GCRI · Energy Nexus
Radiological and nuclear risk
Radiological and nuclear emergencies are rare, but their consequences reach health, food, water, land use, trade and public trust for long periods. Preparedness for them is governed by international conventions, safety standards and independent national authorities. This page sets out how radiological risk is framed, how monitoring networks and protective actions work, and why the decisions belong to designated regulators and emergency authorities rather than to energy analysis.
How the work runs.
Hydro and cooling water watch
Radiological and nuclear risk · Hydro cascade · Dry season
- Hydro storage, % of capacity434Watch
- River temperature at intake24°CWatch
- Derating risk, next 7 days3plantsAlert
River temperature
Plants exposed
| TP-2 | Thermal | 0.5 | Derate plan |
| NP-1 | Nuclear | 2.8 | Monitor |
| HP-3 | Hydro | n/a | Release limited |
Fig.Hydro and cooling water watch: example names and illustrative values, not a record or a live system.
Radiological and nuclear risk: how the risk develops.
Nuclear and radiological safety context and independent regulatory role. The dossier below sets out how the risk develops, what is measured, where the data come from, how it is modelled and who decides.
Source to exposure pathway
Radioactive material released to air deposits on land and water, then reaches people through external exposure, inhalation and ingestion of food and water. Each pathway has its own timing and its own protective actions.
Protective actions are time-bound
Sheltering, evacuation and iodine thyroid blocking act in the early phase; food and water restrictions and relocation follow. Their benefits and harms, including the harms of evacuation itself, have to be weighed together.
Cascades beyond health
Contamination and evacuation interrupt agriculture, fisheries, water supply, trade and local economies, and loss of trust can outlast the radiological hazard. Removing a large plant from service also strains grid adequacy and fuel supply.
Many sources beyond reactors
Radiological risk also arises from lost or stolen industrial and medical sources, transport incidents and contaminated scrap metal. Regulatory control of sources throughout their life is the main barrier against these events.
Energy now in Europe.
Night lights, population density and sunlight over Europe, from NASA GIBS. Each layer carries its own date.
The interactive map needs JavaScript; the layer list and sources are below.
Layers 3
Energy now, for this page
About this layer
- Evidence
- Observed
- Source
- VIIRS Black Marble (VNP46A2) (NASA LAADS DAAC)
- Provider
- NASA LAADS DAAC
- Licence
- NASA open data
- Vintage
- daily; Satellite radiance, corrected for moonlight and atmosphere
- Newest at build
- 2026-10-12
- Resolution
- about 500 m grid
- Uncertainty
- Satellite night-time radiance for the date shown; lights are a proxy for electricity use and outages, not a measurement of supply or access.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
- Evidence
- Estimated
- Source
- Gridded Population of the World v4.11 (NASA SEDAC (CIESIN, Columbia University))
- Provider
- NASA SEDAC (CIESIN, Columbia University)
- Licence
- CC BY 4.0
- Vintage
- null; Census-based estimate, static (2020)
- Resolution
- about 1 km grid
- Uncertainty
- Census-based estimate of people per square kilometre in 2020, shown as exposure context; not a count of people affected by any hazard.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
- Evidence
- Modelled (latest month GIBS publishes)
- Source
- MERRA-2 (NASA GMAO / GES DISC)
- Provider
- NASA GMAO / GES DISC
- Licence
- NASA open data
- Vintage
- monthly; Reanalysis model; latest month GIBS publishes
- Newest at build
- 2026-07-01
- Resolution
- about 2 km grid
- Uncertainty
- Reanalysis model estimate of monthly mean incoming sunlight over land; an indicator of solar resource, not a site yield assessment.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
- Evidence
- Observed
- Source
- VIIRS NOAA-20 corrected reflectance (NASA LANCE)
- Provider
- NASA LANCE
- Licence
- NASA open data
- Vintage
- daily; Satellite image
- Newest at build
- 2026-10-14
- Resolution
- about 250 m grid
- Uncertainty
- Satellite image. Satellite or model raster as the provider publishes it. Clouds, swath gaps and retrieval error leave gaps and noise; values are indicators, not measurements at a place.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
- Evidence
- Modelled (latest year GIBS publishes)
- Source
- MODIS Terra and Aqua land cover (MCD12Q1) (NASA LP DAAC)
- Provider
- NASA LP DAAC
- Licence
- NASA open data
- Vintage
- yearly; Satellite classification; latest year GIBS publishes
- Newest at build
- 2024-01-01
- Resolution
- about 500 m grid
- Uncertainty
- Satellite land cover classes for the year shown, including croplands; a classification with known errors, not a farm register.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
About this layer
- Evidence
- Observed (clouds and overpass timing leave gaps)
- Source
- VIIRS NOAA-20 375 m (FIRMS) (NASA LANCE FIRMS)
- Provider
- NASA LANCE FIRMS
- Licence
- NASA open data
- Vintage
- daily; Satellite detection; clouds and overpass timing leave gaps
- Newest at build
- 2026-10-13
- Resolution
- about 500 m grid
- Uncertainty
- Satellite hot-spot detections for the day shown, including gas flares and industrial heat; not a confirmed fire, an incident report or a warning.
