Feasibility of Measurement Uncertainty Recapture for CANDU Reactors: Licensing and Instrumentation Issues

Abstract

The paper discusses feasibility and path forward for the application of Measurement Uncertainty Recapture for CANDU Reactors, and the potential for use of available methods for accurate Feedwater Flow Measurements. Measurement Uncertainty Recapture is an approach approved by the USA Nuclear Regulatory Commission in 2000, and implemented in a majority of nuclear plants in the USA and numerous plants overseas. The approach allowed those plants that could demonstrate lower uncertainty in reactor power calculation to increase nominal full power. The application of Measurement Uncertainty Recapture approach in CANDU reactors would allow utilities to request a licence amendment and regulatory authorization for reactor power operation at SOE parameter limits. Demonstration of improved uncertainties would allow CANDU utilities to investigate and implement future additional Measurement Uncertainty Recapture opportunities. Since accurate reactor power calculation requires accurate feedwater flow measurements, potential for improving feedwater flow measurement accuracy in CANDU plants is evaluated based on a comparison of available methods. Nine measurement providers were selected and evaluated based on 10 performance criteria.