ML19332F114

Forwards Description of Instrumentation Sys Selected in Response to Generic Ltr 88-17, Loss of DHR, Per Licensee 890127 Commitment.Hardware Changes Will Be Implemented During Unit 1 Tenth & Unit 2 Seventh Refueling Outages

ML19332F114
Person / Time
Site:	Farley
Issue date:	12/07/1989
From:	Hairston W ALABAMA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-88-17, NUDOCS 8912130419
Download: ML19332F114 (3)

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i Alab:rra Power Company I i F - 40 inverness C!ntir Parkway .

• ' Post Office Box 1295 Birmingham, Alabama 35201-

- Telephone 205 868 5581 W. G.'Hairston, ill -

~ Senior Vice President Nuclear Operations Alabama Power. 1 December 7, 1989 " 8#" # 8# '

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10CFR50.4 Docket Nos.'50-348' 50-364 i U. S. Nuclear Regulatory Commission

. ATTN Document Control-Desk Vashington,.D. C. 20555 Gentlemen

[ Joseph'M. Farley Nuclear' Plant - Units 1 and 2

, Loss of Decay Heat Removal L (Generic Letter 88-17)

,' In a' letter dated January 27, 1989, Alabama Power Company provided the NRC l

, responses to the recommended-programmed enhancements of Generic Letter 88-17, " Loss of Decay Heat Removal,".for Farley Nuclear Plant - Units 1.and

2. - In response to the NRC's recommendation concerning- the necessary .

instrumentation for mid-loop operation, Alabama Power Company stated that l

. evaluations of several options for monitoring reactor coolant system (RCS) l water level and residual heat removal (RHR) pump performance were' ongoing.

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'The'1etter further stated that.following plant walkdowns to be performed-during-the Unit 2 sixth refueling outage-(Spring-1989) and the Unit i ninth J refueling outage (Fall 1989), Alabama-Power Company would submit to the NRC l a description of the instrumentation. systems selected. .Provided as an 3- , attachment to this letter are those system descriptions. Also provided is a description of-the proposed main. control board annunciation for core-exit temperature.while operating in a reduced inventory condition. l l

As previously stated in the January 27, 1989 letter, Alabama Power Company's l

? goal.for implementing all required hardware changes in response to the NRC's recommendations is during'the Unit 1 tenth and Unit 2 seventh hefueling outages.

If you have any questions, please advise.

l Respectfully submitted, 1

l l

V. G. Hairston, III l

l VGH,III/BHW md '11.12 Attachment l cc: Mr. S. D. Ebneter

Hr.'E. A. Reeves Mr..G. F. Maxwell J

8912130419.891207 PDR

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P- ADOCK 05000348 PDC il l

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Attachment Description of Instrumentation Systems Required in Response to G.L. 88-17

1. RCS Vater Level Monitoring System _

The existing vide range RCS leve] instrument, which utilizes a differential pressure transmitter connected to a drain line on the

, intermediate Loop B pipe, vill be modified to sense the reference ,

pressure inside the RCS pressure boundary, rather than the containment atmosphere. The differential pressure transmitter reference leg vill be vented to the top of the pressurizer. This modification vill eliminate possible level inaccuracies caused by backpressure in the RCS. The modified vide range RCS level monitor vill be considered as one of-the required independent level instruments per G.L. 88-17. -

Also, permanently installed rigid steel tubing vill be routed from the same Loop B drain line connection to a tygon hose that vill be mounted to a rigid stanchion'to prevent flow obstructions in the hose. The tygon hose vill also be' vented to the top of the pressurizer via rigid steel piping. Although the tygon hose vill not normally be considered as one of the independent indications of RCS level as required by G.L.

? 88-17, it will be used as supplemental and temporary Andication to the

? control room operators should the. vide range.RCS level monitor become inoperable. .Should the tygon hose be temporarily used in such a situation,;the following conditions will be mets.

1. The tygon hose vill be continuously monitored locally, p 2. Communications will be available between the person monitoring the tygon hose and the main control room.

L 3. RCS level readings will be obtained and recorded by the control room operators every 15 minutes.

4. The control room operators vill be notified of unexpected RCS level variations.

5. The tygon hose vill be isolated upon containment evacuation.

l In addition to the modified vide range RCS level transmitter, redundant narrov' range ultrasonic level monitors will be installed on two hot leg pipes. Ultrasonic level monitors provide a very accurate indication of RCS level while operating in the most critical range of mid-loop operation. Ultrasonic transducers vill be permanently mounted directly on the Loop C hot leg pipe adjacent to the RHR suction (active loop) and on the Loop B hot leg pipe which does not have an RHR suction pipe (inactive). Main control board indication vill be provided to display both narrow range level signals (i.e. Loop B and C). The two level signals vill-be routed to the plant computer where an alarm for lov RCS level vill be generated. This alarm vill be both audible and visible to P, the plant operators. Possible effects that might ccuse a difference i g between an inactive loop's indication and that of an active loop vill be reconciled either procedurely or electronically. Either of the two narrow range RCS level monitors will be considered as the second

j. Independent level instrument as required by G.L. 88-17.

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2. RER Pump Perfornonce Monitoring System-As. described above, narrow range indication of RCS level vill be provided as an input to the plant computer. Presently, RHR flovrate is r also an input-to the plant computer. A correlation of these two .

paramcters vill provide the best indicator to predict the onset of-degraded RHR pump performance. An algorithm will be written that translates a curve of RHR flovrate versus RCS-narrow range level for which the onset of air entrainment and subsequent pump cavitation can be predicted. If the calculated value,. based upon actual real-time plant data, exceeds the acceptable limit of the curve, then a main control '

board alarm vill be generated. This RHR-pump' performance. alarm vill be both audible and visible to the plant operator. -In addition, indication

-of RHR pump motor amperes is presently available on the main control board,

3. Cor:-Exit Temperature Annunciation A visible and audible main control board annunciator vill be. installed that vill alert the: operator of high core-exit temperature while operating in's mid-loop condition with the reactor vessel head in place.

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