ML17187A300
| ML17187A300 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 02/08/1996 |
| From: | Stang J NRC (Affiliation Not Assigned) |
| To: | Farrar D COMMONWEALTH EDISON CO. |
| Shared Package | |
| ML17187A301 | List: |
| References | |
| TAC-M94074, NUDOCS 9602120377 | |
| Download: ML17187A300 (3) | |
Text
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Mr. D.
L~ Farrar Manager, Nuclear Reguhtory Services Conunonwealth Edison Company Executive Towers West Ill 1400_-0pus Place, Suite 500 D.owners Grove, IL 60515 February 8, 1996
SUBJECT:
. SAFETY -EVALUATION ON EXTENSION OF-THE 15-MONTH STIPULATED ALLOWABLE OPERATING TIME FOR ORESDEN, UNIT 3 (TAC NO~ M94074)
Dear Mr. Farrar:
By letter dated November 10, 1995, the Commonwealth Edison Company.(ComEd) submitted a request. to extend the current 15-month operating cycle.for the
.Dresden Nuclear* Pow.er Station,- Unit 3., to 18.5 months.. The current 15-morith operating period above 212°F was approved by the staff in regard to its..
assessment of*jntergranular stress c.orrosion cracking in-the Dresden, Unit 3, core shroud.
During the most recent refue ljng :.outage,.* (-"spri.ng 1994) for Dresden,.
Unit 3, ComEd discoyered cracking in the.. cjrc~umferential-.we;i:a~ijn the core shrou~.
- ComEd prov1ded*analyses that Dresaen; Unit 3, could~- operated.and the core shr~ud t:oul~ maintain mar~ins aga~~.~t failure. as,~pecified i.n.Section XI of*
the Amerlcan Soc1ety of 1Mechan1cal Eng1neers (ASME)_,Bo1ler and Pressure Vessel Code (Co.de).
Jhe asses.~ment.of Dre_sden},~~it 3, op~r'ation wit~" t~e degraded core.
shroud was documenteq in.the staff?s--Safety,_Evaluat10ns.(SL).--date*d.~.July 21, 1994.
d A. t 16 1995
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The. *staff eva 1 uat~d C~mEd_' s ~oveinber,10,<Jg*~~~'l ~_ul;fmi.tt1'=b ~ni~;;.toncl,~de_d that the cracked core shroud.w1ll sat1s.fy ASME code margrns ag.a*rns-t ~weld, faTlure for 18.5* months of operation above cold,shutdowrd,s*atisfyJffg the ASME.iCode margins against faHure provid~s reasonable;"*as:sur~* t,ha(*Jhe~cote,.s~rpu,~* ~*tr Dres,~en, Unit 3, will rema.in intact, even,uri~er**;post.u1:ated 1 icensfogfb9si,s~ and: 'beyond *
. 1 ice~sing basis accide~t *conditi(J~ns*.._-
Tti;e_.,_ sta.ff's-'.a"ss~,s~s~en~t?t<lo*k i_11'~0 ~~~-cou~t *
. new rnformat 1 on. regard mg the,~801 ling,Wate11.~eactor~ Ves.sel" an.d~-Interna-ls ProJect
(.BWRVIP)' gen*eri c: guidelines for"irl~.~-~F-! i O,JlS-a~-~; ~~al y~t:i <]llS~~~fv~~~:1~~o~~~;Jshrouds.
Therefore, ~he staff finds that D~e*~~~~:~:L~oi t jJ~~.n,~M~t~afely lp~~~-t~d *with the *.
degraded core shroud. for an additt~nah'~*~*months.a~o,y,e.. 212:
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-F,.o.~'*_a~total of 18.5 months above 212°F w1thout undue nsk tp.. th~:pu,b'.1,1c-hea.Jth *and"safety.
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Docket No. 50-249
Enclosure:
cc w/encl:
Sa~ety E~aluation See next page*
S1~c'er:ely;. ~(.,(_~ ~.. ~J".
Isl. f, ~- :*;* [)* {.
John F. Stjin*g;.Se'oj,.or:~ Project Manag~r Project Directorate 111-2 *
,Division of Reactor Projects**,.. III/IV.
