Hydrogen Explosion - h3010v10313

DOE-HDBK-3010-94

7.0 Application Examples; Reduction Line Example

droplets in an air atmosphere, where combustion was a significant factor in driving

material airborne. In this example, the furnace contains an argon atmosphere, and the

glovebox contains a nitrogen atmosphere. Overall releases under those conditions

should be significantly less. If the conservative estimate of phenomena (i.e., "flowing

metal or actions involving continuous surface renewal of molten metal") is assumed as

the bound, and the glovebox atmosphere is assumed to be air, the initial respirable

source term released to the glovebox atmosphere is:

(1000 to 2000 g) * 1.0 * 1E-2 * 1.0 = 10 to 20 g

If the atmosphere involved is inert (i.e., no molten plutonium combustion), the

bounding release fraction could reasonably be considered at least an order of

magnitude less without the need to provide detailed justifications.

Even if the atmosphere in the glovebox was air, the 10 to 20 g estimate is considered

excessive. This handbook does not delve into damage ratio issues at great length, but

this is one case where such issues must be confronted based on the limitations of the

ARF database. The release estimate is considered excessive, but there is no other

ARF value that can be neatly derived to cover this phenomena. The true release is a

function of how exposed to turbulence the molten plutonium actually is during vessel

venting. Given that the historical record does not include observations of significant

splattering of molten material in the crucible, furnace, or adjacent glovebox floor, it

is not unconservative to consider the effect largely a surface phenomena.

Accordingly, it would not be obviously inappropriate to consider only some fraction

of the plutonium, say 10% to 25%, to be in the affected surface layer. Use of the

10% value, for example, as a damage ratio would reduce the initial estimated release

range to 1 to 2 g. It is not essential to produce a supposedly "defensible" calculations

to incorporate actual experience and understanding of phenomenology into use of the

ARF data in the context of providing "information to support general bases for

decisionmaking."

C. Hydrogen Explosion. The total amount of calcium metal used in a given

reduction charge, including stoichiometric excess, is ~ 740 g, or 18.5 moles. The

specific reaction of concern for calcium and water is:

Cao + 2H2O --> Ca(OH)2 + H2

Therefore, to completely react all of the calcium in a given charge would require

37 moles of water (670 ml) and would generate 18.5 moles of hydrogen (37 g). Such

a complete reaction in a very short time period is not feasible, but is considered as an

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