ALKACYCL: a basic computer program for the analysis of alkali metal Rankine power cycles

ALKACYCL is a computer program that analyzes Rankine power cycles utilizing an alkali metal as the cycle working fluid. Cycles may have from zero to three stages of regenerative feed heating. The program is written in BASICA language and can be used on an IBM-PC or PC-compatible computer with 128 kbytes of RAM. Output results include mass and energy balance information, cycle efficiency, and sizes and weights for piping and feed heaters. Listing and sample program output are included

INVESTIGATION OF EFFECT OF SEAL CONFIGURATION ON MIXING FLOW AND RADIATION DAMAGE IN HRT-TYPE CIRCULATING PUMPS. Supplement No. 1

The effect of seal configuration on the rate of mixing flow between the impeller cavity and the motor cavity of a Westinghouse Model 400 A pump was extended to include a configuration wherein the lower radinl bearing acts as a secondary seal. This arrangement increases the life of the motor windings; however, the life of the lower radial and thrust bearings is shortened because of inadequate cooling. (J.E.D.

Nuclear alkali metal Rankine power systems for space applications

Nucler power systems utilizing alkali metal Rankine power conversion cycles offer the potential for high efficiency, lightweight space power plants. Conceptual design studies are being carried out for both direct and indirect cycle systems for steady state space power applications. A computational model has been developed for calculating the performance, size, and weight of these systems over a wide range of design parameters. The model is described briefly and results from parametric design studies, with descriptions of typical point designs, are presented in this paper

INVESTIGATION OF EFFECT OF SEAL CONFIGURATION ON MIXING FLOW AND RADIATION DAMAGE IN HRT-TYPE CIRCULATING PUMPS

Tests using a Westinghouse 400A canned motor circulating pump with various motor to impeller seal configurations are described. A configuration was found which allows very low flow rates and increases pump life. (T.R.H.

INVESTIGATION OF MECHANICAL METHODS OF SCALE REMOVAL FROM HRT HEAT EXCHANGERS

Tests were conducted to determine methods of removing scale deposits from the HRT heat exchangers. A mockup of the heat exchanger header was cleared of a deposit of iron rust by reverse flushing at a flow rate below 75 gpm. A tube bundle consisting of 109 1/4 in OD X 0.049 in. wall tubes was plugged with rust. Approximately 80% of these tubes were unplugged by using a 70 psi water pressure differential in combination with vibration from a pneumatic rivet gun. No mechanical method was employed in the tests which could clear the remaining tubes. (auth

Global urban environmental change drives adaptation in white clover

Urbanization transforms environments in ways that alter biological evolution. We examined whether urban environmental change drives parallel evolution by sampling 110,019 white clover plants from 6169 populations in 160 cities globally. Plants were assayed for a Mendelian antiherbivore defense that also affects tolerance to abiotic stressors. Urban-rural gradients were associated with the evolution of clines in defense in 47% of cities throughout the world. Variation in the strength of clines was explained by environmental changes in drought stress and vegetation cover that varied among cities. Sequencing 2074 genomes from 26 cities revealed that the evolution of urban-rural clines was best explained by adaptive evolution, but the degree of parallel adaptation varied among cities. Our results demonstrate that urbanization leads to adaptation at a global scale