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Title: General-Purpose Heat Source Development: Safety Verification Test Program. Flyer plate test series

Abstract

The General-Purpose Heat Source (GPHS) is a modular component of a radioisotope thermoelectric generator (RTG) that will provide electric power for space missions. The initial RTG applications will be for the NASA Galileo and the ESA Ulysses missions. Each of the 18 GPHS modules in an RTG contains four /sup 238/PuO/sub 2/-fueled clads and generates 250 W/sub (t)/. A series of Safety Verification Tests (SVTs) has been conducted to assess the ability of the GPHS fueled clads to contain the plutonia in accident environments. Because a launch pad or postlaunch explosion of the Space Transportation System Vehicle (space shuttle) is one conceivable accident, the SVT plan included a series of tests to simulate the fragment environment that the RTG and GPHS modules would experience in such an event. These tests deal specifically with the flat-on collision of flyer-plate-type fragments with bare, simulant-fueled (depleted UO/sub 2/) clads. Results of these tests suggest that the fueled clad is only minimally breached by collision with 3.53-mm-thick flyer-plate-type fragments of space shuttle alloy at velocities up to 1170 m/s. However, collision of a 38.1-mm-thick plate with a bare GPHS clad, at a velocity of 270 m/s, results in a total release of fuel.

Authors:
;
Publication Date:
Research Org.:
Los Alamos National Lab., NM (USA)
OSTI Identifier:
6908353
Alternate Identifier(s):
OSTI ID: 6908353; Legacy ID: DE87002234
Report Number(s):
LA-10742-MS
ON: DE87002234
DOE Contract Number:
W-7405-ENG-36
Resource Type:
Technical Report
Resource Relation:
Other Information: Portions of this document are illegible in microfiche products. Original copy available until stock is exhausted
Country of Publication:
United States
Language:
English
Subject:
07 ISOTOPES AND RADIATION SOURCES; RADIOISOTOPE BATTERIES; IMPACT TESTS; SAFETY; SPACECRAFT POWER SUPPLIES; ACCIDENTS; EXPLOSIONS; PLUTONIUM DIOXIDE; SPACE SHUTTLES; TEST FACILITIES; THERMOELECTRIC GENERATORS; ACTINIDE COMPOUNDS; AIRCRAFT; CHALCOGENIDES; DIRECT ENERGY CONVERTERS; ELECTRONIC EQUIPMENT; EQUIPMENT; MATERIALS TESTING; MECHANICAL TESTS; OXIDES; OXYGEN COMPOUNDS; PLUTONIUM COMPOUNDS; PLUTONIUM OXIDES; POWER SUPPLIES; SPACE VEHICLES; TESTING; TRANSURANIUM COMPOUNDS; VEHICLES NESDPS Office of Nuclear Energy Space and Defense Power Systems 070300* -- Isotopic Power Supplies

Citation Formats

Cull, T.A., and Pavone, D. General-Purpose Heat Source Development: Safety Verification Test Program. Flyer plate test series. United States: N. p., 1986. Web. doi:10.2172/6908353.
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Cull, T.A., & Pavone, D. General-Purpose Heat Source Development: Safety Verification Test Program. Flyer plate test series. United States. doi:10.2172/6908353.
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Cull, T.A., and Pavone, D. Mon . "General-Purpose Heat Source Development: Safety Verification Test Program. Flyer plate test series". United States. doi:10.2172/6908353. https://www.osti.gov/servlets/purl/6908353.
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@article{osti_6908353,
title = {General-Purpose Heat Source Development: Safety Verification Test Program. Flyer plate test series},
author = {Cull, T.A. and Pavone, D.},
abstractNote = {The General-Purpose Heat Source (GPHS) is a modular component of a radioisotope thermoelectric generator (RTG) that will provide electric power for space missions. The initial RTG applications will be for the NASA Galileo and the ESA Ulysses missions. Each of the 18 GPHS modules in an RTG contains four /sup 238/PuO/sub 2/-fueled clads and generates 250 W/sub (t)/. A series of Safety Verification Tests (SVTs) has been conducted to assess the ability of the GPHS fueled clads to contain the plutonia in accident environments. Because a launch pad or postlaunch explosion of the Space Transportation System Vehicle (space shuttle) is one conceivable accident, the SVT plan included a series of tests to simulate the fragment environment that the RTG and GPHS modules would experience in such an event. These tests deal specifically with the flat-on collision of flyer-plate-type fragments with bare, simulant-fueled (depleted UO/sub 2/) clads. Results of these tests suggest that the fueled clad is only minimally breached by collision with 3.53-mm-thick flyer-plate-type fragments of space shuttle alloy at velocities up to 1170 m/s. However, collision of a 38.1-mm-thick plate with a bare GPHS clad, at a velocity of 270 m/s, results in a total release of fuel.},
doi = {10.2172/6908353},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Sep 01 00:00:00 EDT 1986},
month = {Mon Sep 01 00:00:00 EDT 1986}
}
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Technical Report:
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DOI:  10.2172/6908353
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  • The radioisotope thermoelectric generator (RTG) that will supply power for the Galileo and Ulysses space missions contains 18 General-Purpose Heat Source (GPHS) modules. The GPHS modules provide power by transmitting the heat of STYPu -decay to an array of thermoelectric elements. Each module contains four STYPuO2-fueled clads and generates 250 W(t). Because the possibility of a launch vehicle explosion always exists, and because such an explosion could generate a field of high-energy fragments, the fueled clads within each GPHS module must survive fragment impact. The edge-on flyer plate tests were included in the Safety Verification Test series to provide informationmore » on the module/clad response to the impact of high-energy plate fragments. The test results indicate that the edge-on impact of a 3.2-mm-thick, aluminum-alloy (2219-T87) plate traveling at 915 m/s causes the complete release of fuel from capsules contained within a bare GPHS module, and that the threshold velocity sufficient to cause the breach of a bare, simulant-fueled clad impacted by a 3.5-mm-thick, aluminum-alloy (5052-T0) plate is approximately 140 m/s.« less

