• Tepco prepares for restart of Kashiwazaki-Kariwa unit “We are currently adjusting personnel and confirming prior arrangements, and plan to start up the reactor on 9 February,” Takeyuki Inagaki, head of the Kashiwazaki-Kariwa plant, told a press conference on Friday. • Tokyo Electric Power Company (Tepco) restarted the reactor in the evening of 21 January. • However, shortly after midnight on 22 January, “an alarm was triggered in the control rod operation monitoring system for one control rod during the control rod withdrawal operation, causing the withdrawal operation to be suspended”. • The unit’s restart was subsequently suspended while an investigation into the cause of the alarm was carried out. • “As a result of various tests conducted at the plant and elsewhere, we have confirmed that, in rare cases, one of the three electrical wires supplying electricity to the motor experienced a delay in the rise of current when the motor was started,” Inagaki said. • “Although this delay was within the normal range of operation of the equipment, we determined that the inverter had detected the delay as an abnormality.
Article Summaries:
- Tepco’s Kashiwazaki‑Kariwa unit 6, which had been offline since the 2011 Fukushima accident, was restarted on 21 January. An alarm in the control‑rod monitoring system triggered after midnight on 22 January caused a temporary shutdown while the cause was investigated. Tests revealed that a delayed current rise in one of three motor‑supply wires was misinterpreted as a fault by a newly installed inverter. Tepco disabled this fault‑detection feature and is now testing each control‑rod drive individually. The plant plans to resume full startup on 9 February, raise pressure gradually, and aim for commercial operation by 18 March after regulatory checks.
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