ML20059G745
| ML20059G745 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 11/01/1993 |
| From: | Hopkins J Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| RTR-REGGD-01.097, RTR-REGGD-1.097 TAC-M84973, NUDOCS 9311090053 | |
| Download: ML20059G745 (15) | |
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UNITED STATES 4
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NUCLEAR REGULATORY COMMISSION
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WASHINGTON. D. C. 20S$5 5
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V Docket No. 50-346 LICENSEE: TOLED0 EDISON COMPANY FACILITY: DAVIS-BESSE NUCLEAR POWER STATION, UNIT 1
SUBJECT:
SUMMARY
OF MEETING HELD ON OCTOBER 20, 1993, TO DISCUSS REGULATORY GUIDE 1.97 (TAC NO. M84973)
On October 20, 1993, NRC staff members met at Rockville, Maryland, with employees of Toledo Edison Company (TE) to discuss the implementation of Regulatory Guide (RG) 1.97 for the steam generator (SG) pressure instruments at the Davis-Besse Nuclear Power Station. A list of attendees is included as enclosure 1.
The handout used at the meeting is included as enclosure 2.
At the meeting, the following information was discussed.
Each SG has one RG 1.97 Category 1 pressure instrument and one Category 2 pressure instrument.
The power supplies for the Category 1 instruments are Class IE essential non-interruptible power.
The power supplies for the Category 2 instruments are non-Class IE non-interruptible power. The Category 2 power supplies have static transfer devices in the 120 volt ac circuits and automatic buss transfer devices in the de circuits backed up by the Class IE station batteries. TE stated that no single failure can fail both Category 2 transmitters due to the power supply design.
In addition, Davis-Besse has symptom-oriented Emergency Operating Procedures (EOPs) and TE stated that i
operators look at many parameters to make decisions, and that operators would not be lost if SG pressure indication was not available.
1 TE also stated that it would cost approximately $500,000 to upgrade the Category 2 SG pressure instruments to Category 1.
The main reason for the cost is that there is no available Class IE cable tray, so dedicated conduit would have to be run.
In addition, TE stated that from an Individual Plant i
Examination - Probabilistic Risk Analysis perspective upgrading the instruments is insignificant.
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9311090053 931101 DR ADOCK 0500 6
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, i The NRC staff stated that it would complete its review of this issue within a few weeks, and that the information provided concerning the power supplies and i
E0Ps seemed acceptable such that it appeared an upgrade was not warranted.
ORIGINAL SIGNED BY Jon B. Hopkins, Sr. Project Manager l
Project Directorate III-3 Division of Reactor Projects III/IV/V Office of Nuclear Reactor Regulation
Enclosures:
As stated cc w/ enclosures:
See next page e
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OFFICIAL RECORD COPY FILENAME: G:\\DAVISBES\\DBIO20.MTS f
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DISTRIBUTION w/ enclosures:
Docket File NRC & Local PDRs PD III-3 Reading J. Hopkins E. Greenman, RIII w/o enclosure 2 T. Murley/F. Miraglia J. Partlow J. Roe J. Zwolinski J. Hannon M. Rushbrook A. Chaffee, OEAB OGC E. Jordan E. Rossi B. Marcus ACRS (10)
B. McCabe, MS 17G-21 J. Strasma, RIII cc:
Licensee & Service List
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Mr. Louis F. Storz Davis-Besse Nuclear Power Station
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Toledo Edison Company Unit No. I
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i Mary E. O'Reilly Robert E. Owen, Chief j
Centerior Energy Corporation Bureau of Radiological Health j
300 Madison Avenue Services Toledo, Ohio 43652 Ohio Department of Health i
Post Office Box 118 i
Mr. William T. O'Connor, Jr.
Columbus, Ohio 43266-0118 Manager - Regulatory Affairs Toledo Edison Company Attorney General l
Davis-Besse Nuclear Power Station Department of Attorney General l
5501 North State - Route 2 30 East Broad Street 4
Oak Harbor, Ohio 43449 Columbus, Ohio 43216
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j Gerald Charnoff, Esq.
