SESS Flashcards
What is the Safety Equipment Status System (SESS) Function / Design Bases?
- To monitor the status of Engineered Safety Features (ESF) equipment and alert the control room operator by distinct visual and audible means when any of the monitored ESF equipment becomes inoperable or bypassed. (White Light)
- To monitor the status of ESF components in the event of an ESFAS and alert the control room operator by distinct visual and audible means when any of the monitored ESF component did not complete transition to the required safe operating position. (Blue Light)
What conditions can cause a white SEIS light for ‘A’ HPSI pump?
1) Supply breaker is not fully racked in
2) Control power is removed (RRA breaker open or control power fuses removed)
3) 86 lockout is tripped
4) Closing springs are discharged
What conditions are required for a blue SEAS light for ‘A’ HPSI pump?
‘A’ train SIAS & ‘A’ HPSI pump supply breaker is open. (ESFAS actuation and component is not in actuated position)
When should the control room staff enter a manual SESS alarm?
Entered when a system is rendered inoperable by a non-alarmed function or when directed by procedure.
What is the purpose of the Safety Equipment Inoperable Status (SEIS) portion of the Safety Equipment Status System?
To monitor the status of the Engineered Safety Features (ESF) equipment and alert the control room operator by distinct visual and audible means when any of the monitored ESF equipment becomes inoperable or bypassed.
What is the purpose of the Safety Equipment Actuation Status (SEAS) portion of the Safety Equipment Status System?
To monitor the status of Engineered Safety Features (ESF) components in the event of an ESF actuation signal and alert the control room operator by distinct visual and audible means when any of the monitored ESF components did not complete transition to the required safe operating position.
What is the power supply for SESS?
The SESS Panels receive power from the ‘A’ Train and ‘B’ Train 125 VDC Class Distribution buses (PK)
How does SESS interact with PPS?
SESS receives safety signal inputs from PPS.
Describe the interaction between SESS and QSPDS (SH).
SESS sends the status of Containment Isolation Valves to QSPDS.
Describe the Safety Equipment Inoperable Status (SEIS) sub-system.
The Safety Equipment Inoperable Status (SEIS) sub-system indicates any specific component of safety equipment which has been rendered inoperable by illuminating a white light on the component level indicator panel.
Describe the Safety Equipment Actuation Status (SEAS) sub-system.
The Safety Equipment Actuation Status (SEAS) sub-system indicates any specific component of safety equipment that does not transfer to its safe position upon the receipt of a safety actuation signal by illuminating a blue light on the component level indicator panel.
What does the SESS ‘ALARM RESET’ button do?
Acknowledges alarms received on the associated system level window cabinet by silencing the audible device (either SEIS or SEAS tone); the ‘ALARM RESET’ does not affect window or component indicator panel lamp operation.
What does the SESS ‘FLASHER RESET’ button do?
Changes a fast flashing window to steady on for sustained alarms, or a fast flashing window to slow flashing for momentary alarms.
What does the SESS ‘LAMP RESET’ button do?
Changes a slow flashing window to off after the alarm condition has cleared.
What does the SESS ‘BYPASS/INOP TEST’ button do?
Simulates an alarm condition for all SEIS inputs; lights all system level alarm windows (white fast flashing) and component level indicator (white steady on) lamps; testing is completed by operating the reset buttons.
What does the SESS ‘STATUS TEST’ button do?
Simulates an alarm condition for all SEAS inputs along with simulating all safety actuation signals; lights all system level windows (blue fast flashing) and component level indicator (blue steady on) lamps; testing is completed by operating the reset buttons.
What does the SESS ‘STATUS DISPLAY’ button do?
Simulates actuation of all safety actuation signal inputs only to provide the operator with position information (safe/not safe) for all automatically actuated safety equipment; those components that are not in a safe condition (ESF actuated position) when the STATUS DISPLAY button is depressed are indicated by a blue steady on light on the component level indicator panel; testing is complete when the STATUS DISPLAY button is released.
Describe the condition required to generate ‘SESS PWR OR GND TRBL’.
- SESS Panel Power Supply Trbl- SESS Panel Ground- SESS Loss of Power
When is a manual SESS required?
When any SESS annunciator panel monitored component or system is:
- disabled and unable to perform its function by any method that is not alarmed
- rendered incapable of performing its design function by any method that is not alarmed
When is a Manual SESS required to be initiated?
when the condition is anticipated to last longer than the current shift
What does SEIS monitor for pumps and fans?
Control power status
Breaker in operate position for LC and Switchgear powered devices
Overload or 86 status
How are automatically operated valves monitored by SEIS?
Breaker 52 contact for MCC powered MOVs
Control power fuses
Disconnect switch status for SOVs and AOVs
Breaker overload
How are non-auto valves monitored by SEIS?
Valve in proper position
Control power status
How are automatically operated valves monitored by SEAS?
valve in actuated position and actuation signal present
What will happen if a component monitored by SESS loses power?
SEIS alarm
Unit 3 has a LOP on PBA-S03
Train A Spray Pond pump has a blue SESS alarm
What is the status of the A ESP Pump?
Was given signal to start but failed to start
Unit at 100% power and the Essential Chiller A breaker is racked out with control power removed. What SESS indications would be in?
White light only
