Prairie Island 1
Refueling Outage · Day 15Xcel Energy·Welch, MN·PWR·521 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.
1
Current Run
days
#91 of 95
Bottom Quartile
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Longest recorded period of continuous operation between outages.
732
Record Run
days
#17 of 95
Top Quartile
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (612 days for this 24-month cycle unit) with no trips to 0% power.
3
B2B Runs
#71 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.
88.6%
Capacity Factor
#68 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.
8.84 TWh
Net Generation
EIA-923 · 12 mo to 2026-07 · plant total
2033-12
Planned Retirement
EIA-860M announced
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Total NRC-reported scram events (emergency reactor shutdowns). Ranked fleet-wide — fewer scrams = better rank.
5
Scrams
#22 of 94
Top Quartile
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Years since commercial operation began. License remaining: 6.8 years.
52.8
Operating Age
years
6.8 yrs remaining
Excellence Score, Records & Plant Facts
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.
Prairie Island 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 731 days, and its runs average 682 days.
731
Best Run (days)
1R32 (2020-10-14) → 1R33 (2022-10-15)
682
Avg Run (days)
All Runs
| 2020-10-14 | 2022-10-15 | 731 days | 1R32 → 1R33 |
| 2016-11-21 | 2018-09-22 | 670 days | 1R30 → 1R31 |
| 2013-01-02 | 2014-10-08 | 644 days | 1R28 → 1R29 |
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: Prairie Island Nuclear Generating Plant.
Prairie Island Nuclear Generating Plant stands on the Mississippi River in Goodhue County, Minnesota, near Red Wing and Welch, next to the Prairie Island Indian Community reservation.
Read more
The plant was built for Northern States Power Company and has two Westinghouse two-loop pressurized water reactors. Construction of Unit 1 began on June 25, 1968, and Unit 2 on June 25, 1969. Unit 1 entered commercial operation on December 16, 1973, and Unit 2 on December 21, 1974. In May 2006, repair workers were exposed to very low levels of iodine-131 gas, an event the NRC judged to be of very low safety significance. Unit 2 had its steam generators replaced during an outage that began in September 2013.
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.
Prairie Island 1 has operated for about 52.8 years and averaged a 88.6% lifetime capacity factor, generating roughly 116.5 TWh of electricity. Its longest unbroken run reached 732 days.
Lifecycle & Tenure
Operating Age: 52.8 Yrs
Build Time: 5.5 Yrs
Lic. Remaining: 6.8 Yrs
Production & Power
Lifetime CF: 88.6%
Efficiency: 31.1%
Generated: 116.5 TWh
Reliability & Outages
Record Run: 732 Days
Refuelings: 16
Avg Startup: 4.3 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 |
|---|---|---|---|
| Aug 7, 2000 | Operator change | Northern States Power (owner, operated it) | Nuclear Management Co (operator only) |
| Sep 22, 2008 | Operator change | Nuclear Management Co (operator only) | Xcel Energy (owner, took over operation) |
XEL
Xcel Energy Inc.
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75.12
Day's Range
75.14 – 76.45
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68.72 – 84.23
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6,250,924
Delayed quote as of Oct 16, 2026 4:00 PM ET.
Source: Yahoo Finance.
Full quote on Yahoo Finance
Operational Excellence Score Subscribers
Prairie Island 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 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.
Prairie Island 1 has recorded 5 reactor scrams, or emergency shutdowns, since 2011 (3 automatic, 2 manual). On average the unit was back to full power about 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:
PWR
Containment:
PWR-DRYAMB
NSS Supplier:
WEST 2LP
Turbine Supplier:
WESTINGHOUSE ELECTRIC CORPORATION IAEA
Thermal Power:
1677 MWt
Net Capacity:
521 MWe
Gross Capacity:
566 MWe IAEA
Design Capacity:
530 MWe IAEA
Efficiency:
31.1%
Status:
Operating
Lifetime Output:
205.1 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 #:
05000282
License #:
DPR-42
License Type:
OL-FP
Const. Permit:
1968-06-25
Construction Start:
1968-06-25 IAEA
Operating Lic:
1974-04-05
First Criticality:
1973-12-01 IAEA
Grid Connection:
1973-12-04 IAEA
Commercial Op:
1973-12-16
License Renewed:
2011-06-27
License Exp:
2033-08-09
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:
MISO
— Midcontinent Independent System Operator (ISO/RTO)
Market Structure:
Regulated
— Rate-regulated utility (cost-of-service pricing)