Evolved Gases - std301320040062

DOE-STD-3013-2004

Since the initial volume and the final volume are the same, this reduces to

PF = P0(T1/T0).

[7]

The values of P0 and T0 are the pressure and temperature at which the container was loaded

and sealed. This is the first term of the equation given in DOE-STD-3013-99.

B.2.3

Evolved Gases

B.2.3.1

Gases of Concern

The only evolved gas of significance anticipated during extended storage is hydrogen from

decomposition of adsorbed water. Maximum credible hydrogen pressures are expected to be

maintained well within the storage container pressure design basis. The technical basis for these

expectations is provided in Section A.6.1.2 of Appendix A of this Standard. The derivation

conservatively assumes that all the water is decomposed. If, in fact, some water is not

decomposed, but is desorbed, the results are the same.

B.2.3.2

Quantities of Gas Produced

Starting with m kg of oxide with a moisture content of L (in percent by weight), there will be

10mL/18 moles of water in the container. Since one mole of water can theoretically produce one

mole of hydrogen gas, hydrogen production, G, in moles, is assumed to be given by:

G = 10mL/18

[10]

B.2.3.3

Calculation of Gas Pressure

Since a mole of gas has a volume of 22.4 l at STP (14.7 psia and 273K), a generated quantity

of gas would occupy a volume (in liters) given by

V = 22.4 G.

[11]

In using the ideal gas law, this volume could be considered the initial volume so that the

pressure attributable to this gas would be

PG = (14.7)(22.4 G)(T1/273)/V1 = 1.206 GT1/V1.

[12]

PG = 0.67mLT1/V1

[13]

which is the middle term of the equation in DOE-STD-3013-99, if the free gas volume, V1, is

defined as