South Texas 2 nuclear unit enters final repair stage

Thu Apr 5, 2012 3:10pm EDT

HOUSTON, April 5 (Reuters) - Workers at the 1,280-megawatt Unit 2
at the South Texas Project nuclear station in Texas installed the
refurbished rotor on Wednesday as the unit enters the final
restoration phase before it can restart, a plant spokesman said
Thursday.  

After a four-month forced outage, the reactor is expected to return
to service by mid-April, well before the state's peak electric
demand, officials with NRG Energy, which owns the largest stake in
the station, told investors last month.



The final restoration phase includes inspections and post-maintenance
testing before the unit is restarted, the spokesman said.   

STP 2 has been shut since Nov. 29, when the main generator
malfunctioned due to a ground fault that resulted in damage to rotor
and stator coils, South Texas Nuclear Operating Co officials said
previously.  

The 200-ton rotor was removed from the main generator and shipped to
the Siemen's Energy Center in Charlotte, North Carolina, where it
was reworked to original design specifications.  

Unit 2's 72 stator coils, weighing 800 to 1,000 pounds each,  were
removed and replaced with coils from a Siemen's facility in Fort Payne,
Alabama.  

The main generator hydrogen cooler was also shipped to a New York
vendor where it was disassembled, inspected, re-tubed and shipped
back to the site.

The Texas grid agency and regulators are watching the state's
generating supply after a heat wave in 2011 sent electric demand
soaring, straining resources. The grid operator was forced to curtail
power to some industrial customers on certain days, but avoided
rolling outages.  

STP 1, also rated at 1,280 MW, was operating at full power Thursday.    

For eight consecutive years, the STP reactors have produced more energy
than any other two-unit nuclear facility in the nation, the company said.

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