ML19319B825

Cleveland Illuminating Co East Lake Tests.

ML19319B825
Person / Time
Site:	Davis Besse
Issue date:	12/16/1976
From:	CLEVELAND ELECTRIC ILLUMINATING CO.
To:
References
NUDOCS 8001280655
Download: ML19319B825 (11)

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i 1.0 PURPOSE The purpose of the test program was to determine the susceptibility of the 880 Nuclear Instrumentation System to electrical noise pickup when operated in a power plant environment.

2.0

SUMMARY

OF RESULTS At no time during the two weeks 6f noise testing did the output of the l Power Range Channel exceed the 20 my differential between Bistable set point and j input. In the start up channels, intermediate and source range, the set i points for a rod hold function ( 2 Dec./ Min.) were not exceeded.

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It is absolutely essential that good cable connections and grounding are used to maximize the noise rejection characteristics of the system. Also, it should be recognized that the "best" cable connections and grounding method could vary from plant to plant.

3.0 INTRODUCTION

The testing was conducted at the Cleveland Electric Illuminating Company's Eastlake Plant. The equipment tested included'one source range, one inter-

mediate range and one power range channel, mounted in a single system cabinet. .

FIGURE 3.1 below includes block diagrams of how each channel was connected.

i Recording equipment and Bistables were used to monitor the outputs from the cabinet mounted amplifiers. Whenever possible, unusual equipment noise levels were correlated to plant conditions.

l A cable run was selected which should be representative of a noise environment much more severe than the environment to be expected in a nuclear plant.

j' The testing lasted two weeks. During that time, both normal on-line plant operation (which involves speed changes of induced draft fans, forced draf t fans, and the starting and stopping of feed pumps, circulating pumps, l coal crushers, coal conveyers, arc welding and other associated functions l of steam boiler power plant operation) and a start-up and shut down of a l 150 megawatt generator and its associated equipment took place.

l Battery-powered sources were used to simulate the detectors which would provide input signals to the flux channels in actual operation. These three sources were housed in two aluminum boxes, one for the source range and the second for the intermediate and power ranges.

4.0 CHECKOUT RESULTS 4.1 Bailey Meter Conpany Checkout Before taking the system to CEI it was assembled at BMCo. to cor-respond with what would be the setup at the power plant and run for

(

d Bistable #1 Power Range Linear Source Test Amp.

Circuit Recorder K- 500 ' ->l Power Range Channel Bistable #2 Bistable #3 -

Inter-mediate Log.

Source --

Range Amp.

Test Circuit Rate of Redorder l

Change l4500'->l Intemediate Range Channel h 500' - M Bistable #4 -

Bistable #5 Pre- hint Source hte P Amp.

16100'->l Re re gt Source Range Charnel Circuit ,

FIGURE 3.1 .

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two days with the outputs and set points listed below:

' Module Output Bistable Set Point Linear Amplifier 8.15 V 8.25 V Log Amplifier 5.83 V 6.00 V Count Rate Amplifier 8.43 V 8.70 V Bistable #3 0.91 V 2.00 V Bistable #5 9.91 V 2.00 V 4.2 C.E.I. Checkout Upon arrival at the CEI Plant, the system was set up and run on internal test signals for two days while the input cables were being pulled in the existing cable trays. The location of the system cabinet was right underneath #3 Generator's main bus bars with the top of the cabinet being approximately seven inches below the bus bar housings. During this time no indications above the set points were observed but a significant amount of 60 hertz noise was observed on the test jacks. Listed below are the settings and outputs noted during the two day period.

Peak to Peak Module and Test Jack Test Jack Reading 60 Hz Noise Linear Amplifier Output + 3.005 VDC 65 mv Bistable #1 Input + 3.005 VDC 115 mv Bistable #1 Set Point + 3.042 VDC 80 mv

, Paaer Range Channel Peak to Peak Module and Test Jack Test Jack Reading 60 Hz Noise Log Output 19 mv 70 mv Rate of Change Output + 913 mv 60 mv Bistable #2 Input + 22 mv 100 mv Bistable #2 Set point + 153 mv 42 mv B' stable #3 Input + 912 mi 56 mv Bistable #3 set point + 2.027 V 44 mv Intermediate Range l

l (DC) Peak to Peak Module and Test Jack Test Jack Reading 60 Hz Noise Count Rate Output + 6.582 V 100 mv Rate'hf Change Output + 0.915 V 90 mv Bistable #4 Input + 6.586 V 135 mv (cont'd.......)

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( nt nued) (DC) Peak to Peak Test Jack Reading 60 Hz doise Module and Test Jack

+ 6.596 V 80 av Bistable #4 Set Point

+ 0.915 V 105 mv Bistable of #5 Input 0.9 V 100 mv Bistable of #5 Set Point Test Circuit Pulse Amplitude 0.9 V Source Range After the cables were pulled, the system cabinet was moved approximately 50 feet.

The actual noise testing was done with the cabinet in this ,

location.

