There have been some concerns that something is going on at Unit 5 (and possibly 6) at Fukushima Daiichi. A number of reports of pieces of information have been coming out. This is to attempt to gather them together and form some sort of theory as to what is going on. Unit 5 Photos of quake damage at unit 5 http://mainichi.jp/select/jiken/graph/20110924/8.html Videos of intake damage (taken by TEPCO) Unit 5 auxiliary sea water intake  http://www.youtube.com/watch?v=T2igL2Jz5Yc  Unit 5 RHRS sea water intake http://www.youtube.com/watch?v=MjPWWZWXhCc Unit 6 auxiliary sea water intake http://www.youtube.com/watch?v=WYM6lKI3CVo Unit 6 RHRS sea water intake  http://www.youtube.com/watch?v=8QpDuEYkVKk Some damage was noted on the intakes including broken pipes below the intakes at unit 5 and what appears to be a broken wall on the concrete sump box for the auxiliary sea water intake at unit 5. These intakes sit behind the filter screens that block fish and large debris in a concrete sump box/pool. You should see a concrete floor instead they look like sea floor full of sand and debris. This indicates the screens may have been damaged during the tsunami or otherwise filled up with garbage during the tsunami. The broken pipes seen at unit 5’s intakes indicate the impellers and any underwater pump equipment is likely damaged and not operable. Images of above water damage on the dock area of units 5 and 6 (end of page) http://cryptome.org/eyeball/daiichi090911/daiichi090911.htm Page 3-7 describes the cooling circulation systems being used at unit 5  http://www.nrc.gov/reading-rm/basic-ref/teachers/03.pdf Details on this kind of pump as describedfrom another BWR reactor system similar to Fukushima

vertical lift pump

A number of other issues have been brought up related to units 5 and 6 A local resident claimed workers have mentioned concerns at the plant with units 5 and 6 in a video interview. (translated bits of interview http://fukushima-diary.com/2011/10/news-a-raged-fukushima-citizen-talks-about-everything/) Levels of cesium being detected outside the intakes at 5 and 6 have increased. (documented with TEPCO reports) A unverified report that cesium levels near Ibaraki went up on October 16. A list of ongoing incidents at unit 5 mostly and a few at unit 6 that are reported by TEPCO, most having to do with cooling systems. May 30 – A water pump at unit 5 failed and had to be replaced, this caused an increase in reactor temps. http://www.joewein.net/blog/2011/05/30/fukushima-1-unit-5-water-pump-fails/ July 3rd split hose that carried seawater to unit 5 had to be repaired. http://www.upi.com/Top_News/World-News/2011/07/03/Fukushima-reactor-cooling-problem-fixed/UPI-67951309736486/ Possibly the hoses used to get around the damaged intake system and provide sea water to RHRS and auxiliary seawater side of those systems? Below are known events reported by TEPCO for unit 5 and then unit 6. Some things of note is the ongoing issue at unit 5 with the components of the cooling system. UNIT 5 Off-site power has been connected to Units 1 to 6 by March 22, 2011. At approximately 8:00 am on May 31, we confirmed oil leakage to the sea around the curtain wall of the water intake canal of Unit 5 & 6 and reported the issue to Futaba Wide-area Fire Headquarters and Fukushima Coastguard Office. As a result of our investigation, we confirmed that oil leaked from pipes around seawall to the port through holes of steel sheet piles and that the leakage already stopped. Since the diffused area was just around the curtain wall and the surface of the sea around Shallow Draft Quay and the oil film was very thin, we confirmed that there is no spread to the outer sea. We completed installing oil-absorbing mat around seawall at approximately 2:00 pm and also completed installing oil fences at 4:50 pm. We plan to protect pipes around seawall and collect the oil. At 10:00 am on June 14, we closed the open part at the bottom of curtain wall, through which the oil leaked Unit 5 (Outage due to regular inspection) -Sufficient level of reactor coolant to ensure safety is maintained. -At 5:00 am on March 19, we started the Residual Heat Removal System Pump in order to cool the spent fuel pool. -At 2:30 pm on March 20, the reactor achieved cold shutdown. -At 2:45 pm on July 15, we started the operation of the original Residual Heat Removal System (System B) by its original seawater pump. -At this time, we don’t think there is any reactor coolant leakage inside the primary containment vessel. -At 2:06 pm on October 7, we started to spray purified accumulated water brought from Unit 5 and 6 continually in order to prevent dust scattering and potential fire outbreaks from the cut down trees. <Treatment of Accumulated Water> – From 2:06 pm on October 7, in order to prevent from spontaneous combustion of cut trees and dust dispersing we started to sprinkle water in the site of Fukushima Daiichi Nuclear Power Station with cleared-up accumulated water of Unit 5 and 6. We measured radioactivity density in advance and confirmed to meet requirement of the guideline suggested in “Guideline regarding radioactive materials on bathing area”. <Others> From 10:03 am to 10:43 am on August 8, we stopped the residual heat removal system pump (D) in order to switch the power source of the pump (C) as well as conducting its commissioning (C) – In order to repair the outlet valve of Unit 5 residual heat removal system seawater pump (D), from 9:45 am to 10:42 am, September 26, we switched the seawater pump from B system (permanently installed) to A system (temporarily installed). – On September 30, as the repair work for the outlet valve of Unit 5 Residual Heat Removal System Sea Water Pump completed, between 11:30 am and 11:34 am on the same day, the Residual Heat Removal System was switched from A system to B (the Residual Heat Removal System Sea Water Line was also switched from A system to B). – For the purpose of Unit 5 water intake inspection, at 9:05 am October 20, unit 5 seawater pump of Equipment Water Cooing System was shutdown, and stopped cooling the spent fuel pool. At 9:13 am, Residual Heat Removal System (D) was stopped and stopped cooling the reactor. As the inspection was completed, at 2:32 pm, seawater pumps of Equipment Water Cooing System was resumed, which resumed cooling the spent fuel pool. At 3:02 pm, Residual Heat Removal System (D) was resumed, which resumed cooling the reactor. Due to this stop, reactor water temperature temporarily rose from 22.2℃ to 31.1℃. Spent fuel pool water temperature temporarily rose from 25.5℃ to 26.2℃.

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