L-2008-235, Request for Extension of the Completion Date of the St. Lucie Unit 1 NRC Generic Letter 2004-02 Actions

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Request for Extension of the Completion Date of the St. Lucie Unit 1 NRC Generic Letter 2004-02 Actions
ML083080377
Person / Time
Site: Saint Lucie NextEra Energy icon.png
Issue date: 10/29/2008
From: Johnston G
Florida Power & Light Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
L-2008-235
Download: ML083080377 (14)
v • d • e


Text

Florida Power & Light Company, 6501 S. Ocean Drive, Jensen Beach, FL 34957 October 29, 2008 L-2008-235 FPL 10 CFR 50.54(0 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 RE: Florida Power and Light Company St. Lucie Unit 1 Docket No. 50-335 Request for Extension of the Completion Date of the St. Lucie Unit 1 NRC Generic Letter 2004-02 Actions

References:

(1) Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors," dated September 13, 2004 (2) Letter L-2005-034 from J. A. Stall (FPL) to U. S. Nuclear Regulatory Commission, "Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized Water Reactors," dated March 4, 2005 (ML050670429)

(3) Letter L-2005-181 from J. A. Stall (FPL) to U. S. Nuclear Regulatory Commission, "Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized Water Reactors - Second Response," dated September 1, 2005 (ML052490339)

(4) Letter from B. T. Moroney (U. S. Nuclear Regulatory Commission) to J. A.

Stall (FPL), "St. Lucie Plant, Units 1 and 2 - Request for Additional Information (RAI) Related to Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Sump Recirculation During Design Basis Accidents at Pressurized Water Reactors," dated June 2, 2005 (ML051520183)

(5) Letter L-2005-145 from J. A. Stall (FPL) to U. S. Nuclear Regulatory Commission, "Generic Letter 2004 Request for Additional Information -

Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized Water Reactors," dated July 20, 2005 (ML052080038)

(6) Letter from B. T. Moroney (U. S. Nuclear Regulatory Commission) to J. A.

Stall (FPL), "St. Lucie, Units 1 and 2, Request for Additional Information Re:

Response to Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design-Basis Accidents at Pressurized-Water Reactors," dated February 8, 2006 (ML060370396)

(7) Letter from C. Haney (U. S. Nuclear Regulatory Commission) to Holders of Operating Licensees for Pressurized-Water Reactors, "Alternative Approach for Responding to the Nuclear Regulatory Commission Request an FPL Group company FIN

St. Lucie Unit 1 L-2008-235 Docket No. 50-335 Page 2 of 5 for Additional Information RE: Generic Letter 2004-02," dated March 28, 2006 (ML060870274)

(8) Letter from C. Haney (U. S. Nuclear Regulatory Commission) to Holders of Operating Licenses for Pressurized-Water Reactors, "Alternative Approach for Responding to the Nuclear Regulatory Commission Request for Additional Information Letter Regarding Generic Letter 2004-02," dated January 4, 2007 (ML063460258)

(9) Letter from W. H. Ruland (U. S. Nuclear Regulatory Commission) to A.

Pietrangelo (Nuclear Energy Institute), "Content Guide for Generic Letter 2004-02 Supplemental Responses," dated August 15, 2007 (ML071060091)

(10) Letter from W. H. Ruland (U. S. Nuclear Regulatory Commission) to A.

Pietrangelo (Nuclear Energy Institute), "Revised Content Guide for Generic Letter 2004-02 Supplemental Responses," dated November 21, 2007 (ML073110269)

(11) Letter from W. H. Ruland (U. S. Nuclear Regulatory Commission) to A.

Pietrangelo (Nuclear Energy Institute), "Supplemental Licensee Responses to Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors," dated November 30, 2007 (ML073320176)

(12) Letter L-2007-155 from J. A. Stall (FPL) to U. S. Nuclear Regulatory Commission "Request for Extension of Completion Date of the St. Lucie Unit 1, St. Lucie Unit 2 and Turkey Point Unit 3 Generic Letter 2004-02 Actions," dated December 7, 2007 (ML073450338)

(13) Letter L-2007-194 from J. A. Stall (FPL) to U. S. Nuclear Regulatory Commission "Response to Questions Regarding Request for Extension of Completion Date of the St. Lucie Unit 1, St. Lucie Unit 2 and Turkey Point Unit 3 Generic Letter 2004-02 Actions," dated December 20, 2007 (M L080090147)

(14) Letter from T. H. Boyce (U. S. Nuclear Regulatory Commission) to J. A.

