Posts Tagged ‘flood’
Friday, August 30, 2013 @ 04:08 PM gHale
Long-delayed projects designed to protect the Oconee Nuclear Station from catastrophic flood are on schedule, and plans for new “major modifications” will come forward in the coming months, the station’s owner said Wednesday.
For the first time, Duke Energy publicly shared new proposals to divert rushing waters away from the three reactors in case the 385-foot-high Jocassee Dam were to ever fail upstream. Oconee nuclear is on Lake Keowee near Seneca, SC.
The fixes — some of which the company said might prove too costly — would occur not to the Jocassee Dam but to the Keowee Dam and areas of the station, Duke officials told Nuclear Regulatory Commission (NRC) regulators Wednesday in Atlanta.
Duke will formally submit the proposals in December, company officials said.
Meanwhile, other ongoing safety projects — including one designed to provide backup power in case of flood — will meet their newly revised deadlines, the company said.
Earlier this year, the NRC warned Duke the agency could impose civil fines for the company’s delays in completing safety projects.
The agency ruled against imposing fines so Duke could complete the backup power system, known as the “protected service water system,” originally scheduled to wrap up in 2010.
Over the summer, the NRC extended the deadline to 2016 for the backup power system and alterations to the station’s fire-protection plans.
In its presentation, Oconee site vice president Preston Gillespie assured regulators they “won’t be before them asking for forgiveness” in 2016 for not completing the projects and the company has had a new sense of accountability in the first part of this year.
Eric Leeds, director of the NRC’s Office of Nuclear Reactor Regulation, said the agency hopes the company can follow through.
“At this point we are very encouraged by what Duke is doing and very positive about how they’re attacking this issue,” Leeds said. “However, the devil is in the details.”
After the protected service system wraps up, Duke will work on new safety measures to protect against flood, Oconee licensing manager Dean Hubbard said.
The proposals include a discharge diversion wall at the west end of the Keowee Dam and an isolation drain structure in the station’s turbine building to prevent water from infiltrating.
The company also proposed “armoring” the east bank power block and the intake dike to the south of the station. The armoring would involve installing interlocking concrete blocks braced with cable anchors.
Duke ruled out an expensive “hardening” of the bulk of the Keowee Dam, which would involve applying roller compacted concrete.
The final determination on what fixes to implement will come after the company completes its flood hazard analysis required by the federal government in response to the 2011 tsunami-spawned Fukushima nuclear disaster in Japan.
Thursday, July 14, 2011 @ 05:07 PM gHale
The Missouri River level has dropped enough near Brownville, NE, the Cooper Nuclear Station no longer must operate in an alert mode.
Since June 19, the nuclear power plant had been operating at the lowest of four alert levels established by the federal Nuclear Regulatory Commission (NRC). That category is “Notification of Unusual Event.”
At 9:47 a.m. Tuesday this week, Nebraska Public Power District, which owns the plant, was able to lift that designation.
The alert status was because the river reached 899 feet above sea level. For the past several days the river has consistently been below that level, NPPD said. On Tuesday, the river was at 895.8 feet.
Cooper will continue to monitor flood conditions, said Art Zaremba, NPPD’s director of nuclear safety assurance.
The majority of flood barricades at the plant will remain in place. “Should conditions change and river levels increase, plant personnel are prepared – as we always are – to respond appropriately,” Zaremba said.
The state’s second nuclear reactor, Fort Calhoun Nuclear Station north of Omaha, remains in a Notification of Unusual Event mode.
The Fort Calhoun reactor, which belongs to the Omaha Public Power District, has remained off line because of flooding. Cooper has continued operating, uninterrupted.
Friday, June 11, 2010 @ 11:06 AM gHale
By Dan Schaffer
In today’s cyber-sensitive environment, it is imperative IT and engineering work together to ensure a secure operating system. To compound that, it is also important for engineering to protect the control system from IT.
About 6 months ago, while visiting users in Michigan, we stopped in to see the principal controls engineer at one of the Big 3 auto makers.
When we sat down and started talking about various issues on the plant floor, we talked about a solution that allows a manufacturer to isolate a control network from IT and protect against unwanted traffic. His eyes lit up. It seems he had just had his entire test control network taken down (unintentionally) by IT while he was in the middle of a multi-day test.