  • ; ;
    The General-Purpose Heat Source (GPHS) is a modular, radioisotope heat source that will be used in radioisotope thermoelectric generators (RTGs) to supply electric power for space missions. The first two uses will be the NASA Galileo and the ESA Ulysses missions. The RTG for these missions will contain 18 GPHS modules, each of which contains four /sup 238/PuO/sub 2/-fueled clads and generates 250 W/sub (t)/. A series of Safety Verification Tests (SVTs) was conducted to assess the ability of the GPHS modules to contain the plutonia in accident environments. Because a launch pad or postlaunch explosion of the Space Transportationmore » System vehicle (space shuttle) is a conceivable accident, the SVT plan included a series of tests that simulated the overpressure exposure the RTG and GPHS modules could experience in such an event. Results of these tests, in which we used depleted UO/sub 2/ as a fuel simulant, suggest that exposure to overpressures as high as 15.2 MPa (2200 psi), without subsequent impact, does not result in a release of fuel.« less

  • The radioisotope thermoelectric generator (RTG) that will provide power for the Galileo and Ulysses space missions contains 18 General-Purpose Heat Source (GPHS) modules. Each module contains four /sup 238/PuO/sub 2/-fueled clads and generates 250 W(t). Because the possibility of launch-pad or postlaunch explosion exists and because any explosion would generate a field of high-energy fragments, the fueled clads within each GPHS module must be able to survive fragment impact. In this test series we investigated the response of bare, simulant-fueled (UO/sub 2/) clads to the impact of high-energy titanium alloy fragments. We determined that 425m/s is the threshold impact velocitymore » of a 3.25-g titanium bullet that will cause direct mechanical failure of a bare fueled clad. 40 figs.« less

  • ; ;
    The radioisotope thermoelectric generator (RTG) that will provide power for space missions contains 18 General-Purpose Heat Source (GPHS) modules. Each module contains four /sup 238/PuO/sub 2/-fueled clads and generates 250 W/sub (t)/. Because a launch-pad or post-launch explosion is always possible, we need to determine the ability of GPHS fueled clads within a module to survive fragment impact. The bullet/fragment test series, part of the Safety Verification Test Plan, was designed to provide information on clad response to impact by a compact, high-energy, aluminum-alloy fragment and to establish a threshold value of fragment energy required to breach the iridium cladding.more » Test results show that a velocity of 555 m/s (1820 ft/s) with an 18-g bullet is at or near the threshold value of fragment velocity that will cause a clad breach. Results also show that an exothermic Ir/Al reaction occurs if aluminum and hot iridium are in contact, a contact that is possible and most damaging to the clad within a narrow velocity range. The observed reactions between the iridium and the aluminum were studied in the laboratory and are reported in the Appendix.« less

  • ;
    The General-Purpose Heat Source (GPHS) provides power for space missions by transmitting the heat of {sup 238}Pu decay to an array of thermoelectric elements. Because any space mission could experience a launch abort or return from orbit, the heat source must be designed and constructed to survive credible accident environments. Previous testing conducted in support of the Galileo and Ulysses missions documented the response of GPHSs and individual GPHS capsules fueled with {sup 238}UO{sub 2} ({sup 235}U-depleted) to a variety of explosive overpressure and impact events. In the early 1990s, Los Alamos National Laboratory (LANL) resumed fabrication of {sup 238}UO{submore » 2} GPHS pellets. The Cold-Process Verification (CPV) Test Series was designed to compare the response of GPHS heat sources loaded with recently fabricated hot- and cold-pressed {sup 238}UO{sub 2} pellets to the response of urania pellets used in the Galileo and Ulysses performance tests. This report documents eleven bare-capsule impacts and one impact of a fully loaded GPHS module. All of the failures observed in the bare-clad impact tests were similar to failures observed in previous safety tests. No failures occurred in the module impact test.« less