2CAN058801, Requests Relief from Tech Spec 3/4.1.3.4 Re Max Drop Time for Individual Control Element Assemblies.Test Utilizing New Test Method,Detailed Explanation of Circuit Phenomenon & History of Drop Times Encl

Requests Relief from Tech Spec 3/4.1.3.4 Re Max Drop Time for Individual Control Element Assemblies.Test Utilizing New Test Method,Detailed Explanation of Circuit Phenomenon & History of Drop Times Encl

ML20153F854
Person / Time
Site:	Arkansas Nuclear
Issue date:	05/05/1988
From:	Tison Campbell ARKANSAS POWER & LIGHT CO.
To:	Calvo J NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM), Office of Nuclear Reactor Regulation
References
2CAN058801, 2CAN58801, NUDOCS 8805110070
Download: ML20153F854 (20)

Text

__ __

e ARKANSAS POWER & LIGHT COMPANY CAPIT0L TOWER BUILD'NG/P. O. BOX 551/LITTLE ROCK. ARKANSAS 72203/(501) 377 3525 T. GENE CAMPBELL May 5, 1988 v.c. Pres oert rww ocwtes 2CAN058801 1

U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 ATTN: Mr. Jose Calvo, Project Director Project Directorate - IV Division of Reactor Project - III, IV, V and Special Pr0jects

SUBJECT:

Arkansas Nuclear One - Unit 2 Docket No. 50-368 License No. NPF-6 Request for Temporary Waiver of Compliance Technical Specification 3/4.1.3.4 - CEA Drop Time

Dear Mr. Calvo:

Per our recent conversations, ANO-2 is faced with an immediate need for relief from Technical Specification (TS) 3/4.1.3.4, which specifies the maximum drop time for individual Control Element Assemblies (CEAs).

A change in the measurement methodology has revealed that the indicated drop time for certain CEAs exceeds the 3.0 seconds specified by 15 3.1.3.4.

The method used previously for measuring CEA drop time involved interrupting the power to Control Element Drive Mechanism (CEDM) from each individual CEDM breaker.

The new test method implemented during the sixth refueling outage (2R6) involves interrupting the power to all the CEDMs simultaneously via the Reactor Trip Breakers (RTBs).

CEAs and CEDMs are described in the ANO-2 SAR Section 4.2.3. and the reactor trip system is described in Section 7.2.1 and Figures 7.2-5 and 7.2-7A.

Testing utilizing the new test method (further described in Attachment 1) revealed an additional time delay factor due to circuit time constants associated with the electromagnetic decay of multiple CEDM coils vs. the decay time of an individual coil. provides a detailed explanation of this circuit phenomenon.

It is important to note that the actual physical drop time of the CEAs has not increased, as shown by the test performed during 2R6 and the history of drop times included in Attachment 3.

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Mr. Jose Calvo 05/05/88 The accident analyses' presented in Chapter 15 of the SAR are being individually reviewed and evaluated to determine the effects of the increased CEA drop times recorded during the recent surveillance tasting for ANO-2.

Although these evaluations have not been completed for all events, AP&L his addressed those events applicable to "low power" operations.

These efforts are considered adequate to allow entry into Mode 1 operations to perform startup physic's testing and low power (i.e., up to 30% power) operation.

The favorable conclusions are supported by two separate considerations discussed below.

First, it is important to note that the safety analyses typically assume that all CEAs are inserted to 90% at the maximum technical specification limit (3.0 seconds).

This assumption provides a straightforward method for verifying compliance with the technical specification and allows'for relatively simple modeling of reactivity insertion in the safety analyses.

However, this assumption is clearly conservative since the technical specification ensures that the limiting (i.e. slowett) CEA will reach the 90% limit within 3.0 seconds; consequently, most CEAs are inserted sooner.

The recent testing, for example, in which (conservatively) 17 CEAs exceeded the 3.0 second assumption for 90% insertion, demonstrated that the majority of the CEAs (56) were inserted beyond 90% at 3.0 seconds and many were actually fully inserted.

