FLUOLE-2: An Experiment for PWR Pressure Vessel Surveillance

Abstract

FLUOLE-2 is a benchmark-type experiment dedicated to 900 and 1450 MWe PWR vessels surveillance dosimetry. This two-year program started in 2014 and will end in 2015. It will provide precise experimental data for the validation of the neutron spectrum propagation calculation from core to vessel. It is composed of a square core surrounded by a stainless steel baffle and internals: PWR barrel is simulated by steel structures leading to different steel-water slides; two steel components stand for a surveillance capsule holder and for a part of the pressure vessel. Measurement locations are available on the whole experimental structure. The experimental knowledge of core sources will be obtained by integral gamma scanning measurements directly on fuel pins. Reaction rates measured by calibrated fission chambers and a large set of dosimeters will give information on the neutron energy and spatial distributions. Due to the low level neutron flux of EOLE ZPR a special, high efficiency, calibrated gamma spectrometry device will be used for some dosimeters, allowing to measure an activity as low as 7. 10 −2 Bq per sample. 103m Rh activities will be measured on an absolute calibrated X spectrometry device. FLUOLE-2 experiment goal is to usefully complete the current experimental benchmarks database used for the validation of neutron calculation codes. This two-year program completes the initial FLUOLE program held in 2006-2007 in a geometry representative of 1300 MWe PWR.

Determination of a non-measurable quantity using information from calculations and experimental measurements: application to the damage rate determination

“…These dosimeters were irradiated in the same position from the core [4]. The analysis of 8 dosimeters shows relatively good agreement between calculated and measured activity values, as presented in Table 1.…”

“…This weight is obtained by minimizing the variance associated to the best target value ߶ ଵǡ௦௧௧ . The best estimate of the target value ߶ ଵǡ௦௧௧ and its associated variance value ߪ ଶ ሺ߶ ଵǡ௦௧௧ ሻ are given in formulae (3) and (4).…”

Improvement of the activity measurement method for solid dosimeters emitting X-rays

“…This experimental validation aims to compare measurements on rhodium samples of different thicknesses activated in an equivalent neutron flux. These experiments were carried out in the EOLE (Thiollay et al, 2014) mock-up reactor (CEA/Cadarache). An initial experiment consisted in irradiating two sets of three dosimeters, 50 µm, 12 µm and 6 µm thick, respectively, in two symmetrical locations, with comparable neutron flux conditions.…”