Different regression methods have been used to predict radon concentration in soil gas on the basis of environmental data, i.e. barometric pressure, soil temperature, air temperature and rainfall. ...Analyses of the radon data from three stations in the Krško basin, Slovenia, have shown that model trees outperform other regression methods. A model has been built which predicts radon concentration with a correlation of 0.8, provided it is influenced only by the environmental parameters. In periods with seismic activity this correlation is much lower. This decrease in predictive accuracy appears 1–7 days before earthquakes with local magnitude 0.8–3.3.
Anomalies have been observed in Rn content in soil gas from 3 boreholes at the Orlica fault in the Krško basin, Slovenia. To distinguish the anomalies caused by environmental parameters (air and soil ...temperature, barometric pressure, rainfall) from those resulting solely from seismic activity, the following approaches have been used: (i) deviation of Rn concentration from the seasonal average, (ii) correlation between time gradients of Rn concentration and barometric pressure, and (iii) regression trees within a machine learning program. Approach (i) is much less successful in predicting anomalies caused by seismic events than approaches (ii) and (iii) if ±2
σ criterion is used and is equally successful if ±1
σ is used. Approaches (ii) and (iii) did not fail to observe an anomaly preceding an earthquake, but show false seismic anomalies, the number of which is much lower with (iii) than with (ii). Model trees are shown to outperform other approaches. A model has been built which, in the seismically non-active periods when Rn is presumably influenced only by environmental parameters, predicts the concentration with a correlation of 0.8. This correlation is reduced significantly in the seismically active periods.
The nutritional habits of Neolithic farmers living during the period 6400 to 5300 years cal BP in the interior of Slovenia were determined using stable isotopes of carbon and nitrogen. Human and ...domesticated and wild animals bone collagen samples found in Ajdovska jama cave, as well as food residuals composed of wheat grains and plants in associated ceramics were isotopically analyzed. The results indicate that the human diet was based on foods of terrestrial origin consisting primarily of cereals and herbivores, most probably the domestic animals raised at that time. The significantly higher
δ
15N values found in infants and young children indicate “nursing effects”. The pattern of dietary habits rapidly changed in older children accorded similar dietary status as their parents.
Water samples were collected from 124 springs in Slovenia and analysed for tritium (3H). Tritium was enriched electrolytically and its concentration determined by liquid scintillation analysis. ...Tritium concentrations ranged from 325 to ca. 3000 Bq m–3, with a geometric mean of 1223 Bq m–3 and geometric standard deviation of 1.6. Although tritium concentrations in springs are generally low, they proved to be useful in qualitative assessment of recent recharge.
U posljednje vrijeme se u znanstvenim i stručnim krugovima učestalo raspravlja o pronalasku odgovarajuće lokacije za odlaganje radioaktivnog otpada. Ulaskom Republike Hrvatske u Europsku Uniju tema ...će se još više aktualizirati, a samo pitanje je politizirano s obzirom na činjenicu da nuklearnu elektranu Krško Republika Hrvatska dijeli sa susjednom Republikom Slovenijom. Sve potrebne studije o izboru pogodne lokacije odlagališta su već izrađene, a u njihovoj izradi su sudjelovali stručnjaci iz različitih područja. Također, svi stanovnici Republike Hrvatske bi trebali biti upoznati s tom tematikom na način dostupan široj javnosti i putem svih raspoloživih medija. Postavljaju se pitanja: Što su institucije poduzele po pitanju informiranja javnosti i može li to biti dovoljno? Kod odabira pogodne lokacije, uz brojne parametre, osnovni element je prikladna geološka formacija, iako bi lokacija odlagališta trebala biti prihvatljiva i u širim društveno javnim krugovima. Uvriježene metode koje se koriste pri odabiru prihvatljivih područja su analiza višekriterijskog odlučivanja (engl. MCDA - Multi Criteria Decision Analysis), geografski informacijski sustav (GIS) i kombinirana GIS-MCDA metoda. Primjena navedenih metoda je od velike pomoći pri donošenju odluke o lokaciji odlagališta radioaktivnog otpada. Prikaz rezultata, osmišljen u obliku otvorenog sustava potpore prostornom odlučivanju, pomogao bi edukaciji i informiranju šire javnosti.
