ML17179B202
| ML17179B202 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Quad Cities  |
| Issue date: | 11/26/1993 |
| From: | Stang J Office of Nuclear Reactor Regulation |
| To: | Farrar D COMMONWEALTH EDISON CO. |
| References | |
| IEB-93-009, IEB-93-9, TAC-M88112, TAC-M88113, TAC-M88114, TAC-M88115, NUDOCS 9312070250 | |
| Download: ML17179B202 (4) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Docket Nos. 50-237, 50-249, and 50-254, 50-265 Mr. D. L. Farrar Manager, Nuclear Regulatory Services Commonwealth Edison Company Executive Towers West Ill, Suite 500 1400 OPUS Place Downers Grove, Jllinois 60515
Dear Mr. Farrar:
November 26~ 1993
SUBJECT:
RESOLUTION OF MODIFICATIONS RELATED TO REACTOR VESSEL WATER LEVEL INSTRUMENTATION (TAC NOS. M88112, M88113, M88114, AND.M88115)
By letter dated October 29, 1993, Commonwealth Edison Company (CECo) submitted an amendment for review and approval of two unreviewed safety questions (USQ~)
dealing with modifications at Dresden, Units 2 and 3, and Quad Cities, Units 1 and 2, to eliminate possible errors in Reactor Vessel Water Level Indication in accordance with NRC Bulletin 93-03, "Resolution of Issues Related to Reactor Vesse1*water Level Instrumentation in BWRs."
The modifications involve connecting the tontrol rod drive (CRD) water header into the existing reactor vessel water level instrumentation reference leg. This connection provides a continuous backfill of deaerated water through the reference* leg to prevent the accumulation of dissolved gases.
During review of the USQs, the NRC staff discovered that the design of the modifications is such that closure of the root valve in the reference leg
- piping would result in a.major plant transient. -On November 16, 1993, at the re*quest of the NRC staff, CECo made a presentation of the design modifications to meet NRC Bulletin 93-03 and the scenario of the root valve closure and resulting plant transients.
CECo indicated in the meeting that preventi~g inadvertent closure of the root valve would be based only on strict administrative controls.
It is not the* intent of the NRC to allow modifications to be made to satisfy NRC Bulletin 93-03 such that on balance the plant is less safe. Reliance on administrative controls alone as described in your plant-specific USQ is not an acceptable long-term approach to assuring these isolation valves are not inadvertently closed.
Prior to the NRC staff making a final decision on the USQ~; CECo *should reconsider its position relying solely on administrative controls to preverit inadvertent closure of the root valve and factor into the USQs, any lessons learned from the meeting.
Within 30 days following receipt of this letter, please provide the NRC with
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yo~r pos,ition on the modifications required to meetNNRR* CCB~-ll~nCB\\fTBl93-03.. Iniy\\ 1 O r~-c:9:;;3i11~2uo~7"0~2;;-;s;-;.o;;:c-.,c:9:-::3::-:1:-:. 1:-:2-6.,..* --..-~-.-,~--\\
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November 26 ~- 1993 addition, please provide a schedule with justification for ihe completion of the-modifications at Dresden, Unit 2, and Quad Cities, Unit 2.
It is the NRC staff's understanding that the modifications for Quad Cities, Unit 1, are complete and ready fo~ testing. The modifications to meet Bulletin 93-03 should not be made operable at either Qu~d Cities or Dresden Stations until the NRC staff has completed the evaluation* of the USQ~. In addition, final resolution and installation of modifications for Dresden, Unit 3, and Quad Cities~ Unit.I, should be completed in the upcoming spring refueling outages.
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Sincerely, Original signed by:
John F. Stang, Project Manager Project Directorate III-2 Division of Reactor Projects *III/IV/V Office of Nuclear Reactor Regulation*
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ADR3 NAME MVIRGILIO JZWOLINSKI DATE 11/24/93 Ii /7,."1/93 COPY YES NO*
YES/NO
Mr. D. L. Farrar Commonwealth Edison Company cc:
Michael I. Miller, Esquire Sidley and Austin One First National Plaza Chicago, Illinois 60690 Mr. G. Spedl Plant Manager Dresden Nuclear Power Station 6500 North Dresden Road Morris, Illinois 60450-9765 U. S. Nuclear Regulatory Commission Resident Inspectors Office Dresden Station 6500 North Dresden Road Morris, Illinois 60450-9766 Chairman Board of Supervisors of Grundy County Grundy County Courthouse Morris, Illinois 60450 Regional Administrator Nuclear Regulatory Commission, Region III 799 Roosevelt Road, Bldg. #4
- Glen Ellyn, Illinois 60137 Illinois Department of Nuclear Safety Office of Nuclear Facility Safety 1035 Outer Park Drive*
Springfield, Illinois 62704 Robert Neumann Office of Public Counsel State of Illinois Center 100 W. Randolph Suite 11-300 Chicago, Illinois 60601 Dresden Nuclear Power Station Unit Nos. 2 and 3
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Mr. D. L. Farrar Commonwealth Edison Colftf)any cc:
Mr. Stephen E. Shelton Vice President Iowa-Illinois Gas and Electric Company P. 0. Box 4350 Davenport, Iowa 52808 Michael I. Miller, Esquire Sidley and Austin One First National Plaza Chicago, Illinois 60690 Mr. Richard Bax Station Manager Quad Cities Nuclear Power Station 22710 206th Avenue North Cordova, Illinois.. 61242 Resident Inspector U. S. Nuclear Regulatory Commission 22712 206th Avenue North Cordova, Illinois 61242 Chairman Rock Island County Board of Supervisors 1504 3rd Avenue Rock Island County Office Bldg.
Rock Island, Illinois 61201 Illinois Department-of Nuclear Safety Office of Nuclear Facility Safety 1035 Outer Park Drive Springfield, Illinois 62704 Regional Administrator, Region III U. S. Nuclear Regulatory Commission 799 Roosevelt Road, Bldg. #4 Glen Ellyn, Illinois 60137 Robert Neumann Office of Public Counsel State of Illinois Center 100 W. Randolph Suite 11-300 Chicago; Illinois 60601 Quad Cities Nuclear Power Station Unit Nos. 1 and 2