Measurement of the U-236(n, f) cross section in the neutron energy range from 0.5 eV up to 25 keV

The U-236(n,f) cross section has been measured in the energy range from 0.5 eV to 25 keV at the Geel Electron Linear Accelerator neutron time-of-flight facility of the Institute for Reference Materials and Measurements in Geel, Belgium. A highly enriched U-236 sample was mounted back-to-back with a B-10 sample in the center of a Frisch-gridded ionization chamber, hence realizing a 2 pi detection geometry. A U-235(n,f) cross-section control measurement was performed in the same experimental conditions. Special attention has been given to the fission resonance integral I-f and to the strongest resonance at 5.45 eV, for which a resonance analysis has been performed yielding Gamma(f) = 1.7 mu eV Both values are highly overestimated in the literature

Reconstruction of the acetabulum in THA using femoral head autografts in developmental dysplasia of the hip

<p>Abstract</p> <p>Background</p> <p>Severe acetabular deficiencies in cases of developmental dysplasia of the hip (DDH) often require complex reconstructive procedures in total hip arthroplasty (THA). The use of autologous femoral head grafts for acetabular reconstruction has been described, but few data is available about clinical results, the rates of non-union or aseptic loosening of acetabular components.</p> <p>Methods</p> <p>In a retrospective approach, 101 patients with 118 THA requiring autologous femoral head grafts to the acetabulum because of DDH were included. Six patients had died, another 6 were lost to follow-up, and 104 hips were available for clinical and radiological evaluation at a mean of 68 ± 15 (13 to 159) months.</p> <p>Results</p> <p>The average Merle d'Aubigné hip score improved from 9 to 16 points. Seven implants had to be revised due to aseptic loosening (6.7%). The revisions were performed 90 ± 34 (56 to 159) months after implantation. The other hips showed a stable position of the sockets without any signs of bony non-union, severe radiolucencies at the implant-graft interface or significant resorption of the graft.</p> <p>Conclusion</p> <p>The use of autologous femoral head grafts with cementless cups in primary THA can achieve promising short- to midterm results in patients with dysplastic hips.</p

Results of transmission measurements for 40Ca at GELINA

Transmission measurements have been performed at a 50 transmission station of the neutron time-of-flight facility GELINA to determine the total cross section for neutron induced reactions on 40Ca. These measurements are part of a collaboration of the Joint Research Centre and the Oak Ridge National Laboratory (US) to improve nuclear data for nuclear criticality safety applications. They have been supported by the EUFRAT project. This report provides the experimental details required to submit the data to the EXFOR data library which is maintained by the Nuclear Data Section of the IAEA and the Nuclear Energy Agency of the OECD. The experimental details, i.e. measurement conditions, sample characteristics, measurement procedures and experimental uncertainty components, together with the data reduction procedures are described. The experimental results including the full covariance information, based on the AGS-formalism, are reported following the latest recommendations of the International Nuclear Data Committee. This includes the information that is required to derive nuclear reaction model parameters together with their covariances by a least squares adjustment to experimental data.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

TKA following high tibial osteotomy versus primary TKA - a matched pair analysis

<p>Abstract</p> <p>Background</p> <p>High tibial osteotomy (HTO) is a well established technique for the treatment of medial osteoarthritis of the knee with varus malalignment. Results of total knee arthroplasty (TKA) after previous HTO are still discussed controversially. The aim of this study was to elucidate the clinical and radiological results as well as perioperative data of prior HTO on TKA.</p> <p>Methods</p> <p>Forty-one TKA after HTO were compared to 41 primary TKA at minimum of six years follow-up. Patients were matched according to age, gender, follow-up, etiology, and prosthetic design. Surgical data and complications were evaluated. Clinical outcome was assessed using a number of clinical scores and the visual analogue scale (VAS) for pain. X-rays were evaluated by the method of the American Knee Society. The patellar position was measured by the Insall-Salvati ratio.</p> <p>Results</p> <p>There was no significant difference in mean operation time (p = 0.47) and complication rate (p = 0.08). The Knee Score of the KSS (p = 0.0007) and the ROM (p = 0.006 for extension and p = 0.004 for flexion, respectively) were significantly better in the control group. Mid-term results of the VAS, WOMAC, Lequesne, UCLA, Feller's Patellar Score and SF-36 showed no significant difference. Femoral and tibial component alignment were similar in both groups. One tibial component showed suspect radiolucencies in the HTO group. The Insall-Salvati ratio showed three patients with patella alta and one patient with patella baja in the HTO group. At latest follow-up all implants were still in place.</p> <p>Conclusions</p> <p>Evaluating the clinical and radiological outcome, significant differences were only detected for range of motion and the Knee Score of the KSS. The present study suggests that the results of TKA with and without prior HTO are mainly identical. Although patients with a previous HTO had more complications, no statistically significant differences were noted with this group size.</p