As a result, it is apparent that the total reactivity insertion remains greater than the safety analyses assumption since the "early" CEAs more than offset the CEAs which do not meet the technical specification criteria.

Notwithstanding the above considerations, specific evaluations of each affected safety analysis from the SAR Chapter 15 ovents are being undertaken.

In order to support the initiation of startup physics testing and Ecwer operation up to 30%, each analysis pertinent to low power events has been addressed.

For each affected event, it was assumed that all CEAs are inserted to 90% at the same time, but the time to 90% insertion was extended to represent the recent worst case CEA drop test results (3.18 seconds).

In order to determine a more realistic impact of the change in the analysis assumption, the current 1D static reactivity insertion data was replaced by revised scram insertion data based on 1D space-time neutronics methods.

An evaluation of the opposing effects demonstrates that the increased CEA drop i

times are more than offset by the more realistic scram insertion data.

Consequently, the conclusions of the safety 6balyses in question remain valid.

Additional explanation of the applied evaluation technique is pro ided in.

Greater than expected CEA drop tine measurements were first observed on May 1 and were initially believed to be due to problems with the new testing software and/or methodology.

Further troubleshooting and evaluations, however, led to the conclusion on May 3 that the current test results were valid at which time initial notifications were made to the NRR and Region IV staff.

Due to the possible implications relative to previous testing and potential generic implications, a report was also made per 10CFR50.72.

We have now completed our initial assessment of the acceptability of the increased measured CEA crop times and are now awalting resolution of this issue to proceed with startup and initiation of Cycle 7 physics testing.

Based on the attached justification, we request staff approval to proceed with zero power physics testing (moving to Mode 2), which will take about a

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two days, and then to proceed into Mode 1 to~the 30% power test plateau hold for three days, 'During this' time period, AP&L will prepare a detailed

- justification for an' emergency TS amndment request submittal for subsequent full' power;' operation to be~ s' bmitted'to.the NRC as soon.as possible.

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'Very truly yours, MM T. Gene Campbel s

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Regional Administrator Region IV-U. S. Nuclear Regulatory Commission 611 Ryan' Plaza Drive, Suite 1000 Arlington, TX 7601,1 1

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ATTACHMENT 1

'CEA DROP TIME' TESTING AT ANO-2 The following is a summary of the two. methods which have been used at ANO-2 to measure the drop times of the CEAs (see also Figure 1-1):

1)

The first method is the "traditional" method used since the initial-4startup and through the Cycle 6 refueling outage.

This method tests each CEA individually.

.A visicorder'.is connected to the subject CEA reed switch position transmitter (RSPT) to provide the position tnd to the upper gripper coil to show when current is interrupted to the CEA gripper.

The CEA is then withdrawn from the core to its full out position; the visicorder is switchec on to high speed; the CEA is dropped by opening its individual circuit breaker.

Position of the CEA as a function of time is recorded on.the visicorder chart in the form of the changing RSPT signal.

From this chart the time from interruption of power to 90% CEA insertion can be datermlc,ed.

2)

The second method was used for the first time at AN0'2 during the pre-critical testing prior to Cycle 7 startup.

This method uses special software loaded on one of-the Control Element Assembly Calculators (CEACs) which turns the selected CEAC into a specialized high speed data acquisition system capable of the simultaneous monitoring of all 81 CEA positions every 50 milliseconds through their individual RSPTs.

The data may then be transferred to a floppy disk for permanent storage or analysis.

The special software (CEA Drop Time Test, or COTT softwa-initiates the test by transmitting a large penalty factor to et

f the Core Protection Calculator (CPC) channels, producing a

, actor trip.

It should be noted that the point at which power is interrupted to the CEA drive mechanism is the reactor trip breaker, not the individual breakers as in the "traditional" method.

