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Operating Reactor Scrams

Confirmed scram events from the NRC, updated daily. Includes automatic and manual trips for all U.S. commercial nuclear power reactors. Data refreshed 9.8h ago

All
PWR
BWR
All
Auto
Manual
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Total confirmed reactor scrams (automatic + manual trips) reported to the NRC so far this calendar year.
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Scrams This Year
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Average number of days for a reactor to return to 95% power after a scram event. Based on recovery data from the last 5 years.
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Avg Recovery
days to 95% power
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Year-end projection based on the current scram rate. Calculated as: (YTD scrams / days elapsed) × 365.
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Projected This Year
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Rolling count of scram events in the last 365 days, regardless of calendar year boundaries.
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Last 365 Days
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Automatic: Reactor Protection System triggered the trip automatically.
Manual: Operator initiated the trip manually (e.g., via manual scram switch).
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Auto / Manual
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PWR (Pressurized Water Reactor): Uses pressurized water as coolant; ~65% of U.S. fleet.
BWR (Boiling Water Reactor): Water boils directly in the core; ~35% of fleet.
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PWR / BWR
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Interactive map showing the geographic location of each scram event. Marker color indicates recency; border glow indicates automatic (green) vs manual (red) trip.

Scram Events by Location

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Month-by-month comparison of scram counts for the current year and two prior years. Helps identify seasonal patterns and year-over-year trends.

Monthly Scram Trend — Last 3 Years

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Total scram events per calendar year across the U.S. fleet. The dashed red line shows the 5-year rolling average.

Annual Scram Totals

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Average scram count by calendar month across all years. Reveals whether certain months historically experience more scram events.

Seasonal Pattern (All Years)

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Stacked comparison of scram events by reactor type each year. PWR (~65% of fleet) vs BWR (~35%).

PWR vs BWR by Year

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Stacked comparison of automatic vs manual scram trips each year. Automatic = Reactor Protection System; manual = operator-initiated.

Auto vs Manual by Year

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Ranking of reactor units by total scram count. Toggle to show most/fewest scrams, normalize per GW of capacity, or aggregate by owner/operator.

Fewest Scrams — Top 15

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States ranked by total scram events. States with more reactors appear higher; compare with the per-GW plant view for size-normalized rankings.

Scrams by State — Top 15

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Average days for each plant to return to 95% power after a scram. Based on last 5 years. Shorter = faster post-trip restart capability.

Average Recovery Time by Plant (last 5 years)

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Distribution of reactor power levels at the moment of each scram. Most occur at high power (90–100%); low-power trips may indicate different root causes.

Power Level at Time of Scram

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Searchable, sortable table of all scram events matching current filters. Includes date, plant, type, trip, power level, recovery time, and NRC event links.

Scram Event Log

Date Plant Type Trip Power% Recovery Description NRC