31:T7d3,The aim of this notebook is to display and interpret the results of measurements of tritium (H-3) in seawater that have been made available by TEPCO, Fukushima Prefecture, Nuclear Regulatory Authority and the Ministry of Environment as part of Japan's [Comprehensive Radiation Monitoring Plan](https://radioactivity.nra.go.jp/en/plan). All data has been retrieved from: [TEPCO's ORBS Overarching Radiation-monitoring data Browsing System](https://www.monitororbs.jp/en/). The notebook is a work in progress and will evolve. Please send any observations to [NAML-MARIS.Contact-Point@iaea.org](mailto:NAML-MARIS.Contact-Point@iaea.org). References: - [TEPCO's Treated Water Portal Site](https://www.tepco.co.jp/en/decommission/progress/watertreatment/index-e.html) - [IAEA's ALPS Treated Water Discharge Website](https://www.iaea.org/topics/response/fukushima-daiichi-nuclear-accident/fukushima-daiichi-alps-treated-water-discharge) ## What is the current situation? The situation regarding the influence of the discharges can be succinctly summarised by the following two charts. The first shows H-3 activity concentrations in seawater from all sampling locations close to the discharge outlet plotted against sampling date. We can observe that the levels of H-3 in some samples measured since the start of discharges in August 2023 are elevated relative to the long-term background for this region of approximately 0.1 - 1 Bq/L. During discharge periods - indicated by the green areas - a small number of samples were analysed to have H-3 activity concentrations up to 50 Bq/L (October 2024) and 52 Bq/L (August 2025). These activity concentrations fall quickly to background soon after each discharge stops. It can be noted that many measurements of samples result in so called "non-detects" whereby the H-3 levels in the sample are too low to be detected. The limits of detection used vary between 0.1 and 0.4 Bq/L depending on factors including analytical method employed and counting times. 32:T5cb,# In-depth look ## 1: Focus on all sampling locations within 3 km of the discharge outlet We can observe that levels of H-3 in some samples measured since the start of discharges in August 2023 are elevated relative to the long-term background for this region of approximately 0.1 - 1 Bq/L. During discharge periods - indicated by the grey areas - a small number of samples were analysed to have H-3 activity concentrations up to 14 Bq/L (October 2023), 21 Bq/L (June 2024), and 50 Bq/L (October 2024). These activity concentrations fall quickly to background soon after each discharge stops. However, even before the start of discharges levels above background were regularly observed, albeit to a lesser degree (approximately 1 - 3 Bq/L). What is the reason for this? | Category | Details | |-------------------------------|-----------------------------------------------------------| | **Responsible organizations** | TEPCO,Fukushima Prefecture,NRA,MOE | | **Radionuclide** | H-3 | |**Area of interest** | Within 3 km of the discharge outlet | |**Sampling locations** | All | | **Description** | Overview of levels before and after discharges started |33:T646,## 3: Focus on sampling locations close to the FDNPS site The elevated levels observed before the start of the ALPS treated water discharges can be explained by focussing on the monitoring locations close to the FDNPS site, specifically at the perimeter of the port. Continuing low level releases from the FDNPS site, due to various mechanisms including rainwater runoff and