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{{#Wiki_filter:a e PETER E. KATZ                                             Baltimore Gas and Electric Company Plant General Manager                                    Calvert Cliffs Nuclear Power Plant
{{#Wiki_filter:a e
        *d             Calvert Cliffs Nuclear Power Plant                         1650 Calvert Cliffs Parkway Lusby. Maryland 20657 410 495-4101 September 1,1998 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION:               Document Control Desk
PETER E. KATZ Baltimore Gas and Electric Company Calvert Cliffs Nuclear Power Plant Plant General Manager
*d Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby. Maryland 20657 410 495-4101 September 1,1998 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION:
Document Control Desk


==SUBJECT:==
==SUBJECT:==
Calvert Cliffs Nuclear Power Plant Unit No. 2; Docket No. 50-318 Reactor Vessel Water Level Monitor Snecial Reoort The attached special report is submitted in accordance with Calvert Cliffs Unit 2 Technical Specification 3.3.10. The report is required due to the Unit 2 Reactor Vessel Water Level Monitor                 l having less than the required minimum number of operable channels.
Calvert Cliffs Nuclear Power Plant Unit No. 2; Docket No. 50-318 Reactor Vessel Water Level Monitor Snecial Reoort The attached special report is submitted in accordance with Calvert Cliffs Unit 2 Technical Specification 3.3.10. The report is required due to the Unit 2 Reactor Vessel Water Level Monitor having less than the required minimum number of operable channels.
Should you have questions regarding this matter, we will be pleased to discuss them with you.
Should you have questions regarding this matter, we will be pleased to discuss them with you.
Very t ly yours, j              h.
Very t ly yours, h.
PEK/JKK/ dim           -
j PEK/JKK/ dim


==Attachment:==
==Attachment:==
(1) Unit 2 Reactor Vessel Water Level Monitor Special Report cc:     R. S. Fleishman, Esquire                         H. J. Miller, NRC J. E. Silberg, Esquire                           Resident Inspector,NRC S. S. Bajwa, NRC                                 R.1. McLean, DNR A. W. Dromerick, NRC                             J. H. Walter, PSC
(1) Unit 2 Reactor Vessel Water Level Monitor Special Report cc:
                                                                                                                      \
R. S. Fleishman, Esquire H. J. Miller, NRC J. E. Silberg, Esquire Resident Inspector,NRC S. S. Bajwa, NRC R.1. McLean, DNR A. W. Dromerick, NRC J. H. Walter, PSC
9809100038 980901                                                                                     -
\\
PDR     ADOCK 05000318                                                                               b S                           PDR 9
9809100038 980901 PDR ADOCK 05000318 b
S PDR 9


