BYRON 2002-0075, Response to Request for Additional Information Regarding Inspection Plans for the Byron Station Unit 2 Reactor Vessel Head During the Fall 2003 Refueling Outage in Support of NRC Bulletin 2002-01

Response to Request for Additional Information Regarding Inspection Plans for the Byron Station Unit 2 Reactor Vessel Head During the Fall 2003 Refueling Outage in Support of NRC Bulletin 2002-01

ML022190371
Person / Time
Site:	Byron
Issue date:	07/26/2002
From:	Lopriore R Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
BL-02-001, BYRON 2002-0075
Download: ML022190371 (2)

Text

Exekn,.

Exelcn GeCeeration Compary, LLC Byroni Station www.exeloncorp.coM Nuclear 4450 North German Church Road Byron, IL 61010-9794 July 26, 2002 LTR: BYRON 2002-0075 File: 2.07.0200 United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Byron Station, Units 1 and 2 Facility Operating License Nos. NPF-37 and NPF-66 NRC Docket Nos. STN 50-454 and STN 50-455

Subject:

Response to Request for Additional Information Regarding Inspection Plans for the Byron Station Unit 2 Reactor Vessel Head During the Fall 2003 Refueling Outage in Support of NRC Bulletin 2002-01, "Reactor Pressure Vessel Head Degradation and Reactor Coolant Pressure Boundary Integrity"

References:

(1) Letter from J. A. Benjamin (Exelon Generation Company, LLC) to NRC, "Exelon/AmerGen Response to NRC Bulletin 2002-01, "Reactor Pressure Vessel Head Degradation and Reactor Coolant Pressure Boundary Integrity," dated April 1, 2002 (2) Letter from J. A. Benjamin (Exelon Generation Company, LLC) to NRC, "Exelon/AmerGen Sixty-Day Response to NRC Bulletin 2002-01, "Reactor Pressure Vessel Head Degradation and Reactor Coolant Pressure Boundary Integrity," dated May 17, 2002 On March 18, 2002, the NRC issued NRC Bulletin 2002-01, "Reactor Pressure Vessel Head Degradation and Reactor Coolant Pressure Boundary Integrity." In References 1 and 2, Exelon provided the required 15-day and 60-day responses to the bulletin. In References 1 and 2, we indicated that Byron Station was evaluating the extent of visual examinations of the reactor vessel heads during future outages.

On June 28, 2002, a teleconference was held between members of the NRC and Exelon staffs to discuss the scope of the reactor vessel head examination plans during the upcoming Byron Station Unit 2 Fall 2002 refueling outage. In addition, the NRC asked for clarification regarding information provided in Reference 1 that described the results of the Byron Station Unit 1 reactor vessel head examination around the reactor vessel head vent penetration during the Spring 2002 refueling outage. The requested information is presented below. C\ý

• July 26, 2002 U. S. Nuclear Regulatory Commission Page 2 Byron Station Unit 2 Fall 2002 Outage Reactor Vessel Head Examination Scope A 100% bare metal reactor vessel head examination is scheduled for Unit 2 during the upcoming Fall 2002 outage. It should be noted that during the Braidwood Station Unit 2 reactor vessel head bare metal examination during the Spring 2002 outage, an approximate 90 degree arc on one side of the reactor vessel head vent one-inch penetration was not directly viewed due to a structural interference. Although the 90 degree arc was not directly viewed, there is high assurance that no boric acid residue was present based on the very small surface area not directly observed and the excellent condition of the head surface area immediately adjacent to the 90 degree arc. Should a similar interference be present on the Byron Station Unit 2 reactor vessel head, the same visual limitation may exist.

Byron Station Unit 1 Spring 2002 Outage Reactor Vessel Head Examination Clarification In Reference 1, Byron Station indicated that approximately 20% of the reactor vessel head bare metal surface was visually inspected on March 21, 2002, to confirm the inspection results of a previous leak on the reactor vessel head vent valve discovered during refueling outage B1 R03 in January 1990. This 20% bare metal surface inspection included 100% of the local area around the reactor vessel head vent valve penetration. No boric acid accumulation or head wastage was observed around the penetration.