groundwater discharges, result in occasionally higher levels at the monitoring locations in the immediate vicinity of the port. The influence of these low level releases from the FDNPS site is not observed in data from locations close to the discharge outlet. This is demonstrated by the results of measurements of samples taken in the year before the ALPS treated water discharges started for which mainly non-detects and a small number of detected activity concentrations at background levels were observed. | Category | Details | |-------------------------------|-----------------------------------------------------------| | **Responsible organization** | TEPCO | | **Radionuclide** | H-3 | |**Area of interest** | The immediate vicinity of the FDNPS site | |**Sampling locations** | T-0,T-1 and T-2 | | **Description** | Elevated levels close to the FDNPS site |34:T4bd,## 4: Focus on all other monitoring locations with 3km of the discharge outlet At distances greater than 700 m from the discharge outlet, a small number of elevated levels have been detected but, in the main, there was no influence in H-3 seawater activity concentrations form the ALPS treated water discharges. | Category | Details | |-------------------------------|-----------------------------------------------------------| | **Responsible organizations** | TEPCO, MOE, NRA, Fukushima Prefecture | | **Radionuclide** | H-3 | |**Area of interest** | Area influenced neither by ALPS treated water discharges | |** ** | nor low level releases from the FDNPS site | |**Sampling locations** | All sampling locations within 3km but further than 700 m | |** ** | from the discharge outlet and other than T-0, T-1 and T-2 | | **Description** | Extent of influence of ALPS treated water discharges |35:T4b4,## 6: Focus on Cs-137 activity concentrations at sampling locations close to the FDNPS site In contrast, Cs-137 activity concentrations measured at the sampling locations at the perimeter of the FDNPS port, show occasional increases, including before discharges of ALPS treated water started. | Category | Details | |---------------------|-------------------------------------------------------------------------| | **Responsible organization** | TEPCO | | **Nuclide** | Cs-137 | |**Area of interest** | The immediate vicinity of the FDNPS site | |**Sampling locations** | T-0,T-1 and T-2 | | **Description** | Occasional increases of Cs-137 observed even before discharge periods These occasional increases are also explained by continuing low level releases from the FDNPS site, due to various mechanisms including rainwater runoff and groundwater discharges. 36:T4bf,function plot2Cols(data, dischargePeriods, fdnppIndustrialArea, { filter = { nuclide: "H-3", start: new Date("2022-06-01"), stations: allStations, //end: new Date("2024-10-02"), distance: 2.5 }, discharges = { fillOpacity: 1 }, map = { zoomRadius: 1.5, distance: 2, height: 300 }} = {}) { return html`

${plotConcentrations(data, dischargePeriods, {...filter, ...discharges})}

${plotMap(data, fdnppIndustrialArea, {...filter, ...map})}

