No abstract available

[en] Vibration experiments were done on small tube bundles of triangular and square lattice configurations in both liquid and two-phase (air-water) cross-flow. The effects of flow velocity, simulated steam quality, lattice orientation, tube location and tube frequency were explored. Tube response to random flow turbulence excitation and fluidelastic instability were observed in both liquid and two-phase cross-flow. Fluidelastic instability criteria and random forcing function characterizations are derived from this work. This information may be used in the vibration analysis of shell-and-tube heat exchanger components. (author)

No abstract available

No abstract available

No abstract available

[en] An extensive series of experimental vibration tests has been conducted on tube bundles of contemporary interest in a large water tunnel. The main objective of these tests has been to develop a design criterion to limit vibration amplitudes. It has been found that the main excitation mechanisms are turbulence, some vortex shedding, and hydroelastic instability. The results of these tests are correlated and presented. It is found that the most serious excitation mechanism is hydroelastic instability. Criteria are advanced for establishing upper velocity limits based on the experimental findings. The vortex shedding mechanism is found to only be a problem for tubes in the inlet region of some bundles. Strouhal numbers associated with observed resonances are tabulated and discussed. Tube response to random turbulence has been studied for numerous bundles but is found to be of secondary significance

[en] A thermodynamic analysis for surge tank pressure transients during multiple surges in a nuclear reactor is presented. A sinusoidal type of level changes has been assumed. (U.S.)

[en] It has been demonstrated in a convincing fashion by the author that liquid turbulence, some vortex shedding at bundle inlet tubes, and hydroelastic instability are the main causes of vibration in bundles of current interest. Hydroelastic instability thresholds can be fairly well predicted. There are many ways in which real prototype heat exchangers deviate from laboratory tube bundles. In the work reported here, numerous experimental tests have been conducted to determine the effect on permissible design velocity limits of these deviations. All tests have been conducted in a horizontal water tunnel containing tube bundles of contemporary interest. Tests have been conducted to determine whether or not open tube lanes will serve to trigger hydroelastic instabilities at abnormally low velocities. It is found that, in fact, they do not. Further tests were conducted to investigate the effect of varying the clearance between the bundle and the tunnel wall. The effects on vibration of various shapes of baffle plates located along the tunnel wall was investigated. Preferred baffle plate designs have been established. Mixed bundles of tubes of different frequencies were tested. The effects of locating baffles in the bundle inlet region were studied experimentally. It will be appreciated that all of the results reported are immediately applicable in the design of modern heat exchangers and steam generators. (Auth.)

[en] The sources, production and releases of tritium in gaseous and liquid effluents from CANDU stations as well as applicable regulatory and derived emission standards are discussed. To assess the environmental impact of these releases, Ontario Hydro has been carrying out an environmental monitoring programme at all nuclear generating sites since 1971. The programme monitors critical and potentially important pathways and consists of monitoring tritium in air, precipitation, milk, drinking water and vegetation. Tritium releases from stations are of the order of 0.1% of the derived release limits leading to doses to individuals in the vicinity of the stations of about 1 mrem/a^-1. The environmental impact from an expanded CANDU programme is discussed. The effects on the Great Lakes basin are of particular importance since it is expected that the bulk of Ontario Hydro's future nuclear sites will be located along the shores of the Great Lakes. The implication of the recently promulgated International Joint Commission water quality objective is examined. (author)

[en] Real prototype heat exchangers deviate from laboratory tube bundles. In the work reported here, numerous experimental tests have been conducted to determine the effect on permissible design velocity limits of these deviations. All tests have been conducted in a horizontal water tunnel containing tube bundles of contemporary interest. Tests have been conducted to determine whether or not open tube lanes will serve to trigger hydroelastic instabilities at abnormally low velocities. It is found that, in fact, they do not. Further tests were conducted to investigate the effect of varying the clearance between the bundle and the tunnel wall. Results indicate that a clearance of not less than half a tube diameter prevents local vibration problems. The effect on vibration of various shapes of baffle plates located along the tunnel wall was investigated. Preferred baffle plate designs have been established. Clearances of one tube bundle gap width between baffle plates and adjacent tubes are shown to be desirable. Mixed bundles of tubes of different frequencies were tested. Vibration test demonstrated that this is not the way to improve heat exchanger design. The effects of locating baffles in the bundle inlet region were tested. It was found that the distance between the plate and the bundle was not of critical importance. Other geometric effects were studied. The first hydroelastic tests on clamped-simply supported tube bundles have now been completed. The new data are found to fit remarkably well on the previously used stability diagram. At the time of writting, the effect of clearances at the tube end supports is being studied. With controlled clearances in the laboratory, it is found that a knocking action occurs at these supports even at extremely low velocities. The implication of these tests, as they pertain to multi-span heat exchangers is discussed