Document: NUREG-0800
Document ID: 936f16a2-5593-4498-8533-ddca55910376
Document Type: srp
Title: COMBUSTIBLE GAS CONTROL IN CONTAINMENT
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340704.pdf
Revision Date: 2023-06
Chapter: 6
Section ID: 6.2.5
CFR Part: 
CFR Title: 

Content:
ogen generation by a small amount due to a "double-counting" of the gamma energy of those fission products assumed to be released from the fuel rods. Hydrogen generation due to aluminimum corrosion is normally considered only when additives are used in the cooling solution. When applicable, gas produc- tion is governed by the following expression: S c(t) = ApBC(t) (12)(3.15 x 10 ) 6.2.5-13 Rev. 2 - July 1981 Where Sc (t) = hydrogen production rate, lb-mole/sec. A = surface area of aluminum, ft2 p = aluminum density, lb/ft3 B = lb-moles of hydrogen per lb of aluminum C(t) = aluminum corrosion rate, in/year. The aluminum corrosion rate has been described by an exponential fit in COGAP to account for an increased rate due to high temperatures early in the accident followed by a constant rate for the remaining period of the analysis. The chemical relationship by which hydrogen is formed has been assumed to be: 2 Al + 3 H20 3 H2 + Al203 1 lb Al 0 0.111 lb H2 1 lb Al - 0.0555 lb-mole H2 therefore, B = 0.0555 lb-mole H 2/lb Al Zinc corrosion is treated in a similar fashion. COGAP INPUT REQUIREMENTS COGAP has been developed to minimize the required input information. All data associated with the power decay profile have been incorporated into the program and need not be entered. The major input requirements are: 1. Reactor power level, Mwt. 2. Containment free volume, ft3. 3. Second containment free volume, (wetwell), ft3. 4. Zirconium cladding weight, pounds. 5. Oxygen dissolved in primary, pound-moles. 6. Hydrogen dissolved in primary, pound-moles. 7. Initial containment pressure, psia. 8. Initial containment temperature, Rankine. 9. Initial oxygen volume fraction (.209). 6.2.5-14 Rev. 2 - July 1981 10. Recombiner flow rate, cfm. 11. Time recombiner is started, days. 12. Purge rate, cfm. 13. Zirc-water reaction fraction. 14. Aluminum surface area, ft2. 15. G-H2, core solution, mole/100 ev. 16. G-H2, sump solution, mole/100 ev. 17. Fraction of gammas absorbed in coolant in