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ATTACHMENT (1) l l
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                ,,          ,,                        ATTACHMENT (1) l l
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l UNIT 2 REACTOR VESSEL WATER LEVEL MONITOR SPECIAL REPORT l
UNIT 2 REACTOR VESSEL WATER LEVEL MONITOR SPECIAL REPORT l
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l' l                                               Baltimore Gas and Electric Company Calvert Cliffs Nuclear Power Plant September 1,1998 l
Baltimore Gas and Electric Company Calvert Cliffs Nuclear Power Plant September 1,1998 l
                                      ,,r     -                                                -                      -                  -
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ATTACIIMENT (I)                                                   {
ATTACIIMENT (I)
UNIT 2 REACTOR VESSEL WATER LEVEL MONITOR SPECIAL REPORT Baltimore Gas and Electric Company submits this Special Report concerning the inoperable Unit 2 l     Reactor Vessel Water Level Monitor channel as required by Technical Specification 3.3.10, Table 3.3.10-1, Item 5.
UNIT 2 REACTOR VESSEL WATER LEVEL MONITOR SPECIAL REPORT Baltimore Gas and Electric Company submits this Special Report concerning the inoperable Unit 2 l
Reactor Vessel Water Level Monitor channel as required by Technical Specification 3.3.10, Table 3.3.10-1, Item 5.
ACTION TAKEN l
ACTION TAKEN l
The Unit 2 Reactor Vessel Water Level Monitor Channel A experienced a failure of the 10" heated junction thermocouple (sensor) on August 19,1998, at approximately 1500. This failure, coupled with           1 l     previous failures of the 50" and 19" heated junction thermocouples, resulted in the removal from             '
The Unit 2 Reactor Vessel Water Level Monitor Channel A experienced a failure of the 10" heated junction thermocouple (sensor) on August 19,1998, at approximately 1500. This failure, coupled with 1
l    operable status of Channel A as defined by Technical Specification 3.3.10, Table 3.3.101, due to not meeting the required number of operable sensors in the lower five sensors. Note that the Unit 2               .
l previous failures of the 50" and 19" heated junction thermocouples, resulted in the removal from l
I Channel B probe was previously removed from operable status on March 20,1998.
operable status of Channel A as defined by Technical Specification 3.3.10, Table 3.3.101, due to not meeting the required number of operable sensors in the lower five sensors. Note that the Unit 2 I
;      EFFECT ON OPERATION Both Reactor Vessel Water Level Monitor Channel A and B have been removed from operable status.               l Alternate methods of monitoring for core and Reactor Coolant System voiding, using pressurizer level, Reactor Coolant System subcooling, hot leg and cold leg temperature, and core exit thermocouple               i instrumentation, have been incorporated per plant procedures, as required by Technical                       i Specification 3.3.10.                                                                                         l i
Channel B probe was previously removed from operable status on March 20,1998.
EFFECT ON OPERATION Both Reactor Vessel Water Level Monitor Channel A and B have been removed from operable status.
Alternate methods of monitoring for core and Reactor Coolant System voiding, using pressurizer level, Reactor Coolant System subcooling, hot leg and cold leg temperature, and core exit thermocouple i
instrumentation, have been incorporated per plant procedures, as required by Technical Specification 3.3.10.
l i
CAUSES OF INOPERABILITY The cause of the inoperability is the failure of three heated junction thermocouples (sensors) in the lower five sensors. Baltimore Gas and Electric Company believes the failures to be attributable to the bending of the mineral insulated cables during refueling outages (RFOs), which causes undue stress and eventually results in an open thermocouple indication.
CAUSES OF INOPERABILITY The cause of the inoperability is the failure of three heated junction thermocouples (sensors) in the lower five sensors. Baltimore Gas and Electric Company believes the failures to be attributable to the bending of the mineral insulated cables during refueling outages (RFOs), which causes undue stress and eventually results in an open thermocouple indication.
PLANS AND SCHEDULES FOR RESTORING THE SYSTEM TO OPERABLE STATUS Baltimore Gas and Electric Company had already planned to replace the Channel A and B reactor vessel water level probes during the scheduled Unit 21999 RFO. A new design being implemented will                     ,
PLANS AND SCHEDULES FOR RESTORING THE SYSTEM TO OPERABLE STATUS Baltimore Gas and Electric Company had already planned to replace the Channel A and B reactor vessel water level probes during the scheduled Unit 21999 RFO. A new design being implemented will eliminate the need to bend the mineral insulated cables during RFOs, and thus eliminate this failure l
eliminate the need to bend the mineral insulated cables during RFOs, and thus eliminate this failure           l mechanism. Following the replacement of the probes, it is expected the reactor vessel water level             l monitor Channels A and B will be returned to operable status.
mechanism. Following the replacement of the probes, it is expected the reactor vessel water level monitor Channels A and B will be returned to operable status.
We plan to replace the reactor vessel water level monitor probes for both units and both channels so that the above-mentioned failure mechanism is eliminated as a potential cause of Reactor Vessel Water Level Monitor sensor failures. The Unit 1 Channel B probe was replaced during the 1998 RFO, the Unit 2 Channel A and B probes will be replaced during the 1999 RFO, and the Unit 1 Channel A probe will be replaced during the 2000 RFO.
We plan to replace the reactor vessel water level monitor probes for both units and both channels so that the above-mentioned failure mechanism is eliminated as a potential cause of Reactor Vessel Water Level Monitor sensor failures. The Unit 1 Channel B probe was replaced during the 1998 RFO, the Unit 2 Channel A and B probes will be replaced during the 1999 RFO, and the Unit 1 Channel A probe will be replaced during the 2000 RFO.
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Latest revision as of 05:08, 11 December 2024

