A source says Tokyo Electric Power Company is planning to once again restart the No.6 reactor at its nuclear power plant in Niigata Prefecture as early as Monday, February 9.
TEPCO reactivated the reactor at the Kashiwazaki-Kariwa plant on January 21, but shut it down about 29 hours later after an alarm sounded while control rods were being extracted.
It was the first TEPCO reactor to restart since the 2011 accident at the company's Fukushima Daiichi nuclear plant.
The source says TEPCO identified a fault in the alarm settings for a device that controls the movement and speed of the control rods.
It adds that TEPCO believes it can resolve the problem by changing the settings. It is making final arrangements to extract control rods and restart the reactor again as early as next Monday.
The company had initially planned to resume commercial operations at the plant on February 26. In the wake of the problem, TEPCO has indicated it will likely review that schedule.
The source says TEPCO will submit a revised schedule for resuming commercial operation to the Nuclear Regulation Authority.
It also says TEPCO plans to announce the results of its investigation on Friday.

Quiz 1:
When is Tokyo Electric Power Company planning to restart the No.6 reactor?
A. January 21
B. February 9
C. February 26
D. Friday

Quiz 2:
What prompted TEPCO to shut down the reactor on January 21?
A. A fault in the control rods
B. A schedule review
C. An alarm sounding during control rod extraction
D. A revised schedule submission

Quiz 3:
What was significant about the January 21 reactivation?
A. It was the first TEPCO reactor to restart since Fukushima Daiichi
B. It resulted in immediate commercial operations
C. It was planned for February 26
D. It involved submitting a revised schedule



[Answer block]
Answers:
Quiz 1: B
Quiz 2: C
Quiz 3: A