Because the CDTT software begins sampling data as soon as it issues the penalty factor, the recorded drop times must t'e corrected for the delay

, time which is associated with the CPC processing time and actuation of the trip logic and trip breakers.

This delay is part of the CPC instrumentation response time and is therefore already accounted for.

This delay time is detarmined by monitoring a target CEA during its drop using a visicorder which is connected to the CEA in the same way as done for the traditional method.

The visicorder trace drop time and the CDTT computed drop time are then compared to determine the delay time in the CDTT output to be subtracted from each CEA drop time.

(See Figure 1-2).

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ATTACHMENT 2 DESCRIPTION OF CEDM CIRCUIT-TIME CONSTANT EFFECTS

' Figures 2-1 and 2-2 are simplified drawings which illustrate.the CEA trip circuit when tested by the "traditional" method (via the individual CEA o

breaker) vs. the revised testing method via the reactor trip breakers).

The "Traditional" method of response time testing provides coil discharge time of less than 0.3 seconds.

Figure 2-1 represents the path for_the energy stored in the holding coil which is dissipated through the resistor.

The time for the energy to dissipate through the resistor established the response time.

The second method of response time testing (power removal by opening trip circuit breakers) provides discharge times of approximately 0.25 seconds

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longer than the "traditional" method.

The discharge path is presented by 3

Figure 2 2.

.Ncte in this figure the discharge path' is mainly through the lower resistar:e across the two holding coils (Y1 & Y2). A longer time is required for the same aaount of energy to dissipate through a lower resistance path, therefore, the response time measured in this method is longer than the traditional method.

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ATTACHMENT 3 ANO-2 CEA DROP TIME HISTORY Table 3-1 provides CEA drop times for each CEA tested through the most recent Cycle 7 tests.

During the 2R6 refueling outage two independent tests were performed utilizing the enhanced test method described in Attachment 1.,

Both test results are presented.

Also provided are cycle average and maximum and minimum drop times.

The spatial distribution of Cycle 7 test data is shown by Figure 3-1.

A review of this data shows no trend or significant deviation in the rhysical drop times.

Figure 3-1 indicates the slower dropping CEAs tc be located around the core periphery.

This is.

expected as these CEAs are lighter due to their shorter eatension shafts (curvature of the reactor vessel head).

A comparison of Cycle 7 CEA drop times, considering the additional delay of approximately 0.25 seconds associated with the electrical phenomenon described in Attachment 2, to those drop times asscciated with the previous six cycles' test results shows no significant change or trend in the physical drop times for the CEAs.

Table 3-2 summarizes the test results performed for select CEAs.

Test results for all CEAs with drop times exceeding three seconds during Tests 1 or 2 are presented in this table.

Values for CEA drops initiated from the individual breakers were recorded for seven CEAs.

A comparison of these values to previous cycle data shows little difference.

This results would be expected since this test method is identical to those performed for previous cycles.

The RTB visicorder test results shown in Column.4 of the Table shows similar results to the drop times recorded during Test 1 and 2.

These results are expected as all of the CEA coils are denergized simultaneously as was the case during Test 1 and 2, and therefore, the same electrical effect will be present.

The result presented in Column 6 for i

CEAs 01 and 76 reflect drop times recorded for the CEA when the RTB is tripped and all other CEA individual breakers are open.

As expected, these drop times are very similar to the drop times recorded when the individual breaker for these CEAs are utilized to trip the'CEA.

The above demonstrates and verifies the electrical phenomenon described in.

The phenomenon results in approximately 0.25 seconds delay in measured CEA drop time.

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ARKANSAS NUCLEAR ONE -- UNIT TWO 4

CEA DROP TIMES TO 90%' INSERTION (SECONOS),

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. ' CYCLE 6-TEST 1 TEST 2 CYCLE'7 CYCLE 7 CYCLE 1 CYCLE-2 CYCLE 3 CYCLE.4 CYCLE 5 1"

2.38 2.40 2.42 2.41 2.45 2.48 2.75 2.73 2

- 2. 46' 2.45 2.47 2.51 2.47; 2.55 2.81 2.77 3

2.41 2.43 2.50 2.32 2.46.

