– Why are they ‘speeding up’ at Unit 4? — Expert in 2010: Megathrust quake to hit Fukushima ~Nov. 2013… Recurrence interval of 75 years with last rupture Nov. 1938 — Planet’s most powerful type of seismic event — WSJ: Top official concerned quake to destabilize fuel pool (ENENews, Oct 31, 2013):
Wall St. Journal, October 30, 2013 (Emphasis Added): Tepco will remove about 1,300 spent fuel rods and 200 new fuel rods […] the 4 meter-long rods will be pulled out of the pool at a time, is considered unprecedented in its scale. Shunichi Tanaka, chairman of the Nuclear Regulation Authority, has expressed concerns about the fragile state of the nuclear fuel left in three reactors and the spent fuel pool in the No.4 building. If improperly handled or destabilized by another major earthquake at the site, the fuel could discharge large amounts of radiation into the environment. […]
- Kyodo, Oct. 2013: “Tepco plans to start removing nuclear fuel from the spent-fuel pool at the top of the reactor 4 building at the crippled Fukushima No. 1 plant as early as Nov. 8, about a week earlier than scheduled“
- Euronews, June 2013: “The Japanese government along with the Tokyo Electric Power Company (TEPCO) are aiming to speed up the removal of spent fuel rods”
- NHK, Dec. 2012: “Due to concerns over the ability of the destroyed reactor building to withstand earthquake activity as well as emergency operations, TEPCO has decided to speed up operations one year ahead of schedule to remove the spent nuclear fuel”
Ravi V. S. Kanda, California Institute of Technology (Emphasis Added), May 28, 2010: Fukuyshima-oki — ruptures of 1938 […] In the megathrust interface off Fukushima, three large events – Mw7.4 (May, 1938), Mw 7.7 and Mw 7.8 (both in Nov 1938) — occurred in close succession. […] combining the moment release from these three events […] yields a […] moment-magnitude, Mw, of 8.1. […] Since there hasn’t been a Mw>7 earthquake off Fukushima since 1938, we assume a recurrence interval of ~ 75 yrs for a characteristic earth similar to the value assumed for the Tokachi-Oki region [Yamanaka and Kikuchi, 2003]. […]
Science Magazine, June 17, 2011: The only previously recorded large events offshore Fukushima and Ibaraki occurred as a sequence in 1938, which taken together correspond to about an Mw 8.1 event […] the slip budget on the megathrust and the surface velocity data suggest that an earthquake similar to the 2011 event is possible offshore Ibaraki and Fukushima […] area could experience much greater slip than has been documented for previous events, similar to what just occurred offshore Miyagi.
See also: quake