failed rods are stored in aluminum bundles (each "bundle" is a cylindrical can which is 131" long)
with one rod per bundle. Of the 81 bundles, 54 bundles have an inside diameter (ID) of 2.75
inches, and 27 bundles have an ID of 4.00 inches. Though it is possible for a 4.00 inch ID bundle
to contain up to four TRR rods (Ref. 14), there is only one TRR rod in each of the 81 TRR
bundles that will be in this dissolution. The normal 5.00 inch bundle, which can contain up to
seven TRR rods, will not be used in this dissolution. Both the 2.75 inch ID bundles, and the 4.00
inch ID bundles can fit into either the Mark-42/TRR insert or the 3-well insert. The total heavy
metal weights of U, U-235, and Pu in the 54 bundles and the 27 bundles are given in Table 1,
based on data in Ref. 15.
It is planned to dissolve the EBRn bundle DU006 and the 81 TRR bundles in four batches, as
given in Table 2. In all four batches, six TRR bundles will be placed into each of three Mark-
42/TRR inserts (Figure 3), which are to be located in three of the four loading ports. In batches
one, two, and four, three TRR bundles will also be placed into a three well insert (Figure 4),
which is to be located in the remaining port. The EBR-II bundle DU006 will be placed by itself
into the dissolver port in batch 3 without the use of a loading port insert.
The data in Tables 1 and 2 can be used to calculate the expected average loadings for each insert
and for each batch. These are given in Tables 3 and 4. In Table 3, for example, the average
amount of uranium that would be expected in a Mark-42/TRR insert was calculated from data in
Table 1 to be (2758 + 1180) x 6 / (54 + 27) = 291.7 kg, and the average amount of U-235 is
(17.02 + 7.299) x 6 / (54 + 27) = 1.802 kg. In Tables 1, 3, and 4, a conservative value of 2.0 is
used for the Plutonium Equivalency Factor (see Section 6.1) to calculate the equivalent U-235
loading or enrichment. For example, the average value for the equivalent U-235 loading in the
Mark-42URR insert, as listed in Table 3, is (1.802 + 2.0 x 0.246) = 2.29 kg, using the average U-
235 loading (1.802 kg) and the average plutonium loading (0.246 kg) also listed in Table 3. The
equivalent U-235 enrichment is then 2.29 / (291.7 + 0.246) = 0.79 %. In Table 4, the expected
uranium loading in the third batch can be calculated from data in Table 3 to be (3 x 291.7) + 285
= 1160.1 kg.
As listed in Table 3, the maximum fissile content of the TRR rods must also be considered in this
NCSE. Previous data (Ref. 1 and 14) have indicated that the highest plutonium content in a TRR
rod was 79 grams at 0.1475 wt. % Pu. For this rod, the heavy metal weight must have been
79 /.001475 = 53560 grams, which would have had a U-235 weight of (53560 - 79) x 0.0072 =
385 g. If it is assumed that all of the 79 grams plutonium is Pu-239, then the equivalent U-235
enrichment for this rod would be (385 + 2.0 x 79) / 53560 = 1.01 %. If six of these maximum
plutonium TRR rods were loaded into a Mark-42 / TRR insert, then the total uranium loading
would be 6 x (53560 - 79) = 320.9 kg, and the Pu-239 loading would be 6 x 0.079 kg = 0.474 kg.
These values are listed in Table 3 for the "Max. Pu" case for the Mark-42/TRR insert.