Watts Bar Tennessee

TVA uses sand baskets as temporary fixes for flawed flooding calculations

Sand baskets installed to protect against extreme flooding and protect nuclear plants at Watts Bar and three other TVA dams have upstream neighbors unhappy about their new views.

But the safety vs. beauty question — prompted by a decades-old mistaken calculation by TVA — may mean even more dams must be raised with sandbags or permanent fixes, according to the Tennessee Valley Authority and the Nuclear Regulatory Commission.

“We had to fix the problem by raising the embankments as soon as we could or possibly have to shut down [Watts Bar and Sequoyah nuclear] plants. That could result in $3 million to $5 million a day in lost generation,” said Mike Eiffe, TVA program manager for hydrology and hydraulics.

Compared to those numbers, TVA’s cost to prepare for what utility officials have called a “highly unlikely probable maximum flood” would seem to be chump change.

The project involved placing temporary cages of sand — most about 4 by 4 feet —  atop the sides and embankments of the Watts Bar, Fort Loudoun, Tellico and Cherokee dams. The goal was to protect the dams and downstream plants from a flood about four times the amount of the region’s heaviest known rainfall.

The cost was $4.3 million, TVA spokesman Travis Brickey said.

TVA also is paying $2 million for a consultant to study whether similar fixes are needed at its 45 other dams, and it has a $400,000 environmental impact study under way to determine whether the first four dams need a more permanent fix, said Eiffe and Brickey.

“Its easy to think it [the probable maximum flood] will never happen here, but ‘never’ is a big word,” Brickey said. “A lot of people didn’t think the flooding of most of downtown Nashville would happen either, or that anyone would have to blow up dikes on the Mississippi. But those things did happen.”

What happened?

The concern didn’t begin with the nuclear meltdowns at Japan’s Fukushima Dai-ichi Nuclear Plant in March after a 9.0 earthquake and resulting tsunami.

And it wasn’t prompted by changing weather patterns or new rainfall forecasting models.

TVA and other nuclear operators have always had to design plants for what the NRC calls the probable maximum flood. And the size of that flood must have a site-specific estimation.

But when TVA began an effort to relicense the still-unfinished Bellefonte Nuclear Plant in northern Alabama, the utility couldn’t document how its original flood calculation was made. NRC ordered the estimate redone and slapped TVA with three violations in 2008.

Westinghouse to ship fuel to Watts Bar, TN reactor | PROS

June 21 (Reuters) - Westinghouse Electric Company said on Monday it will begin shipping nuclear fuel to the Tennessee Valley Authority's (TVA) Watts Bar Unit 2 reactor in Tennessee. Westinghouse will ship the fuel assemblies between late June and August, it said in a statement. Fuel loading is expected to begin in 2012 at Watts Bar 2, which is currently under construction, Westinghouse said. Last week, Tennessee Valley Authority (TVA) received a license from the Nuclear Regulatory Commission (NRC) authorizing the receipt of fresh nuclear fuel for eventual use in its proposed Unit 2 reactor. [ID:nSGE75E011] Once licensed to operate by the NRC, Unit 2 will be the will add 1,180 megawatts to the TVA power system, Westinghouse said. Pittsburg-based Westinghouse is majority owned by Toshiba Corp (6502.T) and Shaw Group (SHAW.N).

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PLANT BACKGROUND/TIMELINE

STATE: Tennessee

COUNTY: Rhea

TOWN: Spring City

OPERATOR: TVA

OWNER(S): TVA

UNIT(S): 1 - 1,123 MW Westinghouse pressurized water reactor

FUEL: Nuclear

DISPATCH: Baseload

TIMELINE:

1973 - Plant construction starts

1988 - Unit 2 construction stopped when it was about 80 percent complete. TVA said it stopped construction due to a reduction in demand for power. Anti-nuclear activists however hailed the work stoppage as a victory

1966 - Unit 1 enters commercial service - last nuclear power reactor to enter service in the U.S.

2007 - TVA Board approved the completion of the 1,180 MW Unit 2 at an estimated cost of $2.5 billion.

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