French developments in the ultrasonic examination of pressure vessels

In 1985, 34 Pressurized Water Reactors (PWRs) were already in service in France and 21 were being constructed. The manufacturer (Framatome) and the owner (Electricité de France, EDF) have consequently gained great experience in the ultrasonic examination of the various components and particularly of the reactor vessel.

The development work initiated concerns:

• —the improvement of the knowledge of methods used;

• —the beginning of automation in fabrication control;

• —the continuation of the technical implementation of the signal and image processing.

At the fabrication stage, work was carried out to demonstrate the total adequacy of those examinations required by the RCCM Code.

In addition, Framatome is developing the automation of ultrasonic inspection in shop.

Inservice inspection of the vessel is carried out with ‘MIS’ inspection equipment.

Data analysis is improved by special software allowing the performance of different types of UT indications to be presented.

Diffraction echoes from focused probes are used to size underclad defects on reactor nozzles.     

Effect of polynucleotides on the inhibition of neutrophil elastase by mucus proteinase inhibitor and alpha 1-proteinase inhibitor

DNA released from neutrophils at sites of inflammation may modulate tissue proteolysis. We used tRNA and synthetic polynucleotides as models of DNA to study the influence of polynucleotides on the inhibition of neutrophil elastase by its endogenous inhibitors alpha1-proteinase inhibitor (alpha1-PI) and mucus proteinase inhibitor (MPI). Affinity chromatography showed that polynucleotides form electrostatic complexes with elastase and MPI but not with alpha1-PI, the highest affinity being for MPI. The tight-binding partial inhibition of elastase by polynucleotides was used to calculate the Kd of the elastase-polynucleotide complexes which ranged from 4 microM to 21 nM. One mole of tRNA was able to bind 9 mol of elastase. Polydeoxycytosine and tRNA significantly impaired the reversible inhibition of elastase by MPI: they moderately increased the rate of enzyme-inhibitor association, strongly enhanced the rate of complex dissociation, and lowered the enzyme-inhibitor affinity by factors of 34 and 134, respectively. The two polynucleotides also decreased the rate of the irreversible inhibition of elastase by alpha1-PI by factors of 30 and 3, respectively. Polynucleotides also changed the mechanism of inhibition of elastase by the two inhibitors from a one-step inhibition reaction to a two-step binding mechanism. Our data may help explain why proteolysis may occur at sites of inflammation despite the presence of active proteinase inhibitors.     

Growth hormone, insulin-like growth factor-I and insulin-like growth factor binding protein-3 are regulated differently in small-for-gestational-age and appropriate-for-gestational-age neonates

BACKGROUND: TBP-associated factors contain a variety of structural motifs and their related in vivo significance has remained unclear. We have attempted to identify specific biological phenomena linked to a particular domain of a TAF by analysing domain-exchanged chimeric mutants between Schizosaccharomyces pombe (Sp) and Saccharomyces cerevisiae (Sc) counterparts. RESULTS: Contrary to the case of TBP, Sp TAF containing the WD40 repeat cannot be exchanged for its Sc counterpart, despite their highly conserved primary structures. This 'species-specific' function locates in the N-terminal region. The C-terminal region, largely consisting of the WD40 repeat, is exchangeable for the corresponding region of its Sc counterpart. Growth of the strain harbouring this C-terminal chimeric mutant is temperature-sensitive. The chimeric gene product did not disappear at a restrictive temperature, a finding which strongly suggests that the growth defect is caused by an aberration in the interactions through the WD40 repeat structural motif. With temperature elevation, the chimeric mutants underwent drastic morphological changes due to a defect in cytokinesis. CONCLUSIONS: The WD40 repeat of TAF is primarily involved in reactions which might regulate cytokinesis in Sp.     

Expression of a recombinant human growth hormone binding protein in baculovirus/insect cell system

An eucaryotic recombinant human growth hormone binding protein (rGHBP) was expressed in baculovirus-infected insect cells and purified by affinity chromatography from culture supernatant. This mannose-rich 34-kDa protein specifically bound human growth hormone (hGH) with the same affinity (kDa = 0.42 x 10(-9) M) than the 51.5 kDa GHBP we purified and characterised from human plasma (kDa = 1.1 x 10(-9) M). A high molecular form of the rGHBP was detected by silver-stained SDS-PAGE, Western blot (mAb 263), affinity cross-linking and Western ligand blot with 125I-hGH. Reduction experiments with beta-mercaptoethanol suggested that this form involved a disulfide bound between two rGHBPs.     

