PLA-6225, Proposed License Amendment Nos. 285 and 253, Extended Power Uprate Application Supplement to Request for Additional Information Responses

Proposed License Amendment Nos. 285 and 253, Extended Power Uprate Application Supplement to Request for Additional Information Responses

ML071710442
Person / Time
Site:	Susquehanna
Issue date:	06/08/2007
From:	Mckinney B Susquehanna
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
PLA-6225
Download: ML071710442 (8)

Text

Britt T. McKinney Sr. Vice President & Chief Nuclear Officer U. S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop OP1-17 Washington, DC 20555 PPL Susquehanna, LLC 769 Salem Boulevard Berwick, PA 18603 Tel. 570.542.3149 Fax 570.542.1504 btmckinney@pplweb.com ass.

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SUSQUEHANNA STEAM ELECTRIC STATION PROPOSED LICENSE AMENDMENT NO. 285 FOR UNIT 1 OPERATING LICENSE NO. NPF-14 AND PROPOSED LICENSE AMENDMENT NO. 253 FOR UNIT 2 OPERATING LICENSE NO. NPF-22 EXTENDED POWER UPRATE APPLICATION SUPPLEMENT TO REQUEST FOR ADDITIONAL INFORMATION RESPONSES PLA-6225 Docket Nos. 50-387 and 50-388 References.

1) PPL Letter PLA-6076, B. T McKinney (PPL) to USNRC, "Proposed License Amendment Numbers 285 For Unit 1 Operating License No. NPF-14 and 253for Unit 2 Operating License No. NPF-22 Constant Pressure Power Uprate, "dated October 11, 2006.

2) PPL Letter PLA-6210, B. T McKinney (PPL) to USNRC, "Proposed License Amendment Numbers 285 For Unit 1 Operating License No. NPF-14 and 253for Unit 2 Operating License No. NPF-22 Extended Power Uprate Application, RE: Vessels and Internals Integrity Technical Review, Request for Additional Information Responses,"

dated May 30, 2007.

3) PPL Letter PLA-6191, B. T. McKinney (PPL) to USNRC, "Proposed License Amendment Numbers 285 For Unit 1 Operating License No. NPF-14 and 253for Unit 2 Operating License No. NPF-22 Extended Power Uprate Application, RE.- Piping and Nondestructive Examination Technical Review, Request for Additional Information Responses, "dated May 4, 2007.

4) PPL Letter PLA-6193, B. T McKinney (PPL) to USNRC, "Proposed License Amendment Numbers 285 For Unit 1 Operating License No. NPF-14 and 253for Unit 2 Operating License No. NPF-22 Extended Power Uprate Application, RE: Materials and Chemical Engineering Technical Review, Request for Additional Information Responses, "dated May 4, 2007.

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Document Control Desk PLA-6225 PPL has reviewed the "No Significant Hazards Consideration" and the "Environmental Consideration" submitted with Reference 1 relative to the Enclosure. We have determined that there are no changes required to either of these documents.

If you have any questions or require additional information, please contact Mr. Michael H. Crowthers at (610) 774-7766.

I declare under perjury that the foregoing is true and correct.

Executed on: 4

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Enclosure:

Supplement to Request for Additional Information Responses Copy:

NRC Region I Mr. A. J. Blamey, NRC Sr. Resident Inspector Mr. R. V. Guzman, NRC Sr. Project Manager Mr. R. R. Janati, DEP/BRP Document Control Desk PLA-6225 Pursuant to 10 CFR 50.90, PPL Susquehanna LLC (PPL) requested in Reference 1 approval of amendments to the Susquehanna Steam Electric Station (SSES) Unit 1 and Unit 2 Operating Licenses (OLs) and Technical Specifications (TSs) to increase the maximum power level authorized from 3489 Megawatts Thermal (MWt) to 3952 MWt, an approximate 13% increase in thermal power. The proposed Constant Pressure Power Uprate (CPPU) represents an increase of approximately 20% above the Original Licensed Thermal Power (OLTP).

The purpose of this letter is to supplement the responses to several NRC Questions contained in the Request for Additional Information Responses transmitted to NRC in References 2, 3 and 4.

The Enclosure contains the PPL supplemental responses.

