ORNL-1771 - Oak Ridge National Laboratory

ANP QUARTERLY PROGRESS REPORT
SHIELDING FA
R. G. Cochran F. C. Maienschein
G. M. Estabrook
J. D. Flynn
M, P, Haydon
At the Bulk Shielding Facility (WFj mensure-
ments were made of reactor radiations through
thick slabs of graphite. In this experiment the
fast-neutron spectrum through graphite and Q re-
moval cross section of carbon were also determined,
The light to be given off from a nucleor-powered
airplane has been further investigated, and some
quantitative measurements are reported, In ad-
dition, ci method of determining the power of the
ARE by means af fuel activation techniques is
described.
REACTOR WAPiATlONS THROUGH
SCABS aIF: GRAPH~TE
R. G. Cochran
G. M. Estabrook
J. D. Flynn
K. M. Henry
Measurements have been completed for de-
termining the attenuation of large thicknesses of
graphite next to c( reoctor. ' These measurements
are of interest for evaluating a graphite reflector as
n shield component, and they also provide a direct
comparison with LTSF determinations of the carbon
removal cross section. Graphite thicknesses of
1, 2, and 3 ft were used, and the usual gamma-ray,
thermal-neutron, and fast-neutron dose measure-
ments were made hehind each slab thickness. In
addition, the fast-neutron spectrum (above 1.3
Mev) through 1 ft of graphite was measured.
A graphite slab 1 ft thick and one 2 ft thick were
constructed, and the 3-ft thickness was obtained by
strapping thesc two slabs together. When strapped
together, there wos no possibility of watoa getting
between the slabs, Each slab wos constructed
Inrge!y of graphite blocks, 4 in. x 12 in. x 5 ft,
stacked in aluminum tanks in such a way that
there could be no streaming of radiation through
cracks extending through an entire slab thickness.
'The details of this experiment will be reported in a
memorandum by R. G. Cochran et a/., Reactor Radz-
atzons Through Slab7 o/ Graphite, ORNL CF-54-7-105
(to be issued).
R. W. Peelle
P h y s i cs D i vi s ion
K. M. Henry
E. B. Johnson
T. A, Love
'Thin graphite shims were added to fill the tanks,
which were sealed by heliarc welding and were
pressure tested for leaks. The total aluminum wall
thickness for each tank was 1.3 cm.
Bulk Shielding Reactor loading No, 26 (Fig. 13.1)
was used. This configuration is very similar to
looding 22, which has been studied in considerable
detail for other experimentsI2 but loading 26 uses
less fuel to compensate for the presence of the
graphite, which is a better reflector than the water
it replaces. Since the presence of the graphite
perturbed the neutron flux in the reactor cote
rather severely, the neutron flux distributions and
thus the reactor power were determined in the
usual way by means of eobalt foils.
2R. G. Cochran et al., Reactivity Measurements with
the Bulk Shielding Reacior, ORNL-1682 (to be issued).
WbER PEkCECTOR
EXTO7 GR D PLATE
?t4 ELEMENT
~ -
CONTRO. ROD
Fig. 13.1. Loading 26 e~f the Bulk Shielding
Reactor,