The Tennessee Valley Authority said the newest U.S. nuclear power reactor, Watts Bar Unit 2, had completed ascension tests on Friday, Sept. 30, and was ready to enter into pre-commercial operations, which is the start of a 20-day cycle at full power that precedes declaring the unit fully commercial.
The unit reached 100 percent power on Sept. 28 last week, on Wednesday, after reaching first criticality on 24 May of this year, as the first U.S. commercial reactor to do so since 1996, when Watts Bar Unit 1 was fired up. Unit 2 is a 1165 MWe (net) reactor now producing more than 1,150 MW of energy, reports indicate.
After reaching full power last Wednesday, the unit remained at full power until Oct 1., Saturday, and Oct. 2, Sunday, when it was posted at 54 percent and 84 percent, respectively, in the U.S. Nuclear Regulatory Commission status reports. On Monday, the unit was back up to 100 percent power.
A transformer fire in late August was the latest delay in the reactor's ascent to full power. The TVA announced that the unit was connected to the TVA electrical system early in the morning of Sept. 26, returning to service following a fire on August 30 that damaged one of the unit's main transformers.
Technicians followed a rigorous and detailed process to inspect, repair and re-test the transformer before it was returned to service, “ensuring that it performs safely and reliably, as designed,” the TVA said.
“When we decided to complete Unit 2, we made a commitment to the people we serve,” said TVA chief nuclear officer and executive vice president in charge of generation Joe Grimes. “The Watts Bar team has now passed another important milestone in fulfilling that commitment, “ he said.