Memorandum from Raymond L. Murray to Clifford Beck
Handwritten
2 pp.
April 6, 1953
MurNBcontrolrods040653



NCSC-60

April 6, 1953

to: C K Beck
from: R L Murray
Subject: Control and Safety Rods
copies: file

In answer to your questions:


[page 2]

Rod Values:
Critical condition will be achieved with solution at temperature
of cooling water, with one rod completely out (safety) and one
rod completely in (control). As one rod is removed, [delta]k increases,
the power rises, and the temperature rises. The rod value as best
we can compare with Los Alamos is 80 grams of U-235 or 0.016 [delta]k.
If either this rod is dropped or the safety rod falls, the reaction is
suppressed. The average change in reactivity is, for 5"/min removal
0.016/2 minutes = 0.008/min or 0.00013/sec
The maximum rate of change of reactivity is approximately twice
this value, when the rod is half way out.