Unit 2 was at 12.5 percent power when a safety injection actuation occurred, according to a report filed with the U.S. Nuclear Regulatory Commission. The reactor then automatically tripped offline. Preliminary data suggests that the No. 1 high pressure turbine governor valve failed open, causing a steam header pressure rate of decrease safety injection actuation signal. Backup safety equipment performed as designed to safely shut down Unit 2.
Both reactors are stable, and Unit 1 continues to operate at full power.
Unit 2 achieved initial criticality on May 23 and is currently undergoing power ascension testing. Plant owner and operator the Tennessee Valley Authority (TVA) plans to have the operator running at full power by the summer.
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