Failures in nuclear power pipelines

Nuclear Pipe Nightmares, UCS  director, Nuclear Safety Project October 27, 2015 Disaster by Design

If you had a dollar for every foot of pipe—or even just a quarter for every three inches of pipe—used in the nation’s nuclear power plants, you would probably not be reading this post. That chore would be delegated to one or more of your many minions.

Pipes at nuclear power plants carry cooling water to the reactor vessel and spent fuel pool, transport steam to the main turbine, provide hydrogen gas to cool the main generators, supply fuel and lubricating oil to the emergency diesel generators, maintain the fire sprinklers ready to extinguish fires, and numerous other vital functions. Given so many pipes, a success rate of 99.99%—remarkably similar to a failure rate of one broken pipe out of ten thousand pipes—would result in lots of piping failures.

The Electric Power Research Institute’s report revealed lots of piping failures at U.S. nuclear power plants between 1961 and 1997 (Fig. 1). The non-leaking failures are identified by inspections indicating that safety margins had been compromised, forcing the pipes to be replaced before they leak. The leaking failures are identified by puddles on the floor or other obvious signs, again forcing pipes to be replaced.

[excellent charts on original]

The Electric Power Research Institute’s report identified numerous reasons why pipes break (Fig. 2). MIC under corrosion stands for microbiologically induced corrosion—tiny little bugs that eat metal. Pipes can be designed wrong, installed wrong, or weakened via an array of methods during use.

[article goes on to describe pipe failures at:]

Dresden Nuclear Plant

Fission Stories #65 described the January 25, 1994, …..

Browns Ferry Nuclear Plant

On August 14, 1984…..

Surry Nuclear Plant

On December 9, 1986,….

Mihama Nuclear Plant

A 22-inch diameter pipe in the condensate/feedwater system ruptured on August 9, 2004, at the Mihama nuclear plant in Japan …..

Oyster Creek and Dresden Nuclear Plants

Fission Stories #162…..

LaSalle Nuclear Plant

On May 27, 1985…..

Oyster Creek Nuclear Plant

Fission Stories #29 described how 133,000 gallons drained from the condensate storage tank at the Oyster Creek nuclear plant in New Jersey in September 1996…..

Davis Besse Nuclear Plant

Fission Stories #131 described the March 2002 discovery by workers at the Davis-Besse nuclear plant in Ohio that a crack in a pipe allowing a control rod inside the reactor vessel to be connected to and manipulated by its electric motor outside the vessel had been leaking cooling water from the reactor for as long as six years……

Byron Nuclear Plant

On October 19, 2007, workers brushing away rust on the outer surface of a cooling water pipe at the Byron nuclear plant in Illinois poked a hole in it……

Big Rock Point Nuclear Plant

The NRC described a broken pipe at the Big Rock Point nuclear plant in their annual report to the U.S. Congress on abnormal occurrences in 1998…….

Safety by Intent

The table above from the Electric Power Research Institute indicates that 1,816 failures were identified by testing and inspection at U.S. nuclear power plants between 1961 and 1997 while 2,247 failures were found after pipes had leaked.

This data reinforce a theme too often appearing in nuclear safety posts to our All Things Nuclear blog—testing and inspection efforts are less effective than they need to be. Afederal regulation requires that plant owners have extensive testing and inspection programs that find and fix safety problems in a timely and effective manner. If compliance with this regulation were fact rather than fiction, the data should show more piping failures are found via tests and inspections than by puddles on the floor.

The NRC must figure out why testing and inspection efforts are violating federal safety regulations by failing to find and fix piping failures in a timely and effective manner. http://allthingsnuclear.org/nuclear-pipe-nightmares/

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