeurt met het door het RIVM beheerde MONET-meetnet. Van de meting wordt vervolgens de natuurlijke achtergrondwaarde afgetrokken. De resulterende meetwaarde wordt gecorrigeerd met de zogeheten Actuele Blootstelling Correctiefactor (ABC-factor). Een ABC-factor hangt samen met de bestemming van het gebied waar de effectieve stralingsdosis kan worden opgelopen. Rond het terrein van kerncentrale Borssele is de bestemming uitsluitend industriële doeleinden en daarvoor geldt een ABC-factor van 0,2. Na de toepassing van deze ABC-factor is de berekende maximale effectieve dosis 1,04 microsievert per jaar. In 2017 is met vier monitoren op de terreingrens het gammastralingsniveau continu gemeten. In juni 2017 is het reguliere netwerk van acht monitoren hersteld, dat in 2016 vanwege werkzaamheden was onderbroken. In dit rapport zijn de daggemiddelden van de metingen van de MONET-monitoren rond de kerncentrale in 2017 weergegeven. Ook wordt uitgelegd hoe voor elk meetpunt de natuurlijke achtergrondwaarde is bepaald.
    • Stralingsniveaumetingen aan het terrein van de EPZ kerncentrale te Borssele in 2016

      Tanzi CP; ABI; M&V (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2018-05-23)
      In 2016, the radiation level caused by gamma radiation at the site boundary of the Borssele nuclear power plant was below the maximum permitted level. This is the conclusion of this report, which is based on measurements carried out by the RIVM on location. The permit, granted following the Dutch legislation on the use of nuclear energy, requires that the maximum effective dose received by persons outside the site boundary of Borssele NPP does not exceed 10 microsievert annually. Control measurements of the radiation level were therefore carried out continuously at four locations at the site boundary. This is done within the framework of the MONET monitoring network, which falls under the administrative management of the RIVM. The measurements are analyzed by subtracting the natural background value from the measured value. The result is then translated into the effective radiation dose for an individual by applying the so-called Actuele Blootstelling Correctiefactor (ABC-factor). ABC-factors are closely linked with the specific use of the site where the effective radiation dose is calculated. RIVM is tasked by the Authority for Nuclear Safety and Radiation Protection (ANVS) to annually report on whether the Borssele nuclear power plant meets the criterion stipulated in the license. Both the daily averages of the radiation dose recorded by the MONET-monitors around the Borssele nuclear power plant and an explanation of how the background level at each measuring location was determined are provided in the report. In 2016, the highest value of the radiation dose for all four locations with continuous monitoring, after correcting for the natural background level, was 5.7 microsievert per year. An ABC-factor of 0.2 for the site boundary of Borssele NPP has been set in the permit. Following the application of the ABC-factor, this translates into a maximum effective dose of 1.1 microsievert per year, which is lower than the maximum value of 10 microsievert per year stipulated in the permit.
    • Stralingsniveaumetingen rond het terrein van COVRA N.V. te Borsele in de periode 2011-2014 met het MONET-meetnet

      Tanzi CP; ABI; M&V (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2016-09-09)
      Over the years 2011-2014, the radiation level at the site boundary of the Centrale Organisatie voor Radioactief Afval (COVRA N.V.), the Central Organisation for Radioactive Waste, was below the maximum permitted level. This is the conclusion of this report based on field measurements carried out by RIVM. Dutch legislation on the use of nuclear energy requires that the maximum dose rate at the site boundary of the COVRA N.V. does not exceed 40 microsievert annually. Control measurements of the radiation level were therefore carried out with radiation monitors placed at sixteen locations, chosen either at the site boundary or along a fence within the site itself. The radiation monitors are part of the MONET monitoring network, which falls under the administrative management of the RIVM. The measurements are processed by subtracting contributions not caused by COVRA N.V., and the natural background value, from the measured value. This net result is then translated into the effective radiation dose for an individual, by applying the so-called 'Actual Exposure Correction factor' (ABC-factor). ABC-factors are closely linked with the specific use of the site where the effective radiation dose can be incurred. Over the period 2011 to 2014 the highest yearly dose (after correction for the ABC-factor and the natural background), is found to be 18 microsievert (in 2014). In order to fulfill the task assigned in the period 2011-2014 by the Authority of Nuclear Safety and Radiation Protection (ANVS, formerly known as KFD), RIVM reports on whether COVRA N.V. meets the criterion set out in its license. In this report the daily averages of the effective dose around COVRA N.V. are shown, together with an explanation of how the background level for the MONET monitors is determined.
    • Stralingsniveaumetingen rond het terrein van de EPZ kerncentrale te Borssele in 2012

      Tanzi CP; ABI; M&V (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2015-01-16)
      In 2012, the radiation level at the site boundary of the Borssele nuclear power plant (NPP) was below the maximum permitted level. This is the conclusion of this report, which is based on measurements carried out by the RIVM on location. The permit, granted following the Dutch legislation on the use of nuclear energy, requires that the maximum effective dose received by persons outside the site boundary of Borssele NPP does not exceed 40 microsievert annually. Control measurements of the radiation level were therefore carried out at eight locations at the site boundary. This is done within the framework of the MONET monitoring network, which falls under the administrative management of the RIVM. The measurements are processed by subtracting the natural background value from the measured value. The result is then translated into the effective radiation dose for an individual, and the so-called Actuele Blootstellings Correctiefactor (ABC-factor) is applied. ABC-factors are closely linked with the specific use of the site where the effective radiation dose is calculated. An ABCfactor of 0.2 for the site boundary of Borssele NPP has been set in the permit. RIVM is tasked to annually report on whether the NPP Borssele meets the criterion stipulated in the license by the Department of Nuclear Safety, Security and Safeguards of the Human Environment and Transport Inspectorate, Dutch Ministry of Infrastructure and Environment of the Netherlands. Both the daily averages of the eight MONET-monitors around the NPP Borssele and an explanation of how the background level at each measuring location was determined are provided in the report. In 2012, the highest value of all monitors, after correcting for the natural background level, was 6.1 microsievert per year. This translates into a maximum effective dose of 1.2 microsievert per year, following the application of the ABC-factor, and allows comparison with the value stipulated in the permit.
    • Stralingsniveaumetingen rond het terrein van de EPZ kerncentrale te Borssele in 2013

