Document: NUREG-0800
Document ID: 545a669a-51a1-4b1f-9d90-78ee08ca0845
Document Type: srp
Title: COMBUSTIBLE GAS CONTROL IN CONTAINMENT
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070463.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.2.5
CFR Part: 
CFR Title: 

Content:
upon the course of events assumed for the accident. Analytically the reaction can be described by: 1lb(0.4536kg)Zr 0.043956lb(0.019938kg)H2 1lb(0.4536kg)Zr 0.021978lb mole(0.009969kg mole)H2 V MRT P V (0.021978)×(10.71)×(530) (14.7) V 8.4866(scf/lb)Zr (V 0.021978×8314×294.4 101325.0 0.5309m 3 kg Zr) 6.2.5-17 DRAFT Rev. 3 - April 1996 56 57 Therefore, one pound (0.4536 kilogram) of reacted zirconium will produce 0.021978 58 pound-moles (0.009969 kilogram-moles) of free hydrogen. Assuming the perfect gas 59 relationship, this is equivalent to 8.4866 scf/lb Zr (0.5309 m /kg) Zr: 3 60 61 The total amount of hydrogen produced is based on the amount of reacted zirconium, as determined by the assumptions given in Branch Technical Position CSB 6-2 RG 1.7 . The 62 computer program, to maintain a degree of generality, allows the reaction percentage to be specified as an input quantity. The expression used is: WG = (.022)(WZr)(fMW) where WG = pound-moles (0.4536 kg-moles) of hydrogen generated 63 WZr = weight of zirconium fuel element clad f(MW) = zirconium-water reaction fraction. SH(t) P B×N × Gc×Ec(t) Gs×Es(t) 100 DRAFT Rev. 3 - April 1996 6.2.5-18 The rate of gas production from radiolysis depends upon the power decay profile and the amount of fission products released to the coolant. The radiolytic hydrogen production rate at time (t) is given by: where S (t) = hydrogen production rate, lb-mole/sec (0.4536 kg-mole/sec) H 64 P = operating reactor power level, MWt B = conversion factor, 454 gm-mole/lb-mole N = Avogadro's number, 6.023 x 10 molecules/gm-mole 23 G = radiolytic hydrogen yield in core, molecules/100 ev c E (t) = gamma ray fission product energy absorbed by core coolant, ev/sec-MWt c G = radiolytic hydrogen yield in solution, molecules/100 ev s E (t) = energy absorbed in coolant outside core due to fission products dissolved in coolant, s ev/sec-MWt. The quantity E (t) is defined by: c E (t) =(f ) H (t) c q c q where (f ) = fraction of fission product