ML050970118

RAI, 1C Loop Stop Isolation Valve

ML050970118
Person / Time
Site:	Byron
Issue date:	05/04/2005
From:	Dick G NRC/NRR/DLPM/LPD3
To:	Crane C Exelon Generation Co
Dick G F, NRR/DLPM, 415-3019
References
TAC MC6312
Download: ML050970118 (6)

Text

May 4, 2005 Mr. Christopher M. Crane, President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

BYRON STATION, UNIT 1 - REQUEST FOR ADDITIONAL INFORMATION RELATED TO THE 1C LOOP STOP ISOLATION VALVE (TAC NO. MC6312)

Dear Mr. Crane:

By letter dated March 2, 2005, the U.S. Nuclear Regulatory Commission (NRC) received a petition pursuant to Section 2.206 of the Commission's regulations in Title 10 of the Code of Federal Regulations (10 CFR). The petition requested that the NRC take immediate action to address concerns related to the repair of the 1C reactor coolant system cold-leg loop stop isolation valve (LSIV) during the spring 2005 refueling outage. In a letter dated April 5, 2005, the NRC informed the petitioner that the NRC did not believe that a safety concern existed that would necessitate immediate action. However, the NRC has decided to review the condition under the 2.206 process.

During the course of its review, the NRC staff has determined that it needs additional information. A response to the enclosed Request for Additional Information is requested in order for the NRC staff to complete its review of potential safety implications of the performance of the 1C LSIV. The questions were discussed with members of the Exelon staff during a telephone call on May 3, 2005. Based on those discussions, we request a response by May 31, 2005.

Sincerely,

/RA/

George F. Dick, Project Manager, Section 2 Project Directorate III Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. STN 50-454

Enclosure:

As stated cc w/encl: See next page

May 4, 2005 Mr. Christopher M. Crane, President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

BYRON STATION, UNIT 1 - REQUEST FOR ADDITIONAL INFORMATION RELATED TO THE 1C LOOP STOP ISOLATION VALVE (TAC NO. MC6312)

Dear Mr. Crane:

By letter dated March 2, 2005, the U.S. Nuclear Regulatory Commission (NRC) received a petition pursuant to Section 2.206 of the Commission's regulations in Title 10 of the Code of Federal Regulations (10 CFR). The petition requested that the NRC take immediate action to address concerns related to the repair of the 1C reactor coolant system cold-leg loop stop isolation valve (LSIV) during the spring 2005 refueling outage. In a letter dated April 5, 2005, the NRC informed the petitioner that the NRC did not believe that a safety concern existed that would necessitate immediate action. However, the NRC has decided to review the condition under the 2.206 process.

During the course of its review, the NRC staff has determined that it needs additional information. A response to the enclosed Request for Additional Information is requested in order for the NRC staff to complete its review of potential safety implications of the performance of the 1C LSIV. The questions were discussed with members of the Exelon staff during a telephone call on May 3, 2005. Based on those discussions, we request a response by May 31, 2005.

Sincerely,

/RA/

George F. Dick, Project Manager, Section 2 Project Directorate III Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. STN 50-454

Enclosure:

As stated cc w/encl: See next page DISTRIBUTION:

PUBLIC RidsNrrDlpmLpdiii2 (GSuh) RidsNrrLAPCoates RidsNrrPMGDick PDIII-2 R/F RidsAcrsAcnwMail RidsOgcRp RidsRgn3MailCenter TScarbrough DTerao FOrr JWermiel DPassehl,RIII DLPM DPR ADAMS Accession Number: ML050970118 *via phone OFFICE PM:PDIII-2 LA:PDIII-2 SC:EMEB (A)SC:SRXB BC:DRPRIII SC:PDIII-2 NAME GDick PCoates DFischer for YHsii DPassehl* GSuh DTerao DATE 05/03/05 5/3/05 4/26/05 4/25/05 4/26/05 5/4/05 OFFICIAL RECORD COPY

Byron Station Units 1 and 2 cc:

Regional Administrator, Region III Attorney General U.S. Nuclear Regulatory Commission 500 S. Second Street 801 Warrenville Road Springfield, IL 62701 Lisle, IL 60532-4351 Byron Station Plant Manager Illinois Emergency Management Exelon Generation Company, LLC Agency 4450 N. German Church Road Division of Disaster Assistance & Byron, IL 61010-9794 Preparedness 110 East Adams Street Site Vice President - Byron Springfield, IL 62701-1109 Exelon Generation Company, LLC 4450 N. German Church Road Document Control Desk - Licensing Byron, IL 61010-9794 Exelon Generation Company, LLC 4300 Winfield Road Senior Vice President - Nuclear Services Warrenville, IL 60555 Exelon Generation Company, LLC 4300 Winfield Road Mr. Dwain W. Alexander, Project Manager Warrenville, IL 60555 Westinghouse Electric Corporation Energy Systems Business Unit Vice President of Operations - Mid-West Post Office Box 355 Pressurized Water Reactors Pittsburgh, PA 15230 Exelon Generation Company, LLC 4300 Winfield Road Joseph Gallo Warrenville, IL 60555 Gallo & Ross 1025 Connecticut Ave., NW, Suite 1014 Chairman Washington, DC 20036 Will County Board of Supervisors Will County Board Courthouse Howard A. Learner Joliet, Illinois 60434 Environmental Law and Policy Center of the Midwest Mr. Barry Quigley 35 East Wacker Drive 3512 Louisiana Suite 1300 Rockford, IL 61108 Chicago, IL 60601-2110 U.S. Nuclear Regulatory Commission Byron Resident Inspectors Office 4448 North German Church Road Byron, IL 61010-9750 Ms. Lorraine Creek RR 1, Box 182 Manteno, IL 60950 Chairman, Ogle County Board Post Office Box 357 Oregon, IL 61061 Mrs. Phillip B. Johnson 1907 Stratford Lane Rockford, IL 61107

Byron Station Units 1 and 2 Director - Licensing and Regulatory Affairs Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 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 and Byron Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555

REQUEST FOR ADDITIONAL INFORMATION RELATED TO THE 1C LOOP STOP ISOLATION VALVE REFERENCED IN A 10 CFR 2.206 PETITION EXELON GENERATION COMPANY, LLC BYRON STATION, UNIT 1 DOCKET NO. STN 50-454 By letter dated March 2, 2005, the Nuclear Regulatory Commission (NRC) received a petition pursuant to Section 2.206 of the Commission's regulations in Title 10 of the Code of Federal Regulations (10 CFR). The petition requested that the NRC take immediate action to address concerns related to the repair of the 1C reactor coolant system cold-leg loop stop isolation valve, 1RC 8002C, during the spring 2005 refueling outage. In a letter dated April 5, 2005 (ML050970616), the NRC informed the petitioner that the NRC did not believe that a safety concern existed that would necessitate immediate action. However, the NRC staff has decided to review the condition under the 2.206 process. During the course of the review, the staff has developed the following questions:

1. Please provide material properties of the valve guides and related information that demonstrate their capability to maintain structural integrity under the load exerted by the 1RC 8002C motor actuator during a worst-case misalignment orientation.

2. Given the multiple closing attempts needed to close 1RC 8002C in refueling outages 11, 12, and 13, please describe Exelon's corrective actions to address any potential concerns related to structural integrity and loose parts generation.

3. Please provide any long-term plan for resolving the degraded condition of 1RC 8002C including corrective maintenance activities, future diagnostic testing, verification of valve guide integrity, criteria for taking action in response to diagnostic test results, and resolution of poor performance of plant loop stop isolation valves.

4. Please provide a copy of the revised Issue Resolution Documentation Form #2005-02 regarding delay of corrective maintenance for 1RC 8002C that includes topics relative to the following: evaluation of the structural integrity of the valve guides; consideration of applicable design-basis events with 1RC 8002C remaining in a degraded condition for a long period of time, such as the potential for and consequences of a valve disc falling into the reactor coolant system (RCS) flow stream, and impact of a significant loose part on the reactor fuel in the event of a hot-leg line break; confirmation of proper installation of the valve blocks in 1RC 8002C; explanation of the cause of the multiple strokes necessary to close 1RC 8002C; and the potentially increased likelihood of loose parts with degraded guides in 1RC 8002C and of increased wear of RCS components from a large loose part.

5. Please provide a discussion of the Byron loose parts monitoring process that describes timely actions in response to loose part detection as needed, including the following information: (a) what type of alert or alarm is given when a loose part is detected; (b) the action taken by the operator in response to a loose parts monitor alarm; (c) the criteria used to judge whether continued plant operation is appropriate given indication of loose parts, and (d) procedures for use of the loose-parts monitoring system and actions to be implemented in the event of the identification of loose parts in the RCS during plant operation.

6. The Byron UFSAR, Section 5.4, discusses the Byron compliance with the NRC cold shutdown position, RSB 5-1. This UFSAR Section appears to show that Byron 1 can be shut down from full power without using the CVCS letdown or the pressurizer spray systems. Please verify that the discussion in this UFSAR Section does confirm that Byron cold shutdown can be achieved without using CVCS letdown and pressurizer spray, and that Byron, Unit 1 continues to meet the requirements of Standard Review Plan Section 5.4.7, RSB Branch Technical Position 5-1.

7. Please describe the assessment of a 3/16 x 5/8 inch metal debris found in the reactor vessel in refueling outage B1R13.