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Evaluation Results cont'd - s3007cn10116
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Guidelines For Preparing Criticality Safety Evaluations at Department of Energy Non-Reactor Nuclear Facilities
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Figure 2 GB2404 Filter


DOE-STD-3007-93
6.4.2 Seismic: In a seismic event, it is judged that the glass columns would break and up to 2" of
liquid could fill the floor. This is subcritical, as can be seen in TID-7016.
6.4.3 Samples: 1-liter of samples may be taken and handled in this glovebox, since the relatively
small volume of liquid would be bounded by the unrealistically high concentrations for which
equipment in this glovebox has been evaluated. In effect, the most reactive configuration of the
samples would be either next to the R6 filter assembly, evaluated unrealistically to 5000 g/l, or
any of the columns, unrealistically evaluated to 1000 g/l, thus clearly bounding the maximum
credible concentration of 150 g/l in the 1 liter of samples.
6.5 Glovebox 23: GB-23 is located in room 1115. It is constructed of stainless steel with "
lead and 2" waterwall. Precipitate in nominal 2" deep pans from glovebox 18 is dried on a
hotplate in this glovebox. Dried material is then collected into 1-liter containers and bagged out.
Used bag filters and cartridge filters from the CWTS are also dried in this box. This glovebox has
an approved criticality drain and is also open to GB18, which has a standard criticality drain, thus
flooding above a two-inch depth is precluded.
6.5.1. Normal Condition: Normally, a maximum fissionable concentration of 25 g/l is processed
in approximately 20 liter batches in each clarifier column in glovebox 18. This amount of liquid is
measured by a timed metering pump. Before adding Magnesium Oxide for precipitation, each
column is adjusted to remove any liquid in excess of 20 liters. Note that about 7 liters of up to
150 g/l fissionable liquid could be introduced into the columns, instead of 7 liters of 25 g/l
fissionable liquid. This is due to a small amount of liquid which could be left in common tank
transfer lines after blending and sampling. Reference Appendix O. Accordingly, precipitate from
the two columns or processing "run", would have a maximum fissionable mass of 1875 grams (33
liters x 25 g/l + 7 liters x 150 g/l). As only one "run" is allowed in each pan, the three pans
allowed in glovebox 23 would contain a combined fissionable mass of 5625 grams. Since material
is bulk weighed into the two maximum-size one-liter cans and assuming the material is Plutonium
Oxide (Pu atomic weight of 239/Plutonium Oxide atomic weight of 271=88 wt%), the
contribution of fissionable material from the two cans is 1760 grams. The addition of fissionable
material in the three filters is expected to provide no more than 150 grams, particularly as
operators are trained to efficiently scrape precipitate from the R6 filter media, as bag filters
receive only low level filtrate, and as ful-flo filters accumulate less than 50 grams fissionable
material. Reference Appendix O. Thus, the normal fissionable mass loading in glovebox 23 is
7535 grams. This amount of fissionable material is bounded by the mass overbatch condition.
6.5.2 Mass Overbatch: There are four credible means of mass overbatch in glovebox 23. The
first means is by processing the maximum credible solution of 150 g/l in 20 liter batches in each
clarifier column. This overbatch would result in one pan containing 6000 grams of fissionable
material. The second means is by loading two "runs" into one pan for a fissionable mass of 3750
grams. The third overbatch would involve completely filling each clarifier column to its full 30.6
liter capacity with 25 g/l fissionable solution, such that the fissionable mass available to one pan
would be 2405 grams (includes 7 liters at 150 g/l). The fourth overbatch results in the unlikely
event that two pans or 3750 grams of fissionable mass were put into one can before the error was
identified. The first overbatch was evaluated since its higher fissionable material mass bounds the
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