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Test results of Ya-21u thermionic space power system

Journal Article · · Nuclear Technology
OSTI ID:419727
;  [1]
  1. Univ. of New Mexico, Albuquerque, NM (United States)

The Soviet-made TOPAZ-II space nuclear power system unit designated Ya-21u underwent a total of 15 tests both in the Union of Soviet Socialist Republic (USSR) (1989--1990) and in the US (August 1993 to March 1995) for a cumulative test/operation time of 7681 h at conditions far exceeding design limits. These tests included steady-state operation at different power levels, fast start-ups and power optimizations, and shock and vibration tests. Test results are presented and analyzed. Results indicate a gradual change in the performance parameters such as the optimum cesium pressure and optimum load voltage. The electric power and conversion efficiency of the unit at an input thermal power of 105 kW decreased from 3.7 kW (electric) and 4% in the test in the USSR to 2.13 kW (electric) and 2.3% in the last test in the US. A discussion and qualitative assessment of potential causes of the performance changes of the Ya-21u unit are given.

OSTI ID:
419727
Journal Information:
Nuclear Technology, Journal Name: Nuclear Technology Journal Issue: 1 Vol. 117; ISSN 0029-5450; ISSN NUTYBB
Country of Publication:
United States
Language:
English

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