Breaker-to-Breaker Runs
4 runs
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Breaker-to-breaker runs measure continuous operation between refueling outages using a cycle-adjusted threshold (90% of cycle length minus RFO duration). An active streak means the unit has been running continuously since the last refueling with no trips to 0% power.
Sequoyah 2 has logged 4 breaker-to-breaker runs, continuous stretches from one refueling to the next with no trip to zero power. Its longest ran 516 days, and its runs average 510 days.
516
Best Run (days)
U2R10 (2000-11-15) → U2R11 (2002-04-15)
★ Double breaker-to-breaker
U2R23 → U2R24 → U2R25
All Runs
| 2021-11-08 |
2023-03-18 |
495 days |
U2R24 → U2R25 |
| 2020-05-05 |
2021-10-02 |
515 days |
U2R23 → U2R24 |
| 2017-06-06 |
2018-11-03 |
515 days |
U2R21 → U2R22 |
| 2000-11-15 |
2002-04-15 |
516 days |
U2R10 → U2R11 |
About This Site
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Written by NukeWorker from public records: facts that do not change. Operator, status and capacity come from the live data elsewhere on this page. Sources: Wikipedia: Sequoyah Nuclear Plant.
Sequoyah Nuclear Plant is in Hamilton County, Tennessee, on the shore of Chickamauga Lake on the Tennessee River, about 7 miles east of Soddy-Daisy and 20 miles north of Chattanooga. The Tennessee Valley Authority built it.
Read more
The plant has two Westinghouse four-loop pressurized water reactors with ice condenser containments. Construction began on May 27, 1970. The NRC licensed Unit 1 on September 17, 1980, and Unit 2 on September 15, 1981. Commercial operation began on July 1, 1981, for Unit 1 and June 1, 1982, for Unit 2. TVA shut the plant down on August 22, 1985, over safety concerns, and the NRC authorized restart of both units on March 22, 1988.
Facility Statistics
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Key performance and lifecycle metrics calculated from NRC operational data. Includes operating age, construction timeline, capacity factor, efficiency, generation totals, and reliability records.
Sequoyah 2 has operated for about 44.4 years and averaged a 88.3% lifetime capacity factor, generating roughly 245.0 TWh of electricity. Its longest unbroken run reached 549 days.
Lifecycle & Tenure
Operating Age: 44.4 Yrs
Build Time: 12 Yrs
Lic. Remaining: 14.9 Yrs
Production & Power
Lifetime CF: 88.3%
Efficiency: 32.6%
Generated: 245.0 TWh
Reliability & Outages
Record Run: 549 Days
Refuelings: 19
Avg Startup: 6.8 Days
Ownership & Construction
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The utility or company that owns and operates the facility, the architect-engineer responsible for plant design, and the primary construction contractor. Click names to view all facilities by that entity on the map.
Ownership, operation and management history
No change of owner, operator or management company on record. Our history starts in 1999.
Publicly Traded
No — Federal corporation with no common equity. Its listed TVC/TVE securities are power bonds, not stock.
Operational Excellence Score Subscribers
Sequoyah 2 is rated 0 to 100 on how well it actually runs, scored against every other operating reactor in the US fleet from its own operating record. Subscribers see the score, the three sub-scores behind it, and each of the seven measured inputs.
- This unit's composite score and fleet rank
- Reliability, Efficiency and Discipline sub-scores
- All seven measured inputs, with fleet percentiles
- Rank against comparable units, not just the fleet
- Three-year, five-year and lifetime windows
- Five-year trend, and every other operating US reactor
Scram History
6 events since 2011
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Automatic and manual reactor scram (emergency shutdown) events reported to the NRC since 2011. Includes event dates, trip type, and average recovery time. Click the title to view the full fleet scram dashboard.
Sequoyah 2 has recorded 6 reactor scrams, or emergency shutdowns, since 2011 (3 automatic, 3 manual). On average the unit was back to full power about 6 days after each trip.
Recent Events
| 2025-06-24 |
Manual |
UNIT 2 MANUAL REACTOR TRIP The following information was pro... |
|
| 2024-07-30 |
Auto |
AUTOMATIC REACTOR TRIP DUE TO TURBINE TRIP The following inf... |
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| 2019-12-12 |
Manual |
EN Revision Imported Date : 3/4/2020 EN Revision Text: MANUA... |
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| 2015-03-02 |
Auto |
AUTOMATIC REACTOR TRIP "At 06:45 EST on 3/2/2015, Sequoyah U... |
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| 2013-02-24 |
Manual |
MANUAL REACTOR TRIP DUE TO LOSS OF CONDENSER VACUUM INDICATI... |
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| 2012-08-16 |
Auto |
REACTOR TRIP FROM A REACTOR COOLANT PUMP TRIP "At 1926 EDT o... |
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Technical Specs
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Reactor design specifications including type (PWR/BWR), containment design, nuclear steam supply system manufacturer, thermal and electrical power ratings, and current operational status.
Turbine Supplier:
WESTINGHOUSE ELECTRIC CORPORATION IAEA
Thermal Power:
3455 MWt
Net Capacity:
1126 MWe
Gross Capacity:
1,200 MWe IAEA
Design Capacity:
1,148 MWe IAEA
Efficiency:
32.6%
Lifetime Output:
336.1 TWh through 2025 IAEA
Licensing
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NRC licensing history including docket number, license type and number, construction permit date, operating license issuance, commercial operation date, license renewal, and expiration date.
Docket #:
05000328
License #:
DPR-79
License Type:
OL-FP
Const. Permit:
1970-05-27
Construction Start:
1970-05-27 IAEA
Operating Lic:
1981-09-15
First Criticality:
1981-11-05 IAEA
Grid Connection:
1981-12-23 IAEA
Commercial Op:
1982-06-01
License Renewed:
2015-09-24
License Exp:
2041-09-15
Market & Region
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EIA market and grid-region classifications: NERC reliability region, U.S. Census region, balancing authority responsible for grid operations, and whether the unit operates as a rate-regulated utility or a competitive merchant generator. Hover any value for the full name.
NERC Region:
SERC
— SERC Reliability Corporation
Census Region:
ESC
— East South Central
Balancing Authority:
TVA
— Tennessee Valley Authority
Market Structure:
Regulated
— Rate-regulated utility (cost-of-service pricing)