Inhibition of neutrophil elastase by the alpha1-proteinase inhibitor-immunoglobulin A complex

Effect of spaying on liver and plasma phospholipid components was studied in 4-day cyclic rats (Haffkin Institute Strain). Rats were ovariectomized during diestrous stage of estrous cycle. Ovariectomy (OVX) was shown to increase the total phospholipid content in both the liver lobes after 24 hr interval, it remained higher in spigelian lobe up to 72 hr but it was lowered in the right lobe at 48 hr interval. Concentration of sphingomyelin (SHP) in total phospholipids, as assessed by TLC, was slightly increased in both lobes after 48 hr of spaying. It declined significantly by 72 hr only in the spigelian lobe. Phosphotidylcholin, phosphatidylserine and phosphatidylethanolamine concentrations showed fluctuating pattern up to 48 hr of spaying, but most of these changes were seen to be restored to the normal level by 72 hr interval. Results indicate that the relative lack of ovarian hormones due to ovariectomy have obvious influence on hepatic lipid metabolism particularly that of phospholipid components. There appears to be an inverse relationship between hepatic lipid components and blood plasma. Spigelian lobe exhibits distinctly different responses to ovariectomy as compared to those of the right lobe. Maximal alterations are observable by 48 hr post-OVX interval.     

Radiation Embrittlement Understanding for PLIM Activities at EC-JRC-IE

Radiation embrittlement and aging mechanisms for NPP reactor pressure vessels and vessel internals have been studied within NPP Plant Life Management activities for the evaluation, prediction, and monitoring of the critical components' service life. The main achievements of the SAFELIFE project, integrating various networks on PLIM issues, are given. Results of neutron embrittlement of model alloys are presented, and surveillance and research data on WWER reactor pressure vessel and other steels are analyzed. Projects for the development of destructive and non-destructive testing of irradiated materials are outlined.     

Neutron Embrittlement of WWER Reactors: EC-Supported Projects

Results of the implementation of programs on the evaluation of the service life of reactor pressure vessels of NPPs are considered with the account of neutron embrittlement. Data on strength of WWER-440 reactor pressure vessels with a high and moderate content of detrimental impurities (copper and phosphorus) have been analyzed. For the welds of WWER-1000 reactor, drawbacks in the manufacture, dosimetry, and test procedures of surveillance specimens are shown. To ensure safe operation of reactor pressure vessels, new projects have been undertaken, focusing on the effect of neutron embrittlement of steel on the integrity of structures and on advanced experimental methods of studying material strength.     

Stopped flow fluorescence energy transfer measurement of the rate constants describing the reversible formation and the irreversible rearrangement of the elastase-alpha1-proteinase inhibitor complex

Serpins are thought to inhibit proteinases by first forming a Michaelis-type complex that later converts into a stable inhibitory species. However, there is only circumstantial evidence for such a two-step reaction pathway. Here we directly observe the sequential appearance of two complexes by measuring the time-dependent change in fluorescence resonance energy transfer between fluorescein-elastase and rhodamine-alpha1-protease inhibitor. A moderately tight initial Michaelis-type complex EI1 (Ki = 0.38-0.52 microM) forms and dissociates rapidly (k1 = 1.5 x 10(6) M-1 s-1, k-1 = 0.58 s-1). EI1 then slowly converts into EI2 (k2 = 0.13 s-1), the fluorescence intensity of which is stable for at least 50 s. The two species differ by their donor-acceptor energy transfer efficiency (0. 41 and 0.26, respectively). EI2 might be the final product of the elastase + inhibitor association because its transfer efficiency is the same as that of a complex incubated for 30 min. The time-dependent change in fluorescence resonance energy transfer between fluorescein-elastase and rhodamine-eglin c, a canonical inhibitor, again allows the fast formation of a complex to be observed. However, this complex does not undergo any fluorescently detectable transformation.     

Pantechnik new superconducting ion source: PantechniK Indian Superconducting Ion Source

The new ECR ion source PantechniK Indian Superconducting Ion Source (PKISIS) was recently commissioned at Pantechnik. Three superconducting coils generate the axial magnetic field configuration, while the radial magnetic field is done with the multi-layer permanent magnets. Special care was devoted to the design of the hexapolar structure, allowing a maximum magnetic field of 1.32 T at the wall of the 82 mm diameter plasma chamber. The three superconducting coils using low temperature superconducting wires are cooled by a single double stage cryo-cooler (4.2 K). Cryogen-free technology is used, providing reliability and easy maintenance at low cost. The maximum installed RF power (18.0 GHz) is of 2 kW. Metallic beams can be produced with an oven (T(max) = 1400 °C) installed with an angle of 5° with respect to the source axis or a sputtering system, mounted on the axis of the source. The beam extraction system is constituted of three electrodes in accel-decel configuration. The new source of Pantechnik is conceived for reaching optimum performances at 18 GHz RF frequencies. PKISIS magnetic fields are 2.1 T axial B(inj) and 1.32 T radial field in the wall, variable B(min) with an independent coil and a large and opened extraction region. Moreover, PKISIS integrates modern design concepts, like RF direct injection (2 kW availability), dc-bias moving disk, out-of-axis oven and axial sputtering facility for metal beams. Finally, PKISIS is also conceived in order to operate in a high-voltage platform with minor power consumption.