SVPLTR 04-0081, Invessel Visual Inspection (IVVI) Activity Report Submittal for D2R18

Invessel Visual Inspection (IVVI) Activity Report Submittal for D2R18

ML043480030
Person / Time
Site:	Dresden
Issue date:	12/01/2004
From:	Bost D Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
SVPLTR #04-0081 BWRVIP-18, BWRVIP-94
Download: ML043480030 (2)

Text

---Exeltn,,

Exelon Generation Company, LLC Dresden Nuclear Power Station www.exeloncorp.com Ex1 e NucleaT 6500 North Dresden Road Morris, IL 60450-9765 December 1, 2004 SVPLTR #04-0081 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Dresden Nuclear Power Station, Unit 2 Facility Operating License No. DPR-1 9 NRC Docket No. 50-237

Subject:

Dresden Nuclear Power Station, Unit 2 Invessel Visual Inspection (IWI) Activity Report Submittal for D2R18 Reference 1: Letter from Danny G. Bost (Exelon Generation Company, LLC) to U. S. NRC, "Owner's Activity Report Submittal," dated February 9, 2004 This letter submits the results of the inspections of previously identified indications on Core Spray and Jet Pump Riser Piping as well as repairs performed on the Jet Pump #9 Riser Brace during the Dresden Nuclear Power Station (DNPS) Unit 2 refueling outage (D2R18) which began on October 14, 2003, and was completed on November 11, 2003. This submittal meets the reporting requirements of BWRVIP-18, 'BWR Vessel and Internals Project, BWR Core Spray Internals Inspection and Flaw Evaluation Guidelines" and BWRVIP-94, "BWR Vessel and Internals Project Program Implementation Guide."

In the past, this IWI report was submitted as a part of Owner's Activity Report submittal but was inadvertently left out of the last submittal; (i.e., Reference 1).

Should you have any questions concerning this letter, please contact Mr. Pedro Salas, Regulatory Assurance Manager, at (815) 416 - 2800.

Respectfully, Dann4. Bost Site ice President Dresden Nuclear Power Station

Attachment:

Scope of Vessel Interior Examinations cc: Regional Administrator- Region ill koL41 NRC Senior Resident Inspector, Dresden Station

Attachment A Scope of Vessel Interior Examinations Core Spray System Examinations Core Spray piping was examined during the Dresden Nuclear Power Station (DNPS) Unit 2 refueling outage (D2R18) which began on October 14, 2003, and was completed on November 11, 2003, as recommended in BWRVIP-18, "BWR Vessel and Internals Project, BWR Core Spray Internals Inspection and Flaw Evaluation Guidelines." Specifically, visual examinations were performed of the "undemonstrated welds." Flaws identified on four of these welds were verified to have not changed and remained within the maximum lengths predicted for growth.

Also, in anticipation of proposed changes to BWRVIP-18, the "target set" elbow (P4) welds not previously examined for excessive grinding were also examined. General Electric performed a flaw evaluation in accordance with BWRVIP-18 that accepts the known weld flaws for over one additional cycle of operation.

Jet Pump Riser Examination BWRVIP-41, 'BWR Vessel and Internals Project, Core Spray Internals Inspection and Flaw Evaluation," inspections of the RS-1 weld on the Riser of Jet Pump pair 15/16 had previously identified a crack during the DNPS Unit 2 refueling outage (D2R15) in March 1998. A flaw evaluation was submitted to the NRC and was accepted in a safety evaluation dated May 18, 1999. In DNPS Unit 2 refueling outage (D2Rl7) in October 2001, the crack was measured visually to be I 'A" in length. The crack was again measured during D2R1 8 and visually determined to increase in length to 2." The crack remains well within the "critical length" as identified in the Flaw Evaluation and is projected to remain well within the 'critical length" for the next two cycles. The next planned inspection is D2R20 that is currently scheduled for November 2007.

Riser Brace Repairs During D2R17, BWRVIP-41 inspections identified cracking across the riser brace RB-4c weld of the Jet Pump #9 riser brace. The inspection scope was expanded during that outage to inspect 100% of the RB-4 welds and no additional cracking was identified. Restrictions on recirculation speed exclusion zones and a time limitation in that zone were imposed. During D2R18, a repair was installed in the riser brace on the Jet Pump #9 side of the riser. A "mitigation" clamp was installed on the remaining 19 braces. This repair meets the requirements of BWRVIP-51, "BWR Vessel and Internals Project, Jet Pump Repair Design Criteria."