Benchmark analyses on the control rod withdrawal tests performed during the PHNIX end-of-life experiments

Monti, S.*; Toti, A.*; Stanculescu, A.*; Pascal, V.*; Fontaine, B.*; Herrenschmidt, A.*; Prulhiere, G.*; Vanier, M.*; Varaine, F.*; Vasile, A.*; Taiwo, T.*; Takano, Kazuya ; Tiberi, V.*; Adams, R.*; Chawla, R.*; Chenu, A.*; Mikityuk, K.*; Kiefhaber, E.*; Kriventsev, V.*; Maschek, W.*; Rineiski, A.*; Chellapandi, P.*; Devan, K.*; Semenov, M.*

Before the definitive shutdown in 2009, PHNIX end-of-life tests were conducted to gather additional experience on the operation of sodium cooled reactors. Thanks to the CEA, the IAEA decided in 2007 to launch the CRP entitled Control Rod Withdrawal Test performed during the PHNIX end-of-life experiments. The objective of this publication is to document the results and main achievements of the benchmark analyses on the control rod withdrawal test performed within the framework. For the total control rod worth, two groups of results were observed. The difference between the groups can be explained on the basis of the control rod model treatment on self-shielded cross-sections of absorbing media with deterministic codes. Heat transfers and sodium mixing phenomena strengthened by sodium turbulent flows in the hot plenum disturb power balances and degrade the comparisons. It leads the systematic overestimation in power deviation calculations for all the participants.