[en] The subcooling in the downcomer of the reactor calculated by code TRAC-BF1 was not in agreement with the data measured in the reactor vessel at steady state conditions. The most important phenomenon, which influences the subcooling is steam-water separation by gravity above the chimney. The steady-state input model has been changed in several ways in order to investigate the effect on the subcooling. Some alterations have been definitively implemented in the model, not because they strongly influence the subcooling, but because they are physical more correct. The level tracking option was left off. The implementation in the input of a perfect steam separator model, located above the chimney, resulted in calculations with stable water height and subcooling data more consistent with the measured data. It is recommended to conduct additional test in the GKN reactor. The purpose will be comparing calculated results with measured data, such as downcomer subcooling and flow rate in order to improve the validity of the model. (author). 3 refs.; 3 figs.; 3 tabs

No abstract available

[en] A method developed for the prediction of critical flow of subcooled and saturated water is compared to the Marviken full scale experiments and some other relevant data. It is shown that this method gives better agreement with the data than other methods. Besides that, the method is relatively simple to use since its equations give the flow in an explicit form. (author)

[en] Purpose: To prevent cooling water in a pressure vessel from leaking upon dismantling or assembling work of a water-submerged motor for driving a pump. Constitution: Refrigeration pipes are disposed to a flow passage to a pump section and a water-submerged motor passing through the bottom wall of a reactor container and refrigerant is introduced through the refrigeration pipes to refrigerate the cooling water in the flow passage to thereby obtain water sealing effects. That is, a refrigerator is operated upon maintenance work and the refrigerant is cyclically supplied to the refrigeration pipes by opening valves. Then, the cooling water present around the refrigeration pipes is refrigerated to block the flow passage. Then, inspection or like other operation can be carried out by opening the motor case. (Aizawa, K.)

[en] We present an efficient method for subrecoil cooling of neutral atoms by applying Raman cooling in two dimensions to a four-level tripod system. The atoms can be cooled simultaneously in two directions using only three laser beams. We describe the cooling process with a simple model showing that the momentum distribution can be rapidly narrowed to velocity spread down to 0.1v_rec, corresponding to effective temperature equal to 0.01T_rec. This method opens new possibilities for cooling of neutral atoms.

[en] Tests were carried out at Westinghouse Canada Inc., Hamilton, Ontario, to measure impact forces and axial depressurization of initially subcooled water jets discharging into the atmosphere. The purpose of the tests was to provide data for model studies investigating the consequences of a hypothetical nuclear reactor primary coolant circuit rupture. Break openings of 25 mm, 76 mm and 102 mm were tested using simple convergent nozzles. Two targets were used: A 1 m diameter flat circular plate and a section of 57 mm diameter pipe with axis on the jet centreline and perpendicular to it. Further tests were conducted with a slender instrumented probe supported on the jet centreline to measure the depressurization of the 'free' jet. Test conditions included initial reservoir pressures up to 7 MPa and liquid subcooling to 60 K. The impingement plate test results with the 25 mm nozzle indicate that a thrust coefficient of from 1.3 to 1.4 is appropriate, except where surrounding structures restrict free expansion. For the latter case, thrust coefficients up to 4 were measured. Also there are indications that a subcooled core exists within the jet extending to an L/D of at least 1. (orig.)

[en] This invention concerns improvements to secondary coolant-systems for sodium cooled nuclear reactors. It further concerns a protective device for a free level mechanical pump which prevents any gas bubbles due to leaks of the working gas of the pump from entering the secondary system of the nuclear reactor

[en] Control of the RF frequency: (1) 'RF Freq Check' on P85 (E835 Baby Sitter) should be turned OFF. (2) The RF frequency should be adjusted so that it is in the notch of the 4-8 GHz momentum cooling pickup response. The RF frequency device to be controlled depends on which RF system is on. If ARF2 is on, the RF frequency device is A:RLLFS1. If ARF3 is on, the RF frequency device is A:RLLFS0. IMPORTANT NOTE: A:RLLFS0 and A:RLLFS1 have very different data base scaling (A:RLLFS0 is 4 bytes and A:RLLFS1 is 2 bytes). A:RLLFS0 can be safely knobbed with a mult factor of 1.0 (i.e. no multiplier is required). A:RLLFS1 requires a mult factor of 0.02 or smaller. The monitoring and adjustment of the RF frequency is accomplished by the following steps: (3) Set up SA1 so that it is connected to CP48-SCH (4-8 GHz momentum cooling pickup). Set the SA center frequency to a harmonic of the RF frequency. This is most easily accomplished by doing one of the following: (a) If ARF3 is on, send P41 file 22 to SA1. (b) If ARF2 is on, set A:RLLFS0 to the set value of A:RLLFS1 then send P41 file 22 to SA1. (4) SA1 can be viewed on CATV channel pbar 20. If the notch in the momentum cooling pickup response is not at the center frequecy of SA1 adjust the RF. (On the low energy ramp, 1 division on the SA1 display at 5.5 GHz corresponds to 2.3 Hz in revolution frequency). Once you've made an adjustment to the RF frequency you should reset the SA1 display according to step 3 above.

[en] The main activities developed during the year of 1988 are described. (E.G.)

[en] The design parameters for the ORNL proposed Heavy Ion Storage Ring for Atomic Physics (HISTRAP) are reviewed in a series of viewgraphs. Topics considered include beam cooling, space charge, ion sources, beam injection, beam extraction and vacuum systems. Beam optics are described and the present status of the HISTRAP proposal is summarized