2.54' 2.81 2.79 4

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2.50 2.49 2.56 2.36 2.52.

2.51 2.83 2.89 7

2.42 2.43 2657 2.58 2.48 2.50 2.83 2.81 8

2.40 2.43 2.51 2.47 2.48 2.48 2.39 2.54 9

2.42 12.16 5 2.55 2.52 2.50 2.55 2.85 2.79 10 2.46 2.68 2.=55 2.48 2.50 2.48 2.77 2.74 11 2.52 2.60 2.62 2.59 2.58 2.58 2.91 2.88 12 2.40 2.46.

2.47 2.47 2.64 2.42 2.72 2.68 13 2.43 2.50 2.52

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2.50 2.52 2.44 2.53 2.50 2.62 2.88 2.84 15 2.58 2.61 2.62 2.65 2.58 2.65,

'2.90 2.86 16 2.54 2.53 2.56 2.55 2.53 2.63 2.82

>2.80 17 2.50 2.60 2.58 2.51 2.54 2.63

-2.86 2.83 18 2.43 2.53 2.50 2.49 2.50 2.55L 2.85 2.81 19 2.40 2.53 2.52 2.52 2.45 2.55 2.82 2.79 20 2.48 2.53 2.59 2.53.

2.44 2.60 2.82 2.77 21.

2.52 2.58 2.66 2.64 2.46 2.70

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2.64 2.63 2.65 2.70 2.-70 2.68 2.95 2.94 31 2.46 2.48 2.50 2.52 2.50 2.67.

2.83 2.81 32 2.48 2.52 2.55 2.54 2.56 2.53 2.84 2.81 33 2.65 2.67 2.68 2.74 2.70 2.70 2.97-2.95 34 2.52 2.65 2.59 2.64 2.60 2.56

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35 2.50 2.53 2.56 2;62 2.58 2.52 2.77 2.78 -

36 2.65 2.65 2.65 2.65 2.65 2.63 2.93 12.90 37 2.51 2.54 2.55 2.59 2.53 2.47 2.87 2.84 38 2.57 2.55 2.71 2.69 2.67

- 2.' 67 2.98' 2.95 39.

2.50 2.54 2.57 2.53 2.51 2.57-2.83 2.85 40 2.59 2.63 2.67 2.46 2.62 2.64 2.92 2.91 41 2.55 2.60 2.64 2.64 2.58 2.64 2.92 2.92 42 2.55 2.59 2.61 2.61 2.55 2.59 2.93 2.90 43' 2.27 2.48 2.52 2.52 2.54 2.58' 2.84 2.81 44 2.58 2.62

'2.58 2.60 2.59 2.65 2.93 2.90 45 2.55 2.57 2.60' 2.51 2.59 2.61 3.02 2.97 46 2.70 2.72 2.75 2.53 2.73

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TABLE 3-1 (continued)

CEA DROP TIMES TO 90% INSERTION (SECONDS) 52 2.59 2.66 2.70 2.67 2.70 2.66 2.97 2.95 53 2.71 2.70 2.72 2.77 2.75 2.73 3.01 2.99 54 2.65 2.70 2.72 2.58 2.73

'2.73 2.99 2.99 55 2.56 2.62 2.61 2.49' 2.68 2.63 2.89 2.91 56 2.63 2.63 2.62 2.67 2.68 2.63 2.92 2.86 57=