` }37:Tbeb,function plotConcentrations(data, dischargePeriods, { nuclide = "H-3", // Possible values: "cs-134", "cs-137", "h-3" start = new Date("2021-03-15"), end = new Date(), distance = 10, // In km orgs = allOrgs, stations = allStations, excludeStations = false, fillOpacity = 0.7, yDomain = null, width = 800, height = 320 } = {}) { let dataSelected = data.filter((d) => ( d.nuclide == nuclide && d.begperiod >= start && d.begperiod <= end && d.distance <= distance && orgs.includes(d.org) && (excludeStations ? !stations.includes(d.station) : stations.includes(d.station)) )) let dataSelected2 = data.filter((d) => ( d.nuclide == nuclide && d.begperiod >= start && d.begperiod <= end && d.distance <= distance && orgs.includes(d.org) //stations.includes(d.station) )); if (yDomain === null) { yDomain = [d3.min(dataSelected2, (d) => d.valueReported), d3.max(dataSelected2, (d) => d.valueReported)]; } return Plot.plot({ width: width, height: height, x: { label: "Sampling date" }, y: { domain: yDomain, label: "Activity concentration (Bq/L)" }, grid: true, color: { scheme: "Tableau10", legend: true }, marks: [ Plot.rect(dischargePeriods, { x1: "from", y1: yDomain[0], x2: "to", y2: yDomain[1], stroke: null, fill: "green", fillOpacity: 0.1 }), Plot.dot(dataSelected2, { x: "begperiod", y: "valueReported", fill: "gray", fillOpacity: 0.3, sort: (d) => /Detected/.test(d.isDetected), // tip: true }), Plot.dot(dataSelected, { x: "begperiod", y: "valueReported", fill: "isDetected", fillOpacity: fillOpacity, sort: (d) => /Detected/.test(d.isDetected), // tip: true }), Plot.tip(dataSelected, Plot.pointer({ x: "begperiod", y: "valueReported", title: (d) => ["Activity concentration (Bq/L): " + (d.isDetected == "Not detected" ? "<" : "") + d.valueReported, "Sample date: " + d3.utcFormat("%B %d, %Y")(d.begperiod), "Location: " + d.station, "Organisation: " + d.org].join("\n")})), // Plot.ruleY([0]) ], caption: `${nuclide} data from ${(stations.length == allStations.length || excludeStations) ? " all": ""} ${orgs} sampling locations ${excludeStations ? "except " : ""} ${stations.length == allStations.length ? "": stations} within ${distance} km from the ALPS TW discharge outlet.` }); }38:T86d,function plotMap(data, sitePoly, { center = COORD_ORIGIN, zoomRadius = 1.5, nuclide = "H-3", // Possible values: "cs-134", "cs-137", "h-3" start = new Date("2021-03-15"), end = new Date("2024-10-02"), distance = 10, // In km orgs = allOrgs, stations = allStations, excludeStations = false, width = 400, height = 320 } = {}) { let dataSelected = data.map((d) => { let meetsConditions = ( d.nuclide === nuclide && d.begperiod >= start && d.begperiod <= end && d.distance <= distance && orgs.includes(d.org) && (excludeStations ? !stations.includes(d.station) : stations.includes(d.station)) ); return { ...d, isSelected: meetsConditions } }); let uniqueStations = getUniqueStations(dataSelected) return Plot.plot({ width: width, height: height, projection: { type: "azimuthal-equidistant", rotate: center.map((d) => -d), domain: zoomRadius > distance? getCircle(center, zoomRadius) : getCircle(center, distance), inset: 5 }, marks: [ Plot.geo(land, { fill: "#CFD8DC"}), Plot.geo(sitePoly, { fill: "#CFD8DC", }), Plot.geo(getCircle(center, distance), { stroke: "#555", strokeWidth: 0.5, strokeDasharray: "4,3" }), Plot.dot(uniqueStations, { x: "lon", y: "lat", fill: d => d.isSelected ? "#000" : "#FFF", stroke: "#000", strokeWidth: 0.5, r: 3, // tip: true, title: (d) => `Station name: ${d.station}` }), Plot.tip(uniqueStations, Plot.pointer({ x: "lon", y: "lat", title: (d) => ["Location: " + d.station, "Organisation: " + d.org].join("\n")})), Plot.geo(turf.point(center), { fill: "white", stroke: "#BF360C", strokeWidth: 4, r: 4 }) ] })}39:T441,distanceChartAfter = Plot.plot({ inset: 10, x: { type: "log", grid: true, label: "Distance from discharge outlet (km)" }, y: { type: "sqrt", grid: true, label: "Activity concentration (Bq/L)", domain: [0.03, 50]}, grid: true, color: { scheme: "Greens", }, marks: [ Plot.rect(data, { x1: 0.2, y1: 0.1, x2: 200, y2: 1, stroke: null, fill: "lightgray", fillOpacity: 0.1 }), Plot.dot( data.filter(d => (d.nuclide == "H-3" && d.activity != null && d.begperiod >= new Date("24-Aug-2023"))), Plot.hexbin( { fill: "count" }, { x: "distance", y: "activity", binWidth: 10, stroke: "#888", strokeWidth: 0.8, tip: true } ) ), Plot.text(['Tritium activity concentrations in seawater after 24 August 2023'], {frameAnchor: "top-right",dx: -25, dy: 25, fontSize: 12, fontWeight: "bold"}), // Plot.line(data, {x: "distance", y: 1, stroke: "red"}), // Plot.line(data, {x: "distance", y: 0.1, stroke: "red"}), // Plot.ruleY([0]),Plot.ruleX([0]) ]}) 3a:T4d9,distanceChartBeforeInteractive = Plot.plot({ inset: 10, x: { type: "log", grid: true, label: "Distance from discharge outlet (km)" }, y: { type: "sqrt", grid: true, label: "Activity concentration (Bq/L)", domain: [0.03, 50]}, grid: true, color: { scheme: "Greens", }, marks: [ Plot.rect(data, { x1: 0.2, y1: 0.1, x2: 200, y2: 1, stroke: null, fill: "lightgray", fillOpacity: 0.1 }), Plot.dot( data.filter(d => (d.nuclide == "H-3" && d.activity != null && (excludeClose ? !(d.station == "T-0" || d.station == "T-1" || d.station == "T-2"):!(d.station == "x")) && d.begperiod < new Date("24-Aug-2023") && d.begperiod >= new Date("2022-06-01"))), Plot.hexbin( { fill: "count" }, { x: "distance", y: "activity", binWidth: 10, stroke: "#888", strokeWidth: 0.8, tip: true } ) ), Plot.text(['Tritium activity concentrations in seawater before 24 August 2023'], {frameAnchor: "top-right",dx: -25, dy: 25, fontSize: 12, fontWeight: "bold"}), // Plot.line(data, {x: "distance", y: 1, stroke: "red"}), // Plot.line(data, {x: "distance", y: 0.1, stroke: "red"}), // Plot.ruleY([0]),Plot.ruleX([0]) ]}) 3b:T4b6,distanceChartAfterInteractive = Plot.plot({ inset: 10, x: { type: "log", grid: true, label: "Distance from discharge outlet (km)" }, y: { type: "sqrt", grid: true, label: "Activity concentration (Bq/L)", domain: [0.03, 50]}, grid: true, color: { scheme: "Greens", }, marks: [ Plot.rect(data, { x1: 0.2, y1: 0.1, x2: 200, y2: 1, stroke: null, fill: "lightgray", fillOpacity: 0.1 }), Plot.dot( data.filter(d => (d.nuclide == "H-3" && d.activity != null && (excludeClose ? !(d.station == "T-0" || d.station == "T-1" || d.station == "T-2"):!(d.station == "x")) && d.begperiod >= new Date("24-Aug-2023"))), Plot.hexbin( { fill: "count" }, { x: "distance", y: "activity", binWidth: 10, stroke: "#888", strokeWidth: 0.8, tip: true } ) ), Plot.text(['Tritium activity concentrations in seawater after 24 August 2023'], {frameAnchor: "top-right",dx: -25, dy: 25, fontSize: 12, fontWeight: "bold"}), // Plot.line(data, {x: "distance", y: 1, stroke: "red"}), // Plot.line(data, {x: "distance", y: 0.1, stroke: "red"}), // Plot.ruleY([0]),Plot.ruleX([0]) ]}) 3c:T465,distanceChartBefore = Plot.plot({ inset: 10, x: { type: "log", grid: true, label: "Distance from discharge outlet (km)" }, y: { type: "sqrt", grid: true, label: "Activity concentration (Bq/L)", domain: [0.03, 50]}, grid: true, color: { scheme: "Greens", }, marks: [ Plot.rect(data, { x1: 0.2, y1: 0.1, x2: 200, y2: 1, stroke: null, fill: "lightgray", fillOpacity: 0.1 }), Plot.dot( data.filter(d => (d.nuclide == "H-3" && d.activity != null && d.begperiod < new Date("24-Aug-2023") && d.begperiod >= new Date("2022-Jun-01"))), Plot.hexbin( { fill: "count" }, { x: "distance", y: "activity", binWidth: 10, stroke: "#888", strokeWidth: 0.8, tip: true } ) ), Plot.text(['Tritium activity concentrations in seawater