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5.0 TEST DATA The data listed in this section consists of four days at low level inputs, one and one half days at mid-range inputs and sixteen hours at high level inputs.

5.1 Low Level Inputs Listed below are typical readings when the low level inputs were used.

Module Input Output Set Point Linear Amp 5.4 x 10- A +7.980 V .

Biotable #1 +7.981 V + 8.001 V Power Range Channel Module Input Output Set Point

~11 Log Amp 5.4 x 10 A + .890 V Rate of Change + .865 V to Amplifier + .890 V + .944 V

• Bistable #2 + .889 V to + .943 V

- + .892 V Bistable #3 + .876 V to + 2.724 V

+ .926 V Intermediate Range Channel Module Input Output Set Point Count Rate 1 Hz +1.578 V Amplifier Rate of Change + 1.528 V + .901 V to Amplifier + .906 V Bistable #4 +1.580 V + 2.083 V Bistable #5 + .900 V to + 2.719 V

+ .905 V Source Range Channel During this time of low-level inputs, arc welding was done on plant equipment within forty feet of the input cables. There were no ab-normal indications caused by the arc welding.

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5.2 _Fud-Range Inputs The readings listed below are for mid-range inputs.

Module Input Output Set Point

-5 Linear Amp 5.4 x 10 + ,7.907 V Bistable #1 + 7.909 V '

+ 7.930 Power Range Channel Module l Input l Gutpui l Set Point

-7 Log Amp 5.4 x 10 + 5.838 V Rate of Change + 5.838 V + .913 V Amplifier ,

Bistable #2 + 5.834 V + 5.885 V Bistable #3 + .912 V + 2.724 V Intermediate Range Channel Module Input Output Set Point Count Rate Amplifier 400 Hz + 5.110 V

' Rate of Change

Amplifier + 5.110 V + .912 V Bistable #4 + 5.115 V + 5.614 V Bistable #5 + .911 V + 2.728 A Source Range Channel l Module Input Output Set Point Count Rate Amplifier 100 K Hz + 8.455 V Rate of Change Amplifier + 8.455 V + .908 V Bistable #4 + 8.459 + 8.958 V Bistable #5 + .910 V +2.723 V Soure.e Range Channel During the time of the test, the set points were not exceeded.

5.3 High Level Inputs Readings listed below are for the high level inputs.

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[ Module l Input l Output l Set Point

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Linear Amp 5.4 x 10 ' + 7.892 V Bistable #1 + 7.887 V + 7.907 V Power Range Channel I

Module l Input l Output l Set Point '

~4 Log Amp 5.4 x 10 + 9.227 V Rate of Change *~

Amplifier + 9.227 V + .916 V Bistable #2 + 9.222 V + 9.273 V Bistable #3 + .912 V + 2.725 V -

Intermediate Range Channel 5.4 Operation During Generator Unit Shutdown While at C.E.I. the No.1 Generator was taken off the line and brought to a turning motor stage of revolving with all its associated equipment shut down also. Before summarizing the data of the generator shutdown the input current levels, outputs, and set points should be listed to give a feel for how the system was set up and operating.

Module l Input l Output l Set Point

-6 Linear Amp 5.4 x 10 ,7,999 y

Bistable #1 + 7.995 V + 8.015 V Power Range Module l Input l Output l Set Point

~11 Log Amp 5.4 x 10 + .876 V to t .885 Rate of Change Amplifier + .873 V to

+ .889 V Bistable #2 + .871 V to + .943 V

+ .881 V Bistable #3 + .871 V to + 1.417 V

+ .884 V Intermediate Range i

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Module Input Output Set Point Count Rate Amplifier 1 Hz + 1.483 V Rate of Change Amplifier + 1.483 V + .906 V to

+ .910 V Bistable #4 + .906 V + 1.420 7 Bistable #5 + 1.487 V + 1.953 V Source Range In taking the generator off the line, the load was dropped in segments of 15 megswatts. Each load drop caused indications above the 500 my differential (set Point-input) of Bistable #4 and the 0.5 ,

Dec./ Min. set point of Bistable f5. When the generator was actually tripped off the line, Bistable #5 exhibited an indication above the 0.5 Dec./ Min. set point. To take advantage of the heat still left in the boiler, the generator was placed back on the line with a 10 megawatt load. This caused the 68 my differential of Bistable #2, the 500 my differential of Bistable #4, and the 0.5 Dec. Min. set point of the Bistable #5 to be exceeded. The only other indication above any set points occurred when the forced draft fans associated with No.

Generator were shut down. This occurred in the source range Bistable

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6.0 CONCLUSION

S At no time during the two weeks of electrical noise testing did the output of the Power Range Channel exceed the 20 millivolt differential between Bistable set point and input. In the start-up channels, with the Bistable set points adjusted to the expected settings for a rod hold function (2 Dec./ Min.), the intermediate and source range channels did not have any set points exceeded due to electrical noise pick up through the input cables.

The system accuracy or operation is not affected by a large strong field of sixty hertz as shown by initial operation at C.E.I..

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