Release Estimation cont'd

DOE-HDBK-3010-94

7.0 Application Examples; Seismic Release Example

0.6 (subsection 4.4.3.1). If all of the events described above occur, with the 2300 g

in the calciner spilled as opposed to being vibrated, the cumulative initial respirable

source term within the glovebox atmospheres is:

(9,620 g * 1.0 * 1E-3 * 0.1) + (2300 g * 1.0 * 2E-3 * 0.6) = 3.7 g

The precise amount of plutonium surface contamination cannot be determined. Even

survey measurements cannot accurately identify quantities due to shielding

uncertainties and the sheer size of the potentially contaminated areas. The type of

surface contamination is relevant as well. Unlike loose surface contamination, fixed

surface contamination is unlikely to be dislodged to an appreciable degree except by

extremely violent events. The inability to dislodge such material by normal cleaning

actions testifies to the difficulty of removing such material. Another type of

contamination is material holdup in piping and vessels. This material does not receive

the direct or undamped type of stress that other contamination would. Further,

whatever portion of this material is driven airborne is unlikely to be released from

initial confinement if vessel or piping failure does not occur.

This example will concentrate on loose surface contamination outside vessels and

process piping, as it is a reasonable assumption that this is the primary material of

concern for airborne release due to seismic vibrations. Existing studies (Allen,

Arrowsmith, Charlot, and Hooper, 1978) indicate that a surface contamination level

of 0.7 g/ft2 is the level of contamination that would be visible to the naked eye.

Historical data from a mixed oxide fuel fabrication facility indicated a surface

contamination level of 0.1 g/ft2 inside gloveboxes was representative of powder

handling operations (Mishima, Schwendiman, and Ayer, 1978). There is no firm

basis for estimating contamination in less dirty, non-powder operations, but common

practice is to consider contamination levels in such operations at least an order of

magnitude less than those for powder operations. Typical estimates for glovebox

holdup magnitudes are in the range of 0 to 50 g, with interior equipment holdup

estimates going to as high as hundreds to thousands of grams for large furnace and

incinerator operations.

The internal surface area of the gloveboxes is determined from their measurements.

In this construct, that value is multiplied by a factor of 1.25 or 1.5 depending on how

much equipment relative to volume there is in a given glovebox. None of the

plutonium recovery facility gloveboxes have visible surface contamination over

significant areas. Therefore, the available surface area estimate is multiplied by

0.1 g/ft2 for powder handling operations, and 0.01 g/ft2 for liquid operations.

Resulting surface contamination estimates are listed on the following page.

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