Stall (FPL) "St. Lucie Nuclear Plant, Units 1 and 2, and Turkey Point Nuclear Plant, Unit 3 - Generic Letter 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design-Basis Accidents at Pressurized Water Reactors, Extension Request Evaluation," dated December 28, 2007 (ML073610401)

(15) Letter L-2008-030 from G. L. Johnston (FPL) to U. S. Nuclear Regulatory Commission "Supplemental Response to NRC Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors," dated February 27, 2008 (ML080650560)

St. Lucie Unit 1 L-2008-235 Docket No. 50-335 Page 3 of 5 (16) Letter L-2008-137 from G. L. Johnston (FPL) to U. S. Nuclear Regulatory Commission Supplemental Response to NRC Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors," dated June 30, 2008 (MLL081840513)

(17) Letter from B. L. Mozafari (U. S. Nuclear Regulatory Commission) to J. A.

Stall (FPL) "St. Lucie Plant, Unit 1 - Request for Additional Information (RAI) Related to Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Sump Recirculation at Pressurized-Water Reactors," dated September 17, 2008 (ML082610690)

(18) NRC SECY 06-0078, "Status of Resolution of GSI-191, Assessment of

[Effect of] Debris Accumulation on PVVR Sump Performance," March 31, 2006 (M L053620174)

The U. S. Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at.

Pressurized-Water Reactors, (Reference 1) to request that licensees perform an evaluation of the emergency core cooling system (ECCS) and containment spray system (CSS) recirculation functions in light of the information provided in the GL and, if appropriate, take additional actions to ensure system function. Additionally, the GL requested addressees to provide the NRC with a written response in accordance with 10 CFR 50.54(f). The request was based on identified potential susceptibility of the pressurized water reactor (PWR) recirculation sump screens to debris blockage during design basis accidents requiring recirculation operation of ECCS or CSS and on the potential for additional adverse effects due to debris blockage of flowpaths necessary for ECCS and CSS recirculation and containment drainage.

References 2 and 3 provided the Florida Power and Light Company (FPL) response to the GL.

Reference 4 requested additional information regarding the Reference 2 response to the GL for St. Lucie Unit 1. Reference 5 provided the FPL response to Reference 4. Reference 6 requested FPL to provide additional information to support the NRC staff's review of References 2, 3, and 5. Reference 7 provided an alternative approach and timetable that licensees may use to address outstanding requests for additional information (i.e., Reference 6).

Reference 8 supplemented Reference 7 with the NRC expectation that all. GL 2004-02 responses would be provided no later than December 31, 2007. For those licensees granted extensions to allow installation of certain equipment in spring 2008, the NRC staff expects that the facility response will be appropriately updated with any substantive GL corrective action, analytical results, or technical detail changes within 90 days of the change or outage completion. As further described in Reference 8, the NRC expects that all licensees will inform the NRC, either in supplemental GL 2004-02 responses or by separate correspondence as appropriate, when all GSI-191 actions are complete.

Reference 9 describes the content to be provided in a licensee's final GL 2004-02 response that the NRC staff believes would be sufficient to support closure of the GL. Reference 10 revised the guidance provided in Reference 9 by incorporating minor changes which were viewed by the NRC as clarifications.

Reference 11 authorized all PWR licensees up to two months beyond December 31, 2007 (i.e.,

to February 29, 2008), to provide the supplemental responses to the NRC.

St. Lucie Unit 1 L-2008-235 Docket No. 50-335 Page 4 of 5 In Reference 12, FPL requested an extension for completing St. Lucie Unit 1 chemical effects testing and analysis activities until June 30, 2008, and in-vessel and ex-vessel downstream effects evaluations until March 31, 2008. Reference 13 provided FPL's response to NRC questions regarding Reference 12. The extension request was approved in the Reference 14 evaluation.

In Reference 15, FPL provided the initial GL 2004-02 supplemental response using the content guide provided in Reference 9. In Reference 16, FPL provided an updated supplemental response, as discussed in References 12, 13, 14, and 15, using the NRC Revised Content Guide for GL 2004-02 Supplemental Responses, dated November 21, 2007, that was provided by the NRC in Reference 10.

