ML19340C294
| ML19340C294 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 11/04/1980 |
| From: | Crouse R TOLEDO EDISON CO. |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| 661, TAC-10996, NUDOCS 8011140455 | |
| Download: ML19340C294 (7) | |
Text
,
TCLEDO
%mm EDISON ACwC D CUAE Docket No. 50-346
. :,. m,
.m License No. NPF-3 m e ur Serial No. 661 November 4, 1980 Director of Nuclear Reactor Regulation Attention:
Str. Robert W.
Reid, Chief Operating Reactors Branch No. 4 Division of Licensing United States Nuclear Regulatory Commission Washington, D. C.
20555
Dear Sir. Reid,
This is in response to the committments set forth in a NRC letter from D.
- 3. Vassallo, Assistant Director for Light Water Reactors, Division of Project 31anagement, dated September 26, 1977. The letter related to the Instr.aent-Station Ground Grid System at the Davis-Besse Nuclear Power Station, Unit 1 (DB-1).
roledo Edison !:s completed its analysis and testing of the DB-1 instrument system. A summary and status of the results are attached.
The grounds identified do not affect the operability of the associated systems. Staintenance Work Orders (>fWO) have been generated to clear all identified unintentional grounds.
Very truly yours, W;v RDC:RFP:AJT:slc cc:
L.
Reyes Col S
Il THE TOLECO EC:SCN CCMPANY ECibCN PLAZA 3CO VAC:SCN AVENLE TCLECC, CH'O 43E52 8011 no 45 5
Docket No. 50-346 License No. NPF-3 Serial No. 661 Attachment Page 1 of 6 ATTACHMENT 1 INSTRUMENT GROUND SYSTEM TESTING
SUMMARY
To meet NRC commitments concerning inadvertent instr > ment ground (IG) ties, FCR 79-429 was prepared to test the IG system.
Initial testing indicated ground ties in several safety and non-safety systems. Testing concentrated on safety systems that indicated inadver-tent ground ties (See Attachment 1).
One channel of SFAS and the four channels of RPS indicated inadvertent ties.
The tie in SFAS Channel 4 was located and corrected. Supplements 1, 2, 3 and 4 to FCR 79-429 were prepared to troubleshoot the RPS system.
By isolating both design ground ties and inadvertent ground ties it was possible to demonstrate single point grounding of the RPS channels (See Attachment 2).
I
Docket No. 50-346 License No. NPF-3 Serial No. 661 Attachment Page 2 of 6 AT"ACIOiENT 1 SAFETY SYSTDi INSTRUMENT GROUND System Cabinet Ground Tie Indication RPS-1 C5762E-F Yes RPS-2 C5755E-F Yes RPS-3 C5763E-F Yes RPS-4 C5756E-F Yes SFAS-1 C5762C-D No SFAS-2 C5755C-D No SFAS-3 C5763C-D No SFAS-4 C5756C-D Yes Steam Generator 1 Level C5736 No Steam Generator 2 Level C5737 No Steam Generator 3 Level C5738 No Steam Generator 4 Level C5739 No
Docket No. 50-346 License No. MPF-3 Serial No. 661 Attachment Page 3 of 6 ATTACHMENT 1 RPS CHANNEL 1 Indiested Ground Tie Co=ments Reactor Trip Module Not an inadvertent ground tie.
Wired per Bailey drawings. A design tie for proper reactor trip logic operation. Uses IG for signal return.
Wire 1-10-2-12 to V&LPMS A high impedance tie through the V&LPMS input amplifier. Reference MWO IC-525-80.
Source Range Instrumentation An inadvertent tie in the cable shields from the connectors in the RPS cabinet to the source range preamplifier. Reference MWO IC-521-80.
Wire 1-10-4-10 to RCS RTD An inadvertent tie.
Shield (For RC Temperature) drain wire was touching conduit.
Reference MWO IC-519-80.
Auctioneered Average Power Module Not an inadvertent tie.
Wired (Auctioneer) per Bailey drawings. Uses IG for signal return.
Gottom Power Range Module While preparing to troubleshoot (Linear Amplifier) the source range prea=plifier for inadvertent ground ties, an inadvertent ground suddenly appeared in this module.
Ref-erence MWO IC-656-80.
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Docket No. 50-346 License No. NPF-3 Serial No. 661 Attachment Page 4 of 6 ATTACE3ENT 1 RPS CHANNEL 2 Indicated Ground Tie Comments Reactor Trip Module Not an inadvertent ground tie.
Wired per Bailey drawings. A design tie for proper reactor trip logic operation. Uses IG for signal return.
Wire 1-10-2-12 to V&LPMS A high impedance tie through the V&LPMS input amplifier. Refer-ence MWO IC-524-80.
Power Range Instrumentation An inadvertent tie in the cable shields from the connectors in the RPS cabinet to the power range sensors. Reference MWO IC-520-80.
NNI Buffer Pressure Module Not an inadvertent tie.
Injected ground test current passes through the module and returns. Refer-ence MWO IC-516-80.
Total Flux NI-5 Module Note an inadvertent tie.
Injected ground test current passes through this module and returns.
Refer-ence MWO IC-526-80.
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Docket No. 50-346 License No. NPF-3 Serial No. 661 Attachment Page 5 of 6 ATTACHMENT 1 RPS CHANNEL 3 Indicated Ground Tie Comments Reactor Trip Module Not an inadvertent ground tie.
Wired per dalley drawings. A design tie for proper reactor trip logic operation. Uses IG for signal return.
Wire 1-10-2-12 to V&LPMS A high impedance tie through the V&LPMS input amplifier. Refer-ence MWO IC-523-80.
t l
Docket No. 50-346 License No. NPF-3 Serial No. 661 Attachment Page 6 of 6 ATTACHMENT 1 RPS CHANNEL 4 Indicated Ground Tie Comments i
Reactor Trip Module Not an inalvertent ground tie.
Wired per Bailey drawings. A design tie for proper reactor trip logic operation. Uses IG for signal return.
Wire 1-10-2-10 to V5LPMS A high impedance tie through the V&LPMS input amplifier.
Refer-ence MWO IC-518-80.
Wire 1-10-4-10 to RCS RID An inadvertent tie.
Shield (For RC Temperatures) drain wire was touching conduit.
Reference MWO IC-518-80.
Wire 1-10-4-10 to RCS Pressure Not an inadvertent tie.
The Transmitter shield of the field cable was connected to the shield of the RCS RTD.
This inadvertent ground will clear when the RCS RTD shield is repaired.
Ref-erence MWO IC-515-80.
Average Linear Power Module Not an inadvertent ground.
(Averager)
Wired per Bailey drawings. Uses IC for signal return. Reference MWO IC-517-80.
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