6/30/2012 Reactor 4 Spent Fuel Pool Cooling Problems

This development looked somewhat alarming.  Apparently the spent fuel pool from the Fukushima Daiichi reactor 4 building has lost cooling as of 6:25 AM EST Saturday Morning (6/30/2012) as per WSJ MarketWatch.  According to TEPCO the temperature climbed at a rate of 0.26 C by late Saturday afternoon.  Quoting MarketWatch:

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If Tepco continues to be unable to cool the pool, the temperature could reach 65 C, which is the upper limit designated in the safety regulations, on Tuesday morning.

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Here is another estimate from Fukushima Diary if the spent fuel pool cooling is offline for a longer period:

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Prof. Takeda [Link] estimates the coolant water of SFP4 will reach 100℃ in the evening of 7/5/2012 (Thursday).
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Spent fuel pool 4 contains 1535 fuel rods and there have been continued fears that a collapse of the elevated pool due to another earthquake could cause a massive release of radiation in to the environment, possibly rendering Japan uninhabitable.