Leverett’s letter

Reactor design history over the first three post-war decades is fascinating, if only because so many designs were touted as possible, feasible, or competitive. I’ve found it hard to unwind each design’s history and realistic prospects, partly because of the jargon, partly because no one writing on the subject was ever disinterested.

1950 AEC paper

So it was interesting to discover in the archives a mid-1950 letter from a noted nuclear engineer, Miles Leverett, to an Atomic Energy Commission manager, commenting on a left-field design strand. Leverett’s letter was penned on June 13 and a month later was tabled at a meeting of the AEC commissioners. As can be seen from the covering memo from the AEC secretary, Leverett was asked for his comments on the aqueous homogeneous design (back in April) and his letter was “of such interest” that it was put before the august company of the commissioners, phrasing that suggests it’s going to criticize that design and should be read but not necessarily acted upon. I don’t have the AEC minutes at which the letter was discussed (it if was) but it was never mentioned again.

Briefly, Leverett slammed the homogeneous design championed by Oak Ridge as fundamentally impractical at a time when so many designs were clamoring for capital that only only or two could possibly win out. Here’s the flavor of his complaints:

There seem to me to be two such main problems. One of is peculiarly characteristic of a “slurry” type reactor and is the problem of maintaining the solid suspended in the liquid. The other is that of radiation damage to chemical compounds such as UF6, water, NaOH, etc.

Leverett, Miles C. 1950. Leverett to Ward, Jun. 13, 1950. “Critical Assembly Studies, General Electric Company, Sec. 2,” Box 51, Entry 67-A1, RG 326, NARA II, College Park, Maryland.

I don’t wish to go over the many fascinating technical issues raised by Leverett but when I read this letter, two facets beguiled me, both from hindsight. First, he was right about the “two such main problems”: Oak Ridge never did manage to keep its unique liquid fuel “suspended in the liquid” and, yes, chemical compounds did suffer “radiation damage.” That is, Leverett correctly saw through the design. Second, the irony is that at the time of writing the letter, Leverett was a key figure in the Air Force’s hugely expensive quest to design a nuclear-powered airplane. This was cancelled about the same time as the homogeneous reactor project, but while the latter cost a few tens of millions, the nuclear plane boondoggle wasted billions.