In Reference 16, the response included the results of Alion Science and Technology chemical testing at the VUEZ facility, and responses to remaining NRC RAI's. In Reference 17, the NRC stated that they had issues with the testing protocol of the VUEZ testing and included a group of RAI's pertaining to the chemical test program. This letter also recommended that FPL request an extension using the SECY-06-0078 process provided in Reference 18.

As requested in Reference 17, FPL held a teleconference with the NRC on October 3, 2008 to discuss the St. Lucie Unit 1 chemical effects testing. During the telephone conference, it was stated that FPL

  • will be utilizing an alternate testing approach to validate adequate performance of the containment sump,

" will be providing a plan and schedule for demonstrating adequate sump performance,

" will be meeting with the NRC to discuss the plan in more detail,

  • will be submitting an extension request in accordance with SECY 06-0078, and
  • will not be specifically addressing the NRC's RAIs in the extension request.

The purpose of this letter is to request an extension of the completion date for GL 2004-02 closeout for St. Lucie Unit 1 until July 30, 2009. Attachment 1 provides FPL's plan and schedule for validating adequate performance of the containment sump. Attachment 1 also provides the basis supporting FPL's conclusion that it is acceptable to extend completion of the corrective actions required by GL 2004-02 for St. Lucie Unit 1 until July 30, 2009. Additionally, outlines the mitigative actions (including permanent plant modifications) already taken to improve existing margins until the chemical effects testing issues are resolved. The basis for the extension request specifically addresses the criteria contained in SECY 06-0078 (Reference 18).

It is noted that this extension is based on successful confirmation of margins provided by the GL 2004-02 modifications. However, it is possible that additional outage related plant modifications may be required. If needed, these modifications would be installed in the spring of 2010 refueling outage. FPL will contact the NRC if additional corrective actions are required.

In summary, FPL has made substantial improvements with respect to the St. Lucie Unit 1 containment sump. FPL has substantially increased the strainer area. Considerable resources have been expended for insulation modification. Pump seals have been upgraded to improve their reliability. Additionally, FPL continues to participate in GSI-191 industry meetings to facilitate aggressive resolution of open issues. These efforts have significantly improved the safety margin associated with the containment sumps.

St. Lucie Unit 1 L-2008-235 Docket No. 50-335 Page 5 of 5 This information is provided in accordance with 10 CFR 50.54(f).

Please contact Ken Frehafer at (772) 467-7748 if you have any questions regarding this extension request.

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

Executed on d2-.M--4 Z9P, Sincerely yours, Gordon L. Johnston Site Vice Preside~nt St. Lucie Plant Attachments: (1) cc: NRC Regional Administrator, Region II USNRC Project Manager, St. Lucie Nuclear Plant Senior Resident Inspector, USNRC, St. Lucie Nuclear Plant

St. Lucie Unit 1 *L-2008-235 Docket No. 50-335 Attachment Page 1 of 9 ATTACHMENT 1 St. Lucie Unit 1 GL 2004-02 Extension Request Basis for Acceptability of the Request for the Extension of Completion Date of St. Lucie Unit 1 GL 2004-02 Actions

St. Lucie Unit 1 L-2008-235 Docket No. 50-335 Attachment Page 2 of 9 Basis for Acceptability of the Request for the Extension of the Completion Date of St. Lucie Unit 1 GL 2004-02 Actions

1. Background

The U. S. Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors, (Reference 1) to request that licensees perform an evaluation of the emergency core cooling system (ECCS) and containment spray system (CSS) recirculation functions in light of the information provided in the GL and, if appropriate, take additional actions to ensure system function. Additionally, the GL requested addressees to provide the NRC with a written response in accordance with 10 CFR 50.54(0. The request was based on identified potential susceptibility of the pressurized water reactor (PWR) recirculation sump screens to debris blockage during design basis accidents requiring recirculation operation of ECCS or CSS and on the potential for additional adverse effects due to debris blockage of flowpaths necessary for ECCS and CSS recirculation and containment drainage.

