[dundercoder]

Had a buddy on a nuclear sub drink water from the primary coolant loop when he joined the team.

While I do see this as a form of hazing which I am morally opposed to-

8oz (.237 liters) of primary coolant in a properly maintained pressurized water reactor might contain up to 13mrem of orally ingestible radiation, or approximately the radiation of a chest x-ray. (For comparison you get between 3-8 milirem on a 7 hour transatlantic flight)

Don’t make it your primary source of hydration and you’ll be ok. If the fuel is degraded or there is a leak (unlikely in properly maintained PWRs) the radiation dose is significantly higher.

[IAmBroom]

That makes zero sense. Radiation is not a component of water; it is literally photons[0]. In the nanosecond after you fill the glass, all the radiation in it has left the volume.

I'd drink it. It's just extremely pure water, with a nuclear flashlight at the bottom of the pool - which no one could see, even if they had gamma-ray glasses on[1], because the water attenuates it so much.

[0] Or ions of hydrogen or helium, in the case of alpha and beta radiation.

[1] Which it turns out were way less cool than the Sea Monkeys(tm).

[dundercoder]

Radiation isn’t contained in the water as photons, but the coolant itself becomes radioactive through neutron activation. Even with intact fuel rods, oxygen in the water turns into N-16 with a half-life of about seven seconds, and trace metals like nickel and cobalt form isotopes such as Co-58 and Co-60. These emit strong gamma radiation while the reactor operates.

The primary coolant is not simply pure water; it contains boric acid, lithium hydroxide, dissolved hydrogen, and trace corrosion products like iron, nickel, cobalt, and chromium. Under power level neutron flux, some of these elements become short- or medium-lived radionuclides. Once removed from the core, most of the activity decays within minutes, but during operation the water is measurably radioactive.

An eight-ounce sample taken from the loop at power would carry roughly the dose of a chest X-ray before it decayed away, due to these activated isotopes rather than residual photons [EPRI PWR Primary Water Chemistry Guidelines; NUREG-1437][0].

I was on site for the mid cycle outage of three mile island unit 1 around 2005. I did the data sync and transfer for the steam generator inspection, but got tutored by some old PHDs during the down time.

[0] https://downloads.regulations.gov/NRC-2020-0101-0142/content...

[IAmBroom]

Thank you very much! TIL!