Systems Exam 3 - Safety Chill Water

Question 1

Safety Chilled Water Loads

Answer 1

→CCW pump room emergency fan coil units
→CCP room emergency fan coil units
→Spent fuel pool heat exchanger and pump room emergency fan coil units. Fan coil units are common equipment. Can be supplied from either unit.
→SI pump room emergency fan coil units
→Containment Spray pump room fan coil units
→RHR pump room emergency fan coil units
→Aux Feedwater pump room emergency fan coil units
→Electrical switchgear area emergency fan coil units*
→Uninterruptable Power Supply (UPS) FCUs (hurricane blowers)-Local HS controlled

Note: All EFCUs will start when their associated equipment starts for any reason except for Electrical switchgear units which start directly from SI or BO

Question 2

Safety Chiller Aux Oil Pump Start

Answer 2

→In auto starts first when chiller demanded to start, 30 secs after oil pump starts the chiller starts
→Oil pump shuts off 45 secs after chiller starts
→Auto starts on chiller trip

Question 3

What Cools Safety Chiller Condensers?

Answer 3

→Safeguards CCW cools condensers
→20-300 gpm
→control valve has an accumulator to continue operation for 30 minutes following loss of air

Question 4

Safety Chiller Auto Starts

Answer 4

→SI
→BO
→Associated Recirculation Pump starts

Question 5

Safety Chiller Trips That Require Manual Reset

Answer 5

→LO oil pressure
→LO evaporator pressure
→HI condenser pressure
→HI motor temperature
→HI discharge temperature
→Motor overload
→HI oil temperature

Question 6

Chiller Trips that do not require manual reset (chiller restarts when problem clears)

Answer 6

→LO chilled water temperature
→LO CCW flow
→LO chilled water flow

Question 7

Safety Chiller Anti-Recycle feature

Answer 7

Safety Chillers provided with “Anti-Recycle” feature that prevents chiller restart for 30 minutes after chiller S/D

bypassed on SI or BO restart

Question 8

Safety Chiller Normal Start Requirements

Answer 8

→Aux oil pump running (chiller won’t start until 30 secs after LO Pump starts)
→Chill Water Pump running
→Anti-Recycle timer timed out

Question 9

Chill Water Recirc Pump Auto Starts

Answer 9

→SI
→BO
→Start of train related CCW Pump
→Only Recirc pump 5 can be controlled from RSP
→300 gpm ea, P/S uEB3-1, uEB4-1

Question 10

Safety Chilled Water Surge Tank Makeup Sources, Which Valves Cycle?

Answer 10

→Partition plate splits out tank at 88% level
→HV-6719 (Demin Water) normally closed, HV-6720 (RMUW) normally open, no automatic operation for either valve
→Train related fill valves LV-6712 and LV-6713 open and closed based on tank level

Question 11

TS LCO 3.7.20, UPS HVAC System

Answer 11

Two UPS HVAC System Trains shall be OPERABLE (Modes 1-4)
1 hour or less, actions

LCO 3.7.20.A one UPS HVAC System train inoperable

→A.1: Verify the affected UPS & Distribution Room is supported by an OPERABLE UPS A/C Train immediately AND
→A.2: Restore the inoperable UPS HVAC train to OPERABLE status within 30 days

Question 12

TR 13.7.36 “Area Temperature Monitoring”

Answer 12

One or more areas exceeds the normal temperature for more than 8 hours then restore according to CAP and complete analysis immediately.

Question 13

13.7.37 - Safety Chilled Water System

Answer 13

Electrical Switchgear Area Emergency Fan Coil Units shall be OPERABLE in MODES 1-4. If one or more is inoperable, the LCO allows you to either:

1. Declare Safety Chilled Water train(s) inoperable and enter TS LCO 3.7.19 (Immediately), or
2. Declare affected fan coil unit(s) and their support equipment inoperable (Immediately)

Question 14

Chiller Standby to Start Operation / Switch Configuration

Answer 14

→chiller local handswitch in start with chill water recirc pump H/S in auto (after stop) position keeps chiller in standby
→manual or auto start of Chill Water Recirc Pump provides start signal for Chiller
→Once Recirc pump starts and chill water min flow interlock met, then chiller oil pump kicks on and runs for 30 sec. After that, chiller starts.

Question 15

PV-4553/4552 (CCW Flow To Safety Chiller Condenser) Accumulator Sized For?

Answer 15

Control CCW flow to maintain chiller condenser pressure. Valves are air open and an air accumulator is provided which ensures operation for 30 minutes following loss of inst. air.

Question 16

Hot Gas Bypass Valve

Answer 16

Chiller has minimal load during normal ops (ΔT ≈ 10° F), so a hot gas bypass valve is installed to artificially load the chiller to ensure proper circulation of lube oil through system.

Otherwise, lube oil would drain to lower area of evaporator and remain there, starving the rest of the chiller for lubrication.

Works by cycling hot gas from discharge of compressor to evaporator HX.

Question 17

UPS Fan Coil Units
(Hurricane Blowers)

Controls

Answer 17

→locally controlled with manual handswitch
→SI - don’t get shunt tripped, so continue running
→BO - switches remain in start, so restart once power is restored

Question 18

System Limitations Before Compressor Start

Answer 18

→control power to compressor oil heaters must be energized for 12 hrs
OR
→oil temp >107° F for at least an hour
OR
→compressor oil was changed within the last hour

Question 19

Tech Spec 3.7.19

Answer 19

Two safety chilled water trains shall be operable in Modes 1-4

→one train inoperable, restore within 72 hrs or RICT; if not, Mode 3 in 6 hrs, Mode 5 in 36 hrs

→two trains inoperable, LCO 3.0.3 immediately