Like hockey pucks on a jostled tray, the 16-foot tall casks shifted from an inch to 4½ inches, utility company spokesman Rick Zuercher said.
Federal regulators will examine data from the spent-fuel storage area as part of the inspection of the plant that the NRC began Tuesday, said Scott Burnell, a spokesman with the federal agency’s headquarters in Rockville, Md.
“The information available indicates the shifting did not affect safety in any way,” Burnell said. “It is an instance of an event we had not previously seen, so were trying to learn as much as possible.”
Dominion Virginia Power has 27 of the massive TN-32 storage casks standing vertically outdoors on the concrete pad. The casks, made from thick steel, are not fastened to the ground, being held in place by gravity.
Concrete bunkers for other used-fuel containers stored horizontally at the Louisa County power station experienced “cosmetic” damage, he said. “None of these moved.”
NRC regulations specify the spacing of the vertically set dry casks from one another mainly to ensure workers are not exposed to unexpected levels of radiation, Burnell said.
“If the spacing shifts a slight amount, the dose shifts a very slight amount,” he said. “Those doses have to be taken into account. The doses would be very low in any case.”
The two spent-fuel storage pads cover 11.4 acres at North Anna — one pad holds the 27 cylinders and the other has the concrete bunkers for the horizontal storage containers. The first container was placed in storage in July 1998.
The 27 vertically stored casks are each 16 feet tall and 8 feet in diameter. Each has steel walls 18 inches thick.
The containers hold 32 fuel assemblies and weigh 115 tons when loaded with the used-fuel assemblies.
Also, some spent fuel at North Anna is stored horizontally in concrete bunkers, using 50-ton metal containers that are 16 feet long and 6 feet in diameter. These are placed in concrete modules 19 feet high, 10 feet wide and 21 feet long. The modules have 3-foot-thick concrete end walls, and each holds a single container.
A 3.4-magnitude earthquake shook Mineral, Va., early Thursday morning — the latest in a series of aftershocks following last Tuesday’s 5.8-magnitude quake that rocked the Washington area.
The latest quake rumbled at 5:09 a.m. just four miles from Mineral and 81 miles southwest of D.C.
There have been more than 20 aftershocks since the original quake, ranging from 1.8 to 4.5.
There were also two aftershocks on Wednesday that registered 1.8 and 2.1, respectively.
- “Scratch Plates” at North Anna Record Critical Earthquake Data – Despite North Anna Being Taken Off Grid Customers Face No Energy Shortages (enformable.com)
- Unprecedented: Quake caused massive containers of spent fuel to shift at Virginia nuke plant – “We’re trying to learn as much as possible” says NRC (enenews.com)
- Local paper asks “Is North Anna safe?” Did quake damage nuclear reactors or underground piping? (enenews.com)
- North Anna Nuke Plant: Quake May Have Exceeded Nuclear Plant’s Safety Specs (ex-skf.blogspot.com)
- Nuclear Engineer: If quake caused weakness at Virginia’s North Anna nuke plant, hurricane could take it rest of way to failure (enenews.com)
- Nuclear Expert: Quake-hit Virginia nuke plant should be distributing bottled water to nearby residents – Pipes under North Anna are potentially a grave public danger (enenews.com)
- NRC ramps up inspection at Va. nuclear plant; earthquake may have exceeded plant’s design base – Signs That Utilities Knew Of Shortfall (enformable.com)
- North Anna Workers Find 150 Gallon Oil Spill While Purging Carbon Dioxide from Unit 2 Generator (enformable.com)