Digital Correction of Readings Produced by Fluid Level Measurement Channels at NPPs Equipped with Sensors Having a Dead Zone

The introduction and development of computerized digital systems in modern power engineering has led in Russia to a full modernization of domestically produced nuclear power plant measurement systems. In particular, digital methods for correcting the readings of hydrostatic level sensors have been widely put in use since 2013. The experience gained from putting them in use was generalized in the reference and organizational and methodological literature in 2017. However, the subsequent results of preoperational adjustments carried out at newly designed nuclear power units and at those under construction have shown that some issues still remain unresolved in this application field. In particular, there is a need is to develop digital methods for correcting the readings produced by channels measuring the level of liquid media in pressurized process tanks if there occurs a sensor dead zone. The complexity of this problem is stemming from the fact that it is not possible to take the sensor dead zone into account by introducing a constant correction to the measurement channel readings in view of the technological process peculiarities. Thus, during the operation of nuclear power units, the water density in pressurized process tanks and vessels decreases from 980 to 590 kg/m3, and the vapor density increases from 0 to 100 kg/m3. Such changes give rise to complex thermal and physical interphase processes that occur under the conditions of large mass transfers of the vapor--water mixture. As a result, the sensor's dead zone boundary undergoes an essential change in the tank longitudinal section depending on the current values of the working fluid thermal and physical characteristics. To solve this problem, digital methods for online correction of measured level readings are proposed that take into account changes in the two-phase working medium (vapor--water) in the course of a continuous technological process. Nowadays, the introduction of digital methods for correcting the hydrostatic level sensor readings is especially relevant in connection with the development of industry programs aimed at increasing the capacity of newly designed and operating nuclear power units, which pose more demanding requirements to the accuracy of thermal and physical measurements and operational safety as a whole.

CORRELATION OF THE RELIEF CONDITIONS, HYDROGRAPHIC NETWORK FEATURES AND HUMAN INTERVENTIONS WITHIN THE BLAHNIŢA RIVER BASIN (SOUTHWESTERN ROMANIA)

Significance of rivers within plains is increasing nowadays as hydrographic network has become one of the most important strategic axes. The objective of the present study is to highlight the evolution of the Blahniţa River and the adjacent hydrographic network (in relation to the hydrostatic level of the groundwater aquifer) in the context of current modeling (natural and anthropogenic) of the entire river basin. The results are a step forward towards understanding the degree of anthropogenic transformation of a hydrographic network. The digital data obtained from the analysis of the cartographic documents contributed to the identification of hydrographic network along the considered period (1978-2020) with the presentation on four stages of the evolution under the anthropogenic interventions such as: construction of the irrigation system, drainage of the ponds, regularization and earth dams along the Blahnița River and channalization of the Blahniţa course. The geomorphological analysis of the relief conditions was based on the study of the hypsometry variation at the level of the entire hydrographic basin, especially along the watercourse. In this sense, the results highlight the importance of slope for surface flowing: the slope of the Blahniţa river basin presents values of 4 to 2o/oo to the confluence with Orevița and values from 1.8 to 0.06o/oo to the exit from the plain to the Danube Floodplain. The importance of this research consists in rising a red flag on former wetlands that have been dried up, which are currently undervalued and which may be true ecosystems for sustaining habitats in the future.

ANALISIS PENURUNAN PADA TIMBUNAN DENGAN PREFABRICATED VERTICAL DRAIN (PVD) MENGGUNAKAN DATA HASIL UJI CPTu

Investigation of soil is important to do in the planning of building construction such as foundations, piles, roads, etc. To find out the bearing capacity and parameters of the soil where a building will be built. Investigation of the soil can be done in various ways, one of which uses an electrical cone penetration test with pore water pressure. In the embankment project for the calculations on the soil so that it can be known about the settlement in soil and the length of time it reaches the hydrostatic level. Cone penetraton test is reqired and the results produce data in the form of cone resistance (qc), blanket friction (fs) and pore pressure (u) which will be processed in the CPET-IT program in order to produce soil parameters that will be used for soil settlement analysis. To find out the settlement of embankment soil, it will be supported by finite difference program. Results of studies on general is to find the effectiveness of embankment using prefabricated vertical drain (PVD) and without prefabricated vertical drain (PVD).AbstrakPenyelidikan terhadap tanah penting untuk dilakukan pada perencanaan konstruksi bangunan seperti pondasi, timbunan, jalan, dll. Untuk mengetahui daya dukung dan parameter-parameter tanah tempat akan dibangunnya sebuah bangunan Penyelidikan tanah dapat dilakukan dengan berbagai macam cara salah satunya adalah menggunakan uji sondir elektrik dengan tekanan air pori. Pada proyek timbunan memerlukan perhitungan pada tanahnya agar dapat diketahui besarnya penurunan pada tanah dan lama waktu tanah mencapai keadaan hidrostatis. Sehingga dilakukan uji sondir secara elektrik dan dari hasil uji sondir menghasilkan data berupa tahanan konus (qc), gesekan selimut (fs) dan pore pressure (u) yang akan diolah kedalam program CPET-IT agar menghasilkan parameter-parameter tanah yang akan digunakan untuk analisis penurunan pada tanah.Untuk mengetahui besarnya penurunan pada tanah timbunan maka akan dibantu program berbasis elemen higga. Hasil studi secara umum menunjukkan seberapa besar efektivitas pada timbunan dengan menggunakan prefabricated vertical drain (PVD) dan tanpa prefabricated vertical drain (PVD).

Control of surface subsidence based on building deformation monitoring data

This paper presents an approach to the estimation of ground surface distortion based on the data from the online deformation monitoring systems mounted on the foundations of the group of buildings located in the area of ground instability. The local monitoring systems provide control of building foundation settlements using the hydrostatic level measurement technique. These data are used to calculate the inclination foundation angles which reflect the distortion of the earth's surface at local points. The hydrostatic level system allows one to perform measurements with the desired space and time sampling and to obtain a quite detailed picture of the changes in the deformation parameters over time. A set of such local monitoring units forms a distributed system that allows monitoring the state of the earth's surface over a large area. Here, we present long-term results obtained using such system located in the city area above mining. The evolution of the inclination angles of the group of overlying buildings is shown. We discuss the validity of this approach, and estimate the accuracy of the measuring method and the factors that influence it. Finally, we assess the possibility of making short-term predictions of deformation processes inside the rock massif.