There is one new regulatory commitment associated with this submittal. It follows:

Commitment Number: PLA-6225-1 "Enhanced visual testing (EVT-1) of the top guide grid beams will be performed in accordance with GE SIL 554 following the sample selection and inspection frequency of BWRVIP-47 for CRD guide tubes. That is, inspections will be performed on 10% of the total population of cells within twelve years, and 5% of the population within six years. The sample locations selected for examination will be in areas that are exposed to the highest fluence. This inspection plan will be implemented beginning with the refueling outage following EPU operation.

This inspection plan will be implemented until an NRC approved resolution is developed in accordance with the BWRVIP and implemented at SSES Unit 1 and 2."

Enclosure to PLA-6225 Supplement to Request for Additional Information Response

Enclosure to PLA-6225 Page 1 of 4 The following provides supplemental information to several NRC Questions contained in the Request for Additional Information Responses transmitted to NRC in References 2, 3 and 4.

Reference 2: PLA-6210 Response to NRC Vessel and Internal Technical Review Request for Additional Information In response to NRC question 1 (a), PPL indicated that:

"The grid beams, whose fluence exceeds the IASCC threshold, are not required to be inspected. BWRVIP-26-A, Section 2.2.1 states, "There are no safety consequences resulting from failure at a single beam intersection. Failure of an upper beam would have no consequence, and failure of a lower beam may cause some core instrument damage but would not affect safe shutdown. Also, grid beams are interlaced such that a large number of complete separations would need to occur before control rod insertion would be affected."

Based on discussion with the NRC staff and the concern that a large number of complete separations could affect control rod insertion, PPL has determined that an inspection program to manage irradiation assisted stress corrosion cracking (IASCC) for the top guide will be implemented until the issue is resolved generically with the BWRVIP.

The interim inspection program to be implemented for SSES Unit 1 and 2 (until resolution with the BWRVIP is achieved) is as follows:

"Enhanced visual testing (EVT-1) of the top guide grid beams will be performed in accordance with GE SIL 554 following the sample selection and inspection frequency of BWRVIP-47 for CRD guide tubes. That is, inspections will be performed on 10%

of the total population of cells within twelve years, and 5% of the population within six years. The sample locations selected for examination will be in areas that are exposed to the highest fluence. This inspection plan will be implemented beginning with the refueling outage following EPU operation. This inspection plan will be implemented until an NRC approved resolution is developed in accordance with the BWRVIP and implemented at SSES Unit 1 and 2."

Reference 3: PLA-6191 Response to NRC Piping and Nondestructive Examination Technical Review Request for Additional Information Per discussion with the NRC Staff, supplemental information is warranted to PPL Responses to NRC Questions 1, 2 and 4. The supplemental information is provided below.

Enclosure to PLA-6225 Page 2 of 4 NRC Question 1:

In PPL Response to NRC Question 1, PPL provided the RCPB and safe-end material properties. The NRC requested PPL provide a summary of the chemical properties of each material type listed in the Table. The list below provides the summary of each material type listed in the Table.

Carbon and Low Alloy Steels

• SA106GrB(C-.30%Mn--.7%,Ni-.4%,Cr-.4%,Mo-.15%)isa common carbon steel material.

• SA333 Gr 6 (C -. 30%, Mn -. 70%) is a carbon steel.

• SA508 Cl 1 (C -.35%, Mn -. 70%, Ni -. 40%, Cr -. 25%) is a low alloy steel forging.

Austenitic Stainless Steels

" SA182F316L (C <.035%, Mn - 2%, Ni - 10 to 15%, Cr - 16 to 18%,

Mo - 2 to 3%) is a very low carbon, austenitic stainless steel.

" SA213TP304 (C-.08%, Mn - 2%, Ni - 8 to 11%, Cr - 18 to 20%) is a common austenitic stainless steel.

" SA312TP304 (C -.08%, Mn - 2%, Ni - 8 to 11%, Cr - 18 to 20%) is a common austenitic stainless steel.

• SA312TP304L (C <.035%, Mn < 2% Ni, - 8 to 13%, Cr - 18 to 20%) is a very low carbon, austenitic stainless steel.

" SA336 C1 F8 [now F304] (C -. 08%, Mn - 2%, Ni - 8 to 11%, Cr - 18 to 20%) is an austenitic stainless steel forging specification.

• SA358TP304 (C <.08%, Mn < 2%, Ni - 8 to 10.5%, Cr -

18 to 20%) is an austenitic stainless steel.

