Vermont Yankee - Status & History

Comprehensive reactor performance metrics, cycle analysis, and historical outage data.

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Decommissioned

Permanently shut down on 2014-12-29. Outage statistics below reflect only the operating period. The final shutdown is not counted as an outage.
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This unit is permanently shut down (shutdown date: 2014-12-29).
Shut Down
2014-12-29
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Longest recorded period of continuous operation between outages (2005-11-11 to 2007-05-14).
549
Record Run
days
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Breaker-to-Breaker runs — continuous operation exceeding the cycle-adjusted threshold (464 days for this 18-month cycle unit) with no trips to 0% power.
4
B2B Runs
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Lifetime capacity factor: average power level across all recorded days (100% = always at full power).
92.2%
Capacity Factor
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Total number of scheduled refueling outages detected in the historical data. D&D shutdown period excluded.
10
Outages
since 1999
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Average time from first power generation (>0%) to sustained full power (≥95% for 2+ days) across the last 3 scheduled outages. Click to compare against the fleet on the Operator Efficiency Leaderboard.
6
Avg Startup
days (last 3)
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Average fuel utilization — percent of the designed fuel cycle that this unit consumes before refueling, derived from the historical burn-down trajectory. Higher = more efficient operator (refuels with less margin remaining; closer to coastdown). Computed as 100% minus the unit's average refuel-point fuel %, using the last 3 years where available, otherwise lifetime average. Click to compare against the fleet on the Operator Efficiency Leaderboard.
97.6%
Fuel Utilization
lifetime avg
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Duration of each outage in days, shown chronologically. Green bars are scheduled refueling outages, red bars are forced/unscheduled. The orange dashed line marks the average duration. Extended outages (>180 days) and D&D periods are excluded.

Outage Duration Trend

Vermont Yankee has 20 outages plotted here, averaging 15 days each. The most recent, in Mar 2013, was a scheduled refueling outage lasting 26 days.
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Days between consecutive scheduled refueling outage starts, showing operating cycle regularity. The purple dashed line marks the average cycle length. Most U.S. reactors operate on 18-month (547 day) or 24-month (730 day) cycles.

Cycle Length History

Between refueling outages, Vermont Yankee runs about 542 days, or roughly 18 months, per cycle. That average comes from 9 completed cycles, the most recent lasting 518 days.
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Time in days from first power generation (>0%) to sustained full power (≥95% for 2+ consecutive days) after each scheduled refueling outage. The dashed line marks the average. Includes startup testing holds and power dips.

Startup Duration Trend

After a refueling outage, Vermont Yankee takes about 4 days to climb from first power back to full power. That average is drawn from 10 startups on record, and the most recent took 5 days.
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Monthly capacity factor with outage events overlaid as red bands. Green bars show average power level per month. Toggle to Daily view for raw daily data.

Power History

Over its operating life, Vermont Yankee has run at about 92.2% of its rated capacity. Across the last 12 reported months it averaged 86.4%. On the chart, flat stretches near the top are full-power running and drops to zero are outages.
This table logs every recorded outage for Vermont Yankee, 21 in all since 1999. Of those, 10 were scheduled refueling outages and 11 were unplanned or forced. The typical outage lasted about 15 days. Where the Scheduled column shows (Model), the date is a NukeWorker projection because the utility had not published one.
Type ⇅ Actual Start ⇅ Actual End ⇅ Duration ⇅ Days Online ⇅ Scheduled Delta
Unscheduled
2014-12-30 Decommissioned 1 (D&D) 635d - -
Scheduled
2013-03-10 2013-04-04 26 494d 2013-03-09 +1d
Scheduled
2011-10-09 2011-11-02 25 333d 2011-10-16 -7d
Unscheduled
2010-11-08 2010-11-10 3 164d - -
Unscheduled
2010-05-27 2010-05-28 2 5d - -
Scheduled
2010-04-25 2010-05-22 28 532d 2010-04-24 +1d
Scheduled
2008-10-19 2008-11-09 22 415d 2008-10-12 +7d
Unscheduled
2007-08-31 2007-08-31 1 87d - -
Scheduled
2007-05-14 2007-06-05 23 549d 2007-05-13 +1d
Scheduled
2005-10-23 2005-11-11 20 88d 2005-10-22 +1d
Unscheduled
2005-07-26 2005-07-27 2 385d - -
Unscheduled
2004-06-19 2004-07-06 18 47d - -
Scheduled
2004-04-05 2004-05-03 29 186d 2004-04-03 +2d
Unscheduled
2003-09-30 2003-10-02 3 2d - -
Unscheduled
2003-09-28 2003-09-28 1 338d - -
Scheduled
2002-10-07 2002-10-25 19 138d 2002-10-07 0d
Unscheduled
2002-05-12 2002-05-22 11 358d - -
Scheduled
2001-04-28 2001-05-19 22 38d 2001-04-28 0d
Unscheduled
2001-03-20 2001-03-21 2 187d - -
Unscheduled
2000-09-14 2000-09-14 1 288d - -
Scheduled
1999-10-30 1999-12-01 33 - 1999-10-30 0d
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