Nuke Fails Two Restart Attempts

Friday, May 31, 2013 @ 05:05 PM gHale


A second attempt to restart one of the two nuclear reactors at North Anna nuclear plant in Mineral, VA, after a refueling outage failed when a valve closure led to decreasing steam generator levels.

A report from the U.S. Nuclear Regulatory Commission (NRC) said an operations crew at North Anna, in Louisa County 45 miles northwest of Richmond, manually shut down the Unit 2 reactor at 3:07 p.m. Tuesday after a main feed water valve “spuriously closed.” Officials did not know the reason for the closure, the NRC said.

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All control rods fully inserted into the core following the manual reactor trip, and officials were removing decay heat, the NRC said.

The second attempt by Dominion Virginia Power’s workers to restart Unit 2 occurred May 21, and the reactor was operating at 98 percent of capacity when Tuesday’s event occurred.

Unit 2 originally idled April 7 for a scheduled refueling and maintenance outage. But when crews initially tried to restart the reactor, it reached 60 percent of capacity May 10 before operators detected excessive vibrations in the exciter, which sees use during startup to initiate the flow of electricity from the generator to the grid, so the unit shut down for additional repairs.

North Anna’s Unit 1 has remained at full power.



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