ML17191B273
| ML17191B273 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 03/16/1999 |
| From: | Rossbach L NRC (Affiliation Not Assigned) |
| To: | Kingsley O COMMONWEALTH EDISON CO. |
| References | |
| TAC-M99910, TAC-M99911, NUDOCS 9903190288 | |
| Download: ML17191B273 (4) | |
Text
I
' I Mr. Oliver D. Kingsley, President Nuclear Generation Group Commonwealth Edison Company Executive Towers West 111 1400 Opus Place, Suite 500 Downers Grove, IL 60515 March 16, 1999
SUBJECT:
DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3-REVISED CONTAINMENT ANALYSIS WITH TWO-SIGMA ADDER (TAC NOS. M99910 AND M99911)
Dear. Mr. Kingsley:
In NRC's safety evaluation (SE) dated April 30, 1997, for Amendment Nos. 157 and 152 to the operating licenses for Dresden Station, Units 2 and 3, the staff took the position that to maintain conservatism in the containment pressure and temperature analysis, a two-sigma (i.e. two standard deviations) uncertainty shou.ld be added to the decay heat calculation using the American Nuclear Society (ANS) 5.1-1979 model. The staff found that operation without the two-sigmi;i adder was acceptable in the interim based on a sensitivity study submitted by Commonwealth Edison Company (ComEd, the licensee) which evaluated the containment response to a 10 percent increase in power level. By letter dated April 2, 1997, ComEd committed to submit the revised analysis for NRG review. In a submittal datep October 27, 1997, Com Ed submitted the revised analysis.
The staff has reviewed this reanalysis. The reanalysis was done for the same case as the previous most limiting case. The results demonstrate that the interim analysis was indeed conservative. Since the calculation with the two-sigma adder otherwise uses values already found acceptable by the NRG staff, we find this calculation to be acceptable and to satisfy the staff request for a containment analysis including the two-sigma uncertainty factor.
This completes our actions under these TACs.
Docket Nos. 50-237 and 50-249 Sincerely, Original signed by:
Lawrence W. Rossbach, Project Manager Project Directorate 111-2 Division of Licensing Project Management Office of Nuclear Reactor Regulation DISTRIBUTION:
Docket File PUBLIC cc: See next page POI 11-2 R/F J. Zwolinski/SBlack C. Moore
_____ -----~--~ S. Richards
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1 L. Rossbach PDR ADOCK 0500023 i OGG 015B18 C. Berlinger ACRS; T2E26 p
'I M. Ring, Riii DOCUMENT NAME: G:\\PD3-2\\CM\\DRESDEN\\LTR99910 x: "C" = Copy without enclosures "E" = Copy with enclosures "N" = No copy OFFICE PM:PDlll-2 V
BC:SCSB D:PDlll-2 C.
NAME LROSSBACH SRICHARDS ~
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DATE 03/ /L/99 03/ i(:, 199 OFFICIAL RECORD COPY
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'.j Mr. Oliver D. Kingsley, President Nuclear Generation Group Commonwealth Edison Company Executive Towers West Ill 1400 Opus Place, Suite 500 D9wners Grove, IL 60515 March 16, 1999
SUBJECT:
DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3 - REVISED CONTAINMENT ANALYSIS WITH TWO-SIGMA ADDER (TAC NOS. M99910 AND M99911)
Dear Mr. Kingsley:
In NRC's safety evaluation (SE) dated April 30, 1997, for Am19ndment Nos. 157 and 152 to the
. operating licenses for Dresden Station, Units 2 and 3, the staff took the position that to maintain conservatism in the containment pressure and temperature analysis, a two-sigma (i.e. two standard deviations) uncertainty should be added to the decay heat calculation using the American Nuclear Society (ANS) 5.1-1979 model. The staff found that operation without the two-sigmi;t adder was acceptable in the interim based on a sensitivity study submitted by Commonwealth Edison Company (ComEd, the licensee) which evaluated the containment.
response to a 10 percent increase in power level. By letter dated April 2, 1997, ComEd committed to submit the revised analysis for NRC review. In a submittal dated October 27, 1997, ComEd submitted the revised analysis.
The staff has reviewed this reanalysis. The reanalysis was done for the same case as the previous most limiting case. The results demonstrate that the interim analysis was indeed conservative. Since the calculation with the two-sigma adder otherwise uses values already found acceptable by the NRC staff, we find this calculation to be acceptable and to satisfy the staff request for a containment analysis including the two-sigma uncertainty factor.
This completes our actions under these TACs.
Sincerely, Original signed by:
Lawrence W. Rossbach, Project Manager Project Directorate 111-2 Division of Licensing Project Management Office of Nuclear Reactor Regulation
. Docket Nos. 50-237 and 50-249 DISTRIBUTION:
Docket File cc: See next page PDlll-2 R/F
- S. Richards L. Rossbach OGC, 015818 M. Ring, Riii PUBLIC J. Zwolinski/SBlack C. Moore
. C. Berlinger ACRS, T2E26 DOCUMENT NAME: G:\\PD3-2\\CM\\DRESDEN\\LTR99910 x: "C" = Copy without enclosures "E" = Copy with enclosures "N" = No copy OFFICE PM:PDlll-2 D:PDlll-2 C....
NAME LROSSBACH SRICHARDS 'S DATE 03/ /?./99 03/ i(:, /99
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 16, 1999
SUBJECT:
DRESDEN NUCLEAR POWER STATION, UNITS 2 AND 3 - REVISED CONTAINMENT ANALYSIS WITH TWO-SIGMA ADDER (TAC NOS. M99910 AND M99911)
Dear Mr. Kingsley:
In NRC's safety evaluation (SE) dated April 30, 1997, for Amendment Nos. 157 and 152 to the.
operating licenses for Dresden Station, Units 2 and 3, the staff took the position that to maintain conservatism in the containment pressure and temperature analysis, a two-sigma (i.e. two standard deviations) uncertainty should be added to the decay heat calculation using the American Nuclear Society (ANS) 5.1-1979 model. The staff found that operation without the two-sigma adder was acceptable in the interim based on a sensitivity study submitted by Commonwealth Edison Company (ComEd, the licensee) which evaluated the containment response to a 10 percent increase in power level. By letter dated April 2, 19.97, ComEd committed to submit the revised analysis for NRC review. In a submittal dated October 27, 1997, Com Ed submitted the revised analysis.
The staff has revi~wed this reanalysis. The reanalysis was done for the same case as the previous most limiting case. The results demonstrate that the interim analysis was indeed conservative. Since the calculation with the two-sigma adder otherwise uses values already found acceptable by the NRC staff, we find this calculation to be acceptable and to satisfy the staff request for a containment analysis including the two-sigma uncertainty factor.
This completes our actions under these TACs.
Docket Nos. 50-237 and 50-249 cc: See next page Sincerely,
~~~-rt~
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. D.resden Road Morris, Illinois 60450-9765 Commonwealth Edison Company Dresden Station Manager 6500 N. Dresden Road Morris, Illinois 60450-9765 U.S. Nuclear Reg.ulatory 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 Department of 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 Dresden Nuclear Power Station 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 Towers West 111 1400 Qpus 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