Nine Mile Point 1
Online · 100% powerConstellation Energy·Scriba, NY·BWR·621 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.
100%
Power
ONLINE
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Days of continuous operation since the last outage ended. Ranked against all operating units.
563
Current Run
days
#4 of 95
Top Quartile
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Longest recorded period of continuous operation between outages.
728
Record Run
days
#19 of 95
Top Quartile
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (623 days for this 24-month cycle unit) with no trips to 0% power.
3
B2B Runs
90% toward B2B (559/623d)
#69 of 85
Bottom 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.
91.7%
Capacity Factor
#30 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), summed across every unit at this plant. These are authoritative actuals, not an estimate.
15.56 TWh
Net Generation
EIA-923 · 12 mo to 2026-07 · plant total
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Total NRC-reported scram events (emergency reactor shutdowns). Ranked fleet-wide — fewer scrams = better rank.
11
Scrams
#80 of 94
Bottom Quartile
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Years since commercial operation began. License remaining: 2.8 years.
56.9
Operating Age
years
2.8 yrs remaining
Excellence Score, Records & Plant Facts
B2B CHAMPION
2,723 days without a trip
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3 Career Runs · 3 since last trip
Champion since Jan 18, 2021
Breaker-to-Breaker Runs 3 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.
Nine Mile Point 1 has logged 3 breaker-to-breaker runs, continuous stretches from one refueling to the next with no trip to zero power. Its longest ran 702 days, and its runs average 695 days.
702
Best Run (days)
N1R26 (2021-04-10) → N1R27 (2023-03-13)
695
Avg Run (days)
★ Triple breaker-to-breaker
N1R25 → N1R26 → N1R27 → N1R28
All Runs
| 2023-04-20 | 2025-03-17 | 697 days | N1R27 → N1R28 |
| 2021-04-10 | 2023-03-13 | 702 days | N1R26 → N1R27 |
| 2019-05-06 | 2021-03-22 | 686 days | N1R25 → N1R26 |
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: Nine Mile Point Nuclear Generating Station.
Nine Mile Point Nuclear Station is at Scriba, in Oswego County, New York, on the shore of Lake Ontario about five miles northeast of Oswego. It occupies a 900-acre site shared with the James A. FitzPatrick plant.
Read more
Both units are General Electric boiling water reactors. Construction of Unit 1 (BWR-2, Mark 1) began on April 12, 1965, and it connected to the grid on November 9, 1969. Construction of Unit 2 (BWR-5, Mark 2) began on August 1, 1975, and it connected on August 8, 1987. Commercial operation began on December 1, 1969 for Unit 1 and on March 11, 1988 for Unit 2. A site area emergency was declared on August 13, 1991 after an electrical fault.
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.
Nine Mile Point 1 has operated for about 56.9 years and averaged a 91.7% lifetime capacity factor, generating roughly 140.5 TWh of electricity. Its longest unbroken run reached 728 days.
Lifecycle & Tenure
Operating Age: 56.9 Yrs
Build Time: 4.6 Yrs
Lic. Remaining: 2.8 Yrs
Production & Power
Lifetime CF: 91.7%
Efficiency: 33.6%
Generated: 140.5 TWh
Reliability & Outages
Record Run: 728 Days
Refuelings: 14
Avg Startup: 7.1 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 |
|---|---|---|---|
| Nov 7, 2001 | Sold | Niagara Mohawk | Constellation |
| Nov 6, 2009 | Ownership stake | Constellation Energy | Constellation Energy Nuclear Group (Constellation / EDF) |
| Mar 12, 2012 | Merger | Constellation Energy (with EDF) | Exelon (with EDF) |
| Apr 1, 2014 | Operator change | Constellation Energy Nuclear Group (operator) | Exelon (took over operation) |
| Aug 6, 2021 | Ownership stake | Exelon and EDF | Exelon |
| Feb 1, 2022 | Spin-off | Exelon | Constellation Energy |
CEG
Constellation Energy Corporation
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Operational Excellence Score Subscribers
Nine Mile Point 1 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 11 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.
Nine Mile Point 1 has recorded 11 reactor scrams, or emergency shutdowns, since 2011 (8 automatic, 3 manual). On average the unit was back to full power about 10.2 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 2
Turbine Supplier:
GENERAL ELECTRIC CO. IAEA
Thermal Power:
1850 MWt
Net Capacity:
621 MWe
Gross Capacity:
642 MWe IAEA
Design Capacity:
620 MWe IAEA
Efficiency:
33.6%
Status:
Operating
Lifetime Output:
226.9 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 #:
05000220
License #:
DPR-63
License Type:
OL-FP
Const. Permit:
1965-04-12
Construction Start:
1965-04-12 IAEA
Operating Lic:
1974-12-26
First Criticality:
1969-09-05 IAEA
Grid Connection:
1969-11-09 IAEA
Commercial Op:
1969-12-01
License Renewed:
2006-10-31
License Exp:
2029-08-22
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:
NPCC
— Northeast Power Coordinating Council
Census Region:
MAT
— Middle Atlantic
Balancing Authority:
NYIS
— New York Independent System Operator (NYISO) (ISO/RTO)
Market Structure:
Merchant
— Competitive generator selling into wholesale markets