Cooper
Refueling Outage · Day 24Nebraska Public Power District·Brownville, NE·BWR·772 MWe
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Composite Operational Excellence Score (0-100) — average percentile rank across 7 dimensions in three sub-scores: Reliability (capacity factor, forced outage days, B2B avg streak), Efficiency (fuel utilization, refuel duration), and Discipline (startup duration, scram count). 5-year window. Higher = more operationally excellent. Click to see the full breakdown.
Excellence
Rank locked · 93 units
Subscribers
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Current reactor power level from the most recent NRC daily report.
0%
Power
OFFLINE (14 Days)
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Days of continuous operation since the last outage ended. Ranked against all operating units.
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Current Run
offline
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Longest recorded period of continuous operation between outages.
706
Record Run
days
#38 of 95
Mid Quartile
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (613 days for this 24-month cycle unit) with no trips to 0% power.
4
B2B Runs
#52 of 86
Mid Quartile
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Lifetime capacity factor: average power level across all recorded days (100% = always at full power). Ranked against all NRC-tracked units.
89.3%
Capacity Factor
#57 of 95
Mid Quartile
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Net electricity actually generated over the most recent 12 months reported by the U.S. Energy Information Administration (Form EIA-923). These are authoritative actuals, not an estimate.
6.87 TWh
Net Generation
EIA-923 · 12 mo to 2026-07
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Total NRC-reported scram events (emergency reactor shutdowns). Ranked fleet-wide — fewer scrams = better rank.
3
Scrams
#12 of 94
Top Quartile
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Years since commercial operation began. License remaining: 7.2 years.
52.3
Operating Age
years
7.2 yrs remaining
Excellence Score, Records & Plant Facts
B2B CHAMPION
1,400 days without a trip
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4 Career Runs · 2 since last trip
Champion since Aug 24, 2024
Breaker-to-Breaker Runs 4 runs
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.
Cooper has logged 4 breaker-to-breaker runs, continuous stretches from one refueling to the next with no trip to zero power. Its longest ran 697 days, and its runs average 680 days.
697
Best Run (days)
RE 31 (2020-11-04) → RE 32 (2022-10-02)
680
Avg Run (days)
★ Quadruple breaker-to-breaker
RE 30 → RE 31 → RE 32 → RE 33 → RE 34
All Runs
| 2024-11-04 | 2026-09-28 | 693 days | RE 33 → RE 34 |
| 2022-12-20 | 2024-09-29 | 649 days | RE 32 → RE 33 |
| 2020-11-04 | 2022-10-02 | 697 days | RE 31 → RE 32 |
| 2018-11-16 | 2020-09-27 | 681 days | RE 30 → RE 31 |
About This Site
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: Cooper Nuclear Station.
Cooper Nuclear Station is a single-unit nuclear plant in Nemaha County, Nebraska, near Brownville, on a 1,251-acre site on the Missouri River at the Nebraska-Missouri border.
Read more
Construction began on June 1, 1968. The plant has a General Electric BWR-4 boiling water reactor with Mark I containment. It was first connected to the grid on May 10, 1974, and entered commercial operation on July 1, 1974. Missouri River flooding led to a Notification of Unusual Event on June 19, 2011, which ended on July 12, 2011, and another unusual event was declared during flooding on March 15, 2019.
Facility Statistics
Key performance and lifecycle metrics calculated from NRC operational data. Includes operating age, construction timeline, capacity factor, efficiency, generation totals, and reliability records.
Cooper has operated for about 52.3 years and averaged a 89.3% lifetime capacity factor, generating roughly 169.2 TWh of electricity. Its longest unbroken run reached 706 days.
Lifecycle & Tenure
Operating Age: 52.3 Yrs
Build Time: 6.1 Yrs
Lic. Remaining: 7.2 Yrs
Production & Power
Lifetime CF: 89.3%
Efficiency: 31.9%
Generated: 169.2 TWh
Reliability & Outages
Record Run: 706 Days
Refuelings: 16
Avg Startup: 6.2 Days
Ownership & Construction
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
| Date | Change | From | To |
|---|---|---|---|
| Oct 2003 | Management contract | Nebraska Public Power District (owner, operated it) | Entergy (management support under contract) |
| Mar 2022 | Management contract | Entergy (management support under contract) | Nebraska Public Power District (owner, operating it again) |
Publicly Traded
No — Public power district
Operational Excellence Score Subscribers
Cooper 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
Included with every outage subscription and with NukeWorker Gold membership. Trading the outage rather than working it? The same record, cut by power market, is on NukeGryd.
Scram History 3 events since 2011
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.
Cooper has recorded 3 reactor scrams, or emergency shutdowns, since 2011 (1 automatic, 2 manual). On average the unit was back to full power about 5.7 days after each trip.
Technical Specs
Reactor design specifications including type (PWR/BWR), containment design, nuclear steam supply system manufacturer, thermal and electrical power ratings, and current operational status.
Reactor Type:
BWR
Containment:
BWR-MARK 1
NSS Supplier:
GE 4
Turbine Supplier:
WESTINGHOUSE ELECTRIC CORPORATION IAEA
Thermal Power:
2419 MWt
Net Capacity:
772 MWe
Gross Capacity:
801 MWe IAEA
Design Capacity:
778 MWe IAEA
Efficiency:
31.9%
Status:
Operating
Lifetime Output:
271.4 TWh through 2025 IAEA
Licensing
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 #:
05000298
License #:
DPR-46
License Type:
OL-FP
Const. Permit:
1968-06-04
Construction Start:
1968-06-01 IAEA
Operating Lic:
1974-01-18
First Criticality:
1974-02-21 IAEA
Grid Connection:
1974-05-10 IAEA
Commercial Op:
1974-07-01
License Renewed:
2010-11-29
License Exp:
2034-01-18
Market & Region
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:
MRO
— Midwest Reliability Organization
Census Region:
WNC
— West North Central
Balancing Authority:
SWPP
— Southwest Power Pool (SPP) (ISO/RTO)
Market Structure:
Regulated
— Rate-regulated utility (cost-of-service pricing)