2.65 2.69 2.64 2.71 2.70 2.79 2.98 2.95 58 2.63 2.69 2.73 2.69 2.68 2.68 2.97 2.95 59 2.69 2.71 2.76 2.51 2.71 2.74 3.05 3.00 60 2.55 2.62 2.66 2.67 2.67 2.65 2.93 2.91 61 2.69 2.70 2.72 2.75 2.71 2.78 3.06 3.05 62 2.58 2.58 2.60 2.63 2.64 2.63 2.83 2.84 63 2.63 2.62 2.67 2.60 2.64 2.66 2.95 2.93 64 2.58 2.66 2.62 2.60 2.62 2.63 2.90 2.90 65 2.68 2.51 2.83 2.77 2.72 2.67 2.96 2.95 66 2.63 2.61 2.68 2.69 2.68 2.65 2.96 2.96 67 2.70 2.73 2.73 2.76 2.80 2.72 3.03 2.99 i

68 2.72 2.73 2.76 2.77 2.78 2.66 3.04 3.01 i

69 2.61 2.60 2.62 2.67 2.64 2.54 2.96 2.95 70 2.73 2.74 2.74 2.80 2.75 2.73 3.07 3.01 71 2.76 2.63 2.83 2.84 2.76 2.81 3.14 3.10 72 2.66 2.65 2.69 2.68 2.60 2.71 2.95 2.94 73 2.68 2.70 2.76 2.73 2.70 2.68 2.99 2.98 74 2.73 2.76 2.83 2.64 2.73 2.62 3.14 3.16 75 2.67 2.67 2.72 2.77 2.65 2.69 3.04 3.03 76 2.65 2.70 2.77 2.58 2.77 2.64 3.02 3.01 77 2.63 2.61 2.70 2.68 2.67 2.73 2.99 2.96 78 2.62 2.68 2.74 2.74 2.68 2.58 2.92 2.88 79 2.60 2.72 2.75 2.72 2.68 2.71 3.02 3.02 80 2.73 2.75 2.86 2.82 2.79 2.77 3.17 3.18 81 2.66 2.70 2.76 2.78 2.70 2.62 2.99 2.95 AVG.

2.57 2.60 2.64 2.61 2.62 2.63 2.92 2.90 MAX.

2.76 2.76 2.86 2.84 2.80 2.83 3.17 3.18 4

MIN.

2.27 2.40 2.42 2.32 2.44 2.42 2.59 2.54 CCEAs 22 through 29 are part length CEAs and are not subject to TS 3.1.3.4 limits.

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FOR SELECTED CEAs Li CEA's EXCEEDING 3 SECONDS COMPUTER DROP TIME ~

VISICORDER DROP TIME-CEA TEST 1 TEST 2

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(SEC)

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21 3.01 2.94 45 3.02 2.97 46 3.03 3.00 1

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47 3.03-3.02 2.94 2.72 49 3.05 2.98 53 3.01 2.99 fl 59 3.05; 3.00 s

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67 3.03 2.99 68 3.04 3.01

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70 3.07 3.01 3.01 2.76-71 3c14 3.10 3.07 2.81' 74 3.14 3.16 3.11 2.89 75 3.04 3.03 76 3.02 3.01 2.96 2.72 2.72 79 3.02 3.02 80 3.17 3.18 3.16 2.81 l

l ADDITIONAL CEA DATA r

01 2.75 2.73 2.70 2.51 2.54

• NOTE:

CEA Drop Initiated from Reactor Trip Breaker with all IndiUidual CEA Breakers Closed.

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• • NOTE:

CEA Drop Initiated from Individual CEA Breaker.

• • • NOTE:

Single CEA Drop Initiated from RTB with Remaining Individual CEA Breakers Open.

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ATTACHMENT 4 EFFECTS OF DELAYED CEA INSERTION ON SAR SAFETY ANALYSES Scram insertion data is calculated from a "CEA position versus time" curve based on measured CEA drop time data and a "reactivity versus CEA position" curve based on neutronic calculations.

Table 4-1 shows the scram insertion data used in the currently docketed ANO-2 low power safety analyses.

The CEA position versus time data during the ; cram was based on design calcuations and verified during initial startup testing.

This is shown as-the "design" curve in Figure 4-1.

The reactivity insertion data versus CEA position was calculated for the Cycle ? analyses (the ANO-2 reference' cycle) usinr static 10 neutronic methods.

