The most sensitive part. Every statement below is traced to an official source; iodine is taken only on instruction.
Iodine tablets
ON INSTRUCTION ONLY
What it does
Stable iodine saturates the thyroid and blocks uptake of radioactive iodine (I-131) — taken “before or at the beginning of exposure” (WHO). It is a targeted thyroid protection, not general protection.
On instruction from the authorities only
“tablets taken immediately when the prefect gives the instruction, and only then” (original FR: “comprimés pris immédiatement lorsque le préfet en donne la consigne et uniquement à ce moment-là”) — ASNR, France
“Never take iodine tablets on your own initiative” — nuclearrisk.be, Belgium
“only be taken once this is expressly requested by the civil protection authorities” — BfS, Germany
Who, when, contraindications
Priority to children and pregnant or breastfeeding women; above 45, discouraged (BfS; Luxembourg citing the WHO); in Belgium, to discuss with your GP above 40. Contraindications: thyroid conditions, iodine hypersensitivity → raise it in advance with your doctor or pharmacist (ASNR).
Dosage
An official dosage exists (the French 65 mg quarter-scored tablet): it is given with the authorities' instruction, not on this page — assume no dosage on your own.
Availability by country
- 🇫🇷France — in pharmacies, no justification needed; renewal campaign of 15/09/2024 around the 19 nuclear plants (0-10 km + 10-20 km bands).
- 🇱🇺Luxembourg — distributed to all residents by post (collection at the commune or pharmacy); a box handed out at maternity wards; schools stocked.
- 🇧🇪Belgique — free in pharmacies since 2018 (press/VRT); verified doctrine: residents within 20 km + families with children under 18.
- 🇩🇪Allemagne — the Länder are responsible, ~180 million tablets in stock, post-accident distribution (100 km for adults / the whole territory for children in a major release).
- 🇳🇱Pays-Bas — postal distribution to ~1.2 M households in 2017 around Borssele/Doel, “only if the government announces it” ⚠ not verified directly (page 404).
- 🇷🇴Roumanie — free distribution at the town hall around Cernavodă ⚠ 2013 media, unverified.
- 🇪🇸🇵🇹🇧🇬 Spain · Portugal · Bulgaria — ⚠ no verified official scheme found.
FFP2 / FFP3 masks
ANTI-INHALATION — NOT ANTI-RADIATION
What they do
FFP masks filter the inhalation of contaminated particles and aerosols — it is internal contamination they address:
“to avoid turning external contamination into internal contamination” (original FR: “pour éviter de transformer une contamination externe en contamination interne”) — ASNR 2023 guide, citing the IAEA: “the P3 level of dust/aerosol filtration” (p. 25)
“FFP3 mask, failing that FFP2, failing that a surgical mask” (original FR: “masque FFP3, ou à défaut FFP2, ou à défaut chirurgical”) — practical hierarchy, ASNR 2023 guide
What they do not do
No authority claims a mask protects against external gamma or beta radiation — the ASNR frames it strictly as protection against internal contamination. Luxembourg, same logic for clothing: “they do not constitute effective protection against irradiation”.
Standard
EN 149: FFP2 ≥ 94%, FFP3 ≥ 99% filtration (standard value of the norm; no single official page fetched on 28/10).
Shelter-in-place
24-48 H
Where
Luxembourg: “low rooms, without windows preferred” (pièces basses, sans fenêtres privilégiées); Belgium: “central space, preferably on the ground floor” (espace central, de préférence au rez-de-chaussée).
What to switch off
France: “close all windows and openings”; recirculation-mode ventilation is banned. Luxembourg: “switch off heating, ventilation, air conditioning and air regulators if possible” + close rainwater collection. Belgium: “close doors and windows and switch off all ventilation, heating and aircon systems”.
Duct-tape sealing
US OFFICIAL — NOT RECOMMENDED BY EUROPEAN AUTHORITIES
“Seal windows and external doors that do not fit snugly with duct tape” — ready.gov, US
FR/BE/LU do not mention it; the ASNR states the old “sealing” instruction has been dropped. Duct-tape sealing is European folklore: do it only if your authorities say so.
Other Belgian instructions
Belgium (risquenucleaire.be, same page): “Restez à l'intérieur jusqu'à ce que vous receviez le message que la situation est à nouveau sûré” (stay indoors until you receive the message that the situation is safe again); “Rentrez vos animaux domestiques” (bring your pets inside); “Ne téléphonez pas inutilement” (do not make unnecessary phone calls).
Children at school
France — FR original « Vos enfants sont en sûreté dans leur école, où un plan de protection a été mis en place » (your children are safe at school) (ASNR). Belgium — FR original « Laissez vos enfants à l'école. Ils suivent les mêmes recommandations. » (leave your children at school). Luxembourg: ⚠ not found explicitly.
Duration
Luxembourg: ≤ 48 h maximum; France: “a few hours” (ASNR); 24 h (ready.gov, US).
Brief outings
⚠ No official source (ASNR, infocrise.lu, risquenucleaire.be, BfS) explicitly authorises brief outings while sheltering — do not assume them.
Our take — iamin.digital
Fill the bathtub, the sinks? True and false. Verified negatively: France has no filling instruction (it rather bans consuming fresh produce, fresh milk and well water); nothing in Belgium (risquenucleaire.be); the BBK does NOT say fill the bathtub — its doctrine is to stockpile in advance (2 L/person/day × 10 days, bottled water). “Fill the bathtub” comes from an old FEMA PDF seen via an NIST mirror (not verified directly); the current ready.gov/water page does not mention it — it recommends commercially bottled water. Filling is a US legacy, criticised (saurugg.net), not a European official instruction.
Our take: filling every drinkable-water container you can the moment the alert sounds — i.e. before any contamination — is a rational catch-up if you have not stockpiled. But the official fundamental remains: store in advance.