
 DOESTD30132004
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 DOESTD301399.
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 DOESTD301399, if the free gas volume, V1, is
defined as
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