Testing Nation’s Newest Nuclear Generation to Ensure Safety, Quality and Reliability

Power Ascension Testing is the final phase of an extensive “test drive” of Watts Bar Unit 2 to make sure the unit can deliver electricity safely, reliably and efficiently to our consumers.

When you buy a car, one of the first things you do is take it for a test drive. You want to make certain that the vehicle operates as designed, and that safety systems function properly.

That’s essentially what TVA is doing right now with the Power Ascension Testing program for its newest source of carbon-free nuclear power—Watts Bar Unit 2.

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John Manney (left), power ascension test coordinator, reviews PAT procedures with Unit  2 Supervisor Doug Merriot.

Power Ascension Testing is the final phase of an extensive “test drive” to make sure the unit can deliver electricity safely, reliably and efficiently to our consumers. It includes more than 40 required tests at various power levels up to 100 percent output with pauses at several plateaus: 30 percent, 50 percent and 75 percent. The gradual increase in power provides data to make sure everything is operating as designed. At each plateau, our nuclear professionals look at the results of the tests to ensure that each system is performing within acceptable standards before moving to the next power level. This validates that safety systems perform as designed before they may be needed.

The testing also includes intentionally shutting down the reactor or taking it or the generator off line under specific conditions. Known as a “trip,” these operator controlled actions are designed to demonstrate the safety systems will work and perform as intended to support the safe shutdown of the reactor in the unlikely event of an incident.

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The Power Ascension Testing program uses specific test procedures and normal operating procedures to bring the unit gradually and safely to full power operation. The testing assures plant performance satisfactorily meets design criteria and shows the plant is capable of responding safely to abnormal conditions. It’s not unexpected that issues can arise during these tests. When that occurs, plant personnel address the issue and resume testing. Our goal is to make sure every system is safe and reliable—and we’re committed to take the time necessary to do this right—with safety and quality. That’s how we ensure the highest standards of nuclear safety.