On Tuesday, the Tennessee Valley Authority notified federal regulators that it installed fuses at Watts Bar 2 found to be defective by their manufacturer.
Littelfuse notified TVA in late April that fuses manufactured under three date codes are potentially susceptible to "nuisance opening," according to a notice filed with the Nuclear Regulatory Commission. The commercial-grade components were not installed in any of TVA's operating reactors.
Watts Bar 2 is under construction, and the soon-to-be-replaced fuses did not pose an immediate safety threat. TVA plans to finish the 1,150 megawatt reactor in Tennessee in late 2015. Work on the unit was restarted in 2007 after the project had been abandoned nearly complete in the 1980s. The fuse issue did not appear related to NRC enforcement action last year surrounding inadequate documentation for roughly 6,200 parts handled through TVA's commercial-grade dedication program.