Second Nebraska Nuke
At 4:10 AM, Sunday, 19 June 2011, the Cooper Nuclear Power Plant near Brownsville, NE. declared an "Unusual Event" due to rising flood waters along the Missouri River. (NRC # 46969) 1
The Ft. Calhoun Nuclear Power Plant declared an "Unusual Event" on 06 June 2011, due to rising flood waters. (NRC # 46929) This plant is located about 18 miles north of Omaha, an urban population area of some 800,000 people. It is currently in "Cold Shutdown" with no production of electricity. It was shut down in April for refueling and never restarted due to Missouri River flood conditions. The reactor is reported to be at 200 degrees with only normal atmospheric pressure. This is a Pressurized Water Reactor (PWR).
The Cooper Plant is in service and operating at or near 100% capacity. It has not shut down due to the rising flood waters. Cooper is a Boiling Water Reactor, manufactured by General Electric (BWR-4) with a Mark I Containment System. Sound familiar? Think "Fukushima". An earlier "Unusual Event" was reported by the Cooper Plant: "....inability to meet sludge pond discharge permit due to river levels." (NRC # 49941 09 June 2011 ) In the description, the operator states: "uncontrolled discharge ... "low volume' wastewater."
There are several other "Unusual Event" reports in the NRC's Library for these Nuclear Power Plants.
Ft. Calhoun: (NRC # 46932 07 June 2011) "Fire in west switchroom gear."
This event report is dated the day after the rising flood waters event. The operator, Omaha Public Power District (OPPD) downplayed the event as a failure of switch gear and stated that no fire was detected . That's a tricky play on words. The Halon system self-activated and any fire would have been extinguished by the time first responders arrived. The use of Halon was banned by the Clean Air Act of 1994. However, systems installed may continue in use and only recycled Halon may be used to recharge systems. Halon is described a CFC.
Power to the Spent Fuel Rod Ponds was lost, resulting in a loss of cooling capability for these ponds. OPPD reported the "Ponds" can survive 88 hours before boiling, without the cooling capability. Power was restored within a few hours.
Ft. Calhoun: (NRC # 46953 13 June 2011) "Offsite Notification Due To Sewage System Release" This is a low level report required by 10 CFR 50.72(b)(2)(xi) for an event related to the protection of the environment. Most likely due to the flooding conditions.
Ft. Calhoun: (NRC # 46965 16 June 2011) "Additional Penetration Identified For Mitigation During Walkdown" The Event Text states: ""Operations identified a potential flooding issue in the Intake Structure 1007 ft. 6 in. level. The area of concern is a hole in the floor at the 1007 ft. 6 in. level where the relief valve from FP-1A discharge pipe goes through the raw pump bay and discharges into the intake cell. There is one penetration of concern. Flooding through this penetration could have impacted the ability of the station's Raw Water (RW) pumps to perform their design accident mitigation functions. (Italics added.)
The word "Additional" in the description leaves unanswered questions.
Of greatest concern (at least to me) is a breach of the Spent Fuel Rod Ponds at Ft. Calhoun. This seems to be a very unlikely event as the "Ponds" are listed as being at 1,038 feet above sea level and the Missouri River is currently at (approximately - fluctuating) 1,004 feet above sea level. This implies the River would have to rise 34 feet, an unlikely event. However unlikely, the potential remains. Should any of the upstream Dams fail (there are a total of 15) there would likely be a catastrophic wall of water rushing all the way to the Mississippi River. Unlikely? Yes. Impossible? Think "Fukushima". As one commentator recently said: "Breaching the spent fuel ponds would make Fukushima look like an X-Ray. The Army Corps of Engineers has been releasing water from the Gavins Point Dam (first Dam upstream from Ft. Calhoun) at 150,000 cubic feet per second and they have said this will likely be increased.
The fuel ponds at Ft. Calhoun become especially problematic as they contain many times the amount of spent fuel rods from what they were originally designed to hold. Spent fuel rods from nuclear power plants are the most highly radioactive of all nuclear wastes. Every U.S. Nuclear plant I know of has this problem as no National Disposal Site for spent fuel has ever been built and all original designs assumed a place to send spent fuel rods. As a result, the "rods" get "re-racked", meaning they are moved much closer together to enable the pond to hold more rods. But it's not just that simple. Moving the rods closer creates interaction, more neutron releases and fission. Therefore, Boron must be added to the water to absorb the neutrons. To further exacerbate the problem, many ponds have been re-racked more than once, making them much more dangerous and nuclear time bombs if the boron treated water was lost or replace with fresh water. Even the "Big Muddy" as the Missouri River is called is fresh water.