By letter dated June 30, 2008 (Reference 2), Florida Power and Light Company (FPL),

the licensee for St. Lucie Unit 1, submitted the updated supplemental response requested by the GL. In this letter, FPL informed the NRC that all GL related GSI-191 actions for St. Lucie Unit 1 have been completed. These actions included the installation of a new sump strainer system during the St. Lucie Unit 1 refueling outage SL1-21 in spring 2007. The new strainer system is a General Electric design with a surface area of greater than 8100 ft 2 with 1/16-inch perforations to retain debris. This is a significant increase over the surface area of the previous outer sump screens with a surface area of 366 ft 2 and %-inch openings. The previously installed inner screens could filter out particles 1 4-inch and smaller. St. Lucie Unit 1 plant specific strainer sector and chemical effects testing and analysis confirmed that the newly installed strainers are of sufficient size to demonstrate acceptable ECCS pump net positive suction head (NPSH) margin when fully loaded with debris.

Additional corrective actions implemented during the spring 2007 outage included 1) installing stainless steel banding of selected calcium silicate insulation within the zone of influence to reduce the quantity of calcium silicate debris that can be transported to the new strainers, and 2) replacing the High Pressure Safety Injection (HPSI) pump seals and cyclone separators with a seal system that does not use cyclone separators or rely on fluid flushing that uses HPSI pump discharge.

In Reference 3, the NRC stated that they have identified several critical issues with the test protocol used in the chemical effects testing performed at VUEZ for St. Lucie Unit 1, as described in the NRC request for additional information (RAI). The NRC also stated that based on their review of the information provided by Alion on the VUEZ testing, they have concluded that it is highly unlikely that reliance on the VUEZ testing performed to date to demonstrate strainer adequacy will provide an adequate technical basis to resolve GL 2004-02. The NRC stated that an alternative approach to demonstrate adequate performance of the containment sump may need to be considered by FPL; and should an alternate approach be utilized, response to the specific RAIs is not

St. Lucie Unit 1 L-2008-235 Docket No. 50-335 Attachment Page 3 of 9 necessary. The NRC requested a telephone conference to discuss FPL's plan for demonstrating adequate sump performance by October 3, 2008, and stated that they expect that a public meeting with FPL will be needed to discuss the plan in more detail.

Finally, the NRC stated that FPL will need to submit an extension request in accordance with the established process from SECY 06-0078 (Reference 4); and that a detailed description of FPL's plans and schedule will need to be included in the extension request.

On October 3, 2008 a telephone conference was held between FPL and NRC representatives to discuss the St. Lucie Unit 1 chemical effects testing. During the telephone conference, it was stated that FPL

  • will be utilizing an alternate testing approach to validate adequate performance of the containment sump,
  • will be providing a plan and schedule for validating adequate sump performance,
  • will be meeting with the NRC to discuss the plan in more detail,
  • will be submitting an extension request in accordance with SECY 06-0078, and
  • will not be specifically addressing the NRC's RAIs in the extension request.

FPL is requesting an extension of the completion date for GL 2004-02 closeout for St.

Lucie Unit 1 until July 30, 2009, in order to utilize an alternate testing approach to the previous chemical effects tests to validate adequate performance of the containment sump; and to provide a supplemental response to the NRC that addresses the chemical effects tests.

In the GL, the NRC Staff summarized their reasoning and assessment to conclude that existing pressurized water reactors (PWRs) may continue to operate through December 31, 2007 while responding to the GL and implementing the required corrective actions.

The requested extension of the GSI-191 full implementation schedule to July 30, 2009, does not impact the NRC staffs original conclusions summarized in GL 2004-02, wherein the staff concluded that it is acceptable to operate until the corrective actions are completed. An estimate of the potential additional risk forthe requested extension is provided. The following sections also address the three criteria specified in SECY 06-0078 (Reference 4) that the NRC Staff expects to be satisfactorily addressed in an extension request.

2. Risk Estimate Introduction This section summarizes the calculation of the risk impact of extending the completion of Generic Letter 2004-02 actions at St. Lucie Unit 1 until July 30, 2009.

Background

NRC Generic Safety Issue GSI-191 identifies that the current design basis methodology for assessing the potential for debris-induced sump blockage may not be conservative.

