ML20080Q430

Forwards Response to Items 4,5,9,10 & 12 of Re Instrumentation to Detect Inadequate Core Cooling.Response to Item 1 Expected by 840309

ML20080Q430
Person / Time
Site:	Davis Besse
Issue date:	02/10/1984
From:	Crouse R TOLEDO EDISON CO.
To:	Stolz J Office of Nuclear Reactor Regulation
References
1025, NUDOCS 8402240056
Download: ML20080Q430 (7)

Text

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%mm EDISON Docket No. 50-346 RCHt.RO P. CROUSE License No. NPF-3 O **

V 14191259-5221 Serial No. 1025 February 10, 1984 Director of Nuclear Reactor Regulation Attention:

Mr. John F. Stolz Operating Reactor Branch No. 4 Division of Operating Reactors United States Nuclear Regulatory Commission Washington, D.C.

20555

Dear Mr. Stolz:

This is in response to your letter dated September 6, 1983 (Log No. 1360),

concerning the instrumentation to detect Inadequate Core Cooling (ICC).

Toledo Edison provided the schedule for the response on August 9, 1983 (Serial No. 993). Toledo Edison's response for Items 2, 3, 6, 7, 8 and 11 in the Enclosure 2 of your letter was submitted on December 8, 1983 (Serial No. 1003). We have committed that Items 1, 4, 5, 9, 10 and 12 in

'the same enclosure will be submitted to you by February 10, 1984. Enclosed is Toledo Edison's response to these items, except Item No. 1, as we are waiting for additional data to be supplied by a vendor.

It is expected that the response for Item No. I will be submitted to you by' March 9, 1984.

Very truly yours, s

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. Serial'No. 1025 February 10,.1984 Attachment-QUESTION:

4.

The explanation for the displays of the core exit tempera-tures is not clear. The criteria for the backup display are more stringent than those for the primary display, however, the description for both displays refers to-the same figures which illustrate control panel layout. Do the primary and backup systems use the same readout display?

RESPONSE

The_ core map display for core exit thermocouples as described in our March 23, 1983 submittal (Serial No. 924) referred to our backup display.. Please refer to our response to Question.9. in this submittal for a description of the operation and location of our backup display.

Our primary display is a video display available for view-

-ing on the control room CRTs via the plant computer. This display shows a core map with temperature readings for all of the existing 52 incore thermocouples.

QUESTION:

5. -The backup system requires qualification of all the equip-ment from the sensor to the display. The qualification environment should be based on the design basis accident.

Power should be-from a IE power source. The licensees response to Item 5 of II.F.2 Attachment 1 indicates that significant portions of the system are not planned for upgrade. These portions of-the system should be upgraded to environmental qualified equipment.

RESPONSE

The core exit thermocouples and the cables from these thermocouples to the containment vessel penetrations are not-Class IE.

These temperature signals meet the Class 1E requirements from the containment vessel penetrations up to and including the buffers which interface with the station and Technical Support Center computers. Class IE essential instrument power sources supply power to these Class 1E portions of the system.

.The incore. thermocouple system is being reviewed as part of our Emergency Response capability review program. A schedule for any changes to this system will be provided to you in the Regulatory Guide 1.97 Rev. 2 portion of our E

reply concerning schedules for completion of basic require-

'ments of Supp. I to NUR2G 0737 - Rcqu;rements for Emergency Response Capability,-due April 15, 1984, as committed to in our -letter Serial No. 933 to Mr. Darrell G. Eisenhut.

-QUESTION:

-9.

Figures 1 and 2 show TI4627 and TI4628 as incore tempera-tures.

is this equivalent to the backup display of core exit temperature and if so where is the channel selector l

switch located? What type of indicator is used, e.g.,

digital / LED?

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Docket N2. 50-346 w

License No. NPF-3 LSerial-No. 1025 February 10, 1984 Attachment Page 2

-RESPONSE:

The core map for the backup display is located at the hand selector switch.

It shows the spatial location of the eight thermocouples-for that particular channel (see details C&D). The hand switch is used to select one of these temperaturet for display on the temperature indicator for that channel (TI4627 for Channel 1. TI4628 for Channel 2).

~

The core. maps / hand selector switches and associated temper-ature : indicators for the backup display are located on the Post Accident Indicating Panels (see Figures 1 & 2).

Temperature indicators TI4627.and TI4628 are analog indi-cators with a. range of 0-2300*F.

QUESTION:

10. Clarify the schedule for additional upgrading of existing

' instrumentation.

. RESPONSE:

Please refer to our response to Question 5 in this submittal for information concerning the upgrading of existing instrumentation.in.the core exit thermocouple temperature indication system.

QUESTION:

12. Justify the; design adequacy of the various components of-the: reactor coolant pump monitoring system for potential operating environment. Are there potential circumstances of core uncovery where the reactor. coolant pumps may. be.

restarted to achieve core cooling under low coolant inven-tory conditions? If so, can the pump monitor be expected to function and provide information on the progress of coolant recovery?

RESPONSE

.There are three (3) signals provided.to the plant computer for the reactor coolant pump monitoring program.

1.

RCS wide. range temperature-(safety grade) 2.

RCS wide range pressure (safety grade) 3.

RCP electrical power

.The RCS pressure and temperature signals originate from the

' transmitters inside containment with signal conditioning modules ~in the cabinet room. This is all' safety grade equipment and qualified for post accident environmental conditions. The RCP electrical power signal and its instrument modules are all located outside the containment.

They will not be subjected to an adverse post accident

-environment.

There are potential circumstances of core uncovery where

.the RCPs may be started to achieve core cooling. The RCP power monitoring system is expected to be operable barring a concurrent seismic event where the RCP electrical power instrument may fail for not being seismically qualified.

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