For the kinds of radiation coming off spent nuclear fuel, every 7 centimeters of water cuts the amount of radiation in half.
The most highly radioactive fuel rods are those recently removed from a reactor. Based on the activity levels provided by Ontario Hydro in this report, this would be the region of danger for fresh fuel rods:
Swimming to the bottom, touching your elbows to a fresh fuel canister, and immediately swimming back up would probably be enough to kill you.
Yet outside the outer boundary, you could swim around as long as you wanted—the dose from the core would be less than the normal background dose you get walking around. In fact, as long as you were underwater, you would be shielded from most of that normal background dose. You may actually receive a lower dose of radiation treading water in a spent fuel pool than walking around on the street.
The same thing applies to swimming near nuclear submarines.
ReplyDeleteIn any event, I'm not a swimmer, so I'll stay out of the pool.
Deletemakes me wonder... If they are that radioactive, why aren't they inside the power plant producing more electricity?
ReplyDeleteDang, all this time I thought my glow was from my interesting personality...sigh
ReplyDeleteYou may survive the swim, but your genetic structure may not remain intact?
DeleteA few comments from a former US Navy nuclear submarine officer/engineer:
Delete1) Spent fuel doesn't have the "reactivity" left in it to keep inside the core to produce power. The spent fuel is highly radioactive, unlike the fresh new fuel that is added to the reactor, so the spent fuel has to be kept in cooling pools for some time until the decay heat from the radioactive by-products of fission have decayed away. Months or years for this process, depending on how much of the heat you want to go away.
2) A swimmer who swam up next to an *operating* reactor in a floating submarine could experience significant radiation levels, but not nearly as high as those encountered near spent fuel in a cooling pool. Among other reasons, the swimmer outside a submarine would be quite a bit further away from the operating reactor core due to the size of the submarine's hull, and that the reactor core is inside a pretty large pressure vessel which is itself inside a lot of radiation shielding. in the spent fuel cooling pool, non of that, just water sitting over the fuel rods. The spent fuel is producing more radiation than an operating core, and a diver in the pool could get a lot closer to the fuel.