Analysis of C/E results of fission rate ratio measurements in several fast lead VENUS-F cores

Abstract

Abstract. During the GUINEVERE FP6 European project (2006)(2007)(2008)(2009)(2010)(2011), the zero-power VENUS watermoderated reactor was modified into VENUS-F, a mock-up of a lead cooled fast spectrum system with solid components that can be operated in both critical and subcritical mode. The Fast Reactor Experiments for hybrid Applications (FREYA) FP7 project was launched in 2011 to support the designs of the MYRRHA Accelerator Driven System (ADS) and the ALFRED Lead Fast Reactor (LFR). Three VENUS-F critical core configurations, simulating the complex MYRRHA core design and one configuration devoted to the LFR ALFRED core conditions were investigated in 2015. The MYRRHA related cores simulated step by step design peculiarities like the BeO reflector and in pile sections. For all of these cores the fuel assemblies were of a simple design consisting of 30% enriched metallic uranium, lead rodlets to simulate the coolant and Al 2 O 3 rodlets to simulate the oxide fuel. Fission rate ratios of minor actinides such as Np-237, Am-241 as well as Pu-239, Pu-240, Pu-242 and U-238 to U-235 were measured in these VENUS-F critical assemblies with small fission chambers in specially designed locations, to determine the spectral indices in the different neutron spectrum conditions. The measurements have been analyzed using advanced computational tools including deterministic and stochastic codes and different nuclear data sets like JEFF-3.1, JEFF-3.2, ENDF/B7.1 and JENDL-4.0. The analysis of the C/E discrepancies will help to improve the nuclear data in the specific energy region of fast neutron reactor spectra.

Nuclear instrumentation in VENUS-F

“…The fission chambers vary in deposit type and mass, see Table 2. The low-mass (~ 10 g-1 mg) fission chambers are mainly applied for measuring spatial neutron flux profiles [7] and spectrum indices [8] [9]. An example of a fission fragment spectrum obtained with a low-mass fission chamber is shown in Fig.…”

Impact of delayed neutron constants on reactivity effects measured in a fast reactor

“…In this paper, we describe the impact of delayed neutron data on the analysis of reactivity measurements at the fast zero-power VENUS-F reactor located at the Belgian Nuclear Research Center SCK•CEN. VENUS-F has been extensively used for fast neutron data validation [13][14][15][16][17] serving as a mockup of the MYRRHA fast reactor/accelerator driven system [18,19]. Sensitivity and uncertainty analysis of  eff were recently studied for the specific cases of the VENUS-F [20] and MYRRHA reactors [21].…”