[en] This master thesis describes a Simnon model of a boiling water reactor to be used in simulating faults and disturbances. These faults and disturbanses will be detected by noise analysis. Some methods in identification and noise analysis are also described and are applied on some malfunctions of a servo. A Pascal program for recursive parameter identification was also written and tested. This program is to be used in an expert system for noise analysis on the nuclear power plant Barsebaeck. (author)

[en] A literature survey of the behaviour of centrifugal pumps in two-phase flow has been performed. The publications are originating from the USA, and treat pumps of the size of up to 1/3 of a reactor (PWR) pump and with pressures 1 to 70 bar. Conclusions are drawn and a number of recommendations are noted. (G.B.)

[en] A method of predicting the burnout conditions for flow of boiling water in vertical round ducts is presented. The analysis predicts that the burnout conditions are independent of the L/d-ratio and the inlet temperature, and that the burnout steam quality decreases with increasing surface heat flux and increasing mass velocity. It was also found that the burnout steam quality at low pressures increases with the pressure and reaches a maximum at approximately 70 kg/cm, and thereafter decreases with a further increase of the pressure. The theoretical result compares very well with experimental data from different sources

[en] The present report deals with the results of the second phase of an experimental investigation of burnout conditions for flow of boiling water in vertical round ducts. The following ranges of variables were studied and 809 burnout measurements were obtained. Pressure 5. 3 < p < 37. 3 kg/cm²; Inlet subcooling 56 < Δt_sub < 212 deg C; Steam quality 0. 20 < x_BO < 0.95; Heat Flux 50 < q/A < 515 W/cm²; Mass velocity 100 < m'/F < 1890 kg/m²s; Heated length 600 < L < 2500 mm; Duct diameter d = 10 mm. The results are presented in diagrams, where for a certain geometry, the burnout steam qualities, x_BO , were plotted against the pressure with the surface heat flux as parameter. The data have been correlated by curves, and the scatter around the curves is less than ± 5 per cent. In the ranges investigated, the observed steam quality at burnout, X_BO generally decreases with increasing heat flux and mass velocity but increases with increasing pressure. The data have been compared with the empirical correlation by Tong, and excellent agreement was found for pressures higher than 10 kg/cm²

[en] In spite of the fact that full-scope simulators are very powerful training tools, the transfer of knowledge and skills to the trainees during simulator training is completely dependent on the instructors' technical competence and their ability to transfer it to the trainees by efficient use of these training tools. Accordingly, the instructor candidates must pass a technical training programme equivalent to that for shift supervisors and have at least a few months of experience in each operator position at a nuclear power plant. To be authorized, the instructors must also pass a teacher training programme consisting of four 2 week instructor courses. To stay authorized the instructors must pass an annual retraining programme consisting of at least two weeks of technical refresher and one week teacher retraining. The retraining programme also includes at least three weeks of operational practice at a nuclear power plant. (author)

[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] Terminal pumping has recently been installed in the Lund tandem Pelletron electrostatic accelerator. The equipment allows a higher gas density in the stripper and an improved vacuum in the accelerator tubes compared to the former system. This improvement has led to an increased beam transmission and to superior measurements for our accelerator mass spectrometry programme. The pressure profile of the stripper system as well as of the accelerator tubes has been calculated using kinetic gas theory. The result will be used to identify possible technical improvements in the future

[en] The dynamics of electron transfer within an excited ruthenium complex as well as between a ruthenium complex and a nanostructured TiO₂ film is addressed on the core hole few femtosecond lifetime scale. The ruthenium complexes studied are Ru(bpy)₃²⁺·2Cl^- (where bpy is 2,2^'-bipyridine) as well as Ru(bpy)₂(dcbpyH₂)²⁺·2PF₆^- (dcbpy is 4,4^'-dicarboxy-2,2^'-bypyridine) anchored to a nanostructured TiO₂ surface, where the latter system constitutes the photoactive part of a dye-sensitized solar cell. The N1s core level of the ruthenium complexes was excited by using synchrotron radiation, and the experimental techniques used were X-ray absorption spectroscopy (XAS) and resonant photoelectron spectroscopy (RPES). The occupied molecular orbital structure and the N1s partial density of unoccupied states are mapped and compared to calculated orbital structures

[en] As in the rat, gastrin and an extract of the acid-producing part of the stomach (proventriculus) were found to lower the blood Ca2+ concentration in the chicken. Furthermore, gastrin enhanced the uptake of 45Ca into the femur. It has been suggested previously that gastrin causes hypocalcemia in the rat by releasing gastrocalcin, a hypothetical hormone thought to reside in the acid-producing part of the stomach. The results of the present study in the chicken are in agreement with this concept. Not only exogenous, but also endogenous gastrin lowered blood calcium levels. Thus, the serum gastrin concentration was increased in response to ranitidine-evoked blockade of the gastric acid output; the rise in gastrin was associated with a transient drop in blood calcium. Also, food intake produced a rise in the serum gastrin concentration and a transient drop in blood calcium. However, injection of ranitidine or food intake in proventriclectomized (acid-producing part of the stomach extirpated) chickens failed to lower blood calcium, supporting the view that the gastrin-evoked hypocalcemia depends upon an agent in the gastric (proventriculus) mucosa. The authors suggest that endogenous and exogenous gastrin evoke hypocalcemia in the chicken by the same mechanism as that which has been postulated in the rat, i.e. by mobilization of the candidate hormone gastrocalcin from endocrine cells in the acid-producing gastric mucosa

No abstract available