[en] Circumferential liquid stream is generated above tube sheet and caught and removed by suction apparatus. A lance, having liquid jet outlets is moved across heat exchange tubes, washing any sludge deposits from the tubes into the liquid stream to be carried away through the suction apparatus. (UK)

[en] Trepaud's steam generator (G.V.T.) for light-water, heavy water and sodium-cooled reactors constists of a vertical unit, operating with once through counter-current flow. It uses undulating tubes and produces superheated steam. There are two types of steam generators for PWR reactors on the market at the moment: those with U tubes which reduce tube dilatation effects, but do not offer the advantages of a counter-current flow. They produce wet steam (with 0.5 to 1 pc humidity); those with straight tubes which offer a once-through counter-current flow they produce a superheated steam, but with the stresses arising from dilatation. G.V.T. combines the advantages of both, without suffering their disadvantages

[en] To help keep personnel exposure as low as reasonably achievable (ALARA) and reduce critical path outage time, most nuclear plants of Pressurized Water Reactor (PWR) design in the USA are now using improved equipment to service their steam generators (SGs) during outages. Because of the success of this equipment in the USA, three Korean plants have purchased this equipment, and other nuclear plants in the Pacific Basin are also considering procurement The improved SG servicing equipment which this paper discusses consists of the following: Nozzle Dams; Segmented Multi-Stud Tensioners; Primary Manway Cover Handling Devices; Shield Doors; and Fastener Cleaner. This equipment is specifically designed for the individual plant application and can also be specified for replacement SG projects. All of the equipment can be used without modification to the existing SGs. (author)

[en] The successful detection of a water/steam into a sodium leak in the SFR SG (steam generator) at an early phase of a leak origin depends on the fast response and sensitivity of a leak detection system. This intention of an acoustic leak detection system is stipulated by a key impossibility of a fast detecting of an intermediate leak by the present nominal systems such as the hydrogen meter. Subject of this study is to introduce the detection performance of an on-line acoustic leak detection tool discriminated by a back-propagation neural network with a preprocessing of the 1/m Octave band analysis, and to introduce the status of an on-line development being developed with the acoustic leak detection tool(S/W) in KAERI. For a performance test, it was used with the acoustic signals for a sodium-water reaction from the injected steam into water experiments in KAERI, the acoustic signals injected from the water into the sodium obtained in IPPE, and the background noise of the PFR superheater

[en] To enable tube examination on steam generators in service, Framatome has now developed a process for removing sections of steam generator tubes. Tube sections can be removed without being damaged for treating the tube section expanded in the tube sheet

[en] A programme at Westinghouse aimed at improving the efficiency and reliability of steam generators has led to the development of the model F generator. Its design features are described and the performance in model boiler and field tests, and in operating plants is summarised. (U.K.)

[en] About 80 per cent of all plant outages involving steam generators can be traced back to corrosion problems. Such problems arise from the continuous ingress of non-volatile contaminants, ie corrosion products and salt impurities. These have their origin in the balance of plant systems, and the corrosion products generally accumulate in the steam generators - forming both deposits in the flow restricted areas (such as on the tube sheet and tube support plate), and scales on the steam generator heating tubes. For many years, the industry has been involved in developing various types of cleaning techniques. Among these, chemical cleaning especially has been found to be very effective for removing corrosion products. The KWU chemical cleaning process described here consists of two different single-step methods for sludge removal: a high temperature iron process; and a copper process with ambient application temperature. The iron and copper process can be applied either in combination or separately, and uses separate solvents. (author)

[en] This paper describes an evaluation method of primary stress in 3-D structures. In 'Design by Analysis' for nuclear components, the stresses in structures are classified into the primary and the secondary stresses. The primary stress in axisymmetric structures can be evaluated by linearization of stress distribution in the specified section, but it is difficult to define the evaluation section in the 3-D structures, and to evaluate the primary stress with the conventional procedure. From this reason, the alternative evaluation method is needed. In this paper, the evaluation method of primary stress in 3-D structures is presented utilizing the feature of primary stress that is independent from stress re-distribution. (author)

[en] In this study, new detecting technology complement the handicaps of ECT has been introduced, and tested in the Inconel 600 specimen having artificial cracks. The method of AC magnetic flux leakage can offers improvement in speed and resolution compared to the conventional ECT. The information about the defects in the SG tbue can be represented as a degree of induced voltage by the defects instead of the phase difference of ECT. The new technology is free from the signal analysis problems in the conventional ECT. This new technology can solve the permeability variation clusters which is the main source of ECT signal distortion, and can measure circumference cracks with high velocity which is impossible in the ECT bobbin probe

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