1) Reactors SINK. In 20 minutes your precious reactor with it's heat will be on the bottom at the ocean floor. Sure it will leak a LITTLE but after 15 minutes, nothing. ***Baloney. A reactor in thermal runaway would take at least several hours to cool down even under the best of conditions, at a minimum contaminating several million gallons of seawater.
2) Ever seen a volcanic vent ? NO STEAM. ***I've seen it on TV. There is steam, but it quickly reintegrates with the surrounding water because of a couple of factors. The open question is at what depth does the steam no longer vent to the open air, which is probably on the order of several hundred feet.
3) There are thermal gradients in the ocean water that prevent what you are talking about. The irridated water would ride up several hundred feet aznd by the top it got to the top it would be at the surrounding seawater temperature again. ***This is exactly the problem. The factor of rising hot water being replaced by inrushing cool water is an open configuration heat pump. As you stated, the "irridated water would ride up several hundred feet". This configuration just keeps pumping radiation into the sea.
Of course in shallows (less than 500m), then there could be some issue, but the fact remains that the reactor core will be well shielded even in shallows. ***The danger in the shallows would be that the steam could rise to the open air, creating a radioactive cloud.
Of course, there is something else to consider. How exactly are you going to make water radioactive ? Oxygen isotopes ? ***Here are 4 of the 16,500 hits on Google for the term "radioactive water": Las Vegas SUN: Study attacks DOE monitoring of radioactive water Las Vegas SUN. January 18, 2002. Study attacks DOE monitoring of radioactive water. By Mary Manning LAS VEGAS SUN. ... www.lasvegassun.com/sunbin/ stories/text/2002/jan/18/512909846.html - 4k - Cached - Similar pages Fortum.com - Slightly radioactive water leaked in the interior of ... Slightly radioactive water leaked in the interior of the Loviisa Power Plant. 18.8.2000. On Thursday, 17 August 2000, radioactive ... www.fortum.com/news_section_ item.asp?path=14022;25730;551;3508 - 21k - Cached - Similar pages Acidic, radioactive water spills into bay - Independent Media TV ... Environment. Acidic, radioactive water spills into bay. September 06, 2004. By: Janet Zink. ... www.independent-media.tv/item.cfm?fmedia_ id=8893&fcategory_desc=Environment - 21k - Cached - Similar pages Japan Today - News - Radioactive water leaked from nuclear reactor ... Radioactive water leaked from nuclear reactor in Ishikawa Pref. ... nothing like some radioactive water to quench your thirst. Contract employees - man your mops! ... www.japantoday.com/gidx/news262543.html - 12k - Cached - Similar pages
1 mile = 5,280 feet
1 foot = 12 inches
1 mile = 63,360 inches
1 square mile = 4,014,489,600 square inches
1 cubic mile = 254,358,061,056,000 cubic inches
1 gallon = 231 cubic inches
1 cubic mile = 1,101,117,147,429 gallons = 1,101 billion gallons
17 X 10^8 cu mi = 187,189,915,062,930,000,000 = 187,189,915,062 BILLION Gallons of water or about 187 x 10 to the 18th power gallons of water.
I think it can diffuse a few billion gallons of radioactive water.