A last resort for cooling is the nearby seawater. Why do you think they locate these type of reactors near a body of water?
Venting contaminated steam or discharging contaminated seawater, pick your poison.
Either you cool with seawater thereby contaminating, it in this case, and discharging it back into the open ocean (tons and tons of it) or you let the reactors meltdown then have to cool it down anyway and spew contamination (radioactive) into the open air and sea.
As of March 16th...Units 1 and 2: TEPCO has released estimates of the levels of core damage at these two reactors: 70% damage at Unit 1 and 33% at Unit 2...Noted at...http://mitnse.com/page/2/
Recently March 22nd...”Tokyo Electric Power Company released the results of a half-litre sample of water taken 100 metres south of the discharge channel from damaged units 1 to 4.
Testing for a range of radionuclides showed amounts below regulatory limits for cobalt-58, iodine-132 and cesium-136. Detections were far above limits, however, for cesium-137, cesium-134 and iodine-131...
...Iodine-131 has a half-life of eight days, so its potential danger reduces relatively quickly. Caesium-137 has a half life of 30 years, whereas the other isotope, caesium-134, has a half-life of two years. Additional monitoring at eight locations is to be carried out by the Japan Agency for Marine-Earth Science and Technology in conjunction with the Japan Atomic Energy Agency. Results from this are expected on 24 March.” Again this from the MIT site...http://mitnse.com/
It’s not clear to me how the spent fuel ponds are doing but anything using saltwater is toast (never to be used again). The MIT site also says units 5&6 are pumping saltwater through them to remove residual heat. I take that to mean via a heat exchange(r) but saltwater none the less but probably not contaminated.
I'm thinkin' that they are doing both.....a lot........at the same time...........
Either by necessity, or, if there is a rupture or breach, they have no choice..........
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