Mr. James W. Harris, Director 5
Shaw, Pittman, Potts Division of Power Generation l
and Trowbridge Ohio Department of Industrial J
2300 N Street, N. W.
Regulations Washington, D. C. 20037 P. O. Box 825 4
Columbus, Ohio 43216 Regional Administrator, Region III U. S. Nuclear Regulatory Commission Ohio Environmental Protection Agency 799 Roosevelt Road DERR--Compliance Unit i
Glen Ellyn, Illinois 60137 ATTN:
Zack A. Clayton i
P. O. Box 1049 1
Mr. Robert B. Borsum Columbus, Ohio 43266-0149 Babcock & Wilcox Nuclear Power Generation Division State of Ohio 1700 Rockville Pike, Suite 525 Public Utilities Commission Rockville, Maryland 20852 180 East Broad Street Columbus, Ohio 43266-0573 j
Resident Inspector U. S. Nuclear Regulatory Commission Mr. James R. Williams 5503 H. State Route 2 State Liaison to the NRC l
Oak Harbor, Ohio 43449 Adjutant General's Department j
Office of Emergency Management Mr. Donald C. Shelton Agency Senior Vice President - Nuclear 2825 West Granville Road l
Centerior Service Company Columbus, Ohio 43235-2712 6200 Oak Tree Boulevard Independence, Ohio 44101 Mr. John K. Wood, Plant Manager Toledo Edison Company Davis-Besse Nuclear Power Station 5501 North State Route 2 Oak Harbor, Ohio 43449 1
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Attendees of Meeting with Toledo Edison Company on October 20, 1993 NAME ORGANIZATION J. Hopkins NRC B. Marcus NRC P. Staith TE G. Warner TE S. Wise TE M. Borysiek TE
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PURPOSE e Provide Basis for Resolution of R.G.1.97 Steam Generator Pressure Instrumentation Open item i
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BACKGROUND l
= Two Category 1 SIG Pressure Channels
- One per Steam Generator GNTERf0R ENERGY DAVIS-BESSE NUCLEAR POWER STATION
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BACKGROUND (Continued) e Basis
- Within each redundant division of a safety system, redundant monitoring channels are not needed except for steam generator level
- Steam Generators considered to be redundant safety systems
- Two Category 1 Steam Generator Level Channels provided per SIG GNFE.ft.N.N.E DAVIS 4 ESSE MUCLEAR POWER STATSON
R.G.1.97 Statement on Redundancy e No single failure of Accident Monitoring Instrumentation should prevent operators from being presented with necessary l
information
- Where failure of one accident monitoring channel results in information ambiguity, additional information should be provided to allow operators to deduce plant conditions t
- Redundant (Identical)
- Diverse (Independent Parameters with a known Relationship) 1 l
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h W GNTERNHE ENERGY DAVIS 4 ESSE NUCLEAR POWER STAT 1ON I
Davis-Besse Configuration Two Category 1 SIG Pressure Channels, One per SIG Two Category 2 S/G Pressure Channels, One per SIG
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- Instruments
- Power Supplies
- Cable Routing
- Substantial Cost to Upgrade i
Many Alternatives to SIG Pressure Indication I
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% GNTEREOR ENERGY DAVIS-8 ESSE NUCLEAR POWER STAT 1ON i
t Uses of S/G Pressure Instruments i
e Operators are trained to not place reliance on any one parameter to deduce plant conditions e Operators are trained to assess overall plant conditions t
Anomalous indications between diverse parameters are resolved Actions are directed toward reaching and maintaining stability 4
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N DAVIS-8 ESSE NUCLEAR POWER SIATION a
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EOP Uses of S/G Pressure
- SIG Dry following SFRCS Actuation
- SIG Level or Pressure l
- Lack of Heat Transfer
- RCS Temperature increasing l
- Coupling of RCS Tc and SIG Pressure e Check for Overcooling j
- RCS Temperature and Pressure Stable or Approaching Post Trip Target Box
- S/G Pressure r
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-GNTERf0R W
ENERGY
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EOP Uses of S/G Pressure (Continued) e Check Heat Transfer Conditions are Available in One S/G e Determination of Which S/G is Causing Overcooling
- SIG Pressures, Levels, FW Flows, Tcs, Valve Positions i
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e inadequate Core Cooling l
- Depressurize S/G, Maintaining Secondary Tsat < RCS Tsat i
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DAVIS-BESSE MUCLEAR POVWER STAT 10M
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