ML041750179

Units 1 & 2, Letter, Correction to the Request for Additional Information Regarding Bulletin 2003-01. Potential Impact of Debris Blockage on Emergency Sump Recirculation at Pressurized-Water Reactors

ML041750179
Person / Time
Site:	Byron, Braidwood
Issue date:	07/08/2004
From:	Dick G NRC/NRR/DLPM/LPD3
To:	Crane C Exelon Generation Co
Dick G F, NRR/DLPM, 415-3019
References
TAC MB9558, TAC MB9559, TAC MB9560, TAC MB9561
Download: ML041750179 (5)

Text

July 8, 2004 Mr. Christopher M. Crane, President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

CORRECTION TO THE REQUEST FOR ADDITIONAL INFORMATION REGARDING BULLETIN 2003-01 BYRON STATION, UNITS 1 AND 2, AND BRAIDWOOD STATION, UNITS 1 AND 2 (TAC NOS. MB9560, MB9561, MB9558, AND MB9559)

Dear Mr. Crane:

By letter dated May 4, 2004, we issued a Request for Additional Information (RAI) regarding the Exelon Generation Company, LLC (Exelon) response to Nuclear Regulatory Commission (NRC)Bulletin 2003-01, Potential Impact of Debris Blockage on Emergency Sump Recirculation at Pressurized-Water Reactors.

We have determined that there needs to be a clarification to one of the sentences in RAI #2.

Specifically, the fourth sentence should read, Since there may be some time before sump screens plug, for larger break sizes, refilling the RWST upon switchover to sump recirculation, or soon thereafter, could provide a ready source of additional makeup inventory should sump recirculation be lost. The revised RAI is enclosed in its entirety with the word change in bold type. This change has been discussed with the Exelon staff and we have agreed to extend the RAI due date until July 16, 2004, so that Exelon staff can determine if there is an effect on their response and, if so, revise the RAI response accordingly. We apologize for the late change in the RAI.

Please contact me if there are questions regarding the RAI.

Sincerely,

/RA/

George F. Dick, Jr., Project Manager, Section 2 Project Directorate III Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. STN 50-454, STN 50-455, STN 50-456 and STN 50-457

Enclosure:

RAI cc w/encl: See next page

July 8, 2004 Mr. Christopher M. Crane, President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

CORRECTION TO THE REQUEST FOR ADDITIONAL INFORMATION REGARDING BULLETIN 2003-01 BYRON STATION, UNITS 1 AND 2, AND BRAIDWOOD STATION, UNITS 1 AND 2 (TAC NOS. MB9560, MB9561, MB9558, AND MB9559)

Dear Mr. Crane:

By letter dated May 4, 2004, we issued a Request for Additional Information (RAI) regarding the Exelon Generation Company, LLC (Exelon) response to Nuclear Regulatory Commission (NRC)Bulletin 2003-01, Potential Impact of Debris Blockage on Emergency Sump Recirculation at Pressurized-Water Reactors.

We have determined that there needs to be a clarification to one of the sentences in RAI #2.

Specifically, the fourth sentence should read, Since there may be some time before sump screens plug, for larger break sizes, refilling the RWST upon switchover to sump recirculation, or soon thereafter, could provide a ready source of additional makeup inventory should sump recirculation be lost. The revised RAI is enclosed in its entirety with the word change in bold type. This change has been discussed with the Exelon staff and we have agreed to extend the RAI due date until July 16, 2004, so that Exelon staff can determine if there is an effect on their response and, if so, revise the RAI response accordingly. We apologize for the late change in the RAI.

Please contact me if there are questions regarding the RAI.

Sincerely,

/RA/

George F. Dick, Jr., Project Manager, Section 2 Project Directorate III Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. STN 50-454, STN 50-455, STN 50-456 and STN 50-457

Enclosure:

Request for Additional Information cc w/encl: See next page DISTRIBUTION:

PUBLIC PDIII/2 R/F OGC AStone, RIII GCwalina AMendiola ACRS PCoates DLPM DPR WLyon GDick MKowal AWang FTalbot ADAMS Accession Number: ML041750179 OFFICE PM:PDIII-2 LA:PDIII-2 SC:PD3-2 NAME GDick THarris for PCoates DPickett for AMendiola DATE 07/08/04 07/08/04 07/08/04 OFFICIAL RECORD COPY

Byron/Braidwood Stations cc:

Ms. C. Sue Hauser, Project Manager Springfield, IL 62701 Westinghouse Electric Corporation Energy Systems Business Unit Illinois Emergency Management Post Office Box 355 Agency Pittsburgh, PA 15230 Division of Disaster Assistance &

