NRC Shields Duke Energy Nuclear Reactor Methods From Public View

Federal regulators say proprietary reactor analysis data at Catawba, McGuire and Oconee plants can remain secret despite public accountability questions.

The U.S. Nuclear Regulatory Commission has approved a request from Duke Energy to keep portions of its nuclear reactor safety analysis methods hidden from public disclosure — a decision likely to raise questions about transparency surrounding major nuclear facilities operating in the Carolinas.

The May 11 determination letter obtained by WCAB News allows Duke Energy to withhold technical details tied to proposed reactor methodology changes at Catawba Nuclear Station, McGuire Nuclear Station and Oconee Nuclear Station.

The company sought NRC approval in March to revise thermal-hydraulic methodologies — engineering models used to calculate reactor core cooling, heat transfer, and operational safety margins inside nuclear reactors.

But while the request involves systems central to reactor operations and safety analysis, the NRC agreed the underlying technical details should remain confidential because Duke Energy argued the information constitutes proprietary commercial material.

In a letter signed by NRC Project Manager John Klos, the agency concluded the material “contains proprietary information” and should be withheld under federal disclosure regulations and the Atomic Energy Act.

Duke Energy argued that public release could give competitors an economic advantage by revealing specialized engineering methods developed by the company.

The decision highlights a longstanding tension in the nuclear industry: how much technical information should remain protected as trade secrets versus how much scrutiny the public deserves around infrastructure that directly affects regional safety, environmental risk and energy reliability.

The NRC’s letter makes clear the agency is not withholding the existence of the license amendment itself — only the detailed engineering content submitted in a proprietary enclosure. Still, critics of nuclear secrecy have historically argued that broad confidentiality claims can limit independent outside review of safety-related assumptions and reactor modeling.

The methodologies at issue involve revisions to Duke Energy’s VIPRE-01 thermal-hydraulic analysis framework and statistical core design calculations used across seven reactor units in North and South Carolina.

Federal regulators stated the information may still be reviewed internally by NRC consultants operating under confidentiality agreements. The agency also noted the withholding determination could later be revisited if circumstances change or if a Freedom of Information Act challenge is filed.

Neither the NRC letter nor Duke Energy’s affidavit suggests an immediate safety problem at any of the plants. Instead, the filing appears tied to updated analytical methodologies supporting reactor licensing and operational evaluations.

Still, because the calculations govern how reactor cores are modeled under operating conditions, the approval underscores how some of the most technically consequential aspects of nuclear regulation often occur largely outside public view.