ML070730497

Request for Additional Information - Extended Power Uprated Application Regarding Turbine Generator Review

ML070730497
Person / Time
Site:	Susquehanna
Issue date:	03/15/2007
From:	Richard Guzman NRC/NRR/ADRO/DORL/LPLI-1
To:	Mckinney B Susquehanna
Guzman R, NRR/DORL, 415-1030
References
TAC MD3309, TAC MD3310
Download: ML070730497 (5)

Text

March 15, 2007 Mr. Britt T. McKinney Sr. Vice President and Chief Nuclear Officer PPL Susquehanna, LLC 769 Salem Blvd., NUCSB3 Berwick, PA 18603-0467

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION (RAI) - SUSQUEHANNA STEAM ELECTRIC STATION, UNITS 1 AND 2 (SSES 1 AND 2) - EXTENDED POWER UPRATE APPLICATION REGARDING TURBINE GENERATOR REVIEW (TAC NOS. MD3309 AND MD3310)

Dear Mr. McKinney:

In reviewing your letter dated October 11, 2006, concerning the request to increase the maximum steady-state power level at the SSES 1 and 2 from 3489 megawatts thermal (MWt) to 3952 MWt, the Nuclear Regulatory Commission staff has determined that additional information contained in the enclosure to this letter is needed to complete its review. These questions were discussed with your staff during a teleconference on February 20, 2007. As agreed to by your staff, we request you respond within 30 days of the date of this letter.

If you have any questions, please contact me at 301-415-1030.

Sincerely,

/ra/

Richard V. Guzman, Senior Project Manager Plant Licensing Branch I-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-387 and 50-388

Enclosure:

RAI cc w/encl: See next page

March 15, 2007 Mr. Britt T. McKinney Sr. Vice President and Chief Nuclear Officer PPL Susquehanna, LLC 769 Salem Blvd., NUCSB3 Berwick, PA 18603-0467

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION (RAI) - SUSQUEHANNA STEAM ELECTRIC STATION, UNITS 1 AND 2 (SSES 1 AND 2) - EXTENDED POWER UPRATE APPLICATION REGARDING TURBINE GENERATOR REVIEW (TAC NOS. MD3309 AND MD3310)

Dear Mr. McKinney:

In reviewing your letter dated October 11, 2006, concerning the request to increase the maximum steady-state power level at the SSES 1 and 2 from 3489 megawatts thermal (MWt) to 3952 MWt, the Nuclear Regulatory Commission staff has determined that additional information contained in the enclosure to this letter is needed to complete its review. These questions were discussed with your staff during a teleconference on February 20, 2007. As agreed to by your staff, we request you respond within 30 days of the date of this letter.

If you have any questions, please contact me at 301-415-1030.

Sincerely,

/ra/

Richard V. Guzman, Senior Project Manager Plant Licensing Branch I-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-387 and 50-388

Enclosure:

RAI cc w/encl: See next page DISTRIBUTION:

Public RidsOgcMailCenter RidsNrrPmRGuzman RidsNrrCpnbBC JTsao LPLI-1 R/F RidsNrrDorlLpl1-1 RidsAcrsAcnwMailCenter RidsNrrLaSLittle Accession Number: ML070730497

• RAI Input provided by memo. No substantive changes made.

OFFICE NRR/LPLI-1/PM NRR/LPLI-1/LA NRR/CPNB/BC NRR/LPLI-1/BC(A)

NAME RGuzman SLittle TChan*

JBoska DATE 3/15/07 3/15/07 2/12/07 3/15/07 OFFICIAL RECORD COPY

Enclosure REQUEST FOR ADDITIONAL INFORMATION RELATING TO THE APPLICATION FOR EXTENDED POWER UPRATE (EPU)

SUSQUEHANNA STEAM ELECTRIC STATION, UNITS 1 AND 2 (SSES 1 AND 2)

PPL SUSQUEHANNA, LLC DOCKET NOS. 50-387 AND 50-388 The Nuclear Regulatory Commission (NRC) staff is reviewing the request from PPL Susquehanna, LLC (PPL, the licensee) to support the application of the EPU for SSES 1 and 2.

The NRC staff has determined that additional information requested below will be needed to complete its review.

1.

On page 7-2 of the SSES 1 and 2 power uprate safety analysis report (PUSAR), the licensee stated that in 2003 for Unit 2, and 2004 for Unit 1, the low pressure rotors were changed from a monoblock design to a shrunk-on wheel design. The keyway of the shrunk-on wheel has been known to be susceptible to stress-corrosion cracking. The monoblock rotor has no keyway and is considered to be less susceptible to stress-corrosion cracking than the shrunk-on wheel. Discuss why the low pressure rotors were changed to a shrunk-on wheel design and how the shrunk-on wheel design addresses the keyway cracking that has been experienced in the past.

