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Management of Commercially Generated Radioactive Waste - U.S. ...

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HEPA<br />

FILTER<br />

4.40<br />

CHARCOAL<br />

FILTER<br />

- TO FRP APS<br />

SECONDARY | PROCESS OFF-GAS<br />

LIQUID WASTE ENT BITUMEN EN TVENT<br />

SSLURRY WASTE - D RY<br />

MIXING AND IWEIGHT D E A I N<br />

DEWATERING<br />

ANK<br />

I FEIEDER OIL<br />

FILTER -- TO CONCENTRATION<br />

TANKS BITUM DT SYSATEM<br />

S<br />

RECYCLE WATER D<br />

FEED PUMP<br />

FEED PUMP L J CONDENSER<br />

DRUM<br />

EXTRUDER-VAPORATOR<br />

"- vVlJENT TO PROCESS OFF-GAS<br />

S TO CAPPING. OECONTAMINATION. AND STORAGE<br />

FIGURE 4.3.11. Process Flow Diagram for Bitumenization Facility at Fuel Reprocessing Plant<br />

ruthenium may also be converted to a volatile species under normal process conditions. All<br />

<strong>of</strong> the other radionuclides present may also be present in <strong>of</strong>f-gas and ventilation-air<br />

streams; these are present, however, as suspended particles rather than in a gaseous form.<br />

The fraction <strong>of</strong> the nonvolatile radionuclides suspended in the gas streams is generally<br />

quite small.<br />

Gaseous and airborne wastes will have to be treated to remove radionuclides whether the<br />

spent fuel is discarded (the once-through case) or reprocessed. However, the complexity <strong>of</strong><br />

treatment operations might vary widely depending on which cycle is chosen. The treatment<br />

operations will be at a minimum if spent fuel is packaged as intact assemblies (as in Sec-<br />

tion 4.3.1.1) and will be at a maximum if spent fuel is dissolved for disposal or<br />

reprocessing.<br />

4.3.4.1 Filtration<br />

Filtration is employed to remove radioactive particles from air streams being dis-<br />

charged from various equipment and facilities used in the LWR fuel cycle. Such particles<br />

arise from a variety <strong>of</strong> sources and mechanisms and their release to the environment can be<br />

controlled by a variety <strong>of</strong> filtration processes. There has been much experience in this<br />

area, since filtration has been successfully employed for many years in operating nuclear<br />

facilities.<br />

One type <strong>of</strong> filter used almost universally in nuclear installations is the high-<br />

efficiency particulate air (HEPA) filter. These filters are composed <strong>of</strong> a specially formu-<br />

lated glass fiber web contained in a wood or metal frame. HEPA filters are available in<br />

several modular sizes; the size most commonly used for large installations is 61 cm on a<br />

T

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