Steady-state differential calorimeter, which displays good accuracy and reproducibility of results, is used to measure gamma heating in a reactor environment. The calorimeter has a long life expectancy since it is virtually unharmed by the reactor environment

Herbst, D.

Talboy, J. H.

English

NASA Technical Reports Server

Terminal 
Rings 
Sample 
Pedestal 
Lava A 
Divider 
Lava A 
Container 
Heater 
Thermo-
couples 
Heat 
Sink 
Cell 
Heatei 
Cell 
June 196	 Briei6-1012 
ICY C,
AEC-NASA TECH BRIEF 
TES
AEC-NASA Tech Briefs describe innovations resulting from the research and development program 
of the U.S. AEC or from AEC-NASA interagency efforts. They are issued to encourage commercial 
application. Tech Briefs are published by NASA and may be purchased, at 15 cents each, from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Steady-State Differential Calorimeter 
Measures Gamma Heating in Reactor 
The problem: 
To devise a method for measuring the gamma heat 
deposited in different samples in a research reactor. 
Information on the amount of heat generated in 
materials being irradiated in a reactor is of importance 
in the design of in-pile experiments. 
The solution: 
A steady-state differential calorimeter, which dis-
plays good accuracy and reproducibility of results, 
is used to measure gamma heating in a reactor en-
vironment. The instrument has demonstrated the 
ability to reproduce results with an accuracy of 2°. 
Such instruments have been constructed with measur-
ing ranges of from 3 to 500 mW/g of sample using 
copper samples of approximately 4 g. The calorimeter 
has a long life expectancy since it is virtually un-
harmed by the reactor environment. 
How it's done: 
The calorimeter shown is 3.1 cm in diameter and 
15.8 cm long. The instrument consists essentially of 
I his document was prepared under the sponsorship of the Atomic 
I nergy Commission and/or the National Aeronautics and Space 
Administration. Neither the United States Government nor any per-
son acting on behalf of the United States Government assumes any
liability resulting from the use of the information contained in this 
document, or warrants that the use of any information, apparatus, 
method, or process disclosed in this document may not infringe pri-
vately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19680000182 2020-03-12T05:31:05+00:00Z
two aluminum sample cells with internal heaters 
mounted on aluminum pedestals. One cell is empty; 
the other holds a sample material. The pedestals are 
arranged symmetrically on a controlled-temperature 
heat sink, which is also made of aluminum and con-
tains an internal heater. All the heaters are nichrome 
wire wound on cores made of an insulating material 
called lava A. 
Thermocouples are attached to each pedestal and 
to the heat sink. The pedestal thermocouples are con-
nected in electrical opposition, across a null detector, 
to indicate the temperature difference between the 
pedestals. The null meter has a sensitivity of 0.2 iV or 
0.005°C per minor division. The heat sink thermo-
couple is used to indicate temperature. 
The two pedestal units, insulated from each other 
by lava A, are placed in a lava A container. The con-
tainer is designed so that only the bottom of the heat 
sink is left uninsulated. This allows a path for the 
internally generated heat to escape to the environ-
ment. Two terminal rings on the top of the container 
allow cable leads to be connected from the associated 
instrumentation. All connections from the calorimeter 
to the instrumentation are made with cable composed 
of copper conductors insulated with polyvinyl. 
Specific quantities of electrical power are supplied 
to each cell to obtain a zero temperature difference 
between the pedestals in the absence of radiation. 
After this balance is obtained, the calorimeter is 
placed in a radiation field. The presence of the radia-
tion causes heat to be deposited in the sample. This 
additional heat source in the sample cell disturbs the 
calorimeter balance. To compensate, the electrical 
power delivered to the sample-containing cell is 
reduced to reestablish balance. The gamma heating 
value is then obtained by using the measured electrical 
power delivered to each cell, in an equation derived
from the analysis of a theoretical model of the calo-
rimeter. 
It is possible to calibrate the instrument so that 
it will operate in a horizontal position. Thus: it can 
be used to measure gamma heating in reactor beam 
holes as well as vertical facilities. 
Notes: 
I. Additional details are contained in A Steady-State 
Differential Calorimeter Used to Measure Gamma 
Heating in a Reactor Environment, by Dale A. 
Herbst and James H. Talboy, ANL-7178, March 
1966, Argonne National Laboratory, Argonne, 
Illinois 60439. This report is available from the 
Clearinghouse for Federal Scientific and Technical 
Information, Springfield, Va. 22151; price $3.00 
(microfiche copies, $0.65). 
2. This information may be of interest to manufac-
turers of differential calorimeters and research 
laboratories using such equipment. 
3. Inquiries concerning this innovation may be di-
rected to:
Office of Industrial Cooperation 
Argonne National Laboratory 
9700 South Cass Avenue 
Argonne, Illinois 60439 
Reference: B68-10182 
Source: D. Herbst and J. H. Talboy 
Reactor Operations Division 
(ARG-10120) 
Patent status: 
Inquiries about obtaining rights for commercial use 
of this innovation may be made to: 
Mr. George H. Lee, Chief 
Chicago Patent Group 
U.S. Atomic Energy Commission 
Chicago Operations Office 
9800 South Cass Avenue 
Argonne, Illinois 60439 
Brief 68-10182	 Category 01


Steady-state differential calorimeter measures gamma heating in reactor

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