A powerful blizzard packing hurricane-strength winds that hit the northeast U.S. yesterday and dropped as much as two feet of snow in some areas forced the Pilgrim Nuclear Power Station offline after the distribution lines taking its electricity failed.

According to a spokesperson with Entergy, Pilgrim’s owner, the plant shut down safely around 4 a.m. the morning of Jan. 27 after the two lines “became inoperable to due an offsite issue.” The plant was already operating at reduced output because of storm-related constraints on the grid.

Several hours after the shutdown, the plant reported a failure of the high-pressure coolant injection system due to an unknown equipment malfunction. According to the report, reactor pressure control was transitioned to the safety relief valves and the reactor cooldown was continued.

Entergy said it might be several days before the plant could restart.

A similar shutdown occurred during a blizzard in 2013. A subsequent investigation of the incident and three other unplanned shutdowns in 2013 caused the Nuclear Regulatory Commission (NRC) to issue two white Performance Indicators (PIs) to Pilgrim on Jan. 26, finding that Entergy has not yet corrected the underlying problems. A white PI is the lowest level of severity, indicating an incident of low-to-moderate safety significance triggering increased regulatory oversight. According to a statement from the NRC on Jan. 28, Entergy “still has some more work to do” to address its concerns.

The 685-MW plant in Plymouth, Mass., has been thought to be at risk of retirement because of market conditions similar to those that forced the Vermont Yankee plant to close. However, spiking power prices as a result of natural gas supply constraints could help keep the plant viable.

The ISO-New England and PJM Interconnection region lost substantial amounts of gas-fired power during last winter’s Polar Vortex storms, events that caused some observers to point toward the area’s nuclear plants as a more weather-resistant backstop.

The ISO-NE region otherwise sustained fewer blows to its grid than expected. Though National Grid, the region’s largest utility, predicted that as many as 400,000 customers could lose power, estimates on Jan. 27 were that only around 30,000 to 40,000 people were without electricity. The hardest-hit area was the island of Nantucket, which lost all power after a substation froze over.

ISO-NE reported at 8:43 a.m. EST that about 2,800 MW of generation was offline or unavailable, an increase of 1,800 MW from the previous day.

—Thomas W. Overton, JD is a POWER associate editor.