[en] The addition of Ti to the powder mixtures, which will finally give oxide dispersion strengthened ferritic steels, causes the appearance of large oxide particles in the end product. These particles are detrimental to the tensile properties at 700 deg C. The method for preparing powder mixtures is recalled. The effect peculiar to each mill has been shown with binary powder mixtures Fe-TiO₂. In this case, the relationship between the end product properties and the mill type has been defined more accurately

No abstract available

[en] The use of deterministic hazard quotients (HQs) in ecological risk assessment is common as a screening method in remediation of brownfield sites dominated by total petroleum hydrocarbon (TPH) contamination. An HQ ≥ 1 indicates further risk evaluation is needed, but an HQ ≤ 1 generally excludes a site from further evaluation. Is the predicted hazard known with such certainty that differences of 10% (0.1) do not affect the ability to exclude or include a site from further evaluation? Current screening methods do not quantify uncertainty associated with HQs. To account for uncertainty in the HQ, exposure point concentrations (EPCs) or ecological benchmark values (EBVs) are conservatively biased. To increase understanding of the uncertainty associated with HQs, EPCs (measured and modeled) and toxicity EBVs were evaluated using a conservative deterministic HQ method. The evaluation was then repeated using a probabilistic (stochastic) method. The probabilistic method used data distributions for EPCs and EBVs to generate HQs with measurements of associated uncertainty. Sensitivity analyses were used to identify the most important factors significantly influencing risk determination. Understanding uncertainty associated with HQ methods gives risk managers a more powerful tool than deterministic approaches

[en] Under contract with the European Atomic Energy Community the Belgian nuclear research center, S.C.K./C.E.N., has undertaken the development of a conditioning process for the cladding waste of LWR-fuel elements. It is based on mechanical compaction and encapsulation in a low-melting filling alloy. This programme started in November 1976. Basic data on the waste arisings and characteristics are presented. Preliminary experimental results with respect to compaction and encapsulation are rep

[en] Coincident neutron emission from the reaction ²⁰⁹Bi(n,2n)²⁰⁸Bi at Esub(nO) = 14.1 MeV has been measured in a kinematically complete experiment providing direct evidence for pre-equilibrium contributions. The outgoing neutrons were observed at several angles with two time-of-flight detectors. Neutron yields and energy spectra are interpreted with statistical-model calculations including pre-equilibrium decay modes. (author)

[en] The angular and spectral distributions of coincident neutrons from the reactions ¹²⁷(n,2n)¹²⁶I and ²⁰⁹Bi(n,2n)²⁰⁸Bi have been measured with two time-of-flight detectors at the incident energy 14.1 MeV. Neutron emission has been studied for reaction angles Theta sub(lab) between 10⁰ and 150⁰ (relative angles from 60⁰ to 270⁰). Energy spectra, angular distributions and coincidence yields are compared with statistical model calculations including preequilibrium decay modes, and nuclear level density and spin cut off parameters are derived. (orig.)

[en] A constant fraction type electronic circuit is described that performs a pulse shape analysis of organic scintillator pulses. The main features are: stability at high counting rates and energy independent particle identification over a wide energy range. In conjunction with a NE 213 scintillator, n-γ discrimination over a dynamic range of more than 1:100 can be performed at counting rates up to 5 x 10⁴ pulses per second. (Auth.)

No abstract available

[en] Ferritic alloys were studied in view of their application as canning materials for fast reactor fuel. Their creep strength has to be equal to or better than that of AISI 316 at 700 deg C. A Fe-Cr base alloy with addition of Mo and Ti was chosen. The requested properties have been obtained on hot worked alloys, the structure of which can be described as a bamboo structure. Cold working destroys the structure and the mechanical properties are lost. It is however not the case when the alloy is made by powder metallurgy methods with addition of a ceramic oxide. In this case only, heat treatments can rebuild the bamboo structure and the alloy recovers the good mechanical properties

[en] Ferritic steels are interesting for fast reactor core application because of the absence of swelling. As canning material, because of the higher temperature involved, new ferritic steels with oxide dispersion strengthening were developed. Fabrication methods are given and their mechanical irradiation and sodium compatibility properties are reviewed