Reducing Cabling Cost and Complexity with Remote Multiplexing or Distributed Control in Nuclear Power Stations

Since control and instrumentation cabling accounts for more than 1% of the cost of a nuclear power station, interest in remote multiplexing and distributed control is running high. This paper draws a distinction between these two techniques and examines the practical implications in each case. Commercially available remote multiplexers are reviewed and categorized according to their field of application. A detailed method is developed to analyse cabling costs and to estimate the potential savings for both present and future designs. Estimates show that CANDU reactor cabling costs are approximately $ 140 per field point, by comparison with a published example of $ 690 for a HTGR. These variations, which are quite typical in the process industries, are explained, and the current costs for hard-wiring and remote multiplexing are compared.