ML031180006
| ML031180006 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 04/29/2003 |
| From: | Rossbach L NRC/NRR/DLPM/LPD3 |
| To: | Skolds J Exelon Generation Co, Exelon Nuclear |
| Rossbach L, 415-2863, NRR/DLPM | |
| References | |
| TAC MB7562, TAC MB7563 | |
| Download: ML031180006 (5) | |
Text
April 29, 2003 Mr. John L. Skolds, President Exelon Nuclear Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3 - REQUEST FOR ADDITIONAL INFORMATION REGARDING INSERVICE INSPECTION PROGRAM RELIEF REQUEST I4R-02 (TAC NOS. MB7562 AND MB7563)
Dear Mr. Skolds:
By letter dated September 6, 2003, Exelon Generation Company submitted relief request I4R-02 concerning the risk-informed inservice inspection program at Dresden Nuclear Power Station, Units 2 and 3. The staff has identified additional information that is needed in order to complete their review of this relief request in the area of risk assessment. These questions were discussed with members of your staff on April 25, 2003. Your staff agreed to respond to this request for additional information (RAI) within thirty days of the date of this letter.
Should your staff have any questions about this request for additional information (RAI), please contact me at (301) 415-2863.
Sincerely,
/RA/
Lawrence W. Rossbach, Project Manager, Section 2 Project Directorate III Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-237 and 50-249
Enclosure:
Request for Additional Information cc w/encl: See next page
April 29, 2003 Mr. John L. Skolds, President Exelon Nuclear Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555
SUBJECT:
DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3 - REQUEST FOR ADDITIONAL INFORMATION REGARDING INSERVICE INSPECTION PROGRAM RELIEF REQUEST I4R-02 (TAC NOS. MB7562 AND MB7563)
Dear Mr. Skolds:
By letter dated September 6, 2003, Exelon Generation Company submitted relief request I4R-02 concerning the risk-informed inservice inspection program at Dresden Nuclear Power Station, Units 2 and 3. The staff has identified additional information that is needed in order to complete their review of this relief request in the area of risk assessment. These questions were discussed with members of your staff on April 25, 2003. Your staff agreed to respond to this request for additional information (RAI) within thirty days of the date of this letter.
Should your staff have any questions about this request for additional information (RAI), please contact me at (301) 415-2863.
Sincerely,
/RA/
Lawrence W. Rossbach, Project Manager, Section 2 Project Directorate III Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-237 and 50-249
Enclosure:
Request for Additional Information cc w/encl: See next page Distribution:
PUBLIC PDIII/2 r/f A. Mendiola P. Coates L. Rossbach OGC ACRS S. Dinsmore G. Georgiev M. Ring, RIII ADAMS Accession Number: ML031180006 OFFICE PM:PD3-2 LA:PD3-2 SC:PD3-2 NAME LRossbach PCoates AMendiola DATE 04/28/03 04/28/03 04/29/03 OFFICIAL RECORD COPY
Dresden Nuclear Power Units 2 and 3 cc:
Site Vice President - Dresden Nuclear Power Station Exelon Generation Company, LLC 6500 N. Dresden Road Morris, IL 60450-9765 Dresden Nuclear Power Station Plant Manager Exelon Generation Company, LLC 6500 N. Dresden Road Morris, IL 60450-9765 Regulatory Assurance Manager - Dresden Exelon Generation Company, LLC 6500 N. Dresden Road Morris, IL 60450-9765 U.S. Nuclear Regulatory Commission Dresden Resident Inspectors Office 6500 N. Dresden Road Morris, IL 60450-9766 Chairman Grundy County Board Administration Building 1320 Union Street Morris, IL 60450 Regional Administrator U.S. NRC, Region III 801 Warrenville Road Lisle, IL 60532-4351 Illinois Department of Nuclear Safety Office of Nuclear Facility Safety 1035 Outer Park Drive Springfield, IL 62704 Document Control Desk-Licensing Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Senior Vice President, Nuclear Services Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Vice President Mid-West Regional Operating Group Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Senior Vice President Mid-West Regional Operating Group 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 Director - Licensing Mid-West Regional Operating Group Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Senior Counsel, Nuclear Mid-West Regional Operating Group Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Manager Licensing - Dresden and Quad Cities Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555
Dresden Nuclear Power Station, Units 2 and 3 Request for Additional Information on 4th 10-Year Interval Risk Relief Request I4R-02 TAC Nos. MB7562 And MB7563 1.
Have any welds that were selected for inspection in the Risk-Informed Inservice Inspection (RI-ISI) program that was approved by the staff in Reference 1 been removed from the population of welds that will be inspected during the fourth ten-year interval? If so, why was [were] the weld[s] removed from the population of welds to be inspected?
2.
Have any welds that were not selected for inspection in the RI-ISI program that was approved by the staff in Reference 1 been selected for inspection during the fourth ten-year interval? If so, why was [were] the weld[s] added to the population of welds to be inspected?
3.
The relief request includes the following paragraph:
The Risk Impact Assessment completed as part of the original baseline RI-ISI Program was an implementation/transition check on the initial impact of converting from a traditional ASME Section XI program to the new RI-ISI methodology. For the Fourth Interval ISI update, there is no transition occurring between two different methodologies, but rather, the currently approved RI-ISI methodology and evaluation will be maintained for the new interval. As such, the initial screening of the risk impact assessment is not a part of the living program process and is not required to be continually updated.
The staff does not concur with the implication that, if there is no change in methodology, the change in risk assessment is not part of the living process. RG 1.178, SRP 3.9.8, and the EPRI Topical report (Refs. 2, 3, and 4) require an evaluation of the change in risk arising from the proposed change in the ISI program. Please provide a discussion on the potential change in risk between the RI-ISI program proposed for implementation in the fourth interval and the ASME Section XI requirements from which relief was granted in Reference 1. If inspections were discontinued or relocated between the third and the fourth intervals RI-ISI programs, please provide an estimate of the change in risk.
References:
- 1) Letter from A. J. Mendiola (USNRC) to O. D. Kingsley (Exelon) transmitting Safety Evaluation of Third Interval Risk-Informed Inservice Inspection Program Relief Request, September 5, 2001.
- 2) U.S. Nuclear Regulatory Commission, An Approach for Plant-Specific Risk-Informed Decision Making: Inservice Inspection of Piping, Regulatory Guide 1.178, September 1998.
- 3) U.S. Nuclear Regulatory Commission, Standard Review Plan for Trial Use for the Review of Risk-Informed Inservice Inspection of Piping, NUREG-0800, SRP Chapter 3.9.8, May 1998.
- 4) Electric Power Research Institute, Revised Risk-Informed Inservice Inspection Evaluation Procedure, EPRI TR-112657, Revision B-A, January 2000.