Cold slug effects

In the Idaho desert in early March, 1954, Hyman Rickover’s STR Mark I, a land-based prototype for a submarine nuclear power reactor, is being tested by engineers from Argonne. Rickover hates Argonne (and Argonne’s Zinn hates Rickover; Zinn’s name isn’t even on the distribution list below, although his trusted lieutenant John West is) and will soon expel those engineers, but for the moment they’re conducting “emergency cooling tests of the Mark I plant.”

Mar 5 1954 archival document

Such drama! “The attempt to continue for a long time was aborted due to the uncertainty of the operating personnel about some of the temperature measuring instruments and safety considerations dictated a premature discontinuance of the test. … enough to cause smoking and scorched odor from the control drive cables.”

Problems! “As had been suspected the undesirable piping arrangement of the Mark I hard tank loop leads to trouble because of the ‘cold slug’ effects in several peculiar up and down legs. … There is every reason to expect Mark II to operate satisfactorily inasmuch as vertical traps in the piping are avoided…”

It’s fun to read such dramatic, intimate engineering moments. But in the scheme of things, this was just one of many testing sequences carried out and acted upon, to final good effect in the successful performance of the prototype. Too much detail, too much detail.


Silvers, J. P. 1954. Silvers to Jameson, Mar. 5, 1954. “Reading File, March 5, 1954,” Box 97, Laboratory Director’s Reading File, 1949-1957, RG 326. NARA-GL, Chicago, Illinois.