before 24 August 2023'], {frameAnchor: "top-right",dx: -25, dy: 25, fontSize: 12, fontWeight: "bold"}), // Plot.line(data, {x: "distance", y: 1, stroke: "red"}), // Plot.line(data, {x: "distance", y: 0.1, stroke: "red"}), // Plot.ruleY([0]),Plot.ruleX([0]) ]}) 3d:T4ca,dischargePeriods = [ { from: "2023-08-24", to: "2023-09-01", batch: 1 }, { from: "2023-10-05", to: "2023-10-23", batch: 2 }, { from: "2023-11-02", to: "2023-11-20", batch: 3 }, { from: "2024-02-28", to: "2024-03-17", batch: 4 }, { from: "2024-04-19", to: "2024-05-07", batch: 5 }, { from: "2024-05-17", to: "2024-06-04", batch: 6 }, { from: "2024-06-28", to: "2024-07-16", batch: 7 }, { from: "2024-08-07", to: "2024-08-25", batch: 8 }, { from: "2024-09-26", to: "2024-10-15", batch: 9 }, { from: "2024-10-17", to: "2024-11-05", batch: 10 }, { from: "2025-03-12", to: "2025-03-30", batch: 11 }, { from: "2025-04-10", to: "2025-04-27", batch: 12 }, { from: "2025-07-14", to: "2025-08-03", batch: 13 }, { from: "2025-08-07", to: "2025-08-25", batch: 14 }, { from: "2025-09-11", to: "2025-09-29", batch: 15 }, { from: "2025-10-30", to: "2025-11-17", batch: 16 }, { from: "2025-12-04", to: "2025-12-22", batch: 17 }, { from: "2026-03-06", to: "2026-03-24", batch: 18 }, { from: "2026-04-02", to: "2026-04-20", batch: 19 }, { from: "2026-06-01", to: "2026-06-22", batch: 20 }, { from: "2026-07-06", to: new Date(), batch: 21 } ].map((d) => ({ from: new Date(d.from), to: new Date(d.to) }))3e:[{"id":"138c40f115dafdad5b6ccb00b4d83ef62842b522392fa1fb2a8198e46ede014c9f37c69f3727e12b0fc8192ed767850689d48a8173da45b70051f20c3d1b85cb","href":"https://static.observableusercontent.com/files/138c40f115dafdad5b6ccb00b4d83ef62842b522392fa1fb2a8198e46ede014c9f37c69f3727e12b0fc8192ed767850689d48a8173da45b70051f20c3d1b85cb","name":"FDNPP-industrial-area.geojson","type":"application/geo+json","lastModified":1728035489195.585,"size":31778},{"id":"a74a1cb14f7a819cc05e7e9af4b9cfd373f0ea054d7874dfb533256389815299d10c587264530f67aa494eeeda6aed361d5619421e4eff6e63fb46a5bda51741","href":"https://static.observableusercontent.com/files/a74a1cb14f7a819cc05e7e9af4b9cfd373f0ea054d7874dfb533256389815299d10c587264530f67aa494eeeda6aed361d5619421e4eff6e63fb46a5bda51741","name":"seawater_data.csv","type":"text/csv","lastModified":1733228997052.815,"size":1372256},{"id":"3d96e359d958a842194bcd5a60769d352b7c15d89cd843c1ddd5134f75147921cfb8a7aad9384431dc9035356bbb5480e6fa6758cf72b5b7d57a1cc810456ad2","href":"https://static.observableusercontent.com/files/3d96e359d958a842194bcd5a60769d352b7c15d89cd843c1ddd5134f75147921cfb8a7aad9384431dc9035356bbb5480e6fa6758cf72b5b7d57a1cc810456ad2","name":"seawater_data 4.csv","type":"text/csv","lastModified":1732640898026.375,"size":1271385}] 2f:{"title":"Tritium activity concentrations in seawater near to Fukushima Daiichi Nuclear Power Station (FDNPS)","cells":[{"id":0,"value":"# Tritium activity concentrations in seawater near to Fukushima Daiichi Nuclear Power Station (FDNPS)\n\n","pinned":false,"hidden":false,"mode":"md"},{"id":457,"value":"$31","pinned":false,"hidden":false,"mode":"md"},{"id":1709,"value":"plot2Cols(data, dischargePeriods, fdnppIndustrialArea, \n {\n filter:{\n nuclide: \"H-3\",\n start: new Date(\"2022-06-01\"), \n // stations: [\"T-0-1A\", \"T-0-1\", \"T-A2\", \"T-0-2\"],\n distance: 0.70,\n },\n map: {\n distance: 0.70,\n zoomRadius: 3\n } \n }\n )","pinned":false,"hidden":false,"mode":"ojs"},{"id":1739,"value":"The second chart shows detected H-3 activity concentrations in seawater from all sampling locations against the