Office of Nuclear Reactor Regulation Distribution:
Docket File POI 11-2 r/f RCapra JStang
'PUBLIC JRoe (JWR)
CMoore OGC*, 015-818 PHiland, RII I ACRS, T2-E26 G. Carpenter
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 29555-0001 February 8, 1996 Mr. D. L. Farrar Manager, Nuclear Regulatory Services Conmonwealth Edison Company Executive Towers West Ill 1400 Opus Place, Suite 500 Downers Grove, IL 60515
SUBJECT:
SAFETY EVALUATION ON EXTENSION Of* THE 15-MONTH STIPULATED ALLOWABLE OPERATING TIME FOR DRESDEN, UNIT 3 (TAC NO. M94074)
Dear Mr. -Farrar:
By letter dated November 10, 1995, the Co11111onwealth Edison Company (ComEd) submitted a request to extend the current 15-month operating cycle for the Dresden Nuclear Power Station, Unit 3, to 18.5 months.
The current 15-month operating pe.riod above 212°F was approved by the staff in regard to its assessment of intergranular stress corrosion cracking in the Dresden, Unit 3, core shroud.
During the most recent refueling outage (spring 1994) for Dresden, Unit 3, ComEd discovered cracking in the circumferential welds in the core shroud. ComEd provided analyses that Dresden, Unit 3, could be operated and the core shroud could maintain mar~ins against failure as specified in Section XI of the Amerittan Society of Mechan1cal Engineers (ASHE) Boiler and Pressure Vessel Code (~. The assessment of Dresden, Unit 3, operation with the degraded core shroud was documented in the staff's Safety Evaluations (SE) dated July 21, 1994, and August 16, 1995.
The staff evaluated ComEd's November 10, 1995, submittal and concluded that the cracked core shroud will satisfy ASHE code margins against weld failure for 18.5 months of operation above cold shutdown.
Satisfying the ASHE Code margins against failure provides reasonable assure that the core shroud at Dresden, Unit 3, vfll remain intact, even under postulated licensing basis and beyond licensing basis accident conditions *. The staff's assessment took into account new information regarding the Boiling Water Reactor Vessel and Internals Project (BWRVIP) generic guidelines for inspections and evaluations of BWR core shrouds.
Therefore*, the staff finds that Dresden, Unit 3, can be safely" operated 1with the degraded core shroud for an additional 3.5 months above 212°F or a total of 18.5 months above 212°F without undue_ risk to the public health and* safety.
Docket No. 50-249
Enclosure:
- Safety Evaluation cc w/encl: See next page
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f Sincere]:
~~~ F. S ng, Senior Project Manager Project Directorate 111-2 Division of Reactor Projects - Ill/IV Office of Nuclear Reactor Regulation
D. L. Farrar Corrmonwealtb Edison Company cc:
Michael I. Riller, Esquire Sidley and Austin One First National Plaza Chicago, 111iho1s 60603 Site Vice President
- Dresden Nuclear Power Station 6500 North Dresden Road Morris, 111 i1Bois 60450-9765 Station Manager Dresden Nuclear Power Station.
6500 North Dresden Road Morris, llliiaois 60450-9765 U.S. Nuclear :Regulatory Convnission Resident Inspectors Office Dresden Station.
6500 North Dresden Road Morris, Illinois 60450-9766 Regi ona 1 Adim~*ni strator U.S. NRC, Region Ill 801 Warrenvn 1 e Road Lisle, 111imr1 s 60532-4351 Illinois Department of Nuclear Safety Office of Nw:'lear Facility Safety 1035 Outer Park Drive Springfield. 111inois 62704 Chairman Grundy County !Board Administrati~n Building 1320 Union Street Horris, 1111111ois 60450 Document CQ!lil'it*rol Desk-licensing Commonwealtfh Edison Company 1400 Opus Place, Suite 400 Downers Grove, Illinois 60515 Warren Bi hmin, EPRI Task Manager 3412 Hil 1 view Avenue _
Palo Alto, California 94303 Robin Dyle. Technical Chairman BWRVIP Assessment Task Southern Nwclear Operating Company Post Office Box 236 40 Inverness Center Parkway Birmingham. Alabama 35201 Dresden Nuclear Power Station Unit Nos. 2 and 3 J.