Federal officials will hold a conference with South Carolina Electric & Gas next week to address questions surrounding rebar in the foundations of new reactors at the V.C. Summer nuclear plant.
Following an inspection in February, the Nuclear Regulatory Commission asserted that the spacing and anchor systems for rebar installed in portions of the reactors' basemats and walls did not meet the agency's requirements. The resulting inspection report read, "The basis for the NRC’s preliminary significance determination for this issue is that, without adequate spacing and anchorage of the headed reinforcement, the structural components that rely upon this system may be subject to brittle failure at a demand less than that required by the design-basis loads."
The NRC tentatively assigned the condition low-to-moderate safety significance, although the agency will not make a final enforcement decision until after the conference.
Plant owners disagreed with the inspectors' conclusions during the investigation, arguing the design met strength requirements, that the header shearer reinforcement design was approved during certification of the Westinghouse AP600 design, and that the approval extended to the AP1000 units under construction as well, according to the NRC.
The Westinghouse AP1000 is a new reactor, achieving final certification in the U.S. in late 2011, and this is not the first disagreement between plant owners and the NRC over the interpretation of its plans. At Plant Vogtle, which is also building two AP1000 units, the NRC issued license amendments related to basemat concrete and rebar late last year.