Gaseous Radwaste - 1.0

Question 1

What is the purpose of Gaseous radwaste?

Answer 1

Processes the air and non-condensable gases from the discharge of the steam jet air ejectors during startup and power operation.

Reduces H2 concentration to minimize the possibility of a H2 explosion.

Minimizes and controls the release of radioactive material into the atmosphere by delaying passage of radioactive krypton, xenon, iodine, N-13, N-16, and O-19 to allow sufficient decay time.
1. Xenon – 35 days
2. Krypton – 24 hours
3. O/N - 4 hrs

Question 2

What are the gaseous radwaste recombiner train isolation signals?

Answer 2

a. Recombiner Outlet Temperature High – 900°F
b. Feed Gas Cooler Condenser Outlet Temperature High(this occurs on a loss of RACS) – 200°F
c. Recombiner Strip Heater Control Not in Operate (Local Panel 1(0)0C320)
d. Manual PB on Panel 1(0)0C320

Question 3

What indicates moisture in the Gaseous radwaste guard bed and how do you fix it?

Answer 3

High moisture in Guard Bed will be detected by high DP (10” H2O). If this were to occur, the bed can be regenerated (dried) using hot N2.

Question 4

What valves does a recombiner isolation shut?

Answer 4

A recombiner isolation will shut the following valves (valve numbers in parenthesis are for the Common Train):
a. Nuclear Steam Supply Valves
b. SJAE Discharge Inlet Valve
c. Recombiner Outlet Isolation Valve
d. Preheater and Feed Gas Cooler Condenser Drain (Common Train Only)

Question 5

When does a recombiner dilution air addition valve auto open?

Answer 5

upon recombiner start up

Question 6

If there are no trip signals present and the open PB for the gaseous radwaste recombiners is depressed, the following valves will automatically open if the train is not selected to remote.

Answer 6

SJAE Discharge Inlet (unit 1 and common)
Recombiner Outlet(unit 1 and common)
Nuclear Steam Supply Valve(unit 1 and common)
RACS Isolation to Feed Gas Cooler Condenser(unit 1 and common)
Common Recombiner Return to Condenser(common only)

Question 7

What would cause a flashing button on the Gaseous radwaste recombiner controls and what would it look like?

Answer 7

1. If after 130 seconds, all valves (except RACS to Cooler Condenser) are not full open – Red back light will blink.
2. If after 15 seconds, all valves (except RACS to Cooler Ccondenser) are not full closed – Green back light will blink.

Question 8

Describe key design features of the Feed gas recombiner reheater.

Answer 8

1. Uses main or aux steam to preheat
2. Condensed steam drains to flash pot which drains to main condenser
3. Dilution air injects O2

Question 9

What is the Feed Gas Recycle Hydrogen High setpoint?

Answer 9

1.5%

Question 10

What is the function of the holdup pipe in the gaseous radwaste system?

Answer 10

provides for ten minute holdup of short lived radionuclides (N2).

Question 11

What is the potential hazard of having moisture in the adsorber bed in the gaseous radwaste system?

Answer 11

It is a fire hazard. It traps heat given off by decay of fission products on the charcoal

Question 12

Why is Iodine not a concern in the gaseous radwaste system?

Answer 12

Iodine is water soluble, so it just dissolves back into the water in the condenser

Question 13

What serves as a backup to the MSL rad monitors in detecting a FEF?

Answer 13

Pretreatment Rad monitors (Ion Chamber) located in the holdup pipe

Question 14

What is the purpose of the post treatement rad monitors in the gaseous radwaste system?

Answer 14

give an indication of the amount of radiation released and at what rate