Combustible gas control system

Question 1

Lower limits of flammability for Hydrogen is ___ by volume

Answer 1

4%

Question 2

Sources of H2 following a LOCA

Answer 2

Zirc-water reaction
H2 added to RCS for chemistry control
H2 released from corrosion of plant materials
Radiolytic decomposition of water

Question 3

Operational design of hydrogen recombiners:
Containment temperature ______

Containment Pressure ______

Inlet H2 ______

Answer 3

Containment temperature < 225°F

Containment Pressure < 21 psig

Inlet H2 < 5%

Question 4

What is the mass balance for Zr-H20 reaction?
When does the reaction become self sustaining?

Answer 4

Zr + 2H2O ZrO2 + 2H2 + Heat
Reaction accelerates at 2200°F and is self sustaining at 2800 °F.