Critical dimensions of systems containing /sup 235/U, /sup 239/Pu, and /sup 233/U: 1986 Revision Page: 93 of 205
This report is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to Digital Library by the UNT Libraries Government Documents Department.
The following text was automatically extracted from the image on this page using optical character recognition software:
In the other case, rings 4.5 cmii long and 3.8-cm o.d. with 0.32-cnm-t hick walls and cont ain-
ing 0.135 g B cm3 were embedded in slabs of V(93( ), N03)2 -41120. which were t hen
built into concret e-reflect ed parallelepipeds. 1 lii some inst attces moderat ion was increased
b% the insertion of thin Plexiglas sh ts. Ty pically, it 81 .6-cm stare core was judged to
be critical at a height of- 45 cm with H, U -- 8.01. p(l') = 1.058 g'cmin3. and 18.8 vole(
glass. The critical height was judged to be 40 cimi wit h H/1 = 11.14, p(lI) = 0.934 g/cm3.
and 16.4 vol' glass. The corresponding est imat ed sphere radii were 31.0 cm for the first
composition and 29.7 cut for the second. hItinit e-cylinder diameters were about 39.9 and
3S. cm, and infinite-slab thicknesses were about 20.* and 19.8 cut. Deduced percent age of
dImtetnsiotal increase per vohltne percent of glass for spheres, infinite cylinders and infinite
slahs were also given.
Additional ORNL critical dat alt2 - "" and Hocky Flats'2" subcritical extrapolations on the
effects of liet erogetnteous poisons on solut ions cont airing ' l at high enriclnent s are listed
in Table 25. Shape conversions 4f the R cky Flats results for parallel boron-steel plates
in U(93)O2(NO3 )2 solutions lead to the following conclusions for essentially unreflected
systems. At S U = 82 and with 2.5-cm plate separation, t he steel increased the critical
sphere radius by a factor of 2.4. At H "U = 100 the corresponding factor is 4.0 with
2.5-ctn plate separation and 1.9 with 3.8-cm separation. At H/235t1 = 225. the factor
is 3.7 with 3.8-cm separation and 1.4 with 5.4-cm separation. The increases of infinite-
cylitder diatnett rs are only slightly greater t han the above ratios. Corresponding increases
of infinite-slab t hicknesses are 13 to 24 i larger than the sphere-radius factors
( 20 when thlie sphiere factor is 2)_
D)ai a original ing at H afford. 13 N L, and Westinghouse Electric Corporation Atomic
Power Depart ment " from subcrit ical lat i ices of uranium rods of low enrichment poisoned
with boron hottiogetteously distributed in the moderator water are given in Table 26.
The amount of boron required for B2 = 0 was determined by interpolation of bucklings
teasured wit 1h different amounts of boron in the moderator.
Ot her Hanford experiments"' established t he effect of soluble gadolinium or boron on the
crit ical number of V1(4.3)02 fuel pins in t rianguiar lat tices wit h pit ches of 2.29. 2.79 (near
optimum), and 3.30 cm. The fuel pins consisted of 1.26-cm-diam by 82-cm-long UO2 clad
with 0.08-cm-thick stainless steel. At a pitch of 2.79 cm, for example. 0.12 g Gd/L doubled
the critical number of pits (about 167 without absorber) and 0.37 g B/L had about the
The effect of boron dissolved in the water moderating and reflecting lattices of 1'(4.95)
metal rods was mtentitmed earlier. A more detailed account of 0.140 g B L in triangular
lat ties is given itt Table 27.'7
Here’s what’s next.
This report can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Report.
Paxton, H.C. & Pruvost, N.L. Critical dimensions of systems containing /sup 235/U, /sup 239/Pu, and /sup 233/U: 1986 Revision, report, July 1, 1987; New Mexico. (https://digital.library.unt.edu/ark:/67531/metadc1109879/m1/93/: accessed March 20, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.