      Tanzi CP; ABI; M&V (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2015-08-28)
      In 2013, the radiation level at the site boundary of the Borssele nuclear power plant (NPP) was below the maximum permitted level. This is the conclusion of this report, which is based on measurements carried out by the RIVM on location. The permit, granted following the Dutch legislation on the use of nuclear energy, requires that the maximum effective dose received by persons outside the site boundary of Borssele NPP does not exceed 40 microsievert annually. Control measurements of the radiation level were therefore carried out at eight locations at the site boundary. This is done within the framework of the MONET monitoring network, which falls under the administrative management of the RIVM. The measurements are processed by subtracting the natural background value from the measured value. The result is then translated into the effective radiation dose for an individual, and the so-called Actuele Blootstellings Correctiefactor (ABC-factor) is applied. ABC-factors are closely linked with the specific use of the site where the effective radiation dose is calculated. RIVM is tasked to annually report on whether the NPP Borssele meets the criterion stipulated in the license by the Department of Nuclear Safety, Security and Safeguards of the Human Environment and Transport Inspectorate, Dutch Ministry of Infrastructure and Environment of the Netherlands. Both the daily averages of the eight MONET-monitors around the NPP Borssele and an explanation of how the background level at each measuring location was determined are provided in the report. In 2013, the highest value of all monitors, after correcting for the natural background level, was 3.8 microsievert per year. An ABC-factor of 0.2 for the site boundary of Borssele NPP has been set in the permit. This translates into a maximum effective dose of 0.8 microsievert per year, following the application of the ABC-factor, and allows comparison with the value stipulated in the permit.
    • Stralingsniveaumetingen rond het terrein van de EPZ kerncentrale te Borssele in 2014

      Tanzi CP; ABI; M&V (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2015-12-07)
      In 2014, the radiation level at the site boundary of the Borssele nuclear power plant (NPP) was below the maximum permitted level. This is the conclusion of this report, which is based on measurements carried out by the RIVM on location. The permit, granted following the Dutch legislation on the use of nuclear energy, requires that the maximum effective dose received by persons outside the site boundary of Borssele NPP does not exceed 40 microsievert annually. Control measurements of the radiation level were therefore carried out at eight locations at the site boundary. This is done within the framework of the MONET monitoring network, which falls under the administrative management of the RIVM. The measurements are processed by subtracting the natural background value from the measured value. The result is then translated into the effective radiation dose for an individual, and the so-called Actuele Blootstellings Correctiefactor (ABC-factor) is applied. ABC-factors are closely linked with the specific use of the site where the effective radiation dose is calculated. RIVM is tasked to annually report on whether the NPP Borssele meets the criterion stipulated in the license by the Department of Nuclear Safety, Security and Safeguards of the Human Environment and Transport Inspectorate, Dutch Ministry of Infrastructure and Environment of the Netherlands. Both the daily averages of the eight MONET-monitors around the NPP Borssele and an explanation of how the background level at each measuring location was determined are provided in the report. In 2014, the highest value of all monitors, after correcting for the natural background level, was 1.7 microsievert per year. An ABC-factor of 0.2 for the site boundary of Borssele NPP has been set in the permit. This translates into a maximum effective dose of 0.3 microsievert per year, following the application of the ABC-factor, and allows comparison with the value stipulated in the permit.
    • Stralingsniveaumetingen rond het terrein van de EPZ kerncentrale te Borssele in 2015

      Tanzi CP; ABI; VLH (Rijksinstituut voor Volksgezondheid en Milieu RIVM, 2018-02-12)
      In 2015, the radiation level at the site boundary of the Borssele nuclear power plant was below the maximum permitted level. This is the conclusion of this report, which is based on measurements carried out by the RIVM on location. The permit, granted following the Dutch legislation on the use of nuclear energy, requires that the maximum effective dose received by persons outside the site boundary of Borssele NPP does not exceed 40 microsievert annually. Control measurements of the radiation level were therefore carried out at eight locations at the site boundary. This is done within the framework of the MONET monitoring network, which falls under the administrative management of the RIVM. The measurements are processed by subtracting the natural background value from the measured value. The result is then translated into the effective radiation dose for an individual by applying the so-called Actuele Blootstelling Correctiefactor (ABC-factor). ABC-factors are closely linked with the specific use of the site where the effective radiation dose is calculated. RIVM is tasked by the Authority for Nuclear Safety and Radiation Protection (ANVS) to annually report on whether the Borssele nuclear power plant meets the criterion stipulated in the license. Both the daily averages of the eight MONET-monitors around the Borssele nuclear power plant and an explanation of how the background level at each measuring location was determined are provided in the report. In 2015, the highest value of all monitors, after correcting for the natural background level, was 3.2 microsievert per year. An ABC-factor of 0.2 for the site boundary of Borssele NPP has been set in the permit. This translates into a maximum effective dose of 0.6 microsievert per year, following the application of the ABC-factor, and allows comparison with the value stipulated in the permit