Strategies for Accelerating the SLARette Process

Abstract

The SLARette (Spacer Location and Repositioning) process is continuing on several CANDU reactors, where loose fitting garter springs (spacers) were used, to prevent contact between the calandria tube and the pressure tube for the target life. With time, the sag in the fuel channel is increasing and consequently increasing the potential for contact between the pressure tube and the calandria tube. Also, due to increasing sag in the pressure tubes and increasing magnitude of the fuel channel constrictions on the eddy current detection system, the Spacer Location And Repositioning activities are becoming more time consuming and difficult. For CANDU owners, during the SLARette campaigns, station outage time is the most expensive item. Therefore, it is beneficial to complete the SLARette process as early as possible and as fast as possible. New SLARette strategies can substantially accelerate the overall SLARette process and thus minimize the outage time. There are several strategies to perform the SLARette process. These strategies include : Using the SLARette Mark II Delivery System, Using SLARette Advanced Delivery System, Implement creative fuel handling technique, Operate from both sides of the reactor using Mark II Delivery Systems, Operate from both sides using Advanced Delivery Systems. Each strategy offers different benefits, rate of fuel channel processing (SLARette Activity), and schedule constraints. This paper provides the details of each strategy and compare them in terms of outage time, man-rem consumption, and constraints.