TEPCO to dismantle top of exhaust stack at Fukushima plant due to fractures. April 26, 2016, The Mainichi, http://mainichi.jp/english/articles/20160425/p2a/00m/0na/024000c
[excerpted] Tokyo Electric Power Co. (TEPCO) will begin dismantling the upper section of the joint exhaust stack for the No. 1 and 2 reactors of its Fukushima No. 1 Nuclear Power Plant in fiscal 2018, company officials announced on April 25 during a meeting with the Nuclear Regulation Authority (NRA). NRA officials had advised TEPCO to disassemble the structure due to fractures in its pillars that increased the risk of it collapsing....
Radiation measurements conducted at the base of the structure in 2013 stood at an estimated 25 sieverts per hour -- an extremely high level that would kill nearly everyone exposed for that long.
[excerpted] "The joint exhaust stack for the No. 1 and 2 reactors of the Fukushima No. 1 Nuclear Power Plant, whose upper section has been fractured."
Majia here: As you can see from this screenshot, the emissions are relatively high again, calling into question the success of the ice wall.