ML100351213

Request for Additional Information Regarding GL 2004-02, Potential Impact of Debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors

ML100351213
Person / Time
Site:	Turkey Point
Issue date:	02/18/2010
From:	Paige J C Plant Licensing Branch II
To:	Nazar M Florida Power & Light Co
Paige, Jason C, NRR/DORL,301-415-5888
References
GL-04-002, TAC MC4726
Download: ML100351213 (3)

Text

UNITED NUCLEAR REGULATORY WASHINGTON, D.C. 20555-0001 February 18, 2010 Mr. Mano Nazar Senior Vice President, Nuclear and Chief Nuclear Officer Florida Power and Light Company P.O. Box 14000 Juno Beach, Florida 33408-0420 TURKEY POINT NUCLEAR GENERATING UNIT NO.4 -REQUEST FOR ADDITIONAL INFORMATION REGARDING GL 2004-02, "POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY RECIRCULATION DURING DESIGN BASIS ACCIDENTS AT PRESSURIZED-WATER REACTORS" (TAC NO. MC4726)

Dear Mr. Nazar:

By letter dated March 19,2009, Florida Power & Light Company (FPL, the licensee), provided responses to the Nuclear Regulatory Commission's (NRC) request for additional information (RAI) regarding Generic Letter (GL) 2004-02, "Potential Impact of debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors." On August 6, 2009, FPL and the NRC held a public teleconference to discuss the March 19 th licensee responses.

As a result of the August 6 th teleconference, the NRC drafted additional clarifying RAls for Turkey Point Unit 4 Questions 11 and 21. On February 3, 2010, FPL and the NRC held a public teleconference to discuss open items regarding GL 2004-02 and the licensee's responses to Questions 11 and 21. As a result of the meeting, the NRC staff finds that the additional information contained in the enclosed RAI is needed before we can complete the review. If you have any questions, please contact me at (301) 415-5888.

Y .

j , c; Jason C. Paige, Project Manager Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-251

Enclosure:

Request for Additional Information cc w/encl: Distribution via Listserv REQUEST FOR ADDITIONAL INFORMATION GENERIC LETrER 2004-02 FLORIDA POWER AND LIGHT COMPANY TURKEY POINT NUCLEAR GENERATING UNIT NO.4 DOCKET NUMBER 50-251 Regarding the licensee's response, as discussed during the February 3,2010, public teleconference, to request for additional information (RAI) 11s, the Nuclear Regulatory Commission staff has identified certain inadequacies regarding the structural analysis performed to demonstrate the structural adequacy of the debris interceptors: The licensee indicated that "The method of qualification of the structural adequacy of Debris Interceptors (Dis) for the deadweight, seismic, and hydrodynamic load case is outlined.

.. ." Are the deadweight, seismic, and hydrodynamic loads combined to formulate the bounding load combination for the Dis? If this is not the bounding load combination, the licensee should indicate what the bounding load combination is for this structure. The licensee described the hydrodynamic load as the "maximum differential pressure" across the Dis. It does not appear that the hydrodynamic loading effects of sloshing during a seismic event were incorporated into the licensee's structural analyses of the 01 structures.

The licensee should provide the basis for neglecting the effects of loading from sloshing during a seismic event. Additionally, justification should be provided for why this load would not be included in a bounding load combination. The licensee incorporated the use of the momentum function, as it applies to open channel flow, to derive the hydraulic loading on the Dis. Based on the licensee's description of the flow through the Dis in their August 11, 2008, supplemental response, it is difficult to decipher whether a water height gradient exists across the 01 boundary.

Based on the licensee's use of the momentum function from Henderson's Open Channel Flow, the hydraUlic load would be a zero value with no height differential.

The licensee should provide a range of parameters that would be used to compute this hydraulic load (q, Y1, Y2), using the function outlined. The licensee should provide a justification for not considering live loads induced by post-LOCA debris, which may impact the Dis. RAI 11 s requested the licensee to provide the results of their structural analysis.

No results were provided.

The licensee should provide a tabulated data set showing, at a minimum, the maximum and allowable stresses for all of the Dis components structurally analyzed, including structural members, panels, brackets, bolts, anchors, and all other components.

Applicable design margins or interaction ratios based on the aforementioned code allowable values should also be included to provide staff with reasonable assurance of the structural integrity of the Dis. Enclosure February 18, 2010 Mr. Mano Nazar Senior Vice President, Nuclear and Chief Nuclear Officer Florida Power and Light Company P.O. Box 14000 Juno Beach, Florida 33408-0420 TURKEY POINT NUCLEAR GENERATING UNIT NO.4 -REQUEST FOR ADDITIONAL INFORMATION REGARDING GL 2004-02, "POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY RECIRCULATION DURING DESIGN BASIS ACCIDENTS AT PRESSURIZED-WATER REACTORS" (TAC NO. MC4726)

Dear Mr. Nazar:

By letter dated March 19,2009, Florida Power & Light Company (FPL, the licensee), provided responses to the Nuclear Regulatory Commission's (NRC) request for additional information (RAI) regarding Generic Letter (GL) 2004-02, "Potential Impact of debris Blockage on Emergency Recirculation During Design Basis Accidents at Pressurized-Water Reactors." On August 6, 2009, FPL and the NRC held a public teleconference to discuss the March 19 th licensee responses.

As a result of the August 6 th teleconference, the NRC drafted additional clarifying RAls for Turkey Point Unit 4 Questions 11 and 21. On February 3, 2010, FPL and the NRC held a public teleconference to discuss open items regarding GL 2004-02 and the licensee's responses to Questions 11 and 21. As a result of the meeting, the NRC staff finds that the additional information contained in the enclosed RAI is needed before we can complete the review. If you have any questions, please contact me at (301) 415-5888.

Sincerely, IRA! Jason C. Paige, Project Manager Plant Licensing Branch 11-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-251

Enclosure:

Request for A dditional Information cc w/encl: Distribution via Listserv DISTRIBUTION:

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