Experience in the operation of channels with single-pass steam generation in the reactor at the first nuclear power station

Conclusions The reactor tests of fuel elements with heat-exchange intensifiers, operating with full evaporation of the water, with superheated steam, and without the use of an intermediate separator, shows that it is possible in principle to design a single-pass steam generator in reactors with tubular fuel elements.The operations for regulating the parameters in the steady-state regimes have been worked out, and the nature of variations in the heat-engineering parameters under transient conditions has been studied.During the tests (125 days for channel 2) no significant variations in the temperatures of the fuel elements were observed, which directly confirmed the absence of any marked deposition due to boiling on the heat exchange surfaces (even when using relatively poor quality water).It has been established that the fluctuations in reactor power within the dead zone of the power regulator give rise to instabilities in the temperature regime of the fuel elements. Under these circumstances, the temperature fluctuations in the transition zone of heat transfer are significant. To reduce these fluctuations in fuel element temperature in the transition zone, we should reduce the dead zone of the power regulator, use fuel elements of lower power for the part of the evaporation channel containing the heat-transfertransition zone, and increase the heat transfer to steam by increasing the mass flow in the fuel elements within the transition zone. Just these measures alone can reduce the amplitude of the fluctuations of fuel element temperature to a safe level.In our opinion, bearing in mind all the limitations of the experiments, the results achieved are of interest for assessing the prospects of single-pass steam generators in power reactors. The absence of traditional equipment in the form of drum separators and circulating pumps, which are difficult and expensive to manufacture, to a large extent simplifies the nuclear steam-generating plant, and reduces its cost.Translated from Atomnaya Énergiya, Vol. 41, No. 2, pp. 75–81, August, 1976.     

Production of auto-body dual-phase steel with single-step cooling on the output conveyer of the 2000 continuous broad-strip mill at OAO NLMK

The goal is to produce hot-rolled dual-phase steel of strength class DP 450–600 at OAO Novolipetskii Metallurgicheskii Kombinat (NLMK). The steel’s final structure and properties is greatly affected by single-stage strip cooling on the output roller conveyer of the 2000 continuous broad-strip mill. The influence of the hot-rolling parameters on the structure and mechanical properties of the hot-rolled SPRC440R steel from which cold-rolled dual-phase steel is produced at OAO NLMK is studied in the laboratory. The temperatures and rates for accelerated cooling on the output roller conveyer of the 2000 continuous broad-strip mill at OAO NLMK are calculated by means of a mathematical model. The laboratory data and simulation results are used in developing trial conditions for industrial rolling. Recommendations are made regarding the production of hot-rolled dual-phase steel corresponding to strength class DP 450–600.