April 7, 2012
Tokyo Electric Power Company
-At around 5:00 pm today, April 7, a TEPCO employee found the volume of the nitrogen injection to Unit 1-3 decreased to zero (m3/h) while he was checking plant parameters.
-Therefore, we checked the equipment on site and found the nitrogen injection system (Nitrogen/Gas Separator A) was stopped at 4:43 pm due to a "compressor failure" alert.
-After that, at 5:43 pm, using the stand-by nitrogen supply system (Nitrogen/Gas Separator B), we restarted the nitrogen injection to the each unit at 5:56 pm.
-At 6:28 pm, we confirmed the volume of the nitrogen injection was the same as before the system stopped and stabilized.
-No significant changes of the parameters related to the PCVs, the density of hydrogen, or the monitoring-post data were confirmed.
-We will investigate the cause of this trouble.