- Reached through
- gibs.earthdata.nasa.gov, only after you allow the live map
Keyboard, with the map focused
Hold Ctrl or ⌘ and scroll to zoom
Latest available
NASA GIBS / EOSDIS · ASTER GDEM (METI, NASA) · Blue Marble (NASA) · © OpenStreetMap contributors (ODbL) · Natural Earth
Loading the latest NASA imagery.
Drag to move. Ctrl or ⌘ and scroll, pinch or the buttons to zoom; hover for the values under the pointer; reset returns to the region.
Energy now, framed on Europe.Satellite and model products as NASA publishes them, each with its own date. They are indicators, not assessments of any place.
Data: NASA GIBS · ASTER GDEM · Blue Marble · © OpenStreetMap contributors · Natural Earth · NASA EONET · NASA/NOAA VIIRS · NASA JPL OPERA DIST-ALERTSources and licences
- We acknowledge the use of imagery provided by services from NASA’s Global Imagery Browse Services (GIBS), part of NASA’s Earth Science Data and Information System (ESDIS). Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- We acknowledge the use of imagery provided by services from NASA’s Global Imagery Browse Services (GIBS), part of NASA’s Earth Science Data and Information System (ESDIS). Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- VIIRS Black Marble night-time lights, NASA Goddard Space Flight Center; distributed by the NASA Level-1 and Atmosphere Archive and Distribution System (LAADS DAAC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- Center for International Earth Science Information Network (CIESIN), Columbia University. 2018. Gridded Population of the World, Version 4 (GPWv4): Population Density, Revision 11. NASA Socioeconomic Data and Applications Center (SEDAC). Licensed under CC BY 4.0. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). doi:10.7927/H49C6VHW. CC BY 4.0
- MERRA-2 reanalysis, NASA Global Modeling and Assimilation Office; distributed by the NASA GES DISC; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- VIIRS near-real-time products (flood, land surface temperature, snow cover, corrected reflectance), NASA LANCE; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- MODIS land products (vegetation indices, gross primary production, land cover), NASA LP DAAC and LANCE; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- NASA Fire Information for Resource Management System (FIRMS), VIIRS 375 m active fire product, NASA LANCE; vector tiles via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- ASTER GDEM is a product of METI and NASA (ASTER Global Digital Elevation Model V003, NASA LP DAAC); imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). Cite as: NASA/METI/AIST/Japan Spacesystems and U.S./Japan ASTER Science Team (2019). ASTER Global Digital Elevation Model V003. doi:10.5067/ASTER/ASTGTM.003. NASA open data
- Made with Natural Earth. Free vector and raster map data @ naturalearthdata.com. Public domain
- © OpenStreetMap contributors (ODbL), via NASA GIBS (coastlines, boundaries, roads and place names). Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). ODbL
- Blue Marble, NASA Earth Observatory; imagery via NASA GIBS. Colours redrawn from the published colour map; values averaged into hexagonal cells where shown (modified). NASA open data
- Context on the globe and flat map: coastlines, boundaries, roads and place names from NASA GIBS reference layers (OpenStreetMap data, ODbL, © OpenStreetMap contributors); Blue Marble imagery as an optional base; 3D terrain and the elevation read-out from the ASTER GDEM elevation colour index (5 m to 200 m classes, exaggerated for legibility). Boundaries are drawn as published and imply no position on any territory.