Nickel-Chromium-Iron Alloy

• SB-166 - Alloy 600 Rod, Bar, Wire (Ni > 72%, Cr-14 to 17%, Iron-6 to 10%).

NRC Question 2:

The use of the word "Eliminate" is not accurate as used in the PPL response that addressed the evaluation of the effects of the CPPU on the RCPB piping and safe-end material where it is stated "Eliminating the presence of residual stresses by the application of Mechanical Stress Improvement or Inductive Heat Stress Improvement." As a result, the paragraph is reworded as follows:

Enclosure to PLA-6225 Page 3 of 4 "The application of Mechanical Stress Improvement or 'Inductive Heat Stress Improvement redistributes the residual tensile stresses. The results are desirable residual compressive stresses on the inside wall that inhibit IGSCC. Since the system conditions are not changing significantly, CPPU will have negligible effects on tensile stresses due to increased temperatures, pressures, and flows."

NRC Question 4:

Below is a revised PPL Response to NRC Question 4, which is provided in its entirety.

The revisions are underlined.

PPL Response:

Inductive Heat Stress Improvement (IHSI) and Mechanical Stress Improvement Process (MSIP) have been applied at SSES to reduce the RCPB component's susceptibility to IGSCC. Most welds with IGSCC susceptible material, except the dissimilar metal welds, were stress improved using IHSI before operation or within 2 years after operation. MSIP was performed after 10 years of operation on all the dissimilar metal welds and those remaining few welds that could not be stress improved with IHSI. CPPU will not change the effectiveness of these processes since CPPU does not change the IGSCC resistance of a material nor affect the beneficial compressive stresses with the IHSI or MSIP processes.

In addition, the Recirculation Inlet Safe Ends were replaced with 316L material with a carbon content of <0.02% prior to operation in order to reduce susceptibility to IGSCC.

SSES also utilizes a Moderate Hydrogen Water Chemistry (HWC-M) program to mitigate IGSCC. SSES is a Category 1 plant in accordance with BWRVIP-130, EPRI BWR Water Chemistry Guidelines. Hydrogen injection rate will be increased at EPU conditions in order to maintain feedwater hydrogen concentration at a nominal 2.0 parts per million (ppm). The goal is to maintain an electrochemical potential (ECP) value less than -230 mV (Standard Hydrogen Electrode (SHE)) > 80% of the time that reactor water temperature is > 200' F. Prior to and during the initial period of hydrogen injection, ECP sensors were installed as an integral part of a special Local Power Range Monitor (LPRM) assembly, located at core grid 32-09 to monitor water from the lower plenum region of the core. This is considered a limiting location for the purposes of ECP measurement. SSES obtained benchmark ECP measurements as the primary parameter to monitor effectiveness of hydrogen water chemistry. These probes have since burned out and will be replaced on the lead unit prior to operation at EPU conditions in accordance with BWRVIP-62 recommendations. The Unit 1 and 2 probes will be replaced prior to implementation of the CPPU on each unit.

Enclosure to PLA-6225 Page 4 of 4 Secondary parameter data has also been collected, maintained and correlated during the operation of the ECP probes and after failure due to burnout to supplement the ECP probe data. The secondary parameters included feedwater hydrogen injection rate, reactor rate cleanup influent dissolved oxygen and main steam line radiation.

These secondary parameters will continue to be used for mitigation monitoring.

The EPRI Boiling Water Reactor Vessel and Internals Application Radiolysis Model is also used to evaluate the effectiveness of hydrogen injection. The BWRVIP approach consists of deriving a correlation between the measured ECP and calculated total oxidant (02 ppb + '/2 H202) as a function of feedwater hydrogen concentration at a particular location for a plant. The Boiling Water Reactor Vessel and Internals Application radiolysis model will be used to calculate total oxidant. This correlation will be used to determine the total oxidant concentration at which the ECP decreases to -230mV (SHE).

Reference 4: PLA-6193 Response to NRC Materials and Chemical Engineering Review Request for Additional Information Based on discussion with the NRC staff, the following Table is provided to support the PPL Response to NRC Question 2. The Table identifies that the containment coating CPPU DBA-LOCA conditions are within the qualification limits of the current PPL coating program.

PARAMETER QUALIFICATION MAXIMUM

___CPPU Temperature ('F) 340 337 Pressure (psig) 70 48.6 Radiological Dose (R) 1 x10 9 8.95 x10"