Irradiation response of ODS Eurofer97 steel Luzginova, N.V.; Nolles, H.S.; ten Pierick, P. ...
Journal of nuclear materials,
09/2012, Letnik:
428, Številka:
1-3
Journal Article, Conference Proceeding
Recenzirano
Oxide dispersion strengthened (ODS) Eurofer97 steel (EU batch, 0.3wt.% of Y2O3 particles), produced by mechanical alloying followed by hot rolling, is irradiated in the High Flux Reactor in Petten, ...The Netherlands at three different irradiation temperatures (300, 450 and 550°C) up to nominal doses of 1dpa and 3dpa. The effect of neutron irradiation on the mechanical properties of ODS Eurofer97 material is investigated. It is shown that the irradiation hardening of ODS Eurofer97 steel occurs at 300°C, whereas during irradiation at 450 and 550°C no changes in mechanical properties are observed compared to the unirradiated material. This effect is possibly a result of the annealing of the irradiation damage at temperatures higher than 300°C. The observed shifts in the Ductile to Brittle Transition Temperatures due to irradiation at different temperatures are discussed and compared with non-ODS Eurofer97 steel.
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•The schema separates effects on the reactor cycle timescale from effects of the day-to-day timescale.•The calculated reaction rates in flux detectors were compared with experimental ...measurements.•A novel method of real-time measurement of sample power was proposed.
A dedicated neutronics computational scheme is a crucial tool in the preparation and the post-analysis of an irradiation experiment, as it defines the key parameters of the experiment. The complex and very dynamic environment of a Materials Testing Reactor (MTR) core, on the other hand, represents a challenging object for neutronics calculations. Within the framework of the HELIOS experiment conducted at the High Flux Reactor (HFR) in Petten (The Netherlands) in 2009 under the European Project EUROTRANS, a new neutronics scheme has been developed with the objective of finding the optimum balance between accuracy and calculation performance. This scheme is based on the Monte-Carlo technique and employs a two-level approach by separating the problem into overlapping spatial and temporal domains. The underlying physical phenomena are presented, together with elements of validation which gives a further insight into the effects governing the neutron fluxes in the core.
In this paper, an overview of the Swiss Nuclear Power Plant (NPP) activation methodology is presented and the work towards its validation by in-situ NPP foil irradiation campaigns is outlined. ...Nuclear Research and consultancy Group (NRG) in The Netherlands has been given the task of performing the corresponding neutron metrology. For this purpose, small Aluminium boxes containing a set of circular-shaped neutron activation foils have been prepared. After being irradiated for one complete reactor cycle, the sets have been successfully retrieved, followed by gamma-spectrometric measurements of the individual foils at NRG. Along with the individual activities of the foils, the reaction rates and thermal, intermediate and fast neutron fluence rates at the foil locations have been determined. These determinations include appropriate corrections for gamma self-absorption and neutron self-shielding as well as corresponding measurement uncertainties. The comparison of the NPP Monte Carlo calculations with the results of the foil measurements is done by using an individual generic MCNP model functioning as an interface and allowing the simulation of individual foil activation by predetermined neutron spectra. To summarize, the comparison between calculation and measurement serve as a sound validation of the Swiss NPP activation methodology by demonstrating a satisfying agreement between measurement and calculation. Finally, the validation offers a chance for further improvements of the existing NPP models by ensuing calibration and/or modelling optimizations for key components and structures.
In the framework of the materials domain DEMETRA in the European Transmutation research and development project EUROTRANS, irradiation experiment IBIS has been performed in the High Flux Reactor in ...Petten. The objective was to investigate the synergystic effects of irradiation and lead bismuth eutectic exposure on the mechanical properties of structural materials and welds. In this experiment ferritic martensitic 9 Cr steel, austenitic 316L stainless steel and their welds have been irradiated for 250 Full Power Days up to a dose level of 2
dpa. Irradiation temperatures have been kept constant at 300
°C and 500
°C.
During the post-irradiation test phase, tensile tests performed on the specimens irradiated at 300
°C have shown that the irradiation hardening of ferritic martensitic 9 Cr steel at 1.3
dpa is 254
MPa, which is in line with the irradiation hardening obtained for ferritic martensitic Eurofer97 steel investigated in the fusion program. This result indicates that no LBE interaction at this irradiation temperature is present. A visual inspection is performed on the specimens irradiated in contact with LBE at 500
°C and have shown blackening on the surface of the specimens and remains of LBE that makes a special cleaning procedure necessary before post-irradiation mechanical testing.
In the HIDOBE (HIgh DOse irradiation of BEryllium) irradiation program, various grades of constrained and unconstrained beryllium pebbles, beryllium pellets and titanium-beryllide samples are ...irradiated in the High Flux Reactor (HFR) in Petten at four different temperatures (between 698 K and 1023 K) for 649 days 1. The first of two HIDOBE irradiation experiments, HIDOBE-01, was completed after achieving a DEMO relevant helium production level of 3000 appm and the samples are retrieved for postirradiation examination (PIE).
The EWGRD Round Robin Measurement Exercise Thornton, D.A.; Wagemans, J.; Fernandes, A.C. ...
EPJ Web of Conferences,
01/2016, Letnik:
106
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
This paper presents the results of a round robin exercise carried out to compare specific activity measurements performed by eight European organisations on a set of ten neutron activation detectors ...containing the radio-nuclides 110mAg, 60Co, 54Mn, 46Sc and 94Nb. The purpose of the exercise was to demonstrate the level of consistency between the participating organisations in blind tests of measurements relevant to reactor metrology. The samples used were selected from a stock of pre-existing irradiated material held at SCK•CEN. Taking turns over a period of approximately 9 months, the participating organisations received the samples, measured them and provided their results to an independent referee who collated and compared the data. The inter-comparison has demonstrated good agreement between the participants with standard deviations for each dosimeter varying between 1.6% and 3.1%. The paper provides results of the EWGRD Round Robin in an anonymised form together with discussion and conclusions which may be drawn from the exercise.
Dosimetry at the High Flux Reactor in Petten, the Netherlands, serves a variety of purposes ranging from demonstrating compliance with the license for operating the reactor to validating the ...predictions of DPA in material irradiations. It is also used in the validation of the 3D neutron transport calculations during post-irradiation analysis to normalize the spectrum obtained from these calculations. In this paper, a thorough examination of irradiated steel specimens is carried out using the measurements performed with the neutron activation technique as well as the 3D neutron transport calculations to check the consistency in the resulting DPA values.
Quadrigeminal cistern lipoma revisited Kapoor, Anu; Harsha Vardhana, K R; Dudhat, Mahesh D ...
Neurology India,
05/2015, Letnik:
63, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Sir, We wish to share our experience with three cases of quadrigeminal cistern lipomas, all of whom were discovered incidentally during computed tomography/magnetic resonance imaging (CT/MRI) ...examination of patients for related or unrelated conditions. ...histopathologic confirmation is practically never required.
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