- Live events: NASA Earth Observatory Natural Event Tracker (EONET); events are indicative and keep their original source links.
- Observed (EO): NASA/NOAA VIIRS (Suomi NPP). We acknowledge the use of imagery provided by services from NASA’s Global Imagery Browse Services (GIBS), part of NASA’s Earth Science Data and Information System (ESDIS).
- Observed (EO): NASA JPL OPERA DIST-ALERT (contains modified Copernicus Sentinel data 2026). We acknowledge the use of imagery provided by services from NASA’s Global Imagery Browse Services (GIBS), part of NASA’s Earth Science Data and Information System (ESDIS).
- NASA GIBS: We acknowledge the use of imagery provided by services from NASA’s Global Imagery Browse Services (GIBS), part of NASA’s Earth Science Data and Information System (ESDIS).
- Past year, daily temperature (ERA5 via Open-Meteo): Contains modified Copernicus Climate Change Service information 2026.
- Past year, daily temperature and sunshine (NASA POWER): These data were obtained from the NASA Langley Research Center (LaRC) POWER Project funded through the NASA Earth Science/Applied Science Program..
- Weather data by Open-Meteo.com (https://open-meteo.com/), licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/).
- Optional layers (10 sources in the layer list: live, forecast, observed and context) print their provider credit on the map and here when switched on; forecasts are model output and derived indices are estimates.
Layers and dates
- Night-time lights, daily: VIIRS Black Marble (VNP46A2), NASA LAADS DAAC · 12 Oct 2026
- Population density, 2020: Population: CIESIN, Columbia University, Gridded Population of the World v4.11 (2018), NASA SEDAC, CC BY 4.0 · static
- Incoming sunlight at the surface over land, monthly mean: MERRA-2, NASA GMAO / GES DISC · July 2026
- True colour: VIIRS NOAA-20 corrected reflectance, NASA LANCE · 13 Oct 2026
- Land cover type (IGBP), yearly: MODIS Terra and Aqua land cover (MCD12Q1), NASA LP DAAC · 2024
- Active fires and thermal anomalies: VIIRS NOAA-20 375 m (FIRMS), NASA LANCE FIRMS · 13 Oct 2026
The quantities radiological protection uses, and who sets them.
| Quantity | Unit | Use |
|---|---|---|
| Activity | Becquerel (decays per second) | Amount of radioactive material released or deposited |
| Effective dose | Sievert, usually millisievert | Protection quantity for comparing exposures to dose limits (ICRP Publication 103, 2007) |
| Ambient dose rate | Microsievert per hour | Monitoring readings used for protective actions |
| Surface deposition | Becquerel per square metre | Contamination mapping for food and land restrictions |
Emergency preparedness follows IAEA General Safety Requirements Part 7 (2015) and the Convention on Early Notification (1986). Couplings run to food through contamination of crops and milk (food system shocks), to water supply through deposition on sources, and to health through evacuation stress as well as dose; UNSCEAR’s 2020/2021 report on Fukushima Daiichi assessed both.
Model radiological and nuclear risk as a system. Run the cascade.
Assembled from the Nexus Standards area profile Energy risk standards: the hazards it names, the systems and sectors that carry the loss, the controls that dampen it and the data that observe it. Choose the components, pick an initiating hazard and step through the cascade. The Map view places the run on an example geography with open data. Every coupling weight is a stated assumption you can change. A teaching model, not a forecast, an assessment or a certification. To model a place of your own choosing, open the full System Builder.