Preparedness Joseph Gallo 110 East Adams Street Gallo & Ross Springfield, IL 62701-1109 1025 Connecticut Ave., NW, Suite 1014 Washington, DC 20036 Byron Station Plant Manager Exelon Generation Company, LLC Howard A. Learner 4450 N. German Church Road Environmental Law and Policy Byron, IL 61010-9794 Center of the Midwest 35 East Wacker Dr., Suite 1300 Site Vice President - Byron Chicago, IL 60601-2110 Exelon Generation Company, LLC 4450 N. German Church Road U.S. Nuclear Regulatory Commission Byron, IL 61010-9794 Byron Resident Inspectors Office 4448 N. German Church Road U.S. Nuclear Regulatory Commission Byron, IL 61010-9750 Braidwood Resident Inspectors Office 35100 S. Rt. 53, Suite 79 Regional Administrator, Region III Braceville, IL 60407 U.S. Nuclear Regulatory Commission 801 Warrenville Road Chairman Lisle, IL 60532-4351 Will County Board of Supervisors Will County Board Courthouse Ms. Lorraine Creek Joliet, IL 60434 RR 1, Box 182 Manteno, IL 60950 Braidwood Station Plant Manager Exelon Generation Company, LLC Chairman, Ogle County Board 35100 S. Rt. 53, Suite 84 Post Office Box 357 Braceville, IL 60407-9619 Oregon, IL 61061 Ms. Bridget Little Rorem Mrs. Phillip B. Johnson Appleseed Coordinator 1907 Stratford Lane 117 N. Linden Street Rockford, IL 61107 Essex, IL 60935 George L. Edgar Morgan, Lewis and Bockius 1800 M Street, NW Washington, DC 20036-5869 Attorney General 500 S. Second Street

Byron/Braidwood Stations Document Control Desk - Licensing and LaSalle Exelon Generation Company, LLC Exelon Generation Company, LLC 4300 Winfield Road 4300 Winfield Road Warrenville, IL 60555 Warrenville, IL 60555 Site Vice President - Braidwood Exelon Generation Company, LLC 35100 S. Rt. 53, Suite 84 Braceville, IL 60407-9619 Senior Vice President - Nuclear Services Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Vice President of Operations - Mid-West Pressurized Water Reactors Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Director - Licensing and Regulatory Affairs Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Regulatory Assurance Manager - Braidwood Exelon Generation Company, LLC 35100 S. Rt. 53, Suite 84 Braceville, IL 60407-9619 Regulatory Assurance Manager - Byron Exelon Generation Company, LLC 4450 N. German Church Road Byron, IL 61010-9794 Associate General Counsel Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Vice President - Licensing and Regulatory Affairs Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Manager Licensing - Braidwood, Byron

REQUEST FOR ADDITIONAL INFORMATION BULLETIN 2003-01, "POTENTIAL IMPACT OF DEBRIS BLOCKAGE ON EMERGENCY SUMP RECIRCULATION AT PRESSURIZED WATER REACTORS" EXELON GENERATION COMPANY, LLC BYRON STATION, UNITS 1 AND 2 BRAIDWOOD STATION, UNITS 1 AND 2 DOCKET NOS. STN 50-454, STN-455, STN-456, AND STN-457 By letter dated August 6, 2003, Exelon Generation Company, LLC (Exelon, the licensee) responded to Nuclear Regulatory Commission (NRC)Bulletin 2003-01, Potential Impact of Debris Blockage on Emergency Sump Recirculation at Pressurized-Water Reactors, for Byron Station, Units 1 and 2, (Byron) and Braidwood Station, Units 1 and 2 (Braidwood).

During the course of review of the licensees bulletin response, the staff has determined that it needs the following information:

1. The Westinghouse Owners Group (WOG) has developed operational guidance in response to Bulletin 2003-01 for Westinghouse and Combustion Engineering type PWRs. For Byron and Braidwood, the licensees response stated that they will monitor the WOG activities and will consider implementation of any issued guidance. Please provide a discussion of the WOG recommended compensatory measures that have been or will be implemented for the plants. Include a discussion of the evaluations or analyses performed to determine that these compensatory measures are acceptable for Byron and Braidwood, and provide technical justification for those WOG compensatory measures not being implemented. Also include a detailed discussion of the procedures being modified, the operator training being implemented, and the schedule for implementing these compensatory measures.

2. In response to Bulletin 2003-01, the licensee stated that guidance is given in emergency procedures to address refueling water storage tank (RWST) refill once it has been determined that a complete loss of emergency coolant recirculation capability exists.

The intent of Bulletin 2003-01 is for licensees to consider implementing compensatory measures to reduce the risk associated with potentially degraded or nonconforming emergency core cooling systems (ECCS) and containment spray system recirculation functions. As such, the timing of implementing this guidance in the plants emergency procedures may not be consistent with the intent of the bulletin. Since there may be some time before sump screens plug, for larger break sizes, refilling the RWST upon switchover to sump recirculation, or soon thereafter, could provide a ready source of additional makeup inventory should sump recirculation be lost.

For smaller break sizes, early initiation of RWST refill, such as prior to sump recirculation, could effectively prolong the time to switchover and possibly increase the opportunity for plant recovery without necessitating switchover, thereby reducing the potential for ECCS recirculation sump blockage. In the August 6, 2003, response, the licensee did not commit to modifying the procedures to include refilling the RWST prior to or upon switchover to ECCS recirculation. Given the uncertainty associated with this issue, and the potential benefits of implementing this compensatory measure, please

explain the basis for not including refilling the RWST earlier in the procedures.

In addition, please provide a detailed description of how the current emergency operating procedures address a loss of ECCS recirculation capability.

3. NRC Bulletin 2003-01 provides possible interim compensatory measures licensees could consider to reduce risks associated with sump clogging. In addition to those compensatory measures listed in Bulletin 2003-01, licensees may also consider implementing unique or plant-specific compensatory measures, as applicable. Please discuss any possible unique or plant-specific compensatory measures that were considered for implementation at Byron and Braidwood. Include a basis for rejecting any of these additional measures considered.