One of the reactor’s control rods malfunctioned twice in less than 24 hours.
The control rods absorb neutrons, preventing them from striking the fuel rods and starting the fission process that generates heat. The latest incident was at about 1 a.m. Thursday, Indian Point and federal officials said, and was one of several events this week at the plant.
Clamps above the reactor hold the rods in place. The clamps are powered by
an electromagnetic current and not enough current was getting to one of the
clamps, said Jim Steets, a spokesman for Entergy Nuclear Northeast.
”Today we’re installing a modified electrical board that will increase the
current to the clamp,” Steets said Thursday afternoon.
Workers discovered the problem Wednesday when more than the usual amount
of water used to cool the reactor passed through a valve. To make up for the
temperature drop, the reactor produced more power. Workers then began
inserting the rods into the reactor to slow the nuclear reaction process. Steets said one rod improperly inserted itself completely into the reactor about 2:30 a.m. Wednesday. It did it again Thursday.
Later Wednesday, Entergy performed a test of its 156 warning sirens in four
counties near the plants. Two devices didn’t work.