ML20058N795
| ML20058N795 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 10/15/1993 |
| From: | Freeland L DUQUESNE LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| References | |
| ND3MNO:3492, NUDOCS 9310200325 | |
| Download: ML20058N795 (4) | |
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"pg TE aphone (412) 393-6000 Nuckser Group P O Box 4 Shippingport, PA 150n4004 October 15,1993 ND3MNO:3492 Beaver Valley Power Station, Unit No.1 Docket No. 50-334, Licensee No. DPR-66 Special Report 7
United States Nuclear Regulatory Commission Attn: Director, Office of Nuclear Reactor Regulation Document Control Desk Washington, DC 20555 Gentlemen:
In accordance with Appendix A, Beaver Valley Technical Specification 3.3.3.3
" Seismic Monitoring", the following Special Report i abmitted. This report documents the malfunction of Seismic Monitor XT-ER-105B, and the plans for restoring this monitor to operable status.
On September 7,1993, the Seismic Accelerometer located on the Operating Deck of Containment, XT-ER-105B, failed its monthly Operational Surveillance Test. As required by Technical Specification 3.3.3.3, XT-ER-105B was declared inoperable and the action statement applied, requiring restoration of the inoperable monitor within a thirty (30) day period, or the submittal of a Special Report to the Commission outlining the cause for the mWc ion and the plans for restoration.
There a'.
t '3? fri-axial Time-History Accelerometers which are part of the Seismic Monitorm umentation. They are located in the Containment Foundation, the Containment G,.:
Jag Deck (" Charging Floor" as described in technical specifications), and in the Auxiliary Building. Each accelerometer provides inputs to a tape recorder and associated alarm circuit for annunciation in the Control Room. In addition to the accelerometers, there are three tri-axial response spectrum recorders and one seismic switch with Control Room Alarm capability, and foui recording Tri-axial Peak Accelerographr Beaver Valley does not incorporate a seismic initiated reactor trip in its design. A normal Pia It Shutdown to Mode 3 - Hot Standby is performed in accordance 190079 9310200325 931015-E'
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m with' Abnormal Operating Procedures, when the Seismic Instmmentation indicates ground acceleration greater than 0.06g. ' A Plant Shutdown to Mode 5 - Cold Shutdown is
. similarly initated if acceleration exceeds 0.125g.
. Troubleshooting has determined that the accelerometer requires replacement. The
- cause of the malfunction cannot be determined until the accelerometer is removed. The
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' instmment is located on the Operating Deck, elevation 767', under a bolted access cover
.in the floor on Containment, adjacent to the Refueling Cavity. A radiation survey of the area,.with the Reactor at power, found the neutron dose rate to range from 100-250 e mrem /hr, and the ganuna dose rate to range from 160-240 mrem /hr, taken at waist high locations surrounding the access cover. The reason for the elevated dose rate is the proximity of the Reactor Vessel Head to tk location of the instrument. Approximately.
twenty bolts must be removed from the cover to access the accelerometer. Two
. Instrument Technicians'and a Health Physics Technician are required to perform the task W
.of replacing the instrument. ' Based on a stay time of approximately 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, the total dose P
e' stimate for thejob, ifpdformed at power, has been approximated at 1700 mrem. Each
. Instrument Technician is estimated to receive 700 mrem, and the Health Physics
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- Technician 300 mrem..As a result of our commitment to maintain personnel dose rates as i low as reasonhbly achievable, we postponed repair of this Seismic Accelerometer until
~ Plant conditions and subsequent dose rates allowed lower personnel exposure.
A forced outage that began on October 12,1993, has provided the opportunity to L
repair this 5 e 1erometer while allowing for lower personnel exposure. This accelerometer
. wdl be op 4or to resumption of power operation.
.,-u The remaining portions ofthe seismic instrumentation were operable while at l power. These instruments would have been sufficient for the operators to determine if a.
, Seismic Event had occurred which may have required a Plant Shutdown. There was,
' therefore, minimal safety significance associated with Plant Operation with the inoperable sdsmic instrument..
. Free and General Manager Nuclear Operations
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. Bill Wagner, Consultant'
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4 October 15,1993 ND3MNO:3492 Page 3 cc:
Mr. T. T. Martin, Regional Administrator United States Nuclear Regulatory Commission Region 1 475 Allendale Road King of Prussia,PA 19406 Mr. G. E. Edison, BVPS Licensing Project Manager United States Nuclear Regulatory Commission Washington, DC 20555 Larry Rossbach, Nuclear Regulatory Commission, BVPS Senior Resident inspector J, A. Holtz, Ohio Edison 76 S. Main Street Akron, OH 44308 Larry Beck Centerior Energy 6200 Oak Tree Blvd.
Independence, OH 44101-4661 INPO Records Center 700 Galleria Parkway Atlanta, GA 30339-5957 Mr. Robert Barkanie Department of Emironmental Resources P,0. Box 2063 16th Ficor, Fulton Building Harrisburg, PA 17120 Director, Safety Evaluation & Control Virginia Electric & Power Co.
P.O. Box 26666 One James River Plaza Richmond, VA 23261 W, Hartley Virginia Power Company 5000 Dominion Blvd.
25W Glenn Allen, VA 23060