Bilibino Nuclear Power Research Articles

Special Features of the Statistical Processing of Seal Monitoring Data on Fuel-Cell Cladding in the ÉGP-6 Reactors at the Bilibino Nuclear Power Plant

The results of a statistical analysis of the indications of the seal-monitoring system for the outer cladding of the fuel elements in the fuel assemblies of the EGP-6 reactors at the Bilibino nuclear power plant are presented. It is shown that the distribution of the indications deviates substantially from the normal law, approaching the log-normal law. It is suggested that this phenomenon is due to seepage of reactor gas into the gas channels of a fuel assembly through the gaps between the graphite sleeves of the assemblies.

Radiological investigations in the surroundings of Bilibino, Chukotka, Russia

This paper presents the results of radiological investigations in different parts of Chukotka comprising especially the Bilibino area. About 70 samples including sediments, soils, lichens, mosses, and reindeer meat and bones were measured. 137 Cs ground contamination measured on several locations in Chukotka, NE Siberia, ranges between 586 and 1243 Bq/m 2 (reference date 1 Sept 1994), with a mean of 850 Bq/m 2 and a coefficient of variation (1 sigma) of 27%. No 134 Cs was detected; from its lower level of detection, a possible contribution of Chernobyl releases to total 137 Cs fallout of less than 48 Bq/m 2 could be derived. 90 Sr and 239,240 Pu contaminations were found to be 510±42% and 19±47% Bq/m 2, respectively. Natural radionuclides were determined to be 564±15% Bq/kg dry soil for 40 K , 29±32% for 226 Ra and 33±25% for 228 Ra , which is within normal levels. The highest plant contaminations were found in moss and lichen, with 137 Cs up to 75 and 46 Bq/kg d.m. respectively, in remote areas, and 91 and 103 Bq/kg, respectively, in the vicinity of the Bilibino nuclear power plant (NPP). Near the NPP, significant traces of 60 Co, 54 Mn and 51 Cr were also found in certain soil, plant and sediment samples, as well as enhanced levels of 137 Cs, 90 Sr and 239,240 Pu . In sediments from the floodplain where the waste water of the NPP is discharged, 60Co and 239,240Pu contaminations up to 120 and 34 Bq/kg dm., respectively, and gamma dose rates up to 10 μSv/h were found, compared to a 0.1–0.2 μSv/h background level typical for the region. Two samples of reindeer meat (September 1994 harvest) showed 137 Cs contaminations of 9.0 and 28.4 Bq/kg fresh weight. Taking into account that meat obtained from reindeer slaughtered in winter contains more 137 Cs , the mean activity concentration in meat calculated for 1 year of production is 74 Bq/kg f.w. Apart from the vicinity of the NPP, the anthropogenic radioactive contamination of the region seems to be somewhat lower than expected from mean global fallout levels typical for the geographical latitude according to UNSCEAR data, but is in good accordance with AMAP figures ( Strand et al., 1998). Due to the tundra food-chain, a certain exposure of the local population to anthropogenic radionuclides can be anticipated. A rough calculation (after Strand et al., 1998) based on the reindeer samples and taking into account the well-known seasonal variation of reindeer contamination, dietary habits of the indigenous population and, finally, external radiation resulted in an individual committed effective dose of 18–70 mSv (integrated from 1950 to infinite time) from atomic bomb fallout for the indigenous population, depending on the amount of reindeer meat consumed (90–350 kg/year per person). The individual dose rates today are about 0.1–0.4 mSv/year. For the non-indigenous people, the individual committed effective dose is only about one tenth, viz. 6.6 mSv, and the dose rate today about 0.03 mSv/year.

Atmospheric transport pathways from the Bilibino nuclear power plant to Alaska

The Bilibino nuclear power plant (68°03′N, 166°20′E, 340 m asl) in northeastern Siberia is the closest Russian nuclear power plant to the USA. We used an isentropic trajectory model to estimate the probability that air in the Bilibino region would be transported to Alaska following a hypothetical accident. This estimate is based on the meteorological data from 1991 to 1995. Our calculations indicate that the probability that air in the Bilibino region will be transported to Alaska is approximately 6–16%, averaged over the entire year. This probability doubles in the summer and early fall with a maximum in August of 12–33%. For the entire year the mean, median, and minimum transport times from the plant to Alaska are 4, 3.5 and 1 d, respectively. Since rapid transport (1–2 d) could bring air parcels containing short-lived radionuclides, these events potentially represent the greatest risk to inhabitants of Alaska.

