No. 2 N-plant was prepared for venting, The Yomiuri Shimbun, August 10, 2011:
Preparations for opening the vents of nuclear reactors to prevent hydrogen explosions were made at the Fukushima No. 2 nuclear power plant [...] to release steam accumulated in the containment vessels.
On the day of the disaster, the Nos. 1, 2 and 4 reactors suffered damage to cooling pumps, the data showed. It was feared that the containment vessels might be damaged as pressure built up inside.
Preparations were being made to open the vents of the vessels at all four reactors, including the No. 3 reactor, on March 12. But venting operations did not actually take place as the temperature of the reactors was successfully lowered [...]
Published: August 10th, 2011 at 4:37 pm ET