Hazards
- Heatwave
- Windstorm
- Widespread power outage (set off downstream)
- Large forest disturbance (set off downstream)
- Wildfire (set off downstream)
- Extreme fire weather (set off downstream)
- Heat-driven grid stress (set off downstream)
- Agricultural drought (set off downstream)
- Flash drought (set off downstream)
- Snow drought (set off downstream)
- Ground-level ozone episode (set off downstream)
- Meteorological drought (set off downstream)
- Extreme night-time heat (set off downstream)
- Lake and river heatwave (set off downstream)
- Cooling-water curtailment of power plants (set off downstream)
- Heat-induced track buckling (set off downstream)
- Shoreline ice shove (set off downstream)
- Seiche (set off downstream)
Systems and couplings
- Energy risk standards
- Water risk standards Common driver
- Critical infrastructure and critical entities Cascade
- Climate risk standards Feedback
- Space weather, spectrum and timing risk standards Common driver
Controls
NS-0Constitution and principlesNS-1The UNI and the artefact catalogue (grammar v0.2: domain, sector, region and environment segments)NS-3Risk record UNIs (grammar, legacy crosswalk, allocation authority)NS-9Contextual UNIs (deployments, instances, programme instances)NS-10Policies and clauses (machine-readable obligations: definition, binding, evaluation and enforcement)NS-11Verification and monitoring (evidence, attestations, zero-trust conformance observation)NRS-H84Hazard family: Energy system instability and shortfall (NHS-1 infra.energy)NRS-H61Hazard family: Cascading failure (NHS-1 sys.cascade)NRS-U8Universe platform profile: Energy NexusNRS-H48Hazard family: Utility and communication network outage (NHS-1 infra.utilities)NRS-H109Hazard family: Energy-transition technology failures (NHS-1 tech.energy-transition)NRS-H54Hazard family: Signal and platform disruption (NHS-1 cyber.platform)
Observation
- Global Power Plant Database (listed for reference)
- NASA Black Marble night-time lights (VNP46) (listed for reference)
- Ember electricity data (listed for reference)
- ENTSO-E Transparency Platform (listed for reference)
- EIA Open Data API (listed for reference)
- Proportion of population with access to electricity
- Renewable energy share in total final energy consumption
- Number of disruptions to basic services attributed to disasters
- Damage to critical infrastructure attributed to disasters
Example geography
- Europe: 113 hexagonal cells
- Surface air temperature, daytime (AIRS), NASA GIBS
- Rain rate, last half hour (IMERG), NASA GIBS
- Night lights tonight, outages (VIIRS Day/Night Band), NASA GIBS
- Vegetation disturbance alerts, 30 m (OPERA DIST-ALERT), NASA GIBS
Radiological evidence and its boundaries.
Studies of preparedness and of cascading effects are designed for the Strategic Systems series. The Global Centre for Risk and Innovation (GCRI) does not monitor radiation, issue protective actions or advise on emergencies; national authorities and the IAEA hold those roles. Contributions that help: published monitoring data from authorities, and evaluations of past emergency arrangements.
How radiological and nuclear risk is modelled, measured and tested.
The model, its assumptions, its data and its uncertainty, in the form a scientist or engineer would check. Structures follow published methods. The values drawn are illustrative, not findings.
System model
The couplings between the systems in radiological and nuclear risk: signs of influence, a reinforcing and a balancing loop, and cross-links where stress jumps.
What is measured, and how well.
Each indicator carries its unit, its cadence, the kind of source behind it and the evidence label a value would carry. No values are shown: a programme supplies them under its own authority.
| Indicator | Unit | Cadence | Source type | Label |
|---|---|---|---|---|
| Ambient gamma dose rate | microsieverts per hour | continuous | National radiation monitoring networks | OBSERVED |
| Activity concentration in air | becquerels per cubic metre | daily during events | Air samplers | OBSERVED |
| Activity concentration in food and drinking water | becquerels per kilogram or per litre | per sample | Laboratory analysis | OBSERVED |
| Projected dose for protective action planning | millisieverts | per scenario | Atmospheric dispersion and dose models | MODELLED |
| Events rated on the INES scale | count by level | per event | Regulator communications through the IAEA | Published statistics |
| Population within emergency planning zones | persons | periodic | Gridded population on planning zones | ESTIMATED |
Where the evidence comes from.
Named public datasets and institutional records, each with its licence class. Sources by agreement are used only under their terms and never republished.
| Source | What it gives | Licence class |
|---|---|---|
| EURDEP European Radiological Data Exchange Platform | Gamma dose rates from national monitoring stations in Europe | Public map; data exchange by agreement |
| US EPA RadNet | Near-real-time ambient radiation monitoring in the United States | Public domain |
| UNSCEAR reports | Scientific assessments of sources, exposures and effects of ionising radiation | Free access, UN terms |
| IAEA safety standards and emergency preparedness publications | Requirements and guidance on protective actions and their criteria | Free access, IAEA terms |
| IAEA Incident and Trafficking Database fact sheets | Summaries of incidents involving nuclear and radioactive material out of regulatory control | Public summaries, IAEA terms |
| Safecast | Citizen radiation measurements with documented instruments | Public domain dedication |
Who decides, and what the evidence serves.
