TEPCO retracts criticality call

· We found a possibility to detect short-half-life radionuclide such as
  Xe-133 and Xe-135 according to our radionuclide analysis sampled on
  November 1 by the gas management system of the reactor containment
  vessel of Unit 2. We continued to monitor the temperature, pressure and
  data from monitoring post and there was no significant fluctuation from
  those data. As we can't be denied a possibility of fission reactions,
  we decided to start injecting boric acid water from reactor feed water
  system at 2:48 am on November 2 and stopped it at 3:47 pm on the same
  day. At around 7:20 pm on the same day, Japan Atomic Energy Agency
  evaluated that the TEPCO's analysis result of the short-half-life
  radionuclide such as Xe-133 and Xe-135 detection was valid. We consider
  that they were generated by the spontaneous fission on the grounds that
  the concentration of detected short-half-like radionuclide (Xe-135) is
  low, that short-half-like radionuclide (Xe-135) was detected even after
  the boric acid, which stops nuclear fission chain reactions, was
  injected, and that the parameters of the reactor were not significantly
  changed.
· At 10:00 am on November 3, we started transferring accumulated water
  from the basement of the Unit 6 turbine building to temporary storage
  tanks.
· At 12:40 pm on November 3, we started the work to install an additional
  flow meter into the nitrogen gas injection line into Unit 2 to improve
  the reliability of the nitrogen injection. It was finished at 2:00 pm
  on the same day, For this work the nitrogen injection was suspended for
  approximately 10 minutes, however, there were no significant changes in
  the parameters of Unit 2.