The US Nuclear Regulatory Commission said on 31 May that it had approved a request by Energy Northwest to increase the generating capacity of the Columbia nuclear plant in Washington state, by 1.7%.

NRC staff found that Energy Northwest could safely increase the reactor’s output primarily through more accurate means of measuring feedwater flow.  NRC’s decision was based on its review of Energy Northwest’s evaluations showing that the plant’s design can handle the increased power level.

The safety evaluation of the proposed power uprate focused on several areas, including the nuclear steam supply system, instrumentation and control systems, electrical systems, accident evaluations, radiological consequences, fire protection, operations and training, testing, and technical specification changes. NRC staff also conducted independent calculations and evaluations of selected areas.

The uprate will increase the reactor's  generating capacity from approximately 1190MWe to 1210MWe. The single-unit Columbia nuclear plant, with a boiling water reactor, began commercial operation in 1984.  

Since the 1970s, NRC-approved uprates at US NPPs have collectively added the equivalent of seven new reactors’ worth of electrical generation to the power grid, NRC said.