http://www3.nhk.or.jp/daily/english/27_12.html



Or to put it another way 1 litre of water will have 2.9 Trillion Becquerels of radiation or approx 174 Trillion atomic disintegration per minute. As most will be gamma packets of various energies i.e. different desolved fission products, does anyone want to guess the dosage an average man would receive standing 1 metre away for an hour or a day?

Ok a little calculation.

The area of the sphere is 4*pi*r*r, where pi=3.1415 and r=1
thus the area is 12.56 m squared. assuming negligible absorption of the gamma photon as it exits the 1 litre surface volume and the shadow area of the man is 1 m squared this will give a flux of gamma particles per minute of 174/12 Trillion = 14.5 Trillion per minute.

If we assume a gamma decay energy per particle of 1.17 MeV (1.1874x10-13 J) i.e. Cs 137 this give a flux energy of 0.00172 J/min or around approx 0.1 Sv/hr (q=1 for gamma photon) or around 2.4 Sv over a 24 hr period of irradiated dose (enough to give an LD5 - LD50, i.e enough of a radiation dose to give a 5-50% mortality rate, probably around 10-20% mortality rate)

Thats a lot of radiation from a 1 Litre of dissolved water fission products sitting in a Nalgene bottle 1 metre away esp with a half life of Cs137 being around 30 years.