[en] In october 1992, at the time of a television inspection on the secondary side of one of the steam generators (SG) in Dampierre 2, it was found the burst of a plugged SG tube. Since then, in order to analyze this phenomenon and its immediate consequences on the surrounding tubers, EDF has carried out model representative tests. This study shows the absence of immediate risks of damaging the tubes adjacent to the tube broken by boiler effect. (authors). 3 refs., 4 figs., 3 tabs

[en] Background: The aim of this study is to evaluate the therapeutic success rate and serum thyroglobulin change after 131I ablation therapy in patients with differentiated thyroid carcinoma post-total thyroidectomy. Methodology: Thirty four patients with differentiated thyroid carcinoma post-total thyroidectomy treated with low-dose 131I ablation therapy (32 patients with 30 mCi and 2 patients with 60 mCi) between March 2011 and April 2014 were involved in this retrospective study. The imaging results of 131I whole body scintigraphy and the change of serum thyroglobulin before and six months after therapy were analysed. Results: Twenty seven (79%) out of 34 patients were found to have no thyroid uptake on their 131I whole body scintigraphy image after 131I ablation therapy and six months later. 7 patients (21%) were found to have thyroid uptake on their WBS. Serum thyroglobulin had significantly decreased from the time of treatment to six months follow up (Wilcoxon Signed Rank Test P < 0.001). Serum thyroglobulin was significantly decreased in successful cases (N = 27, Wilcoxon Signed Rank Test P < 0.01,). There was no significant decrease of serum thyroglobulin in unsuccessful cases (N=7, Wilcoxon Signed Rank Test P=0.612) Conclusion: Our findings suggest that low therapeutic dose of 131I is useful for the ablation of differentiated thyroid carcinoma post-total thyroidectomy, with the success rate of 79%. High serum thyroblobulin level group is unlikely to be successful and needs a higher dose of 131I. (author)

[en] The modelling of a safety valve behaviour requires the knowledge of the hydraulic force exerted by the flow on the disc during an operating cycle. Two different approaches have been applied to estimate this data. (1) Finite element calculations: results demonstrate that they can be helpful for designing, as they reproduce the influence of geometrical characteristics on hydraulic force well. (2) Experimental characterization: a test method has been qualified to get accurate value for the hydraulic force. Furthermore the program gives some explanation on the phenomena occurring at the very small lifts and on the influence of temperature on set pressure. (author)

[en] The French 'Commissariat a I'Energie Atomique' (CEA/DRN, Nuclear Reactor Division) is carrying out a new programme devoted to the thermal-hydraulics of steam injectors. This programme was called DIVA. Both experimental and theoretical works are planned. Motivations, objectives, test facility and test section dimensioning of this new programme are presented. A first test series was just performed. The validation of the test section dimensioning and experimental procedures was obtained. These first experimental data are presented and preliminary analyses are given. (author)

[en] CABRI is an experimental pulse, pool-type reactor, with a core made of 1487 UO₂ fuel rods with a 6 % ²³⁵U enrichment with stainless steel cladding. The reactor is able to reach a 25 MW steady state power level. CABRI has been recently refurbished in order to be able to provide RIA (reactivity initiated accident) and LOCA (loss of coolant accident) experiments in prototypical PWR conditions (155 bar, 300 C. degrees). This paper focuses on the analyses of the linearity of the 5 ex-core boron ionization chambers used to measure online the power of the CABRI driver core during RIA power transients. The neutron detectors have been calibrated thanks to thermal balances performed on the primary cooling system for steady states of power up to 23 MW. In the first part of the paper, the method used and the tests realized to calibrate the neutron detectors at low power will be explained. The second part will concentrate on the method used to demonstrate the linearity of the detectors under transient conditions.

[en] In October 1992, at the time of a television inspection on the secondary side of one of the steam generators (SG) in Dampierre 2, it was found the burst of a plugged SG tube. Since then, i order to analyse this phenomenon and its immediate consequences on the surrounding tubes, EDF has carried out model representative tests. This study shows the absence of immediate risks of damaging the tubes adjacent to the tube broken by boiler effect. (author). 3 refs., 4 figs., 3 tabs

[en] Concerning to steam generator tubes support mechanical loadings due to the impact f the ruptured one, Electricite de France, with the support of Commissariat a l'Energie. Atomique, has undertaken a large study in order to evaluate the consequences of such loadings. This paper first presents the results of the tests performed on AQUITAINE 2 facility (CEA Cadarache research center) for nominal, faulted and boiler effect conditions. Those results are then compared with numerical dynamic elastoplastic analyses performed with CASTEM 2000 code (CEA system). (author). 1 ref., 14 figs

[en] One goal of the SPARTE code is to be used as a guide to select the experiments design parameters for future CABRI power transients. This paper focuses on methods for optimizing a specific CABRI power transient (FWHM (Full Width at Half Maximum) ≃30 ms, Deposited energy ≃130 MJ) using the target characteristics of the pulse. The selection of a method may help the experimentalists and the operation team to minimize the number of “white” power transients to perform before the final test with the fuel sample. The optimization can lead to different results, that can be ranked according to their projected uncertainties. Different optimization methods are tested and compared in this paper. The Subplex method based on reiterations of the Nelder-Mead algorithm (simplex method) was selected for its high precision. Indeed, the CABRI power transients are not completely reproducible and present some uncertainties linked to the test parameters. This article focuses on the uncertainties propagation in order to identify and select the parameters that minimize the output uncertainties. The results are very satisfactory and lead to several optimized scenarios that will be tested during the next qualification test campaign.

[en] CABRI is an experimental pulse reactor at the Cadarache research center. CABRI is designed to study fuel behavior under RIA conditions. In order to produce the power transients, reactivity is injected by depressurization of a neutron absorber (³He) situated in transient rods inside the reactor core. The shapes of power transients depend on the total amount of reactivity injected and on the injection speed. The injected reactivity can be calculated by conversion of the ³He gas density into units of reactivity. So, it is of upmost importance to properly master gas density evolution in transient rods during a power transient. The ³He depressurization was studied by CFD calculations and completed with measurements using pressure transducers. The CFD calculations show that the density evolution is slower than the pressure drop. Studies also show that it is harder to predict the depressurization during the power transients because of neutron/³He capture reactions that induce a gas heating. Surrogate models were built based on CFD calculations and validated against preliminary tests in the CABRI transient system. Two methods were identified to evaluate the gas density evolution: CFD calculations and reverse point kinetics. The first one consists in adding a heat source in transient rods based on the experimental power conversion. The second one consists in using the measured power by boron ionization chambers to evaluate the net reactivity by a reverse point kinetics (PK) method and to subtract the reactivity feedbacks calculated with the DULCINEE multi-physics code. (authors)