> [intermediate level nuclear waste] is not radiologically dangerous in any realistic way This is ***false*** to the point of being irresponsible. > If you put a completely legal luminous watch in a barrel containing half a tonne of dirt, that dirt would technically be intermediate-level nuclear waste according to the regulations. If the watch used tritium at the legal limit you'd need seven, not one. But the point remains that ***seems*** absurd. But wait, if the watch used promethium-147 you'd need 3300 watches! And if it used radium 226 you'd need 140,000 watches! What's going on? The problem stems from the measurement used, the becquerel. # The Regulations According to the [linked regulations](https://web.archive.org/web/20121031031838/http://www.nda.gov.uk/documents/upload/WNM-PP-007-Intermediate-Level-Waste-ILW-Issues-1-January-2008.pdf) from "*Introduction to Intermediate Level Waste (ILW) issues*"... > ILW is radioactive waste with radioactivity levels exceeding the upper boundaries for Low Level Waste (LLW): > * Alpha emitters greater than 4 GBq/tonne. > * Beta/gamma emitters greater than 12 GBq/tonne. > * Waste that does not need radiological self-heating to be taken into account in the design of storage or disposal facilities. Half tonne of dirt needs 2 gigabecquerels of alpha emissions or 6 gigabecquerels of beta or gamma emissions. Note that this is an *Introduction* to Intermediate Level Nuclear Waste. I suspect the full regulation is much more detailed. # What's a becquerel? A [becquerel](https://en.wikipedia.org/wiki/Becquerel) is the decay of one atomic nucleus per second. Its equivalent units are the curie (3.7e10 Bq) and the rutherford (1 MBq). GBq is a gigabecquerel, 1 billion becquerels. A becquerel is a distinct measurement from a [sievert](https://en.wikipedia.org/wiki/Sievert) (effective dose) or [roentgen](https://en.wikipedia.org/wiki/Roentgen_(unit)) (exposure). See [US Environmental Protection Agency - Radiation Terms and Units](https://www.epa.gov/radiation/radiation-terms-and-units). This is critically important. ***A becquerel only measures how many nuclei decay per second***. It does not measure the type nor energy, nor does it measure the danger to humans. That's what sieverts and roentgens are for. # How many becquerels in a luminous watch? According to the [The Radioactive Substances (Clocks and Watches) (England and Wales) Regulations 2001](https://www.legislation.gov.uk/uksi/2001/4005/regulation/2/made)... > (i) Clocks or watches having their dials marked at the time of manufacture with “T 25” (Tritium), “Pm 0.5” (Promethium 147) or “Ra 1.5” (Radium 226) > * Tritium 9.3e8 bq > * Promethium 147 1.9e7 bq > * Radium 226 5.6e4 bq > > (ii)Clocks bearing radioluminescent deposits and not falling within category (i) > * Tritium 3.7e8 bq > * Promethium 147 7.4e6 bq > * Radium 226 7.4e3 bq > > (iii)Watches bearing radioluminescent deposits and not falling within category (i) > * Tritium 2.8e8 bq > * Promethium 147 5.5e6 bq > * Radium 226 5.6e3 bq > > (iv)Watches containing small sealed glass tubes internally coated with a phosphor and filled with tritium gas > * Tritium 7.4e9 bq The claim approaches plausibility with the regulation of 930 MBq of tritium per T25 marked watch. [Tritium](https://en.wikipedia.org/wiki/Tritium) is a beta emitter meaning 12GBq per tonne or 6GBq for a half tonne of dirt. We'd need 7 tritium watches. But there's a problem. Why is one allowed 400 times more becquerels from tritium than promethium-147? And 20,000 more from tritium than radium-226? Promethium-147 is also a beta emitter, but the beta particles is emits are much more energetic. When a [tritium nucleus decays](https://periodictable.com/Isotopes/001.3/index2.p.full.dm.html), one becquerel of tritium, it emits 19 keV. When [Promethium-147 decays](https://periodictable.com/Isotopes/061.147/index2.p.full.dm.html) it emits 224 keV. They're both beta particle emitters, but Promethium-147 decays with 10 times the energy. ***Becquerels only measure the number of nuclei decaying per second*** it does not account for the type nor energy. As such safety regulations must consider both becquerels and the material being measured. # Conclusion The claim is incorrect, but not too far off the mark that it can't be used to make a point about how the regulation is written. However, it fails to explain its point, instead resorting to generic moaning about regulations. A better critique would have used the tritium watch example to illustrate why using sieverts or roentgens would make a better regulation than becquerels. However, they reference an *Introduction* to Intermediate Level Nuclear Waste. The full regulation may contain additional measurements. > [intermediate level nuclear waste] is not radiologically dangerous in any realistic way For the same reason this claim is ***false*** to the point of being irresponsible. Becquerels do not measure dosage nor exposure. 4 GBq of [radium 226 is very dangerous](https://en.wikipedia.org/wiki/Radium#Hazards). Radium 226 emits [alpha particles](https://en.wikipedia.org/wiki/Alpha_particle#Biological_effects) which, if ingested, are very hazardous. It accumulates in the bones. It decays into [radon gas](https://en.wikipedia.org/wiki/Health_effects_of_radon) which is very harmful.