Aux Steam

Question 1

Auxiliary Steam (AS) system provides low pressure steam
to...

Answer 1

• Gas Stripper
• Liquid Radwaste (LRS) system Evaporator
• Boric Acid Concentrator (BAC) for water and boron reclamation.
• Moisture Separator Reheaters (MSRs) for steam
  blanketing when the Main Turbine is secured
• Fourth point feedwater heating for startup feedwater heating
• Gland Sealing steam to the Main Turbine and Main Feedwater Pumps during unit startup.
• During refueling outages, the AS system will provide low pressure steam to
  the main feedwater pumps and the class steam driven auxiliary feed pump, AFA-P01 for overspeed testing.

Question 2

Normally, the __(1)__ supplies the Auxiliary Steam loads via a reducing station consisting of three reducing valves, which reduce the normal main steam pressure of __(2)__ down to the AS system pressure of __(3)__.

Answer 2

(1) Main Steam system
(2) 1000-1150 psig
(3) 250 psi

Question 3

Condensate receiver transfer pumps are powered from…

Answer 3

Non-Class IE 480V Power MCC System (NH)

Question 4

If radiological contamination of the condensate exists, as sensed by radiation monitor RU-7, the pump effluent will be diverted to…

Answer 4

… the LRS (Liquid Radwaste System) TDS Holdup Tanks.

Question 5

The AS system’s vent condenser is cooled by…

Answer 5

…the NC system. If NC is lost to the condenser,

auxiliary steam into the auxiliary building will have to be secured until NC can be restored.

Question 6

Describe the Auxiliary Building protection in the event of a High Energy Line Break (HELB) related
to the Auxiliary Steam piping that is routed through the building

Answer 6

In the event that a pressure of 1 psig is reached in any of 20 areas in the Aux Building, steam will
be isolated by the closure either ASNPV0331 or ASNPV0332 in order to mitigate the effects of a
possible Aux Steam line break. This condition would also cause an alarm which would pinpoint the
area affected.

Question 7

In the event of high radioactivity within the condensate, as sensed by radiation monitor RU-7, what automatic actions will occur?

Answer 7

ASN- RV-11A (discharge to the condenser) will close and ASN-RV-11B (discharge to the Low TDS Hold Up Tanks) will open, directing the condensate to the in-service LRS TDS holdup tank. This will cause an alarm to be received in the Control Room

Question 8

Upon a loss of instrument air, how will the Aux Steam condensate system respond?

Answer 8

RV-11A (discharge to the condenser) fails closed, RV-11B (discharge to the Low TDS Hold Up Tanks) fails open directing the condensate to the in-service LRS TDS holdup tank

Question 9

Describe the normal line-up and purpose of the cross tie valves ASN-V015 and ASN-V014 (bypass).

Answer 9

ASN-V015 is kept open on the Unit supplying the cross tie header. ASN-V014 (bypass) is
kept open in the Units not carrying the cross tie to allow quick restoration of AS in the
event of a Unit trip.


Question 10

Loss of the receiver transfer pumps or NC cooling flow to the vent condenser requires what actions and why.

Answer 10

Securing AS loads to prevent flooding of the HA ventilation ducting.