In order to support the safe operation of the Krško Nuclear Power Plant (Westinghouse, 676
MW
e PWR), the seismotectonic structure of the Krško basin has been thoroughly investigated. As part of a ...wider study, a study on radon in soil gas was started in April 1999. Combined barasol detectors buried in six boreholes, two along the Orlica fault and four on either side of it, measure and record radon activity, temperature and pressure every 60
min. The results have been evaluated and the possibility of a correlation with seismic activity is discussed. Correlation between radon concentration and barometric pressure has been observed for all barasols. Preliminary results show that, at one location, the correlation coefficient between radon and barometric pressure changed sign before earthquakes.
The nuclear accident in Japanese plants in 2011 has initiated a quick response from the
countries utilizing a nuclear power. Krsko Nuclear Power Plant (NEK) was required by Slovenian
Nuclear Safety ...Administration (SNSA) to perform consequential actions to reduce the risk of severe
accidents and their consequences as low as feasible. NEK have analyzed the response to the severe
accidents, and based on the results of this analysis, proposed the measures to be implemented in the
shortest possible time.
In response to SNSA request NEK has developed the Safety Upgrade Program (SUP) which
contains a comprehensive set of measures for plant safety improvements. SUP Phase 1 has been
implemented during the Outage 2013.
This paper presents the work done on the evaluation of impact of plant modifications planned
for implementation in Phases 2 and 3 of NEK Safety Upgrade Program on the quantitative figure of
merit for the plant risk significance – total core damage frequency (CDF). A significance of the
most valuable measures in terms of contribution to the CDF reduction was determined and a new
fractional contribution of initiators categories was obtained.
The quantification of total CDF was made by employment of RiskSpectrum PSA code and
running a predefined set of analytical cases for all initiator categories covered by the scope of NEK
PSA model.
The basis for analysis was NEK’s most recent at-power PSA model which reflects the plant
status with plant modernization implemented in SUP Phase 1. The analysis was done in two steps.
In the first step plant modifications planned for SUP Phase 2 were addressed and in the second step
plant modernization measures and upgrades planned in SUP Phase 3 were modeled in addition to
those already modelled in the first step.
To improve the geologic model and test the approach, high-resolution seismic reflection methods were used in a re-evaluation study of earthquake hazard assessment at the Krško nuclear power plant ...(NPP) site. In a 13-km long profile recorded across the eastern part of the Krško basin (20-km long and 10-km wide), which is filled with up to 2 km of Neogene to Quaternary molasse sediments, the most prominent reflection was obtained from the top of the Badenian limestone, whereas the Mesozoic basement was less reflective. A syncline–anticline was interpreted that indicates a compressional tectonic style contrary to the prevailing hypothesis of a graben structure with normal border faults. In addition, very high-resolution shallow reflection profiling was performed at two locations close to the NPP for the detection of near-surface faults. Portable engineering seismic equipment was used for data acquisition to reduce costs and enable measurements in areas with difficult access. Geophone arrays were necessary for the suppression of strong ground roll and guided waves generated in the thick layer of dry gravel. Serious spatial aliasing of ground-coupled air-waves precludes
f-k filtering, necessitating the application of an internal mute. Two new subvertical normal faults with displacements of 50 and 80 m at the middle/upper Miocene interface were interpreted in the central part of the basin, while other faults, suggested by surface geological observations, were not confirmed. The further north of the two faults was traced in Pliocene–Quaternary deposits to a depth of 250 m. Reinterpretation of old analogue oil-exploration seismic profiles and gravity modelling has allowed the extension of results to a wider area. In the very high-resolution profile, recorded 0.5-km east of the NPP site, some discontinuities in reflections were established that were interpreted as faults. The possible vertical displacement at the sand (Pl, Q)/marl (Pl) interface is 7 m. The new structural-tectonic data obtained in the vicinity of the NPP requires essential changes to the model for earthquake hazard assessment.
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