CNMT H2 Recombiners

Question 1

Purpose of H2 recombiners

Answer 1

Reduce [H2] in CNMT following accident

Question 2

Maximum set temp of H2 recombiners?why?

Minimum set temp of H2 recombiners?why?

Answer 2

1450 deg, protect recombiners

1135 deg, promote recombination

Question 3

What % [H2] is it dangerous to operate H2 recombiners?

Answer 3

4% could result in ignition of H2

Question 4

P.S. H2 recombiners

Answer 4

1. …..G

2. ….H

Question 5

How does H2 recombiners work?

Answer 5

• CNMT ventilation circulates air to unit
• flow enters intake via preheater section (not actual separate heaters just hot metal from main heaters) down to flow orifice
• as flow rises it contacts convection heaters
• H2, O2 gas is heated to point of recombination into water vapor mixture
• exits mixing chamber (mixes w/cooler cnmt air)

Question 6

What two parameters used to determine H2 recombiners setpoint?

Answer 6

Pre-LOCA CNMT temp

Post-LOCA CNMT pressure