EVACUATION ZONE?!?!?! WHATEVER FOR?
H/T Phil Seagrave via Mike Aiello.
As of now the Fort Calhoun nuclear plant is under a 10 mile mandatory evacuation and no fly zone enforcement action. There appears to be discrepencies between what the plant and government officials are telling the public and the facts.
Dry cask storage of spent fuel rods in red circle
Comment: As of this date, the Fort Calhoun nuclear plant is under a 10 mile mandatory evacuation and no fly zone enforcement action. There appears to be discrepencies between what the plant and government officials are telling the public and the facts:
NRC spokesman: No need for Nebraska spent nuclear fuel casks to be protected
A Nuclear Regulatory Commission spokesman told The Iowa Independent Friday that dry cask storage of spent nuclear fuel rods at two Nebraska facilities are not being protected from flood waters because the situation poses no public or environmental threat.
Victor Dricks, an NRC Region 4 spokesman, said by phone Friday afternoon ...“They are not within the flood protection barrier,” Dricks said. “There’s no reason for them to be. Those are large, sealed canisters that are bolted down — no risk with the floodwaters.”
Spent fuel rods are first cooled in a spent fuel pool for a year before being placed in dry cask storage. The fuel is surrounded by inert gas inside a large container, typically steel cylinders that are either welded or bolted closed. That container is then surrounded by another protective layer — typically steel or concrete — as a further radiation shield.
Comment: The U. S. Nuclear Waste Technical Review Board stated in the following summary that the science of dry cask storage is very experimental and there is no information available on the behavior of materials of components. The consensus of the board was that corrosive mechanism can cause degradation of the canisters.
United States Nuclear Waste Technical Review Board
Evaluation of the Technical Basis for Extended Dry Storage and Transportation of Used Nuclear Fuel – Executive Summary
December 2010
The fuel inside concrete dry-storage casks is in bolted or welded canisters that are loaded in the spent-fuel pool and transferred to the ISFSI in an on-site transfer cask. Similar canisters are used for fuel that is stored in horizontal storage modules and may be used to contain fuel in metal storage casks, although some metal casks contain the fuel in open baskets without an inner canister.
...'No information is available on the behavior during dry storage of the more advanced materials now being used for fuel cladding and fabrication of fuel-assembly structural components.'...
...'The physical state of the cladding when fuel is placed into dry storage is not currently well characterized. There may be zones of physical weakness and, in some cases, the cladding may be close to failure. Normal handling of fuel assemblies, off-normal occurrences, and accident events would then be more likely to result in additional damage to fuel rods.'...
...'Consequently, if fuel material is released inside the canister or cask, containing and repackaging it safely once the canister or cask is opened should not present any undue problem. Fission-product gases also would be released inside the canister or the cask, and they would need to be dealt with by the ventilation system in the fuel-handling facility.'...
...'Corrosion mechanisms will cause degradation of the metal components of dry-storage systems during extended dry-storage periods: for example, the outer surfaces of fuel canisters.'...
...'Several concrete deterioration and rebar-corrosion mechanisms are known to cause degradation of reinforced concrete in dry-storage systems, including the storage pad. Consequently, establishing a regular inspection and maintenance program for these systems is important. Some plausible off-normal and accident scenarios for the handling and transport of used-fuel casks have not been fully evaluated.'...
'...many utilities have built dry-storage facilities (referred to as Independent Spent Fuel Storage Installations, or ISFSIs) on their sites. ...'Because the experience base for extended dry storage of used fuel is short and the credible degradation phenomena are several and not robustly predictable in a quantitative sense,...'
Comment: How can dry cask storage unit ventilation systems operate under water?
Intake Structure that cools reactor probably most vulnerable at Ft. Calhoun nuke plant??
Intake structure probably the most vulnerable, not auxiliary and containment buildings.
Intake structure draws in river water that cools reactor and spent fuel pool... critical that it stay dry.
Comment: Fort Calhoun plant officials state below safety risks are minimal even if flood levels rise 30 feet above the current level of 1,006 feet. If upsteam earthen dams fail, can the plant sustain a Fukushima like tsunami? Have the ground level entrances to the plant and outbuildings been retrofited with airlock tight seals?
