Design Features (Passive and Active) and Administratively Controlled Limits & Requirements

DOE-STD-3007-93

2758 / 54 = 51.1 kg of uranium. Since the EBR-II bundle contains 285 kg of uranium, and the

enrichment is essentially the same as for the TRR rods, shipping the EBR-II bundle is equivalent

to shipping 5.6 average TRR rods. So, from a criticality standpoint, the EBR-II bundle could be

shipped along with up to 42 - 6 = 36 TRR rods in the shipping cask. However, since the EBR-II

bundle has a larger diameter and length than the TRR bundle, the EBR-II bundle may not fit into

the shipping cask together with TRR bundles, so that it may be necessary to ship the EBR-II

bundle by itself. This would, of course, also be critically safe.

7.0

Design Features (Passive and Active) and Administratively

Controlled Limits & Requirements

The design of the dissolver provides for the use of inserts in the four loading ports, which are

separated by 90 around the top of the inner annulus. Previous studies have shown that this

separation of the loading ports assures that fissile material loaded into any one insert will be

neutronically separated from fissile material in the other inserts. Previous studies (Ref. 12 and 13)

have also shown that the design of the dissolver and the dissolution process assures that the

plutonium mixes with the uranium throughout the dissolution process. This means that the

plutonium dissolves as the uranium dissolves, and that the mixing within the dissolver is sufficient

to preclude regions of high concentration solution forming in the vicinity of undissolved material.

These things occur due to convective mixing, as well as air sparging. Also, the annular design of

the dissolver, and neutron absorption in the steel walls of the dissolver, significantly increase the

fissile material limit in the dissolver, as shown in Ref. 1.

Based on the contingency considerations in Section 5, criticality safety controls (CSCs) are

required to assure a critically "safe" dissolution process. To assure the non-occurrence of

initiating events IE #1 (other than intended EBR/TRR material being loaded into the dissolver)

and IE #2 (insufficiently acidic dissolver solution), the administrative controls for this EBR/TRR

dissolution must be based on the administrative controls for previous TRR dissolution. This will

satisfy the CSCs arising from the DCA for TRR dissolution (Ref. 2). To assure the non-

occurrence of E #3 (significant fissile in initial dissolver solution), the following CSCs are

required:

IE#

CSC#

DESCRIPTION OF CONTROL REOUIREMENT

The process operator must determine whether the enrichment of the

previous dissolution campaign > 0.9635 %. If it is, then CSC 3B to

3D must be performed. If it is not, then CSC 3B to 3D can be

omitted. CSC 3E must be done in either case.

During the last rinse prior to EBR/TRR material loading, dual

independent sampling and chemical analysis (blue label) of the

fissile concentration must be performed.

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