If you have any questions regarding this information, please contact Mr. William Grundmann, Regulatory Assurance Manger, at (815) 406-2800.

Respectfully, Richard P. Lopniore Site Vice President Byron Station RL/DD/rah cc: Regional Administrator- NRC Region III NRC Senior Resident Inspector - Byron Station

Text

Exekn,.

Exelcn GeCeeration Compary, LLC Byroni Station www.exeloncorp.coM Nuclear 4450 North German Church Road Byron, IL 61010-9794 July 26, 2002 LTR: BYRON 2002-0075 File: 2.07.0200 United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Byron Station, Units 1 and 2 Facility Operating License Nos. NPF-37 and NPF-66 NRC Docket Nos. STN 50-454 and STN 50-455

Subject:

Response to Request for Additional Information Regarding Inspection Plans for the Byron Station Unit 2 Reactor Vessel Head During the Fall 2003 Refueling Outage in Support of NRC Bulletin 2002-01, "Reactor Pressure Vessel Head Degradation and Reactor Coolant Pressure Boundary Integrity"

References:

(1) Letter from J. A. Benjamin (Exelon Generation Company, LLC) to NRC, "Exelon/AmerGen Response to NRC Bulletin 2002-01, "Reactor Pressure Vessel Head Degradation and Reactor Coolant Pressure Boundary Integrity," dated April 1, 2002 (2) Letter from J. A. Benjamin (Exelon Generation Company, LLC) to NRC, "Exelon/AmerGen Sixty-Day Response to NRC Bulletin 2002-01, "Reactor Pressure Vessel Head Degradation and Reactor Coolant Pressure Boundary Integrity," dated May 17, 2002 On March 18, 2002, the NRC issued NRC Bulletin 2002-01, "Reactor Pressure Vessel Head Degradation and Reactor Coolant Pressure Boundary Integrity." In References 1 and 2, Exelon provided the required 15-day and 60-day responses to the bulletin. In References 1 and 2, we indicated that Byron Station was evaluating the extent of visual examinations of the reactor vessel heads during future outages.

On June 28, 2002, a teleconference was held between members of the NRC and Exelon staffs to discuss the scope of the reactor vessel head examination plans during the upcoming Byron Station Unit 2 Fall 2002 refueling outage. In addition, the NRC asked for clarification regarding information provided in Reference 1 that described the results of the Byron Station Unit 1 reactor vessel head examination around the reactor vessel head vent penetration during the Spring 2002 refueling outage. The requested information is presented below. C\ý

• July 26, 2002 U. S. Nuclear Regulatory Commission Page 2 Byron Station Unit 2 Fall 2002 Outage Reactor Vessel Head Examination Scope A 100% bare metal reactor vessel head examination is scheduled for Unit 2 during the upcoming Fall 2002 outage. It should be noted that during the Braidwood Station Unit 2 reactor vessel head bare metal examination during the Spring 2002 outage, an approximate 90 degree arc on one side of the reactor vessel head vent one-inch penetration was not directly viewed due to a structural interference. Although the 90 degree arc was not directly viewed, there is high assurance that no boric acid residue was present based on the very small surface area not directly observed and the excellent condition of the head surface area immediately adjacent to the 90 degree arc. Should a similar interference be present on the Byron Station Unit 2 reactor vessel head, the same visual limitation may exist.

Byron Station Unit 1 Spring 2002 Outage Reactor Vessel Head Examination Clarification In Reference 1, Byron Station indicated that approximately 20% of the reactor vessel head bare metal surface was visually inspected on March 21, 2002, to confirm the inspection results of a previous leak on the reactor vessel head vent valve discovered during refueling outage B1 R03 in January 1990. This 20% bare metal surface inspection included 100% of the local area around the reactor vessel head vent valve penetration. No boric acid accumulation or head wastage was observed around the penetration.

If you have any questions regarding this information, please contact Mr. William Grundmann, Regulatory Assurance Manger, at (815) 406-2800.

Respectfully, Richard P. Lopniore Site Vice President Byron Station RL/DD/rah cc: Regional Administrator- NRC Region III NRC Senior Resident Inspector - Byron Station