Memorandum from N. Underwood, A. Waltner, and G. Webb to Clifford K. Beck
3 pp.
May 22, 1952

Reac Memo

Submitted May 22, 1952

TO: Clifford K. Beck
FROM: N Underwood, A Waltner, and G Webb
CC: Reactor Committee
SUBJECT: Instrumentation requirements for Achieving Critical Mass

These intrumentation requirements are of a dual nature. First,
the instrumentation specifically needed for the technical
operation of determining the critical mass. Secondly, the
instrumentation required from the viewpoint of possible hazards
which might arise from some accidental occurrence.

The instrumentation falling in the first category is as follows-
1. U235 pulse channel
2. BF3 " "
3. BF3 " "These have sluggish level trips
4. BF3 " "
5. B10 integrating channel
6. B10 " "These have fast level trips and
are the primary safeties
7. [gamma] " "
8. Liquid level indicator
9. Rod and shim position indicators
10. Sampling and liquid transfer device
11. Monitoring systems for the critical procedures
 a. [alpha] monitor
b. air monitor
c. personnel monitors - film n sensitive
film [beta], [gamma] sensitive
dosimeter n sensitive
dosimeter [beta], [gamma] sensitive

In the second classification we have the following-

[page 2]

Below are listed partial cost estimates-
1.U235 pulse chambercost information unavailable
Atomic Inst 205B120.
" " 204B395.
" " 1010 scaler430.
" " 410 rate meter325.
Keleket timer60.
Cable and connectors(50)
Level trip modification(100)
2.BF3 G.E, or R C L130 or 105.
Nuclear Inst 128 scaler525.
Atomic Inst 410 rate meter325.
Cable and connectors(50)
Level trip modification(100)
3.Duplicate of 2
4.Duplicate of 2 except omit ratemeter
5.B10 ionization chamber(400)
Shop estimate from Mr. Morris(100)
Quartz insulation from G E(100)
Special alloy materials Dow(100)
Special B10 coating.. requires special techinque involving
induction heating with inter gas flow. It may be advisable
to make arrangements with Gundlach to have him coat our
chambers. This cost cannot be estimated.
Pre amp(250)
Level trip(100)
Difference amp(50)
Pure lead shield(50)
6.Duplicate of 5 except add 3 motors105.
7. Scintillation [gamma] channel. This has not been studied with
sufficient care to make a sound estimate but it it believed
that it will be of the order of
8.Liquid level indicator (see Lancaster)
9.Rod and shim position indicators approximately
10.Sampling and liquid transfer (see Beck)
11.Monitoring for critical procedures
2 [alpha] Zeuto750
air monitor(100)
personnel monitor per person
 2 film badge10.
 2 dosimeters [beta], [gamma]25.
  " neutron50.
use reading devices already have

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1. Campus monitors installed in permanent(1200)
2. Stack monitor(1000)
3. Dust monitor(200)
4. mobile monitorno estimate
5. Alarm systemno estimate
(6. Consoleno estimate )
7. Liquid monitor(2500)
8. Log channel submitted to Nuclear Inst?
9. Indium foilsno estimate
10. Recombiner and disposal system (Menius and Murray)
11. Gas masks(300)
Interlocks, light panel, and hook up(1500)