When stuff first started acting odd and crashing, he called IT and asked if they were doing anything to cause this. The reply was a surly “no, don’t be ridiculous” type of statement.
But the problems persisted. His network was still sluggish and unstable so he used Wireshark, which is a free and open-source packet analyzer used for network troubleshooting, analysis, software and communications protocol development, to see if he could figure out what was wrong.
He found huge amounts of traffic hitting all of his devices. He called IT back and asked again if they were doing anything odd or unusual to cause his network grief; again the response was a resounding “nope.”
He then asked about the address that was the source of the bulk of the traffic in Wireshark. After checking around, IT begrudgingly told him it was “one of ours” and after a little more investigation on their part he found out one of the IT guys was running a utility to check who/what was out on the network.
It was essentially a flood or arp and ping-type traffic. Since there was no firewall or even a router (which doesn’t forward broadcast traffic) between the office network and the control network, the PLCs, HMIs, etc. got overwhelmed and started locking up.
He became a customer within a week.
Dan Schaffer is a networking security specialist at Phoenix Contact.
Tuesday, April 13, 2010 @ 04:04 PM gHale
After the levee failures in New Orleans during Hurricane Katrina, the challenge now confronting experts is to develop the technology that can quickly seal a levee breach and reduce floodwaters through the opening within four to six hours of detection—before any water can do major damage.
That is where Wil Laska of the Science & Technology Directorate (S&T), the research arm of the Department of Homeland Security, comes in.
Laska is on the hunt for innovative technologies from industry, academia, and government that can meet this challenge. Any proposed system had to not only be capable of quickly closing breaches, but also be suitable for scenarios in which the breach may be difficult or impossible to reach with conventional construction equipment, he said.
“The thing is there’s an effective structural material that’s readily available during floods…water,” he said.
He found four technologies that met his requirements, and in November they all passed their second test at the U.S. Department of Agriculture’s Agriculture Research Service, Hydraulic Engineering Research Unit in Stillwater, Okla. The Army Corps of Engineers uses that facility to test hydrology equipment and study water flow, dams and levees.
The top technology, proposed by the Army Corps of Engineers Engineering Research and Development Center in Vicksburg, Miss., is a large balloon or tube. The tube is light enough to carry by helicopter and flexible enough to adapt to a wide range of environmental situations. The engineers said when they launched the tube, it would quickly fill with water, float on the flood currents to the breach, and adhere to the breach in the earthen berm or levee.
The “Portable Lightweight Ubiquitous Gasket (PLUG)” is a tube of non-stretch fabric officials can drop into floodwaters and an attached pump rapidly fills it to 80% capacity—a bubble of air inside keeps the tube from sinking beneath the waters. Positioned upstream, flood currents pull it toward the breach. The incompressible nature of water and the unyielding fabric turn the tube into a rigid plug that conforms to the breach and seals it.
The PLUG is mainly for narrow, deep breaches, however other technologies tailored for other types of levee breaches are also under development:
- A smaller version of the PLUG–designed to prevent the over-topping flow of a long, shallow breach.
- The Rapidly Emplaced Protection for Earthen Levees (REPEL)—designed to protect against erosion during the intentional overtopping of levees, mitigating erosion from the back slope of a levee which over time could cause a deep breach.
- The Rapidly Emplaced Hydraulic Arch Barrier (REHAB)—an arched tube designed to hold back a surge of water during a levee breach repair, to seal breaches obstructed by debris or other structures, and can see use as a rapidly emplaced surge or flood gate.
The U.S. Army Corps of Engineers owns and maintains 14,000 miles of levees and an estimated 85,000 miles of privately owned and operated levees. Most are more than 50 years old, and many went up in agricultural areas now deeply embedded in the urban landscape.
Levees fail for many reasons, not all of which are weather related. For instance, California’s major concern is liquefaction of their levees during an earthquake. And some Midwestern levees have failed under sunny skies due to erosion caused by the long-term effects of previous high water and flood conditions.
The intended primary customer of the PLUG would be local levee boards and State Emergency Management Agencies.