distance from the discharge outlet. We contrast data from before and after the first ALPS treated water discharges started on 24 August 2023. The historical background range is indicated by the grey area. In the right-hand graph - showing results since discharges started - we can observe elevated levels of H-3 out to a distance of approximately 10 km from the discharge outlet. Values of greater than 2 Bq/L are not observed at distances beyond 2km. \n\nSome elevated levels can also be observed in the left-hand graph - showing results from before discharges started. These are due to continuing low level releases of H-3 from the FDNPS site and are discussed in more detail below. ","pinned":false,"hidden":false,"mode":"md"},{"id":1599,"value":"

\n ${distanceChartBefore}\n

\n ${distanceChartAfter}\n

\n\n","pinned":false,"hidden":false,"mode":"md"},{"id":505,"value":"$32","pinned":false,"hidden":false,"mode":"md"},{"id":1170,"value":"plot2Cols(data, dischargePeriods, fdnppIndustrialArea, \n {\n filter:{\n nuclide: \"H-3\",\n start: new Date(\"2022-06-01\"), \n distance: 3\n },\n map: {\n distance: 3,\n zoomRadius: 1.5\n } \n }\n )","pinned":false,"hidden":false,"mode":"ojs"},{"id":487,"value":"## 2: Focus on sampling locations near to the discharge outlet\n\nHere we observe more clearly the immediate but transient increases in H-3 activity concentrations during discharge periods, which quickly return to background levels.\n\n| Category | Details |\n|-------------------------------|-----------------------------------------------------------|\n| **Responsible organizations** | TEPCO, MOE, NRA, Fukushima Prefecture |\n| **Radionuclide** | H-3 |\n|**Area of interest** | Within 700 m of the discharge outlet | \n|**Sampling locations** | All |\n| **Description** | Elevated levels close to the discharge outlet |","pinned":false,"hidden":false,"mode":"md"},{"id":1164,"value":"plot2Cols(data, dischargePeriods, fdnppIndustrialArea, \n {\n filter:{\n nuclide: \"H-3\",\n start: new Date(\"2022-06-01\"), \n // stations: [\"T-0-1A\", \"T-0-1\", \"T-A2\", \"T-0-2\"],\n distance: 0.70,\n },\n map: {\n distance: 0.70,\n zoomRadius: 3\n } \n }\n )","pinned":false,"hidden":false,"mode":"ojs"},{"id":566,"value":"$33","pinned":false,"hidden":false,"mode":"md"},{"id":1176,"value":"plot2Cols(data, dischargePeriods, fdnppIndustrialArea, \n {\n filter: {\n nuclide: \"H-3\",\n start: new Date(\"2022-06-01\"), \n stations: [\"T-0\", \"T-1\", \"T-2\", \"F-P02\", \"F-P03\", \"F-P01\"],\n // end: new Date(\"2024-12-31\"),\n orgs: \"TEPCO\",\n distance: 3,\n },\n map: {\n zoomRadius: 3\n }\n }\n )","pinned":false,"hidden":false,"mode":"ojs"},{"id":1797,"value":"The influence on H-3 levels in seawater of continuing low level releases from the FDNPS site can also be observed when plotting H-3 activity concentrations against distance. When data from sampling locations close to the FDNPS port - 1- 2 km from the ALPS treated water discharge outlet - are included, numerous instances of measurements slightly greater than the H-3 background can be observed. ","pinned":false,"hidden":false,"mode":"md"},{"id":1678,"value":"viewof excludeClose = Inputs.toggle({ label: \"Exclude T-0, T-1 & T-2?\" })","pinned":false,"hidden":false,"mode":"ojs"},{"id":1757,"value":"

\n ${distanceChartBeforeInteractive}\n

\n ${distanceChartAfterInteractive}\n

