Pump failure nearly brings No. 5 to a boil

From the Japan Times website today, it tells us that the cooling system in Reactor 5 malfunctioned, and had to be replaced.

The seawater pump in the cooling system for the Fukushima power plant's No. 5 reactor broke down Saturday evening, prompting repair crews to install a backup pump 15 hours later on Sunday afternoon, Tokyo Electric Power Co. said.

The reactor came very close to hitting the 100 degree mark, which causes water evaporation leading to exposure of the rods, but said redundancy systems where in place to deal with that.

By noon Sunday, the core had reached a temperature of 93.6 degrees and the fuel pool had reached 46 degrees, compared with 68 degrees and 41 degrees, respectively, at 9 p.m. Saturday. The backup pump kicked in at 12:31 p.m., bringing the core back down to 83 degrees by 1 p.m., a Tepco spokeswoman said by phone later Sunday. The temperature of the core must stay below 100 degrees to maintain cold shutdown status. Anything above might cause the water to evaporate and expose the fuel rods.

Again, the conversation turns to highlight the disclosure issues with Tepco, as I highlighted in this thread.

Still, Matsumoto admitted that "it might have been better" to notify the media sooner about the pump's failure. Tepco is under fire for failing to disclose information fully and quickly since the nuclear crisis began on March 11. The quake and tsunami severely damaged units 1, 2, 3 and 4 at Fukushima No. 1, but Nos. 5 and 6 were already shut for regular inspections at the time of the disaster.

Sorry, not doom and gloom, but when you couple this information with the other lead story on the Japan Times, it is quite apparent that this is going to take some time to get under control.
Stabalizing reactor by year end immposible

Japan Times

15 hours to install a backup pump? That seems not so good. You would think they would have a backup pump inline with the main pump. Extra redundancy on a nuke plant is not a bad thing I would think..

reply to post by jaydeePNW

I suppose the backup generators for the pumps were the redundancy plan!

From what I understand, they didn't work and reactor 5 had to be rewired.

reply to post by sheepslayer247

Yikes. I used to design and build water cooling systems for PCs as a hobby. On my always on system I used two water pumps in case one failed and had automatic shutdown if the temps go to high. Thats just a home PC. Seems odd they would not have at very least 2 working pumps on hand for a freaking nuke plant... It doesn't project much confidence in the worlds nuke plants. What bothers me most is these plants are supposed to be pretty well managed, what happens when the Pakistans plan goes live or any of the other countries with no real standards that are already running? Not a good outlook.

reply to post by jaydeePNW

From what I understand, there was a backup power system, but not a backup pump itself. Therefore that's the reason why it had to be replaced.

I don;t know much about engineering, but it's would seem wise to me to have a backup in case of such events...considering it's a nuclear plant and all!