Westinghouse developed a report, WCAP-16362, "PRA Modeling Template for Sump Blockage" (Reference 5) that addresses the implications of sump blockage on risk. This

St. Lucie Unit 1 L-2008-235 Docket No. 50-335 Attachment Page 4 of 9 WCAP provides a general model for sump blockage but did not produce quantitative values. The WCAP modeling approach was used in this simplified evaluation.

Evaluation The risk impact is limited to large-break LOCAs, since only these LOCAs are large enough to create enough debris to clog the containment sump. The frequency of a large-break LOCA is 1.33E-06 per year (NUREG/CR-6928, "Industry-Average Performance for Components and Initiating Events at U.S. Commercial Nuclear Power Plants" (Reference 6). Minimal credit is taken for mitigation of sump blockage given a large-break LOCA. At St. Lucie Unit 1, mitigation includes establishing the minimum required sump suction (stopping safety injection pumps and containment spray pumps as conditions permit) and making up to the refueling water tank (RWT) to allow extended injection. These actions are based on steps in the emergency procedures. For these recovery actions, a screening value of 0.2 was used for the probability of failing to successfully perform these mitigating activities.

Conclusion The increase in the core damage frequency due to clogging of the sump is therefore (1.33E-06 per year) * (0.2) = 2.66E-07 per year.

This calculated increase in the core damage frequency is well below the Regulatory Guide 1.174 (Reference 7) definition of less than 1E-06 per year for a "very small change" in core damage frequency. Therefore, extending the completion of GL 2004-02 Actions at St. Lucie Unit 1, until July 30, 2009, does not pose a significant increase in risk.

3. SECY 06-0078 Criteria SECY 06-0078, "Status of Resolution of GSI-191, Assessment of [Effect of] Debris Accumulation on PWR Sump Performance" (Reference 4) specifies three criteria to be addressed in GL 2004-02 extension requests. These criteria and the FPL responses are provided below.
a. SECY 06-0078 Criterion 1 "The licensee has a plant-specific technical/experimental plan with milestones and schedule to address outstanding technical issues with enough margin to account for uncertainties."

FPL Response:

As described above, on October 3, 2008 a telephone conference was held between FPL and NRC representatives to discuss the St. Lucie Unit 1 chemical effects testing; and the plan and schedule for the alternate approach. FPL's plan and schedule are provided in Table 1.

St. Lucie Unit 1 L-2008-235 Docket No. 50-335 Attachment Page 5 of 9 Table 1 St. Lucie Unit 1 Plan and Schedule for Verifying Adequate Performance of the Containment Sump Activity Target Completion Date Develop a draft test protocol. November 30, 2008 Meet with the NRC to discuss FPL's plan and schedule. December 31, 2008 FPL to review conservatisms in input parameters and the January 15, 2009 base analysis Identify methods to reduce debris loads (e.g. insulation January 15, 2009 replacement) in order to develop scenarios for "test for success".

Perform testing. This testing will include contingency March 31, 2009 debris and chemical load tests to achieve acceptable results (test for success).

Revise calculations and analyses. June 30, 2009 Provide a supplemental response addressing the July 30, 2009 chemical effects testing to the NRC.

b. SECY 06-0078 Criterion 2 "The licensee identifies mitigative measures to put in place prior to December 31, 2007, and adequately describes how these mitigative measures will minimize the risk of degraded ECCS and CSS functions during the extension period."

FPL Response:

The following mitigative measures have been implemented and will minimize the risk of degraded ECCS and CSS functions during the extension period:

St. Lucie Unit 1 L-2008-235 Docket No. 50-335 Attachment Page 6 of 9 Leak- Before-Break St. Lucie Unit 1 has NRC approval (Safety Evaluation Report attached to NRC letter dated March 5, 1993) (Reference 8) to invoke the leak-before-break technology to eliminate the dynamic effects of postulated primary coolant piping (hot leg, cold leg, and cross-over piping) ruptures from the licensing and design basis of the plant. The approval was based on the conclusion that the leakage detection systems are diverse and provide reasonable assurance that primary system leakage (both identified and unidentified) will be detected and meet the requirements of General Design Criterion 30 with respect to provisions for reactor coolant pressure boundary (RCPB) leakage detection and identification, and the guidelines of Regulatory Guide 1.45 (Reference 9) with respect to RCPB leakage detection system design are, therefore, acceptable.

