Knowing precisely what prompted the shutdown of the station’s two 980-megawatt reactors is critical for validating the safety of the plant’s design.
Realizing that whatever was happening could affect the plant, Russell said, he immediately told his reactor operators to bring their reactor off line. “By the time the operators reached for the switches, the (automatic system) shutdown was already over.”
Plant officials also said they found a horizontal crack in a non-safety-related wall of a room inside the Unit 1 reactor containment building.
The temblor also caused 25 of the 115-ton steel casks storing highly radioactive used nuclear-fuel rods to shift as much as 4½ inches out of position on their concrete storage pad.
Though the power company has not completed its analysis of the event, the earthquake apparently produced combinations of shaking forces larger than the plant was initially designed for, Stoddard said Friday.
Damage at the plant: Cracks between concrete blocks in an administration building wall, a slight buckling in a corridor floor in that building, and damaged seals on some large electrical transformers.
North Anna’s reactors remained out of service Friday as company officials continued detailed inspections of the station structures and systems. A Nuclear Regulatory Commission‘s augmented inspection team also is reviewing the effects of the earthquake. Stoddard said the final analysis is expected to be completed by the end of next week.
Utility officials had said earlier that electrical switches in the systems carrying power to the generating station had shaken open, signaling the reactors to trip. “We believe right now that was not the case,” Stoddard said.
“There were multiple trip signals coming in,” North Anna Site Vice President Larry Lane said. “We’re talking about a difference of a second.”
- Confirmed: Virginia nuke plant went into automatic shutdown after quake – Shaking interrupted circuits causing loss of power to cooling systems (enenews.com)
- Earthquake caused crack in containment building for North Anna Nuclear Power Plant (enformable.com)
- Multiple Reports: Black smoke seen rising from North Anna nuclear plant after Virginia quake (enformable.com)
- NRC Commits North Anna Nuclear Power Plant to Further Investigation – Likely to have extra margins built into the design” (enformable.com)
- Strange: Spokesman says workers at Virginia nuke plant were preparing to manually shut down reactors after quake when system went into automatic shut down – Another spokesman says “it was a manual shutdown” (enenews.com)
- JUST IN: Black smoke seen rising from North Anna nuclear plant after Virginia quake (enenews.com)
- NRC to increase inspections at Perry Nuclear Power Plant in Ohio after 4 workers exposed to radiation (enformable.com)
- New Photos Of North Anna Nuclear Power Plant Venting Steam And Inspections After Earthquake (enformable.com)
- North Anna Nuke Plant: Quake May Have Exceeded Nuclear Plant’s Safety Specs (ex-skf.blogspot.com)