Special Rept:On 980819,declared Rv Water Level Monitor Channel a Inoperable.Caused by Failure of Three Heated Junction Thermocouples (Sensors) in Lower Five Sensors. Channel a & B Rv Water Level Probes Will Be Replaced
ML20151T528
Person / Time
Site: Calvert Cliffs Constellation icon.png
Issue date: 09/01/1998
From: Katz P
BALTIMORE GAS & ELECTRIC CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9809100038
Download: ML20151T528 (3)
v • d • e


Text

a e

PETER E. KATZ Baltimore Gas and Electric Company Calvert Cliffs Nuclear Power Plant Plant General Manager

  • d Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby. Maryland 20657 410 495-4101 September 1,1998 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION:

Document Control Desk

SUBJECT:

Calvert Cliffs Nuclear Power Plant Unit No. 2; Docket No. 50-318 Reactor Vessel Water Level Monitor Snecial Reoort The attached special report is submitted in accordance with Calvert Cliffs Unit 2 Technical Specification 3.3.10. The report is required due to the Unit 2 Reactor Vessel Water Level Monitor having less than the required minimum number of operable channels.

Should you have questions regarding this matter, we will be pleased to discuss them with you.

Very t ly yours, h.

j PEK/JKK/ dim

Attachment:

(1) Unit 2 Reactor Vessel Water Level Monitor Special Report cc:

R. S. Fleishman, Esquire H. J. Miller, NRC J. E. Silberg, Esquire Resident Inspector,NRC S. S. Bajwa, NRC R.1. McLean, DNR A. W. Dromerick, NRC J. H. Walter, PSC

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9809100038 980901 PDR ADOCK 05000318 b

S PDR 9

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ATTACHMENT (1) l l

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l UNIT 2 REACTOR VESSEL WATER LEVEL MONITOR SPECIAL REPORT l

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Baltimore Gas and Electric Company Calvert Cliffs Nuclear Power Plant September 1,1998 l

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ATTACIIMENT (I)

UNIT 2 REACTOR VESSEL WATER LEVEL MONITOR SPECIAL REPORT Baltimore Gas and Electric Company submits this Special Report concerning the inoperable Unit 2 l

Reactor Vessel Water Level Monitor channel as required by Technical Specification 3.3.10, Table 3.3.10-1, Item 5.

ACTION TAKEN l

The Unit 2 Reactor Vessel Water Level Monitor Channel A experienced a failure of the 10" heated junction thermocouple (sensor) on August 19,1998, at approximately 1500. This failure, coupled with 1

l previous failures of the 50" and 19" heated junction thermocouples, resulted in the removal from l

operable status of Channel A as defined by Technical Specification 3.3.10, Table 3.3.101, due to not meeting the required number of operable sensors in the lower five sensors. Note that the Unit 2 I

Channel B probe was previously removed from operable status on March 20,1998.

EFFECT ON OPERATION Both Reactor Vessel Water Level Monitor Channel A and B have been removed from operable status.

Alternate methods of monitoring for core and Reactor Coolant System voiding, using pressurizer level, Reactor Coolant System subcooling, hot leg and cold leg temperature, and core exit thermocouple i

instrumentation, have been incorporated per plant procedures, as required by Technical Specification 3.3.10.

l i

CAUSES OF INOPERABILITY The cause of the inoperability is the failure of three heated junction thermocouples (sensors) in the lower five sensors. Baltimore Gas and Electric Company believes the failures to be attributable to the bending of the mineral insulated cables during refueling outages (RFOs), which causes undue stress and eventually results in an open thermocouple indication.

PLANS AND SCHEDULES FOR RESTORING THE SYSTEM TO OPERABLE STATUS Baltimore Gas and Electric Company had already planned to replace the Channel A and B reactor vessel water level probes during the scheduled Unit 21999 RFO. A new design being implemented will eliminate the need to bend the mineral insulated cables during RFOs, and thus eliminate this failure l

mechanism. Following the replacement of the probes, it is expected the reactor vessel water level monitor Channels A and B will be returned to operable status.

We plan to replace the reactor vessel water level monitor probes for both units and both channels so that the above-mentioned failure mechanism is eliminated as a potential cause of Reactor Vessel Water Level Monitor sensor failures. The Unit 1 Channel B probe was replaced during the 1998 RFO, the Unit 2 Channel A and B probes will be replaced during the 1999 RFO, and the Unit 1 Channel A probe will be replaced during the 2000 RFO.

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