Taking account of spatial effects in measurements of the effectiveness of control rods in the reactors at the bilibino nuclear power plant

The effect of deformation induced in the neutron flux by the introduction of negative reactivity on the indications of a reactimeter is considered for the EGP-6 reactor at the Bilibino nuclear power plant. The approach to determining the reactivity, specifically, an accurate approximation of the solution of the kinetic equation, remains unchanged, but a computational correction is introduced in the reactimeter indications. The calculation of the correction is based on the computational determination of the change in the neutron flux at the location of the neutron detector and on the computational simulation of the operation of a reactimeter. The calculations are compared with measurements. 2 figures, 1 table, 6 references.

Justification for extending the operation of the graphite cladding in the reactors of the bilibino nuclear power station

in Table 1. In addition to these samples, control samples were drilled from a reserve block. Nondestructive monitoring methods were used to determine certain characteristics of the cores and of the unirradiated control samples, including the volume density (dk)i the thermal conductivity (~,), the electrical resistivity (9), and the dynamic modulus of elasticity of the first kind (E). The thermal conductivity determined at room temperature was scaled to the operating temperature. The compressive strength was determined with 10-mm high samples cut from the cores with a diamond wheel. In addition, 6-mm diameter 10-17-mm high rods were drilled out of the cores in order to determine the linear expansion coefficient (ct) in the range from -196 to +20~ The values of ct were scaled for the operating temperature. The same rods were used to make 8-ram high samples for tests of compressive loading. Powder was employed for x-ray analysis with a DRON-3 diffractometer using Cu K s radiation. A determination was made of the C lattice parameters, the height L c of the crystals, and the degree of graphitization. The control samples of unirradiated graphite of the same dimensions were simultaneously tested. The largest spread in the characteristics was less than 14%. Table 2 gives the averaged properties of the irradiated and control samples of t~GP-6 graphite at room temperature together with data from [3] and the characteristics of standard reactor graphite [4]. It is well known that there are laws governing the relative changes in the properties of irradiated graphite from their original values [5]. The relative change in the lattice parameters, in the compressive strength, and in the thermal resistance of artificial graphite are, to a first approximation, independent of their initial values. The relative changes in the electrical resistivity and in the dynamic elasticity modulus are inversely proportional to their initial values. The relative change in the coefficient ct is related to the degree of graphitization. For better quality graphite Atx/~ < 0 at 550-600~ Since there are no data

Void coefficient of ÉGP-6 reactors at the Bilibino nuclear power plant

Void coefficient of ÉGP-6 reactors at the Bilibino nuclear power plant

Characteristics of the indications of the system monitoring the vacuum seal of the fuel element claddings in separate fuel assemblies in the reactors at the bilibino nuclear power plant

Characteristics of the indications of the system monitoring the vacuum seal of the fuel element claddings in separate fuel assemblies in the reactors at the bilibino nuclear power plant

Anthropogenic radioactivity in the vicinity of the Bilibino nuclear power station, Chukotka, Russia1

Abstract During vegetation, soil, and water sampling conducted in 1995, we were unable to confirm previous reports that the Bilibino Nuclear Power Station in the Russian Far East is a significant source of anthropogenic radioactivity to the surrounding region. A localized area of radionuclide contamination was observed for at least 400 m downstream of an effluent discharge point into a small stream, underlain by permafrost, which drains the area surrounding the power plant. It appears likely that the localized contamination observed is the result of poor drainage and the lack of adequate mixing of the discharge, rather than radionuclide discharges that are abnormally high. Radionuclides such as Co and 5 Mn that are associated with nuclear energy generation also were detected on upland vegetation at distances of 700 m (<100 Bq/kg dry weight) to 4 km (<10 Bq/kg dry weight) from the power station, indicating that airborne releases from the power plant also contribute to the overall radionuclide burden. Total...

The internal power-distribution monitor system in the reactors at the Bilibino Nuclear Power Station

The internal power-distribution monitor system in the reactors at the Bilibino Nuclear Power Station

Bilibino nuclear power station

Bilibino nuclear power station