Gamma spectrometry in continuous monitoring of the impurity concentration in the coolant of a reactor circuit

Institute of Nuclear Energy, Academy of Sciences of the Belorussian SSR. Translated from Atomnaya Énergiya, Vol. 70, No. 3, pp. 176–177, March, 1991.     

Decontamination of the reactor coolant pump in Maanshan nuclear power plant

To reduce the radiation dose that accumulated on the reactor coolant pump, decontamination work was carried out at the Maanshan Nuclear Power Plant. A four-step alkaline permanganate (AP)-CanDecon process was applied to remove the activity on the turning vane diffuser and pump impeller. The first step consisted of 8 h of AP treatment and 7 h of decontamination. It was followed by 2.5 h of AP treatment and 5 h of decontamination. An average decontamination factor of 2.9 was obtained. To understand the corrosion of the decontaminating reagents on the materials, coupons were installed in the decontamination tank. These were as-received and sensitized 304SS, alloy 600, casting stainless steel (CF-8), stellite-6, and carbon steels (A508 and A533). The exposure rates (mR h⁻¹) of the carbon steels were approximately five times higher in magnitude than those of the other materials. The decontamination levels (dpm per 100 cm²) of the A508 and A533 carbon steels were 5432 and 3701 respectively, while most of the rest of the materials were below the low limit of detection. Apparently, the corrosion product on the materials was a major factor in sustaining the exposure rate and the contamination level. The corrosion rate of the materials was also examined and compared with published data. An examination of the surface morphology of the materials after decontamination showed intergranular attack on the 304 stainless steel.     

New concept for the vessel of a nuclear power reactor with supercritical coolant parameters

A multiwall design, akin to a Russian nested doll, of a nuclear reactor vessel is described. This design is intended for reactors with supercritical coolant parameters. The interwall gaps of a multiwall vessel are hydraulically connected with the reactor coolant via a separative device. A system of pressure regulators distributes the coolant pressure successively over the gaps in a manner so that in the operating regime a wall would be under the optimal nominal stress. To eliminate any danger of the vessel collapsing in the event that the counter pressure system malfunctions, ribbed rings with axial channels are tightly installed in the gaps between the walls. This makes it possible to freely fill the gaps in the vessel with a working body, for example, water. In the event that the counterpressure system fails the multiwall vessel is automatically converted into a multilayer wall, which eliminates the possibility of the vessel being destroyed. To increase the reliability of such a vessel, one or two additional walls, which can carry a load, for example, at the end of operation when the inner walls, which are subjected to the highest neutron irradiation, partially lose their strength, are installed in the vessel. Translated from Atomnaya énergiya, Vol. 105, No. 6, pp. 322–325, December, 2008.     

Design calculations for valves which control the flow of coolant in channels in a nuclear reactor

In designing the valves which control the coolant flow in the channels of a tube reactor one must choose an appropriate shape for the plunger. In the present paper a method is given for plotting the control curve for the coolant flow using the experimental characteristics of the valve; a method is also given for determining the shape of the plunger required to fit a given control curve. As an example, we present a calculation for the shape of a plunger with and without ball check.     

Concept and salient design features of a high-temperature nuclear reactor with solid coolant

The salient features of using a solid substance to cool the core of a nuclear reactor and the associated advantages and limitations are examined. Conceptual proposals concerning the core design and the arrangement of the in-reactor space of a high-temperature nuclear reactor with a solid coolant are presented. Evaluated data and some results for a model reactor are presented. __________ Translated from Atomnaya énergiya, Vol. 103, No. 3, pp. 156–161, September, 2007.     

The nuclear reactor circulation circuit as a radiation source

The solution of the problem of circulation circuits with a single radioisotope, which has been found earlier [1], is applied to the general case where several radioisotopes having radioactive progeny are formed in the substance to be activated. The problems of the absolute maximum circuit power and the consumption of neutrons per unit power for a number of elements which can be used as substances to be activated in the circuit are considered. From among them, the most promising are indium and its alloys.Special attention is paid to a circulation circuit where the substance to be activated contains a fissionable isotope (uranium circuit). It is shown that the specific power of such a circuit, all other conditions being equal, is considerably lower than the specific power of circuits with metallic indium or its alloys. As a particular case of a uranium circuit, the circulation from the reactor into the radiation unit,and the reverse,of fuel elements which have not burned up completely is considered. It is shown that, in this case, the power of the unit can be increased two- to fourfold in comparison with the power of a unit, which makes a single use of completely burned-up fuel elements.     

Gas-transfer kinetics and regulation of the gas content of coolant in the first loop of a water-cooled-water-moderated reactor

OKBM. Translated from Atomnaya Énergiya, Vol. 72, No. 6, pp. 554-559, June, 1992.