The researcher, Fumiya Tanabe, is the same one who also said back in August that the fuel of Reactor 3 had melted twice and dropped onto the Containment Vessel.
If what he says is true that the Reactor 2's Suppression Chamber broke during the earthquake, it may have grave implications for all the other nuclear reactors in Japan with the same earthquake specifications.
Reactor 2's building exterior is pretty much intact, with only one hole on the side of the building. Yet, the NISA's estimate shows this reactor may have released more radioactive materials than the other reactors (1 and 3). If the Suppression Chamber was broken as soon as the earthquake hit on March 11, that may explain it.
From Kyodo News Japanese (11/19/2011):
An expert in nuclear safety complied the result of the analysis by November 19 that shows the high possibility of the Suppression Chamber of Reactor 2 at Fukushima I Nuclear Power Plant having been damaged or degraded by the earthquake.
TEPCO still maintains its position that there was no visible damage to the reactors by the earthquake, and the cause of the accident was the loss of power because of tsunami. If the reactors were damaged by the earthquake, it would affect other nuclear power plants in Japan whose anti-earthquake standards are the same as those of Fukushima I Nuclear Power Plant. A closer look at the result of investigation by TEPCO and the fact-finding committee of the national government would be warranted.
The researcher who did the analysis is Fumiya Tanabe, a former researcher at the Japan Atomic Energy Agency (JAEA) and the current head of the Research Institute on Safety of Technology Systems (my translation, and not the formal name of the organization; 社会技術システム安全研究所) in Hitachinaka City in Ibaraki Prefecture.
I am trying to locate the details of his findings.