Document Details
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Title:
SNAP-15C Program - Large Milliwatt Radioisotope Power Supply, Progress Letter Number 37
Author(s):
Document Type:
REPORT
Publication Date:
1968 Aug 01
Declassification Date:
2009 Jan 07
Declassification Status:
Declassified
Document Pages:
29 p.
Accession Number:
None
Document Number(s):
MMM-3209-61
Originating Research Org.:
Minnesota Mining and Manufacturing Company, St. Paul, MN (United States)
OpenNet Entry Date:
2017 Dec 13
OpenNet Modified Date:
2023 Nov 03
Description/Abstract:
Testing of five SNAP-15C series B design power supplies (with copper hot electrodes) has been conducted continuously for more than one year to evaluate long-term performance of these units. One additional PU-238 fueled unit (3M-31BF5) of similar design (with steel hot electrodes) has been included in the test program; this unit has been operating continuously for approximately 1500 hours. Data observed from the five long-term devices illustrates relative stability of power output for more than six months. In particular, three fueled units (3M-31BF1, 3M-31BF3, and 3M-31BF4) have exhibited an extremely slow rate of power decrease during that period (approximately 1.1 microwatts per hour, or less than 10 milliwatts per year). In addition, the previously reported changes in Seebeck voltage and generator resistance appear to be leveling, lending further support to the expected end-of-life performance predicted for these units. Data observed from the latest device (3M-31BF5) illustrates the continuation of the apparent early stability trend reported previously. Comparison of the electrical performance data of this device with the performance data of the other "B" series devices for the same initial time period is presented as an indicator of that stability trend.