W3P84-2891, Interim Rept of Significant Const Deficiency 118 Re Protection Sys/Monitoring Computer Interface.Initially Reported on 840928.Plug-in Connectors Disconnected,Tagged & Logged for Five Setpoint Signals
| ML20107K830 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 10/17/1984 |
| From: | Cook K LOUISIANA POWER & LIGHT CO. |
| To: | Knighton G Office of Nuclear Reactor Regulation |
| References | |
| 118, W3P84-2891, NUDOCS 8411130292 | |
| Download: ML20107K830 (2) | |
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5 POWER & L1GHT / NEW CRLEANE LOuteuWA 70174-8008 9 (So4) 3SS-9345 MIDDLE SOUTH UTIUTIES SYSTEM October 17, 1984 W3P84-2891 3-A1.01.04 3-C41 u
Director of Nuclear Reactor Regulation Attention:
Mr. G. W. Knighton, Chief Licensing Branch No. 3
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Division of Licensing r
U. S. Nuclear Regulatory Commission Washington, D.C. 20555 t
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Dear Mr. Knighton:
r Subj ect: Waterford 3 SES Docket No. 50-382 Meeting with ERC Staff October 11, 1984
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Reference:
Significant Construction Deficiency No. 118
" Plant Protection System (PPS)/ Plant Monitoring Computer (PMC)
Interface" E
This letter is to confirm discussions held during the subject meeting, and to F
document our position regarding actions in resolving the referenced 10CFR50.55(e) g deficiency (SCD-118) which was reported by LP&L to the NRC on September 28, 1984.
E In response to a request by the NRC staff for a detailed discussion on SCD-113, members of LP&L, Ebasco Services, and Combustion Engineering met with NRC E
staff personnel on October 11, 1984. A description of the details of SCD-118 was given with special note made that the condition or failure mode never actually g
happened (there was no event), and the condition was discovered by plant technicians while troubleshooting a different problem in a related circuit.
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The problem is related to only those analog setpoint signals generated in the Plant Protection System (PPS), and in particular only to those process measurements with two dropping resistors in the transmitters current loop. For g
Waterford 3 this is steam generator (SG) 1 & 2 Level, SG 1 & 2 Pressure, and Containment Pressure for each of four protection channels.
Since the failure mode connects the common together effectively altering only one of the setpoint
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signals, the result i's conservative for all but the containment pressure reactor i
trip signal.
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- E lMr.:G.W..jnighton~
-Page:2 Our analysis of o'ther consson mode failure.s. including complete fusion of.the -
- computer input cabinet, shows that the tying' together 'of the cocunons and
- connecting ther. to ground does' not compromise or effect. the PPS fun'etion 'other than for-the above two dropping resistors circuits.
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Immediate corrective action has been to disconnect, tag, and log the plug-in connectors at the PPS for the five'setpoint signals discussed above. We have obtained concurrence fion both Ebasco and CE that the removal of these inputs from the plant computer is acceptable, tad this action satisfies all. isolation concer.ts.
We believe that.we have comprehensively explained'.the details of SCD-ll8 to.the
. staff and are available to discuss it further if you require.
Very truly yours, K.W. Cook Nuclear Support & Licensing Manager KWC:RVS:GEW:sms 1
cc:
E.L. Blake, W.M. Stevenson, J.T. Collins, D.M. Crutchfield, J.H. Wilson, G.L. Constable T.A. Flippo, G. Holahan, J.T. Beard, J.P. Joyce e
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