39 research outputs found
Interstellar OH+, H2O+ and H3O+ along the sight-line to G10.6-0.4
We report the detection of absorption lines by the reactive ions OH+, H2O+
and H3O+ along the line of sight to the submillimeter continuum source
G10.60.4 (W31C). We used the Herschel HIFI instrument in dual beam switch
mode to observe the ground state rotational transitions of OH+ at 971 GHz, H2O+
at 1115 and 607 GHz, and H3O+ at 984 GHz. The resultant spectra show deep
absorption over a broad velocity range that originates in the interstellar
matter along the line of sight to G10.60.4 as well as in the molecular gas
directly associated with that source. The OH+ spectrum reaches saturation over
most velocities corresponding to the foreground gas, while the opacity of the
H2O+ lines remains lower than 1 in the same velocity range, and the H3O+ line
shows only weak absorption. For LSR velocities between 7 and 50 kms we
estimate total column densities of (OH+) cm,
(H2O+) cm and (H3O+) cm. These detections confirm the role of O and OH in
initiating the oxygen chemistry in diffuse molecular gas and strengthen our
understanding of the gas phase production of water. The high ratio of the OH+
by the H2O+ column density implies that these species predominantly trace
low-density gas with a small fraction of hydrogen in molecular form
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Decommissioning Project of Bohunice A1 NPP
The first (pilot) nuclear power plant A1 in the Slovak Republic, situated on Jaslovske Bohunice site (60 km from Bratislava) with the capacity of 143 MWel, was commissioned in 1972 and was running with interruptions till 1977. A KS 150 reactor (HWGCR) with natural uranium as fuel, D2O as moderator and gaseous CO2 as coolant was installed in the A1 plant. Outlet steam from primary reactor coolant system with the temperature of 410 C was led to 6 modules of steam generators and from there to turbine generators. Refueling was carried out on-line at plant full power. The first serious incident associated with refueling occurred in 1976 when a locking mechanism at a fuel assembly failed. The core was not damaged during that incident and following a reconstruction of the damaged technology channel, the plant continued in operation. However, serious problems were occurring with the integrity of steam generators (CO2 gas on primary side, water and steam on secondary side) when the plant had to be shut down frequently due to failures and subsequent repairs. The second serious accident occurred in 1977 when a fuel assembly was overheated with a subsequent release of D2O into gas cooling circuit due to a human failure in the course of replacement of a fuel assembly. Subsequent rapid increase in humidity of the primary system resulted in damages of fuel elements in the core and the primary system was contaminated by fission products. In-reactor structures had been damaged, too. Activity had penetrated also into certain parts of the secondary system via leaking steam generators. Radiation situation in the course of both events on the plant site and around it had been below the level of limits specified. Based on a technical and economical justification of the demanding character of equipment repairs for the restoration of plant operation, and also due to a decision made not to continue with further construction of gas cooled reactors in Czechoslovakia, a decision was made in 1977 to terminate plant operation. The decision on the A1 plant decommissioning was issued in 1979