\n\n","pinned":false,"hidden":false,"mode":"md"},{"id":1320,"value":"$34","pinned":false,"hidden":false,"mode":"md"},{"id":1329,"value":"plot2Cols(data, dischargePeriods, fdnppIndustrialArea, \n {\n filter: {\n nuclide: \"H-3\",\n start: new Date(\"2022-06-01\"), \n stations: [\"E-S6\", \"E-S5\", \"T-0-1\", \"T-0-1A\", \"E-S10\", \"E-S8\", \"M-101\", \"E-S13\", \"E-S11\", \"T-A2\", \"T-0-2\", \"E-S12\", \"T-0\", \"T-1\", \"T-2\"],\n excludeStations: true,\n // end: new Date(\"2024-11-31\"),\n distance: 3,\n },\n map: {\n zoomRadius: 3\n }\n }\n )","pinned":false,"hidden":false,"mode":"ojs"},{"id":575,"value":"## 5: Focus on Cs-137 activity concentrations at sampling locations near the discharge outlet\n\nWhen focusing on the monitoring stations by the discharge outlet, we do not observe any Cs-137 activity peaks during discharges. This is to be expected as Cs-137 is removed during [ALPS processing](https://www.tepco.co.jp/en/decommission/progress/watertreatment/index-e.html).\n\n| Category | Details |\n|---------------------|-------------------------------------------------------------------------|\n| **Responsible organizations** | TEPCO, NRA, Fukushima Prefecture |\n| **Nuclide** | Cs-137 |\n|**Area of interest** | Within 700 m of the discharge outlet\n|**Sampling locations** | All |\n| **Description** | No increase of Cs-137 observed","pinned":false,"hidden":false,"mode":"md"},{"id":1191,"value":"plot2Cols(data, dischargePeriods, fdnppIndustrialArea, \n {\n filter: {\n nuclide: \"Cs-137\",\n start: new Date(\"2022-06-01\"), \n // orgs: [\"TEPCO\"],\n //stations: [\"T-0-1A\", \"T-0-1\", \"T-A2\", \"T-0-2\"],\n distance: 0.70\n \n },\n discharges: {\n yDomain: [0, 5]\n },\n map: {\n zoomRadius: 3\n }\n }\n )","pinned":false,"hidden":false,"mode":"ojs"},{"id":1436,"value":"$35","pinned":false,"hidden":false,"mode":"md"},{"id":1199,"value":"plot2Cols(data, dischargePeriods, fdnppIndustrialArea, \n {\n filter: {\n nuclide: \"Cs-137\",\n start: new Date(\"2022-06-01\"), \n stations: [\"T-0\", \"T-1\", \"T-2\"],\n distance: 1.9,\n orgs: \"TEPCO\"\n },\n discharges: {\n fillOpacity: 0.7,\n yDomain: [0, 5]\n },\n map: {\n zoomRadius: 1\n }\n }\n )","pinned":false,"hidden":false,"mode":"ojs"},{"id":84,"value":"## The necessary but boring bits ...","pinned":false,"hidden":false,"mode":"md"},{"id":1135,"value":"$36","pinned":false,"hidden":false,"mode":"ojs"},{"id":128,"value":"$37","pinned":false,"hidden":false,"mode":"ojs"},{"id":704,"value":"function getCircle(center, radius_km) {\n return d3.geoCircle()\n .center(center)\n .radius((radius_km / (6371 * Math.PI * 2)) * 360)\n .precision(10)()}","pinned":false,"hidden":false,"mode":"ojs"},{"id":982,"value":"function getUniqueStations(data) {\n let uniqueStations = new Set() \n data.forEach(d => uniqueStations.add(d.station))\n const uniqueStationsData = Array.from(uniqueStations).map(station => {\n const stationEntries = data.filter(d => d.station === station);\n const isSelected = stationEntries.some(d => d.isSelected);\n const firstEntry = stationEntries[0];\n return {\n lon: firstEntry.lon,\n lat: firstEntry.lat,\n station: firstEntry.station,\n org: firstEntry.org,\n distance: firstEntry.distance,\n isSelected: isSelected\n };\n });\n return uniqueStationsData\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":720,"value":"$38","pinned":false,"hidden":false,"mode":"ojs"},{"id":1703,"value":"$39","pinned":false,"hidden":false,"mode":"ojs"},{"id":1707,"value":"$3a","pinned":false,"hidden":false,"mode":"ojs"},{"id":1764,"value":"$3b","pinned":false,"hidden":false,"mode":"ojs"},{"id":1761,"value":"$3c","pinned":false,"hidden":false,"mode":"ojs"},{"id":101,"value":"### Constants","pinned":false,"hidden":false,"mode":"md"},{"id":34,"value":"//COORD_ORIGIN = [141.045563099841, 37.42964719370964]\nCOORD_ORIGIN = [141.045417, 37.429167]","pinned":false,"hidden":false,"mode":"ojs"},{"id":87,"value":"### Scales","pinned":false,"hidden":false,"mode":"md"},{"id":36,"value":"distScale = d3.scaleThreshold([2.5], distThresholdLabel)","pinned":false,"hidden":false,"mode":"ojs"},{"id":38,"value":"distThresholdLabel = [\"< 2.5 km\", \">= 2.5 km\"]","pinned":false,"hidden":false,"mode":"ojs"},{"id":5,"value":"## Data loading","pinned":false,"hidden":false,"mode":"md"},{"id":714,"value":"### Geographical layers","pinned":false,"hidden":false,"mode":"md"},{"id":710,"value":"fdnppIndustrialAreaRaw = FileAttachment(\"FDNPP-industrial-area.geojson\").json()","pinned":false,"hidden":false,"mode":"ojs"},{"id":793,"value":"fdnppIndustrialArea = turf.rewind(fdnppIndustrialAreaRaw, { reverse: true })","pinned":false,"hidden":false,"mode":"ojs"},{"id":716,"value":"world = (\n await fetch(\"https://cdn.jsdelivr.net/npm/world-atlas@2/land-50m.json\")\n).json()","pinned":false,"hidden":false,"mode":"ojs"},{"id":726,"value":"land = topojson.feature(world, world.objects.land)","pinned":false,"hidden":false,"mode":"ojs"},{"id":718,"value":"### Measurements","pinned":false,"hidden":false,"mode":"md"},{"id":135,"value":"$3d","pinned":false,"hidden":false,"mode":"ojs"},{"id":1470,"value":"dataRawInit = d3.csv(\"https://raw.githubusercontent.com/RML-IAEA/iaea.orbs/refs/heads/main/stations/transformed/csv/seawater_data.csv\")","pinned":false,"hidden":false,"mode":"ojs"},{"id":1485,"value":"dataRaw = dataRawInit.map((d) => ({ ...d,\n lon: +d[\"lon\"],\n lat: +d[\"lat\"],\n \"Cs-134\": d[\"Cs-134\"].length > 0 ? +d[\"Cs-134\"] : null,\n \"Cs-134_nd\": d[\"Cs-134_nd\"].length > 0 ? +d[\"Cs-134_nd\"] : null, \n \"Cs-137\": d[\"Cs-137\"].length > 0 ? +d[\"Cs-137\"] : null,\n \"Cs-137_nd\": d[\"Cs-137_nd\"].length > 0 ? +d[\"Cs-137_nd\"] : null, \n \"H-3\": d[\"H-3\"].length > 0 ? +d[\"H-3\"] : null,\n \"H-3_nd\": d[\"H-3_nd\"].length > 0 ? +d[\"H-3_nd\"] : null, \n}))","pinned":false,"hidden":false,"mode":"ojs"},{"id":51,"value":"function parseData(data) {\n const nuclides = ['Cs-134', 'Cs-137', 'H-3'];\n return data.flatMap(\n ({ begperiod, station, org, depth, lon, lat, ...rest }) =>\n nuclides.map(nuclide => ({\n begperiod: new Date(begperiod),\n station,\n org,\n depth,\n nuclide,\n activity: rest[nuclide],\n dl: rest[`${nuclide}_nd`],\n isDetected: rest[nuclide] !== null ? \"Detected\" : \"Not detected\",\n valueReported: rest[nuclide] !== null ? rest[nuclide] : rest[`${nuclide}_nd`],\n lon,\n lat,\n distance: turf.distance(turf.point(COORD_ORIGIN), turf.point([lon, lat]))\n })).filter(d => !(d.activity == null && d.dl == null)).map((d) => ({ ...d, distanceGrp: distScale(d.distance) }))\n );\n}","pinned":false,"hidden":false,"mode":"ojs"},{"id":53,"value":"data = parseData(dataRaw)","pinned":false,"hidden":false,"mode":"ojs"},{"id":327,"value":"allStations = [...new Set(data.map(d => d.station))]","pinned":false,"hidden":false,"mode":"ojs"},{"id":508,"value":"allOrgs = [...new Set(data.map(d => d.org))]","pinned":false,"hidden":false,"mode":"ojs"},{"id":635,"value":"new Set(data.map(d => d.nuclide))","pinned":false,"hidden":false,"mode":"ojs"},{"id":9,"value":"## Imports","pinned":false,"hidden":false,"mode":"md"},{"id":12,"value":"turf = require(\"@turf/turf@7\")","pinned":false,"hidden":false,"mode":"ojs"},{"id":14,"value":"_ = require(\"lodash\")","pinned":false,"hidden":false,"mode":"ojs"}],"files":"$W3e","stdlib":"1","titling":"auto"}