[en] Reactor coolant (RC) pump seal failures have resulted in the excessive leakage of primary coolant into reactor containment buildings. In some cases, high levels of airborne activity and surface contamination following these failures have necessitate extensive cleanup efforts and personnel radiation exposure. The cost of reduced plant availability and increases in radiation exposure have been serious concerns to reactor vendors and the utilities. The RC pump monitoring and diagnostic system has been developed, designed, and installed at Toledo Edison's Davis-Besse Nuclear Power Station to examine the relationships between seal failures and the environment in which the pumps operate. The data collection task, started recently, will closely examine the rotordynamic aspects of pump behavior and the operational environment that is controlled by the plant operator to characterize the effects upon pump seal performance. 7 refs., 6 figs

[en] Reactor Coolant (RC) pump seal failures have resulted in the excessive leakage of primary coolant into the containment buildings. In some cases, high levels of airborne and surface contamination following these failures have necessitated extensive cleanup efforts and personnel radiation exposure. The cost of reduced plant availability and increases in radiation exposure have been serious concerns to reactor vendors, the Nuclear Regulatory Commission, and the utilities. The RC pump monitoring and diagnostic system has been developed, designed, and installed at Toledo Edison's Davis-Besse Nuclear Power Station to examine the relationships between seal failures and the environment in which the pumps operate. The data collection task ended in September 1984. A major goal of data collection and reduction was to closely examine the rotodynamic aspects of pump behavior and the operational environment that is controlled by the plant operator to characterize the effects upon pump performance. As a result of excellent recent pump seal performance, no significant correlations have yet been identified. Such correlations may be identified later as Toledo Edison continues to use the monitoring system to perform the intended functions. 11 refs

[en] The production of gamma rays with energy above 10 MeV from the interaction of cosmic rays with matter is simulated using Monte Carlo methods. The first case considered is the interaction of cosmic rays in the earth's atmosphere. The gamma-ray flux is calculated as a function of direction, energy, and atmospheric depth. These calculations are compared with experimental results from a number of balloon flights, and with the earth albedo observed by the SAS-2 satellite. Calculations for cosmic ray interactions with the lunar surface are presented, and the results compared with an upper limit for the lunar albedo based on SAS-2 measurements. These same methods are applied to the interaction of cosmic rays with the interstellar medium. A number of models for astrophysical gamma-ray production are examined, and results of the Monte-Carlo calculations are used to set limits on various parameters of these models. Part of the balloon data was obtained during the flight of a digitized spark chamber gamma-ray telescope. This telescope has an active area of 50 cm x 50 cm and is sensitive to gamma rays of energy above about 10 MeV. The construction and operation of this instrument are described

[en] Reactor coolant (RC) pump seal failures have resulted in excessive leakage of primary coolant into reactor containment buildings. In some cases, high levels of airborne activity and surface contamination following these failures have necessitated extensive cleanup efforts and personnel radiation exposure. Unpredictable pump seal performance has also caused forced outages and frequent maintenance. The quality of operating data has been insufficient to allow proper evaluation of theoretical RC pump seal failure mechanisms. The RC pump monitoring and diagnostic system being developed and installed at Toledo Edison's Davis-Besse Nuclear Power Station will examine the relationship between seal failures and three other variables. This report describes system software and hardware development, testing, and installation work performed during the period of December 1981 through May 1982. Also described herein is a parallel effort being conducted by a B and W/Byron Jackson/Utility group to improve pump seal performance

[en] The objective of the project is to develop a reactor coolant pump monitoring and diagnostic system and collect sufficient data to permit analysts to determine why high outleakage and failures occur at Davis-Besse Nuclear Power Station, Unit 1. This report summarizes the work completed during the first period of performance, October 1, 1980, through November 30, 1981. During this period the members of the Project Team were selected and the detailed work management plans developed to take this project from conception, through detailed engineering, and finally to construction in the early part of 1982. The scope of work described includes system design, equipment selection for the computer-based data collection and diagnostic system, and computer software development to permit data collection and analysis

[en] A pressuriser for a water cooled reactor is described. It comprises a pressure vessel divided into a water space and a gas space by a movable diaphragm sealingly secured to the pressure vessel. The pressuriser may be arranged as an integral unit in a reactor pressure vessel. In this case, the pressure vessel is divided into an upper chamber and a lower chamber by a casing. The reactor core and primary coolant circuit are arranged in the lower chamber and the pressuriser is arranged in the upper chamber. The diaphragm may be loaded by springs and dampers to prevent its oscillation or it may be an elastic membrane. Alternatively, the pressuriser may be a unit separate from the reactor pressure vessel. (author)

[en] The quality of operating data has been insufficient to allow proper evaluation of theoretical reactor coolant (RC) pump seal failure mechanisms. The RC pump monitoring and diagnostic system being developed and installed at Toledo Edison's Davis-Besse Nuclear Power Station will examine the relationship between seal failures and three other variables: The rotordynamic behavior of the pump shaft and related components, the internal conditions and performance of the seals, and the plant or pump operating environment (controlled by the plant operator). Interrelationships between these areas will be developed during the data collection task, scheduled to begin in October 1983 (for a full fuel cycle at Davis-Besse). This report describes system software and hardware development, testing, and installation work performed during this period. Also described is a parallel effort being conducted by a B and W/Byron Jackson/Utility group to improve pump seal performance

[en] Rolls-Royce has been interested for some time in putting its experience to use in the design and construction of small PWR power stations for use in the grids of developing countries and in other areas where there is a more localized need for a compact power plant. (author)

No abstract available

[en] In the past few years the development of probabilistic risk/consequence techniques for the evaluation of reactor plant safety has culminated in the publication of studies like WASH-1400 for land-based reactor systems. At the same time safety requirements for land-based reactors are largely based on compliance with increasingly stringent pre-determined absolute criteria. To-date published regulations for nuclear ships mirror the approach used for land-based reactors. This paper develops the case for increased utilisation of risk-consequence criteria and techniques in nuclear ship safety to cope with the different constraints and conditions appertaining to the construction and operation of nuclear ships