SM: Seismic Montoring Flashcards
What is the ‘g’ rating for a SSE?
0.20g or about 6.0 on the Richter Scale
PVNGS used 0.25g when designing the plant for operational conservatism.
How do the lights behave on the Seismic Monitoring individual recorder panels? (Run, Charge, Alarm, Event)
The RUN and CHARGE lights are always on.
The EVENT light flickers unless theres an event. Then it goes solid.
ALARM light on when theres an alarm.
When is an alarm considered to be False in regards to the SM System?
When an alarm comes in but no one feels the ground move.
Where are the Seismic Monitoring Force Balance Recorders located?
All in Unit 1
Containment (55’, 80’, 140’)
Control Building (70’, 160’)
South of the Outage Support Building
If a SM alarm is determined to be >OBE, what must be done in regards to the plant?
Go to Mode 3
How are the SM recorders powered?
They receive AC power that is converted to DC locally. This DC power runs the unit and charges an internal battery that provides 30 hours of backup supply should normal AC power be lost.
How do the SM recorders behave when an accelerometer exceeds its setpoint?
Any accelerometer exceeding its setpoint will cause all digital recorders to start.
How can one verify if there was ground movement in the plant?
Look at the Spent Fuel Pool. Waves in the pool indicate motion.
If OBE was exceeded, what must be declared?
Alert
What is the definition of a Safe Shutdown Earthquake (SSE)?
“Maximum earthquake potential considering the regional and local geology and seismology that would produce maximum ground motion”.
What kind of time constraints are placed on E-Plan classification when a valid seismic event has occurred?
You have 15 minutes to classify a valid seismic event.
What kind of time limit is the STA under if a SM alarm occurs?
They have 1 hour to perform their evaluation (79IS-9SM01)
If a SM alarm is between 0.01g and OBE, what actions must be taken?
Call the U2 and U3 Shift Managers
Inspect the plant
Walk down AFN
How long does Civil Engineering have to determine if SSE was reached?
7 days
What is the definition of an Operational Basis Earthquake (OBE)?
“The vibratory ground motion for which those features of the plant necessary for continued operation without undue risk to the health and safety of the public will remain functional”
