nuclear-news

Engineers concerned at design flaw in US nuclear reactors

U.S. NRC engineers urge fix for nuclear power stations Reuters, By Timothy Gardner 1 Mar 
A group of engineers within the U.S. nuclear power regulator is concerned that a design flaw in nearly all U.S. nuclear plants could endanger emergency core cooling systems. The group has urged the regulator to order power station operators to either fix the problem or face mandatory shutdowns.

Seven engineers in late February petitioned the Nuclear Regulatory Commission to order immediate enforcement actions against licensees of U.S. nuclear power plants, in a little-noticed, but public move.

The petition, filed under a standard NRC process, urges the agency to respond by March 21.

The engineers are concerned that a design flaw in nearly all U.S. nuclear facilities leaves them vulnerable to so-called open phase events in which an unbalanced voltage, such as an electrical short, could cause motors to burn out and reduce the ability of a reactor’s emergency cooling system to function. If the motors are burned out, backup electricity systems would be of little help, the petition said.

In early 2012 an unbalanced voltage event forced Exelon Corp’s Byron 2 reactor in Illinois to shut down automatically. The unit was shut for about a week.

Later that year, the NRC alerted nuclear power plant operators in a bulletin to a potential design vulnerability concerning open phase and collected feedback from the operators.

But the agency never ordered the plants to make changes to reduce any open phase vulnerabilities. The petition said 13 open phase events have occurred at U.S. and international nuclear plants over the last 14 years……http://www.reuters.com/article/usa-nuclear-regulator-idUSL2N1692BF

March 2, 2016 - Posted by Christina Macpherson | safety, USA