ML17191B266
| ML17191B266 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 03/15/1999 |
| From: | Rossbach L NRC (Affiliation Not Assigned) |
| To: | Kingsley O COMMONWEALTH EDISON CO. |
| References | |
| REF-GTECI-A-46, REF-GTECI-SC, TASK-A-46, TASK-OR GL-87-02, GL-87-2, TAC-M69442, TAC-M69443, NUDOCS 9903180251 | |
| Download: ML17191B266 (5) | |
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M~. Oliver D. Kingsley, P.dent.
March
~ 5, 99.
Nuclear Generation Group Commonwealth Edison Company Executive Towers West Ill 1400 Opus Place, Suite 500 Downers Grove, IL 60515
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION FOR THE RESOLUTION OF UNRESOLVED SAFETY ISSUE A-46, DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3 (TAC NOS. M69442 AND M69443)
Dear Mr. Kingsley:
By letter dated June 28, 1996, Commonwealth Edison Company (ComEd, the licensee) provided the plant-specific summary report for Dresden Nuclear Power Station, Units 2 and 3, in accordance.with Generic Letter 87-02 which addresses Unresolved Safety Issue (USI) A-46.
On April 11, 1998, ComEd transmitted its response to our request for additional information (RAI) dated January 12, 1998. *Additional guidance addressing implementation of Method A was issued by the Seismic Qualification Utility Group (SQUG) by letter dated August 18, 1998.
Our staff has reviewed both the summary report and ComEd's response to our RAI, and has determined that additional information is necessary to complete our review of ComEd's USI A-46 response. The questions in the enclosed RAI were discussed with your staff on
- January 28 and February 4, 1999. It was agreed that the response would be provided within 60 days of receipt of this letter.
Docket Nos. 50-237 and 50-249
Enclosure:
RAI cc w/encl: See next page
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S. Richards D. Dorman M. Ring, Rill PUBLIC.
C. Moore J. Chen Sincerely, ORIG. SIGNED BY Lawrence W. Rossbach, Project Manager Project Directorate II 1-2 Division of Licensing Project Management Office of Nuclear Reactor Regulation PDlll.. 2 r/f L:. Ros,sbach OGC, 01,5B18 J. Zwolinski/S. Black K. Manely ACRS, T2E26.
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UNITED STATES NUCLEAR REGULATORY COMMISSION Mr. Oliver D. Kingsley, President Nuclear Generation Group Commonwealth Edison Company Executive Towers West Ill 1400 Opus Place, Suite 500 Downers Grove, IL 60515 WASHINGTON, D.C. 20555-0001 March 15,
- 1999
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION FOR THE RESOLUTION OF UNRESOLVED SAFETY ISSUE A-46, DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3 (TAC NOS. M69442 AND M69443)
Dear Mr. Kingsley:
By letter dated June 28, 1996, Commonwealth Edison Company (ComEd, the licensee) provided the plant-specific summary report for Dresden Nuclear Power Station, Units 2 and 3, in accordance with Generic Letter 87-02 which addresses Unresolved Safety Issue (USI) A-46.
On April 11, 1998, ComEd transmitted its response to our request for additional information (RAI) dated January 12, 1998. Additional guidance addressing implementation of Method A
.was issued by the Seismic Qualification Utility Group (SQUG) by letter dated August 18,.1998.
Our staff has reviewed both the summary report and ComEd's. response to our RAI, and has determined that additional information is necessary to complete our review of ComEd's USI A-46 response. The questions in the enclosed RAI were discussed with your staff on January 28 and February 4, 1999. ltwas agreed that the response would be provided within 60 days of receipt of this letter.