Flood test not over for nuke plant
Monday, June 27th, the Missouri River stood at about 1,006.3 feet above sea level at Fort Calhoun.
New problems could start in the 1,010- to 1,012-foot range.
At around 1,010 feet, water would overflow an earthen levee protecting the electrical switchyard, based on the levee's current height.
Barriers at entrances to the buildings are keeping that water from entering. A “minor” amount of water did seep into the plant's turbine building and was pumped out.
The buildings themselves and associated pumps and electrical equipment are designed to handle flooding up to 1,014 feet above sea level. The river is a little over 1,006 feet now and is forecast to reach a crest of 1,008 feet, barring extraordinary rains.
The switchyard is important because it transfers electricity to the plant from the power grid. Even though the reactor is shut down, electricity is crucial for operating pumps and other equipment that circulate water to cool both the fuel in the nuclear reactor and the plant's spent fuel pool.
Bannister, Omaha Public Power District [OPPD]'s chief nuclear officer, said the generators have weeks of fuel on site. The generators are protected against flooding to 1,014 feet above sea level, which means they should be able to provide energy to the plant if the river rises 7.5 feet above its current level.
At another location on the plant site, a temporary levee has been built around the storage area where casks containing older and cooler used nuclear fuel are kept. At some point above 1,014 feet, the Missouri River would overflow that berm, according to OPPD. Hanson said the 88-ton casks are anchored and will not float.
Also at 1,014, floodwater would incapacitate OPPD's backup generators if they were still being used. The utility has developed plans for tying directly into the transmission lines above the plant, if necessary, Bannister said. It also could shift to secondary backup generators, which are stationed about 22 feet above the worst-case design standard — at an elevation of 1,036 feet, Bannister said.
Water would have to rise to 1,038.5 feet above sea level to reach the spent fuel pool, a water-filled pool that holds the plant's most recently used uranium fuel.
If floodwater made it to the reactor, Bannister said, it couldn't get inside. That's because the reactor is itself a watertight vessel that holds nuclear fuel in its own deep pool of water.
An NRC risk analysis released last year determined that under OPPD's now-discarded plans, flooding above 1,010 feet would have led to a 100 percent chance of a fuel damage if the emergency gasoline pumps didn't work.
Bannister said those pumps had been tested and were working, and workers would have been able to deploy them. With the pumps in place, the NRC calculates that the pumping plan had a 97.5 percent chance of success of protecting the reactor core.
Fort Calhoun and Nebraska's other reactor, Cooper Nuclear Station, aren't being factored into the Army Corps of Engineers schedule of dam releases, said Erik Blechinger, corps spokesman.
Sitting above Nebraska's nuclear plants are six upstream dams, part of one of the nation's largest reservoir systems. Failure of any of those dams would send devastating amounts of water downstream.
Could the dams fail?
“The short answer is no,” said Brig. Gen. John McMahon, who oversees the corps' 12-state northwestern division.
“It's not to say there aren't issues at different places that we're monitoring closely. But in terms of the integrity of the dams, that absolutely is not a concern.”
Dam Danger, Flooding and Ft. Calhoun Nuclear Power Plant
The Fort Peck Dam is built with a flawed design that has suffered a well-known fate for this type of dam — liquefaction — in which saturated soil loses its stability.
Garrison, Oahe and three other downstream earthen dams would have to catch and hold a massive amount of water, an area covering nearly 250 square miles 100 feet deep. But earthen dams, when overtopped with floodwater, do not stand. They break and erode away, usually within an hour. All are full.
There is a possibility a failure of Fort Peck Dam could lead to a domino-like collapse of all five downstream dams. It probably would wreck every bridge, highway, pipeline and power line and split the heartland of the nation, leaving a gap 1,500 miles wide. Countless sewage treatment plants, toxic waste sites and even Superfund sites would be flushed downstream. The death toll and blow to our economy would be ghastly
Fort Calhoun 10 mile mandatory evacuation area! Official map!
Aerials of Fort Calhoun Nuclear Plant Flooding - No-Fly Zone Enforced as of June 14, 2011
