Neutronenflussdichten und Temperaturfelder in einem Stahlblock : Vorversuche für das Forschungsprojekt "Reaktor-Komponentensicherheit" des BMFT
Neutronenflussdichten und Temperaturfelder in einem Stahlblock : Vorversuche für das Forschungsprojekt "Reaktor-Komponentensicherheit" des BMFT
For irradiations of large steel specimens which are planned in the framework of a research programme ("Reactor Components' Safety", projected by the German Federal Ministry of Science and Technology), the construction data have been evaluated in a test experiment. Two 4"-CT steel...
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Personal Name(s): | Borchardt, G. |
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Lang, H. / Schneider, W. / Sievers, A. / Stelzer, F. / Weise, L. / Welzel, R. | |
Contributing Institute: |
Publikationen vor 2000; PRE-2000; Retrocat |
Imprint: |
Jülich
Kernforschungsanlage Jülich, Verlag
1976
|
Physical Description: |
IV, 88 p. |
Document Type: |
Report Book |
Research Program: |
Addenda |
Series Title: |
Berichte der Kernforschungsanlage Jülich
1344 |
Link: |
OpenAccess OpenAccess |
Publikationsportal JuSER |
For irradiations of large steel specimens which are planned in the framework of a research programme ("Reactor Components' Safety", projected by the German Federal Ministry of Science and Technology), the construction data have been evaluated in a test experiment. Two 4"-CT steel specimens arranged one upon another were put at the core edge of the research reactor FRJ-1 in such a manner that the radiation entered laterally. In the steel blocks 180 activation detectors have been placed for flux density determination of fast and epithermal neutrons, further 44 thermocouples for measurement of the temperature fields, one arrangement of 10 activation detectors to evaluate the neutron spectrum and 2 ionization chambers indicating the gamma-ray dose rate. In a second irradiation the steel blocks were surrounded from three sides by a lead shield, to measure its influence on the temperatures and flux densities within the specimens. The result was a decidedly flatter temperature profile in the cracking plane. The maximum temperature difference was 7 K with, resp. 23 K without the lead shield. The profiles of the neutron fluxdensities are not essentially influenced by the shield. It results from the measured flux density values that a fluence $\Phi^{f}_{Ni} \approx 1 \cdot 10^{19}cm^{-2}$ will be reached after 56 days at the chosen irradiation position in the central axis between the notches of the steel specimens, referring to a reactor power of 10 MW, if the specimens are rotated by 180° after one half of the irradiation time. Then the fluence will be about 35 % higher at the broadsides of the blocks than in the block centre. The resulting neutron spectrum shows that the real neutron fluence above 1 MeV in the block centre is about 85 % higherthan the above mentioned fictitious fission spectrum equivalent fluence $\Phi^{f}_{Ni}$ above 1 MeV which was obtained by the Nickel activation. The considerable deviation of the neutron spectrum in the steel compared with the spectrum in the moderator at the same reactor position demands the measurement of neutronsalready above 0.1 MeV for the monitoring of such steel irradiations. The results of the temperature measurements have been introduced as input values into an equation system for a threedimensional temperature field. From that the spatial distribution of heat sources, the boundary conditions of the heat transition and the temperature distribution has been calculated, the latter one in 605 nodal points of an inch-by-inch network of the block. The measured and calculated temperaturefields are in a good agreement. So the calculation model may be expected to give useful directions for the construction of steel irradiation capsules in different temperature fields. |