Docket Nos. 50-237 and 50-249
Enclosure:
- cc w/encl: See next page
- Sincerely, c/=------& -It~
Lawrence W. Rossbach, Project Manager Project Directorate 111-2 Division of Licensing Project Management Office of Nuclear Reactor Regulation
- 0. Kingsley Commonwealth Edison Company cc:
Commonwealth Edison Company Site Vice President - Dresden 6500 N. Dresden Road Morris, Illinois 60450-9765 Commonwealth Edison Company Dresden Station Manager 6500 N. Dresden Road Morris, Illinois 60450-9765 U.S. Nuclear Regulatory Commission Dresden Resident Inspectors Office 6500 N. Dresden Road Morris, Illinois 60450-9766 Regional Administrator U.S. NRC, Region Ill 801 Warrenville Road Lisle, Illinois 60532-4351 Illinois Departmentof Nuclear Safety Office of Nuclear Facility Safety 1035 Outer Park Drive Springfield, Illinois 62704 Chairman Grundy County Board Administration Building
- 1320 Union Street Morris, Illinois 60450 Document Control Desk-Licensing
- Commonwealth Edison Company 1400 Opus Place, Suite 400 Downers Grove, Illinois 60515 Commonwealth Edison Company Reg. Assurance Manager., Dresden 6500 N. Dresden Road Morris, Illinois 60450'-9765 Mr. David Helwig Senior Vice President Commonwealth Edison Company Executive Towers West Ill 1400 Opus Place, Suite 900 Downers Grove, Illinois 60515
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Dresden Nuclear Power St.ation Units 2.and 3 Mr. Gene H. Stanley PWR Vice President Commonwealth Edison Company Executive Towe rs West Ill 1400 Opus Place, Suite 900 Downers Grove, Illinois 60515 Mr. Christopher Crane BWR Vice President Commonwealth Edison Company Executive Towe rs West 111 1400 Opus Place, Suite 900 Downers Grove, Illinois 60515 Mr. R. M. Krich Vice President - Regulatory Services Commonwealth Edison Company Executive Towers West Ill 1400 Opus Place, Suite 500 Downers Grove, Illinois 60515 Ms. Pamela B. Stroebel Senior Vice President and General Counsel Commonwealth Edison Company P.O. Box 767 Chicago, Illinois 60690-0767
ll REQUEST FOR ADDITIONAL INFORMATION
. ON UNRESOLVED SAFETY ISSUE A-46 DRESDEN NUCLEAR POWER STATION. UNITS 2 AND 3
- 1.
In response to the staffs question on the appropriate use of Method A of Table 4. 1 of generic implementation procedure number two (GIP-2), you make reference to the Seismic Qualification Utility Group's (SQUG) letter of January 1998 (Reference 3). The staff is aware of the bases provided in the reference. More recently, SQUG has acknowledged in its letter of.August 18, 1998, and the staff has agreed to in its letter to SQUG of September 21, 1998: "Any plant-specific implementation concerns should be addressed in the plant-specific evaluations." The restriction on the use of Method A comes from the discussion of "Advantage and Limitations" in Section.4.2.3 of GIP-2, where it is noted that "Seismic Capability Engineers should be alert for unusual, plant specific situations which could cause the amplification factor to be greater than that of typical nuclear plant structures."
A review of some of the in-structure response spectra (IRS) provided in Appendix B (Reference 1) shows that at several elevations, the IRS in the Reactor Building and Turbine Building have double peaks (broadened); (1) between 4 and 8 Hz, and (2) between 12 and 20 Hz. This indicates a plant-specific situation. The staffs concern is about the seismic adequacy of equipment including their supports and anchorages (such as electrical equipment, valves, and electrical relays or contacts) located within 40 ft.
- above the effective grade of 517 ft.. In light of this discussion (1) provide justification for the use of Method A, (2) as an example, provide your justification for seismic adequacy of safe shutdown equipment list (SSEL) equipment installed on Elevation 549 ft. of the
. Turbine Building.
- 2.
In response to the staffs question on the use of epoxy-grouted anchors (Response 7, Reference 2), you state "ComEd is not aware of any test data for epoxy~grouted anchors."
You attempt to provide justification for using the GIP-2 capacities spec.ified for the cast-in-place (CIP) anchors installed in uncracked concrete. The technical basis is not sufficient as it is known that the failure modes associated with the epoxy-grouted anchors are different from those associated with CIP anchors.
An ACl-published paper, "Behavior and Design of Single Adhesive Anchors under Tensile Load in Uncracked Concrete," by Ronald Cook, et. al., in the Structural Journal, January-February 1998, addresses this issue. The paper provides an explanation of various failure modes (different from those of CIP anchors) that are specific to epoxy-grouted anchors, as well as an analysis of the available test data. ComEd is requested to confirm that the allowable loads (i.e., 25 percent of the ultimate average capacities) used for epoxy-grouted anchors were justifiable.
ENCLOSURE
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A review of the calculations performed by your consultant in Attachment F of Reference 2
_ to resolve the seven cable-tray ~upport outliers indicates that five outliers were resolved by using the litnit state evaluation of Section 8.4.8 of GIP-2. One outlier (LAR 007) is unresolved and one outlier (LAR 009) was just recently resolved.. Provide information about the resolution of supports LAR 007 an<;j LAR 009.
- 4.
ComEd's response number 1 in Reference 2 stated that approximately 40 percent of the equipment outliers had been resolved (closed) at that time. Provide the status and schedules for completing the resolution ofthe remaining outliers by submitting the updated Attachment H to Reference 2.
References:
- 1.
Letter from J. Stephen Perry (ComEd) to NRC, "Summary Report for Resolution of USI A-46," dated.June 28, 1996.
- 2.
Letter from J. F. Hefley (ComEd) to NRC, "Responses to Request for Additional Information Regarding Unresolved Safety Issue (USI) A-46," dated April 11, 1998.
- 3.
Letter from N. Smith (SQUG) to John Stolz (NRC), "NRC Response to SQUG Letters of USI A-46 Generic RAls," dated January 26, 1998.
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