Review of the C-nat(n,gamma) cross section and criticality calculations of the graphite moderated reactor BR1

A review of the experimental data for natC(n,c) and 12C(n,c) was made to identify the origin of the natC capture cross sections included in evaluated data libraries and to clarify differences observed in neutronic calculations for graphite moderated reactors using different libraries. The performance of the JEFF-3.1.2 and ENDF/B-VII.1 libraries was verified by comparing results of criticality calculations with experimental results obtained for the BR1 reactor. This reactor is an air-cooled reactor with graphite as moderator and is located at the Belgian Nuclear Research Centre SCK-CEN in Mol (Belgium). The results of this study confirm conclusions drawn from neutronic calculations of the High Temperature Engineering Test Reactor (HTTR) in Japan. Furthermore, both BR1 and HTTR calculations support the capture cross section of 12C at thermal energy which is recommended by Firestone and Révay. Additional criticality calculations were carried out in order to illustrate that the natC thermal capture cross section is important for systems with a large amount of graphite. The present study shows that only the evaluation carried out for JENDL-4.0 reflects the current status of the experimental data

NRD Demonstration Experiments at GELINA

Neutron Resonance Densitometry (NRD), a non-destructive analysis method, was presented. The method has been developed to quantify special nuclear material (SNM) in debris of melted fuel that will be produced during the decommissioning of the Fukushima Daiichi nuclear power plants. The method is based on Neutron Resonance Transmission Analysis (NRTA) and Neutron Resonance Capture Analysis combined with Prompt Gamma–ray analysis (NRCA/PGA). The quantification of SNM relies on the NRTA results. The basic principles of NRD, which are based on well-established methodologies for neutron resonance spectroscopy, have been explained. To develop NRD for the characterization of rock- and particle like heterogeneous samples a JAEA/JRC collaboration has been established. As part of this collaboration a NRD demonstration workshop was organized at the time-of-flight facility GELINA of the JRC-IRMM in Geel (B). The potential of NRD was demonstrated by measurements on a complex mixture of different elements. It was demonstrated that the elemental composition of an unknown sample predicted by NRTA deviated on average by less than 2% from the declared value. In addition the potential to identify the presence of light elements by NRCA/PGA was shown.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

Recommendations for MYRRHA relevant cross section data to the JEFF project

Within the framework of Work Package 10 of the EC FP7 CHANDA project, nuclear data of importance for the operation of MYRRHA, a lead-bismuth cooled accelerator driven reactor under development at SCK•CEN (BE), were studied. Based on data in the main nuclear data libraries, i.e. JEFF, JENDL, ENDF/B and BROND, and in the TENDL and CIELO libraries and on experimental data reported in the literature, recommendations to the JEFF project were made for several nuclides of interest to the MYRRHA reactor.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard

Neutron nuclear data measurements for criticality safety

To support the US Department of Energy Nuclear Criticality Safety Program, neutron-induced cross section experiments were performed at the Geel Electron Linear Accelerator of the Joint Research Center Site Geel, European Union. Neutron capture and transmission measurements were carried out using metallic natural cerium and vanadium samples. Together with existing data, the measured data will be used for a new evaluation and will be submitted with covariances to the ENDF/B nuclear data library