Energy Nexus prepares evidence. The decisions below are taken by the authorities named, under their own rules, and never by the platform.
| Who decides | The question | Evidence this page serves |
|---|---|---|
| Independent nuclear and radiation regulators | How sources and installations are licensed, inspected and controlled | Regulatory records and safety standards; energy analysis supplies context only |
| National emergency management and civil protection authorities | When to shelter, evacuate, distribute iodine or restrict food and water | Monitoring data, dispersion projections and the operational criteria in national plans |
| Food safety and drinking-water authorities | Which products and supplies to test and restrict after a release | Activity concentrations against national limits and Codex Alimentarius guideline levels |
| Public health agencies | How to communicate risk and support affected populations over the long term | UNSCEAR and WHO evidence, local monitoring, health surveillance |
Outputs this topic produces
- Plain-language guides to the roles of regulators, emergency authorities and international bodies
- Cascade maps from a radiological emergency to food, water, energy and trade
- Directories of public monitoring networks with their data terms
- Briefs on the security of radioactive sources for infrastructure planners
What radiation protection experts ask.
- What exposure pathways exist from a source or event: external radiation, inhalation, ingestion through food and water?
- How are doses estimated, and how certain are those estimates?
- Which protective actions, such as sheltering, evacuation or food restrictions, reduce dose, and what harms do they cause in turn?
- How are risks communicated clearly to a public that may fear radiation strongly?
How radiological risk arises and is controlled.
Ionising radiation can damage living cells. At high doses this causes acute effects; at lower doses the main concern is an increased probability of cancer over time. Radiation protection rests on three principles: justification of practices, optimisation so that exposures are as low as reasonably achievable, and dose limits for individuals.
Nuclear installations are designed on defence in depth: multiple independent barriers and layers of protection so that no single failure leads to release. Major accidents have shown that common-cause events, loss of power and cooling, and organisational factors can defeat several layers at once. Experience also shows that the disruption of evacuation and long displacement can cause serious health and social harm of its own, which emergency planning must weigh.
How risk is assessed.
- 01
Probabilistic safety assessment
Structured models of accident sequences used by operators and regulators. They depend on data for rare events and on assumptions about human and organisational performance.
- 02
Atmospheric and environmental dispersion
Models estimate where released material travels and settles. They depend on source terms and weather, which are uncertain early in an event.
- 03
Dosimetry and monitoring
Measurement networks and personal dosimetry provide the ground truth. Coverage varies between countries.
How it is studied, and what the methods cannot say.
- 01Process and industrial safety engineeringNatural hazards triggering accidents · Layers of protection reviewApplied here
- 02Reliability and resilience engineeringRestoration curve analysis · Fault trees for critical sites · Fragility curves for grid assetsApplied here
- 03Materials science and chemistryBattery chemistry and thermal runaway · Ageing and corrosion of grid assetsApplied here
- 04Network science and contagionInterdependency mapping · Cascades on multilayer networks · Criticality rankingApplied here
- 05Forecasting and time-series analysisLoad forecasting with weather · Wind and solar power forecasts · Seasonal adequacy outlooksApplied here
Where this page’s references lead.
The bodies and documents this page is read against. Status and editions change; each link goes to the issuing body.
- ICRP Publication 103, The 2007 Recommendations of the International Commission on Radiological Protection (ICRP, 2007)
- Preparedness and Response for a Nuclear or Radiological Emergency, General Safety Requirements Part 7 (IAEA and co-sponsors, 2015)
- Convention on Early Notification of a Nuclear Accident (IAEA, 1986)
- UNSCEAR 2020/2021 Report, Annex B on the levels and effects of radiation exposure due to the accident at the Fukushima Daiichi nuclear power station (UNSCEAR, 2022)
Questions and answers.
Who decides on evacuation after a nuclear accident?
What does the INES scale communicate?
Are citizen radiation measurements reliable?
Does Energy Nexus give radiation protection advice?
Where should I look for advice during a radiological emergency?
Is any radiation dose safe?
Does Energy Nexus assess specific installations?
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