siemens - Public Service Commission

OTHER LONG TERM RELIABILITY ISSUES
Disc keyway cracking was the most serious risk to long term reliability and economical operation of
the original Susquehanna LP turbines which led to their replacement. On the current operating LP
turbine, the main concerns that were a challenge to long term operation were:
Dovetail Cracking: Dovetail cracking is stress corrosion cracking that occurs at the rim of a turbine
disc, which is the attachment for the turbine blades. This type of failure is not as serious because it
cannot generate missiles that would be potentially dangerous to plant safety systems. Nevertheless,
this is becoming a significant industry concern and is causing some utilities to implement repair
programs to prevent further damage to their turbine rotors. Typical repair costs could be $5 million
per rotor and may require extended refueling outages to implement. The current SSES LP turbine
rotors, which are a monoblock design, have not exhibited dovetail cracking. A crack mitigation
program was in process at Susquehanna. The dovetail inspection and crack mitigation programs
were discontinued after the decision to replace the turbines was formally approved.
Inner Casing Erosion: Casing erosion was also a serious long-term reliability issue on the current LP
turbines at Susquehanna Steam Electric Station. Many nuclear operators, especially BWRs, are
considering replacement or have replaced their older turbine rotors and inner casings because of
high cost repairs associated with the severe erosion and loss of generation. Again, this was a major
consideration in the turbine retrofit.
TURBINE BID REQUEST ISSUANCE AND MmESTONE DATES
In November 1999, PPL Susquehanna LLC issued a request for bids to four vendors for retrofit LP
turbines at the Susquehanna site. This bid request also gave the bidders flexibility to quote on
options such as improved materials, high-pressure turbine components, and installation services.
Bids were received in late February 2000 with PPL project evaluations extending through November 2000.
The selection process entailed:
0 Technical Evaluations
0 Design Considerations and Clarification Meetings with Vendors
Options Assessments
Internal Meetings to Discuss Potential Future Station Uprates and Other Equipment Limitations
The evaluation period was extended by these considerations plus the need to analyze and
incorporate information from an LP turbine inspection during the Spring 2000 Unit 1 refuel outage.
In addition, meetings were held with the vendors submitting quotations to ensure their offerings
were accurately being evaluated.
A letter of intent was issued to Siemens Westinghouse on November 17*, 2000. After two months
of detailed negotiations and contract language review, the project agreement between PPL and
Siemens Westinghouse Power Corporation (SWPC) was signed on January 23,2001.