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Re: Prophylactic decon
Prerinsing a fuel pool cask with clean water is standard practice, not so much for airborne as for contamination control. The clean water fills the
pores and will prevent hard to remove contamination if the cask is not in the pool for an extended time. For airborne control, the cask should be
rinsed as it is removed from the pool and promptly deconned. The airborne problem will occur as the cask dries out. Also, don't forget to decon any
rigging equipment that goes in the pool. You may also need hot particle controls. (See the recently issued NRC Information Notice 2002-03 "Highly
radioactive particle control problems during spent fuel pool cleanout.")
The time the cask spends in the pool should be minimized. If it is left in the pool for more than one shift, the contamination will get into the
pores and will be difficult to remove.
If the cask has been left in the pool for more than one shift, you should plan on several days for decontamination. You have to decon, wait a day for
contamination in the pores to weep out, survey and then decon again, if necessary. Otherwise, the cask could arrive with contamination above the
limits.
The opinions expressed are strictly mine.
It's not about dose, it's about trust.
Let's look at the real problems, for a change.
Bill Lipton
liptonw@dteenergy.con
Jack_Earley@RL.GOV wrote:
> Does anybody have any data on the effectiveness of a demin water rinse
> before submerging a SS (125 RMS) cask into a contaminated pool? Anecdotal
> evidence indicates pre-rinsing results in lower airborne contamination when
> the cask is removed from the pool, if the cask is submerged for one shift (8
> hours) or less.
>
> Jack Earley
> Radiological Engineer
>
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