Limerick 2
Online · 100% powerConstellation Energy·Pottstown, PA·BWR·1,122 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.
512
Current Run
days
#8 of 95
Top Quartile
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Longest recorded period of continuous operation between outages.
726
Record Run
days
#24 of 95
Top Quartile
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (628 days for this 24-month cycle unit) with no trips to 0% power.
2
B2B Runs
81% toward B2B (510/628d)
#74 of 84
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.
94.3%
Capacity Factor
#8 of 95
Top 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.
19.35 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.
5
Scrams
#24 of 94
Top Quartile
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Years since commercial operation began. License remaining: 22.7 years.
36.8
Operating Age
years
22.7 yrs remaining
Excellence Score, Records & Plant Facts
B2B CHAMPION
1,297 days without a trip
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2 Career Runs · 1 since last trip
Champion since Feb 5, 2025
Breaker-to-Breaker Runs 2 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.
Limerick 2 has logged 2 breaker-to-breaker runs, continuous stretches from one refueling to the next with no trip to zero power. Its longest ran 710 days, and its runs average 700 days.
710
Best Run (days)
2R17 (2023-05-19) → 2R18 (2025-04-28)
700
Avg Run (days)
All Runs
| 2023-05-19 | 2025-04-28 | 710 days | 2R17 → 2R18 |
| 2019-06-07 | 2021-04-26 | 689 days | 2R15 → 2R16 |
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.
Limerick 2 has operated for about 36.8 years and averaged a 94.3% lifetime capacity factor, generating roughly 265.6 TWh of electricity. Its longest unbroken run reached 726 days.
Lifecycle & Tenure
Operating Age: 36.8 Yrs
Build Time: 15.6 Yrs
Lic. Remaining: 22.7 Yrs
Production & Power
Lifetime CF: 94.3%
Efficiency: 31.9%
Generated: 265.6 TWh
Reliability & Outages
Record Run: 726 Days
Refuelings: 14
Avg Startup: 4.9 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 20, 2000 | Merger | PECO Energy | Exelon |
| Feb 1, 2022 | Spin-off | Exelon | Constellation Energy |
CEG
Constellation Energy Corporation
NasdaqGS
$298.07
▲ +13.00 (+4.56%)
Previous Close
285.07
Day's Range
286.83 – 300.98
52-Week Range
228.63 – 412.70
Volume
3,785,046
Delayed quote as of Oct 9, 2026 4:00 PM ET.
Source: Yahoo Finance.
Full quote on Yahoo Finance
Operational Excellence Score Subscribers
Limerick 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
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 5 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.
Limerick 2 has recorded 5 reactor scrams, or emergency shutdowns, since 2011 (2 automatic, 3 manual). On average the unit was back to full power about 4.6 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 2
NSS Supplier:
GE 4
Thermal Power:
3515 MWt
Net Capacity:
1122 MWe
Efficiency:
31.9%
Status:
Operating
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 #:
05000353
License #:
NPF-85
License Type:
OL-FP
Const. Permit:
1974-06-19
Operating Lic:
1989-08-25
Commercial Op:
1990-01-08
License Renewed:
2014-10-20
License Exp:
2049-06-22
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:
RFC
— Reliability First Corporation
Census Region:
MAT
— Middle Atlantic
Balancing Authority:
PJM
— PJM Interconnection (ISO/RTO)
Market Structure:
Merchant
— Competitive generator selling into wholesale markets