Hydrogen Explosion cont'd

DOE-HDBK-3010-94

7.0 Application Examples; Dissolving Operations Examples

However, since this value is essentially indeterminate, the conservative bounding ARF

and RF values of 5E-5 and 0.8 (subsection 3.2.2.3.2) are used. It is also assumed

that dissolution is virtually complete so all of the plutonium feed is in solution in the

slab vessel. The resulting initial respirable source term is:

1200 g * 1.0 * 5E-5 * 0.8 = 5E-2 g

If it is assumed that the vessel failed, an additional effect is liquid free-fall spill less

than 3 m, for which the ARF and RF are 2E-4 and 0.5 or 2E-5 and 1.0 (subsection

3.2.3.1) depending on the density of the solution. The lesser concentration of the

sulfamic acid (14%) may warrant use of the larger value, in which case an additional

0.1 g is added to the source term, making the spill phenomena dominant.

If detonation phenomena is assumed, the TNT equivalent must be estimated. The

maximum explosive energy potential occurs when a stoichiometric mixture of

hydrogen and air exists (i.e., 30% hydrogen by volume). If the explosion occurred in

the slab dissolver, stoichiometric conditions would involve 4.2 l of hydrogen in the

14-l vapor space. At standard temperature and pressure (22.4 l/mole), 0.2 moles of

hydrogen would be available. Correction for actual temperature is neglected as it

would only reduce the moles of hydrogen present. The available energy is ~ 13,700

calories for a heat of combustion of 68,317 cal/mole H2. This value corresponds to

12.5 g of TNT (1100 cal/g). The value for an explosion in the 2-liter dissolving

chamber vapor space would be ~ 2 g of TNT.

A detonation can be assumed to occur in either the dissolution chamber or the slab

vessel. If it is assumed to happen in the slab vessel, which would have to be

considered confined, the maximum TNT equivalent for a stoichiometric mixture of air

and hydrogen is calculated to be 12.5 g. Subsection 3.2.2.1 indicates that it is

bounding to assume an amount of inert material equal to the mass of TNT equivalent

becomes a respirable aerosol. In this case, that would be 12.5 g of solution.

Assuming an aqueous solution density of 1.1 g/cm3 yields an airborne release of

~ 12 ml of solution from the available total of 30 l. Because the plutonium is

considered uniformly distributed in the solution, the resulting ARF x RF value is 4E-4

(0.012 l/30 l). If the dissolution process is considered almost complete at the time of

the explosion (i.e., 1200 g Pu available in solution), the initial respirable release is:

1200 g * 1.0 * 4E-4 = 0.5 g

If the detonation is assumed to occur in the dissolving chamber, the release will be

maximized if plutonium metal is the affected material because it is not diluted

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