While leak-before-break is not being used to establish the design basis load on the sump strainer, it does provide a basis for safe continued operation until completion of GL 2004-02 actions.

Chokepoint Walkdown A walkdown of the St. Lucie Unit 1 containment, to identify chokepoints in the recirculation flow paths, did not identify any chokepoints.

Procedural Guidance, Training and Actions As discussed in our responses to NRC Bulletin 2003-01, "Potential Impact of Debris Blockage on Emergency Sump Recirculation at Pressurized-Water Reactors,"

(Reference 10) St. Lucie Unit 1 has implemented a number of interim corrective actions to assure core cooling and containment integrity (References 11 and 12). In the NRC letter of September 30, 2005 (Reference 13) the staff concluded that FPL was responsive to and met the intent of Bulletin 2003-01 for St. Lucie Unit 1.

Operators are trained and have guidance for continuously monitoring ECCS and CSS pump parameters, including loss of NPSH as indicated by erratic pump current or discharge flow. Training briefs presented during operator requalification training have increased operations personnel awareness of the potential for the containment recirculation sump to become clogged during operation of the ECCS and CSS pumps in the recirculation cooling mode. Procedural actions were developed to provide additional RWT makeup in the event that sump blockage prevents continued recirculation. Initial RWT levels are being maintained higher than required by the Technical Specifications to delay entry into recirculation and provide additional available NPSH.

Containment Cleanliness FPL has implemented a number of actions to enhance containment cleanliness as documented in the response to NRC Bulletin 2003-01, Potential Impact of Debris Blockage on Emergency Sump Recirculation at Pressurized-Water Reactors, (Reference 12). Detailed containment cleanliness procedures exist for unit restart readiness and for containment entry at power. These procedures incorporate the industry guidance of Nuclear Energy Institute (NEI) 02-01, revision 1 (Reference 14) to minimize miscellaneous debris sources within the containment. The requirements to assure that

St. Lucie Unit 1 L-2008-235 Docket No. 50-335 Attachment Page 7 of 9 the containment is free of loose debris and fibrous material, and that items not approved for storage in the containment are removed, are specifically addressed. Plant procedures also require that the Plant General Manager and the Site Vice President perform a detailed walkdown of the containment prior to entry into Mode 4 at the end of each refueling outage to ensure plant readiness. Detailed containment sump inspections are performed at the end of each outage.

Information Notice (IN) 2005-26 On September 16, 2005, the NRC issued IN 2005-26, "Results of Chemical Effects Head Loss Tests in a Simulated PWR Sump Pool Environment" (Reference 15). The IN applies to plants that have calcium silicate (Cal-Sil) insulation and utilize trisodium phosphate (TSP) as a buffering agent in the containment sump. St. Lucie Unit 1 uses sodium hydroxide as a buffering agent, not TSP. Therefore, St. Lucie Unit 1 is not susceptible to the chemical effects issues delineated in the IN.

Permanent Modifications The following permanent physical improvements to St. Lucie Unit 1 were implemented during refueling outage SL1-21 (spring 2007):

The sump screens have been completely replaced with a strainer system that has a total strainer surface area of greater than 8100 ff2 with perforations of 1/16-inch. The new system consists of 21 strainer modules with interconnecting piping and is completely passive.

The High Pressure Safety Injection (HPSI) pump seals and cyclone separators have been replaced with a seal system that does not use cyclone separators or rely on the HPSI pumped water for flushing and cooling the mechanical seals. The new seal system recirculates the clean seal cavity water through an external heat exchanger to flush and cool the seal faces; Calcium-silicate insulation (Cal-Sil) on selected piping in the containment has been fitted with a banding system to reduce the Cal-Sil zone of influence (ZOI) from 5.45D to 3D which significantly reduces the quantity of debris that can reach the strainers. A Westinghouse jet impingement test report performed specifically for FPL documents the testing of the banded Cal-Sil insulation and demonstrates that banded Cal-Sil insulation at St. Lucie Unit 1 can be excluded as a debris source when the ZOI > 3D (pipe diameters).

c. SECY 06-0078 Criterion 3 "For proposed extensions beyond several months, a licensee's request will more likely be accepted if the proposed mitigative measures include temporary physical improvements to the ECCS sump or materials inside the containment to better ensure a high level of sump performance."

