Jul 01 2012 TOKYO--The cooling system for the spent fuel pool at the crippled Fukushima Daiichi power plant's No. 4 reactor automatically suspended operation Saturday, Tokyo Electric Power Co. said,

Some unconfirmed reports are now coming in stating the pumps have been re-started..  Jul 01 2012 9:45 PM ET

By MarketWatch

TOKYO--The cooling system for the spent fuel pool at the crippled Fukushima Daiichi power plant's No. 4 reactor automatically suspended operation Saturday, Tokyo Electric Power Co. said, Kyodo News reported Saturday.

The utility known as Tepco has been unable to activate a backup cooling system for the pool and is looking into the cause of the trouble, officials of the plant operator said later in the day, adding it is unlikely the temperature will rise rapidly.

The water temperature of the pool was 31 C at the time of the suspension at around 6.25 a.m. local time and no leakage of water with radioactive materials has been found, Tepco said.

The temperature of the pool rose 0.26 C per hour by late Saturday afternoon, according to the utility.

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. The cooling system at the No. 4 reactor was previously suspended on June 4.  Read Story >>>

http://www.marketwatch.com/story/fukushima-reactor-cooling-system-suspended-kyodo-2012-06-30

 http://www.marketwatch.com/story/fukushima-reactor-cooling-system-suspended-kyodo-2012-06-30

Jul 1 2012 NOTE: Last Night through early this morning several United States stations on the  Map of the RadiationNetwork.com web site recorded CPM readings above 100 CPM, but for unknown reasons the entire network was rebooted and all the graphs which documented the sudden rise in detected radiation were lost.



[...] The particular model used at Fukushima had inherent design flaws in the containment structure from the outset and engineers predicted the exact scenario that happened at Fukushima. The General Electric Corporation began constructing the Mark-1 BWR reactors in the 1960s, claiming that they were cheaper and easier to build in part because they used a smaller and less expensive containment structure, and this is where the main problems lie. [...] More questions arose about the design in the mid-1980s, after Nuclear Regulatory Commission official Harold Denton stated that the Mark-1 reactors had; “…a 90 percent probability of bursting should the fuel rods overheat and melt in an accident.” Thirty-five years ago, while reviewing the design for the Mark-1, Nuclear Engineers Dale G. Bridenbaugh and two of his colleagues at General Electric were pressured into okaying the designs for the Mark-1 and were forced to resign after becoming convinced that the Mark 1 was so flawed it could lead to a catastrophe.