2.

On page 7-2 of the SSES 1 and 2 PUSAR, the licensee stated that prior to constant pressure power uprate (CPPU), the high pressure turbines in SSES 1 and 2 were replaced in 2004 and 2003, respectively. The licensee stated further that...For CPPU, the existing 12-stage high pressure monoblock rotor is being replaced by a 11-stage high pressure monoblock rotor while the existing low pressure turbine rotors are being retained...

(a)

Discuss why the high pressure turbines in both units will be replaced again after only 3 to 4 years of operation and why the low pressure turbines in both units do not need to be replaced or modified for the power uprate.

(b)

Confirm that Siemens is the turbine vendor for the 11-stage high pressure turbine rotor.

Discuss whether the structural integrity of the last stages of the low turbine (c) blades and discs will be affected due to increased steam flow as a result of CPPU in terms of (1) corrosion on the blade surfaces, (2) stress-corrosion cracking at the root of blades, and (3) vibration of the blades and discs.

(d)

Discuss whether a vibration analysis has been performed, and provide details of the analysis to demonstrate that the power uprate will not cause excessive vibration on the low-and high-pressure turbines and the generator.

3.

On page 7-2 of the SSES 1 and 2 PUSAR, the licensee states,...the missile analysis for the turbine replacement is supported by the Siemens Technical Report CT-27332, Revision 2 which was approved by the Nuclear Regulatory Commission (NRC)

(Reference 28). Reference 28 is listed on page 11-2 of the PUSAR as TP-04124-NP-A, dated June 7, 2000. The licensee states that Reference 28 refers to a prior NRC safety evaluation (Reference 54); however, Reference 54 was issued after the above referenced date. Clarify the statement on page 7-2 in terms of these two references.

4.

On page 7-3 of the SSES 1 and 2 PUSAR, the licensee stated that the results of revised turbine missile analysis showed that the turbine missile probability remains below the NRC-specified limit of 1E-05 per year.

(a)

Provide the exact missile probability value (i.e., the P1 value) after CPPU.

(b)

Discuss whether under CPPU, the high-and low-pressure turbine rotors in SSES 1 and 2 will satisfy the guidance in Standard Review Plan Section 10.2.3, Turbine Rotor Integrity.

Susquehanna Steam Electric Station, Unit Nos. 1 and 2 cc:

Robert A. Saccone Vice President - Nuclear Operations PPL Susquehanna, LLC 769 Salem Blvd., NUCSB3 Berwick, PA 18603-0467 Terry L. Harpster General Manager - Plant Support PPL Susquehanna, LLC 769 Salem Blvd., NUCSA4 Berwick, PA 18603-0467 Rocco R. Sgarro Manager - Nuclear Regulatory Affairs PAL Susquehanna, LLC Two North Ninth Street, GENPL4 Allentown, PA 18101-1179 Walter E. Morrissey Supervising Engineer Nuclear Regulatory Affairs PAL Susquehanna, LLC 769 Salem Blvd., NUCSA4 Berwick, PA 18603-0467 Michael H. Crowthers Supervising Engineer Nuclear Regulatory Affairs PAL Susquehanna, LLC Two North Ninth Street, GENPL4 Allentown, PA 18101-1179 Steven M. Cook Manager - Quality Assurance PAL Susquehanna, LLC 769 Salem Blvd., NUCSB2 Berwick, PA 18603-0467 Luis A. Ramos Community Relations Manager, Susquehanna PAL Susquehanna, LLC 634 Salem Blvd., SSO Berwick, PA 18603-0467 Bryan A. Snapp, Esq Assoc. General Counsel PAL Services Corporation Two North Ninth Street, GENTW3 Allentown, PA 18101-1179 Supervisor - Document Control Services PAL Susquehanna, LLC Two North Ninth Street, GENPL4 Allentown, PA 18101-1179 Richard W. Osborne Allegheny Electric Cooperative, Inc.

212 Locust Street P.O. Box 1266 Harrisburg, PA 17108-1266 Director, Bureau of Radiation Protection Pennsylvania Department of Environmental Protection Rachel Carson State Office Building P.O. Box 8469 Harrisburg, PA 17105-8469 Senior Resident Inspector U.S. Nuclear Regulatory Commission P.O. Box 35, NUCSA4 Berwick, PA 18603-0035 Regional Administrator, Region 1 U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Board of Supervisors Salem Township P.O. Box 405 Berwick, PA 18603-0035 Dr. Judith Johnsrud National Energy Committee Sierra Club 443 Orlando Avenue State College, PA 16803