FPL Response:

There are no temporary physical improvements required for St. Lucie Unit 1 to support the requested extension until July 30, 2009. As discussed under criterion 2, the final

St. Lucie Unit 1 L-2008-235 Docket No. 50-335 Attachment Page 8 of 9 sump strainers and other modifications for St. Lucie Unit 1 have been installed and appropriate plant mitigative measures have already been implemented.

d. Conclusions An extension until July 30, 2009 for completing the required GL 2004-02 actions is acceptable because:
1. The calculated increase in the core damage frequency is well below the Regulatory Guide 1.174 definition of less than 1E-06 per year for a "very small change" in core damage frequency. Therefore, extending the completion of the confirmation of the acceptability of the sump modifications at St. Lucie Unit 1 does not pose a significant increase in risk.
2. FPL has taken aggressive action, including extensive analysis and testing, and has implemented physical improvements (including a new larger sump strainer) to better ensure a high level of sump performance.
3. FPL has implemented mitigative measures that will minimize the risk of degraded ECCS/CSS functions during the extension period.
4. FPL has a plant-specific plan with milestones to address outstanding technical issues with margin to account for uncertainties.
4. References
1. Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors,"

dated September 13, 2004

2. Letter L-2008-137 from G. L. Johnston (FPL) to U. S. Nuclear Regulatory Commission "Supplemental Response to NRC Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors," dated June 30, 2008 (ML081840513)
3. Letter from B. L. Mozafari (U. S. Nuclear Regulatory Commission) to J. A.

Stall (FPL) "St. Lucie Plant, Unit 1 - Request for Additional Information (RAI)

Related to Generic Letter 2004-02, "Potential Impact of Debris Blockage on Emergency Sump Recirculation at Pressurized-Water Reactors," dated September 17, 2008 (ML082610690)

.4. NRC SECY 06-0078, "Status of Resolution of GSI-191, Assessment of [Effect of] Debris Accumulation on PWR Sump Performance," March 31, 2006 (ML053620174)

5. Westinghouse WCAP-16362, "PRA Modeling Template for Sump Blockage,"

April 2005

St. Lucie Unit 1 L-2008-235 Docket No. 50-335 Attachment Page 9 of 9

6. NUREG/CR-6928, "Industry-Average Performance for Components and Initiating Events at U.S. Commercial Nuclear Power Plants", February 2007 (ML070650650)
7. Regulatory Guide 1.174, Rev. 1, "An Approach to for Using Probabilistic Risk Assessment in Risk Informed Decisions on Plant-Specific Changes to the Licensing Basis," November 2002 (ML023240437)
8. NRC Letter, from J. A. Norris (NRC) to J.H. Goldberg (FPL), "St. Lucie Units 1 and 2 - Application of Leak-Before-Break Technology to Reactor Coolant System Piping (TAC M84560 and M84561)," dated March 5,1993
9. Regulatory Guide 1.45, "Reactor Coolant System Boundary Leakage Detection System," May 1973 (ML073200271)
10. NRC Bulletin 2003-01, "Potential Impact of Debris Blockage on Emergency Sump Recirculation at Pressurized-Water Reactors", June 9, 2003 (ML031600259)
11. Letter from J. A. Stall, "NRC Bulletin 2003-01, Potential Impact of Debris Blockage on Emergency Sump Recirculation at Pressurized-Water Reactors,"

August 8, 2003 (ML032240419)

12. Letter from W. Jefferson, "St. Lucie Units 1 and 2 - Response to Request for Additional Information Regarding NRC Bulletin 2003-01, Potential Impact of Debris Blockage on Emergency Sump Recirculation at Pressurized-Water Reactors," May 20, 2005 (ML051530153)
13. Letter from B. T. Moroney to J. A. Stall, "St. Lucie Units 1 and 2 - Response to NRC Bulletin 2003-01, Potential Impact of Debris Blockage on Emergency Sump Recirculation at Pressurized-Water Reactors," (TAC Nos. MC9605 and MC9606), September 30, 2005 (ML052640542)
14. NEI 02-01, Rev. 1, "Condition Assessment Guidelines: Debris Sources Inside PWR Containments"
15. NRC Information Notice 2005-26, "Results of Chemical Effects Head Loss Tests in a Simulated PWR Sump Pool Environment," September 16, 2005
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