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[cdn-nucl-l] start of SONGS U3 SG replacement
Unit 3 shut down Oct. 10 for refueling, maintenance and steam generator
Posted October 10 
Southern California Edison shut down Unit 3 of its San Onofre Nuclear
Generating Station today at 1:26 a.m. (Pacific) for a planned maintenance
and refueling outage that will include replacement of the unit's two steam
generators. The utility expects the outage to last three to four months.
Unit 2 continues to operate normally. Edison replaced the Unit 2 steam
generators during a similar outage last fall.
How Do You Replace a Steam Generator?
Step 1 - All nuclear fuel is removed from the reactor and placed in a
building designed for safe storage.
Step 2 - A temporary 28'-by-28' opening is created to allow removal of the
original steam generators and installation of the new components.
Step 3 - The original steam generators are disconnected from their piping
Step 4 - A special crane lifts the original steam generators and places them
on a rail system running through the opening, sliding them outside the dome
where they are lowered to a heavy haul vehicle and transported to a storage
Step 5 - The new steam generators are lifted and placed inside the dome
using the process described in Step 4 in reverse.
Step 6 - The new generators are connected to their piping and supports; the
crane system removed; the opening resealed; and equipment located where the
opening was created reinstalled.
Step 7 - Extensive inspections and testing are done to ensure the new
components and reactor coolant system are working correctly.
Step 8 - Personnel start up the unit and conduct functional testing. Then
power production resumes.