Rod insertion method analysis – A methodology update and comparison to boron dilution method. (March 2018)

• Record Type: Journal Article
• Authors: Merljak, Vid; Kromar, Marjan; Trkov, Andrej
• Is Part Of: Annals of nuclear energy. Volume 113(2018)
• Page Start: 96
• Page End: 104
• Publication Date: 2018-03
• Subjects: Rod insertion method -- Control rod worth -- Simulation -- Pre-calculated correction factors -- Comparison to experiment -- Boron dilution method -- Nuclear power plant; Nuclear energy -- Periodicals; Nuclear engineering -- Periodicals; 621.4805
• DOI: 10.1016/j.anucene.2017.11.020
• Languages: English
• ISSNs: 0306-4549

Abstract

Highlights: The rod insertion method is updated with a novel correction, namely the reactivity overshoot compensation. Other correction factors are also revised, as well as the assumptions of numerical simulation. Comparison is made between the control rod worth measured by the rod insertion method and boron dilution method. Updated rod insertion methodology accurately reproduce the results of boron dilution method, but is way faster to perform. Abstract: The rod insertion method for control rod worth measurement is explained and past as well as recent developments are outlined. The original methodology is updated with a more consistent use of the flux redistribution correction, conversion from dynamic to static reactivity and a new procedure to account for the so-called reactivity overshoot. As an example, the procedure is applied to real measured data from Krško NPP. Resulting integral and differential worth curves are compared with reference measurements by the boron dilution method, where a previously unattainable match is observed. Additional research is presented in order to assess the remaining small deviations. Besides other advantages, the rod insertion method is demonstrated to produce results that are in excellent agreement with those of boron dilution method and can therefore be used as replacement.