[simonh]

From the article:

"International Isotopes contractors had set up a secure steel “chamber” wherein they would perform a crucial, most perilous part of the operation: removing the capsule with cesium-137 from the irradiator."

The problem is they didn't realise it had happened straight away. They only discovered the leak later, when performing a routine wipe-down check of the area. There are still details missing though, like how come they didn't perform the wipe-down check before opening the chamber? Or did they? As the article says, it's not clear exactly what happened.

[jcims]

I’m curious how you don’t know that you cut into the capsule. It’s supposedly a white powder, wouldn’t it make a cloud?

Also if this is possible wouldn’t you put sone contingencies in place, like mount the grinder on limited travel arm or something? Sound’s like they just went at it with a $30 DeWalt.

The whole thing seems kind of ridiculous.

[kevan]

When you're grinding there's significant metal and abrasive dust thrown into the air. Given the airflow they generate and how fine the radioactive powder is even a small nick in the capsule could end up with a lot of material in the air without you noticing it.

A jig to limit grinder motion sounds like really cheap insurance to prevent this failure mode.

[ethbro]

I'm curious if the capsules like this are standardized or one-off. The description of the tungsten plug makes it sound like the latter.

In which case a more sane procedure would probably mandate some examination of the capsule, formulation of a plan off-site, then implementation of said plan.

[a3n]

They're only a 20 something million dollar company, so everything is probably done as cheaply and simply as possible.

Like many companies, they may also have trouble hiring people.

[johntb86]

If you're using an angle grinder on something you expect some smoke to come out. You might not notice if it's slightly the wrong color.

[simonh]

It depends how heavily it was disturbed. They describe it as like talcum powder. If it's that fine, tiny particles could disperse in the air invisibly.

[pvaldes]

> They didn't realise it had happened. They only discovered the leak later

"Trained experts in radiation equiped with geiger counters and all the stuff, were unable to see it coming" Chapter 35.

They had one job. One small area to check for radiation leak in a controlled environment. How this could happen?

A) Maybe geiger counters can't detect Caesium radiation? I'm not expert in the area but would appreciate the point of view of some experts.

B) Geiger counters failed. How? didn't have batteries?

C) The leak was detected in time, but the culprit keeped his/her mouth firmly closed because... human nature. Not my fault. I didn't cut it.

D) There was not leak to detect (Leak was in a different area, Hidden second point of radiation like waste containers accumulated in the broom closet, ect)

Choose your option. In any case it feels like a lie again. This is not how you build trust on nuclear safety procedures.

[lnx01]

Caesium-137 emits Beta radiation decaying to Barium-137, which then emits Gamma radiation. Geiger counters can definitely detect "Caesium radiation".

[pvaldes]

We can discard (A) then, as expected. Thanks

In films at least, Geiger counters do a peep constantly when turned on. Could a geiger counter fall silently and be mistaken for absence of radiation? Aren't equiped with visual clues also? (lights blinking... etc)

[petschge]

A) If it can not see beta and gamma radiation it is completely broken. You should test that before you use the Geiger counter. It is neutrons and to some extend alpha radiation that you might be blind to.

B) Of course there is batteries in there. But if they are dead, the Geiger counter would be completely dead and not even detect the natural background. You should notice that before you actually use the device.

C) You had one job...

D) that's the problem with invisible dangers and why we have fixed procedures to follow.

A simple Geiger counter give a current pulse when a bit of ionizing radiation makes the tube conductive and then has an external circuit switch of the supply voltage to extinguish the current in the tube. During that dead time it is unable to detect radiation. After a set time the tube is powered up again. Some models would detect if there is too much current flowing and would switch of the voltage again. This current flow could happen for two reasons: it is _STILL_ flowing from the first event or it is _AGAIN_ flowing because there is too much radiation. So depending on models it might simply stay completely silent when there is a lot of radiation (failing silently when it should really warn you) or it could detect that simulation and raise an alarm (possibly giving a false positive if the tube ages and the current takes a long time to shut down after an ionization even in the tube). It is important to know which of the two the model in your hand does.

Source: Radiation Safety training more than a decade ago when studying physics.

[jsjohnst]

Everything I’ve read so far points at C. Gross negligence on the part of the UW nuclear safety officer, then attempted cover up of what happened. The points made in this article support that theory, so no further reading necessary unless you care.