Direct draining of Building 371 tanks to tanks D-2401 A/B/C/D

DOE-STD-3007-93

effluent liquids from the CWTS have undergone precipitation to remove Plutonium, and supernate

liquids from glovebox 18 have been filtered through an R6 filter and three l-micron bag filters,

rigorous controls have been instituted to preclude any likely contingency in the CWTS which

could cause concentrations exceeding the waste transfer limit to be inadvertently sent to tanks D-

811 A/B. Note that caustic liquids are only filtered since particles are suspended and not

dissolved. Valve MV-24425 is closed and locked out, and valves MV-24401 and MV-24527 are

verified as closed when solution is pumped into clarifier columns T-2411 A/B to preclude bypass

of the precipitation process in glovebox 18. Note that residual liquid between closed valves

would not pose a criticality safety issue as it would be of small volume. Also note that

correspondence from T.E. Boyd to L. Martella, "Precipitation of Plutonium with Magnesium

Hydroxide: TES 008.97", October 10, 1997, shows that supernate liquid from precipitation of 25

g/l fissionable liquids would be less than 7 g Pu/l. Reference Appendix O.

6.8.2 Supernate liquid from clarifier columns T2411 C/D are pumped through either of the banks

of three 1 -micron bag filters FL2416-1, 2, 3 (A/B) into either of tanks D-2402 A/B. It would be

unlikely for this liquid to be in excess of 7 g/l Pu since it would require a combination of upset

conditions, including failure to precipitate, failure to use the R6, and/or failure to use the one or

more of the l -micron bag filters. This forms the first contingency.

6.8.3 Waste liquid in tank D-2402 A or B is mixed via vacuum sparge and sampled by the

Building 371 operating group prior to transfer to tank D-2403. If lab results show the liquid to be

less than the waste transfer limit, valve AOV-213, which is normally locked out in the closed

position, is opened and the tank contents transferred to tank D-2403. Liquid above the waste

transfer limit is recycled back to tanks D-2401 A/B/C/D and reprocessed in the CWTS. Waste

liquid in tank D-2403 is then mixed via vacuum sparge and sampled twice by the Liquid Waste

Treatment organization from Building 374, with additional mixing between samples. If both of

these samples are less than the waste transfer limit, valves AOV-201, AOV-206, and MV-0884,

all normally locked in the closed position, are opened and the waste liquid is pumped to tanks D-

811 A/B in Building 374. In addition, tank D-2403 is limited to a maximum of 200 grams total

fissionable material (39% of the minimum critical mass of Pu-239) and assayed on a bi-monthly

basis as additional barriers. Since two independent organization have multiple opportunities to

verify waste liquid concentration, numerous independent samples would have to be misanalyzed,

and several normally locked closed valves would have to fail or be left open, it is judged that

failure to transfer only waste liquids below the waste transfer limit from tank D-2403 to tanks D-

811 A/B is unlikely. This forms the second contingency.

6.9 Direct draining of Building 371 tanks to tanks D-2401 A/B/C/D:

One method of draining Building 371 tanks involves the installation of a tap in the outlet of a

tank, which is then directly connected to tanks D-2401 A/B/C/D via nominal " tygon tubing into

the manifold in GB-2401. The contents of the target tank are then drained into the CWTS using

gravity assisted by the vacuum (PROVE Vacuum System) on tanks D-2401 A/B/C/D. This

activity can be conducted with Building 371 General Comments and Miscellaneous

NMSL/CSOLs. Since Building 371 tanks were pumped systems and no fissionable solution was

introduced into the vacuum system by overfilling tanks, no specific criticality controls are

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