Table 4-2 shows the revised scram insertion data which incorporates the effect of the increased CEA drop times and advanced 10 neutronic methods as i

discussed in CE Topical Reports "HERMITE Space Time Kinetics", CENPD-188-A, March 1976 and "FIESTA One Dimensional Two Group Space Time Kinetics Code for Calculating PWR Scram Reactivities", CEN-122, November 1979.

The CEA position versus time data during the scram is determined from the slowest i

CEA measured during the current outage.

This was CEA 80 which had a drop time of 3.18 seconds to 90% insertion.

It should be noted that the average drop time for all CEA's is 2.92 seconds to 90% insertion and that 17 CEAs have drop times in excess of 3.00 seconds.

The "revised" CEA position 1

versus time data, based on the slowest CEA, is compared to the "design" data in Figure 4-1.

The revised CEA reactivity versus CEA position data is derived from 10 space-time neutronic results which have been utilized for other CE plants (Arizona-1, 2 & 3, SONGS-2/3, Waterford-3, BG&E-1 & 2, St. Lucie 1 & 2).

Applicability of the data and methods is valid for ANO-2 based on parametric studies performed by Combustion Engineering.

Figure 4-2 compares the design curve of reactivity versus> time (Table 4-1) to the revised curve (Table 4-2) which incorporates the increased CEA drop time and the space-time neutronics methods.

As shown in Figure 4-2, the revised reactivity insertion curve is the same as the design curve up to approximately 2.0 seconds and is conservative relative to the design curve between approximately 2.0 and 2.8 seconds after the trip breakers open.

Beyond this point, the design curve is more conservative than the revised curve.

.The SAR Chapter 15 events were reviewed to determine which could be affected by a trip delay of approximately 0.25 seconds.

Only three events result in rapid approach to the sraecified acceptable fuel design limits (SAFDL) and i

these are terminated by a reactor trip.

For these events (listed in Table 4-3), the time to closest approach to a SAFDL is between 2.0 and 2.8 seconds.

Figure 4-2 shows that the revised curve is conservative during this time.

The remaining transients are either much slower to develop or approach a SAFDL after the scram (i.e, main steam line break) such that the delay of reactivity insertion does not significantly affect the conclusions.

t-v 7

f:

'i TAELE 4-1 ANO-2 DESIGN SCRAM INSERTION (USE0 FOR ORIGINAL ANALYSIS OF LOW ~ POWER' EVENTS)

' \\

if

'Timi Positibn-

' Reactivity sec

% Inserted Fraction 7

i 0.00 0

0.0 1

0.30 0

0.0 0.66 5

0.0009 0.84 10 0.0024-Position vs. time Based

- 1. 00 '

15 0.0035-on Design calculation 1.16 20 0.0040

& start up Testing 1.31 25 0.0042 l

1.46 30 0.0045 "

1.60 35 0.0052 Reactivity vs. Position N

1.72 40 0.0064 calculated using static l

1.86 45 0.0086 Methods.

i 2.00 50 0.012 2.11 55' O.018 2.25 60 0.027 2.38 65 0.040 l

2.50 70 0.061 l

1 2.63 75 0.096 2.76 80 0.160 i

2.88 85 0.28 l

~

3.00

-90 0.51 3.24 100 1.0 J

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,h>

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1 t

4

=

0 9

l_

FIGURE 4-1 CEA POSITION VS. TIME ANO UNIT 2 CYCLE 7 STARTUP l

CEA POSITION

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j 100 -

i

% %g%

90-g 7

C 80 -

's f,

O N s 6

70 -

N O

N O-I 60-N l

2 N

i N

3 s

50 -

4 i

g g

40 -

Ng I

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~

30 -

SLOWEST j

20 -

DESIGN N

MEASURED i

- g 1

10 -

\\ g '

N o_

%m i

l 1

I I

I i

I l

0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 i

4 EL APSED TIME (seconds).

o

TABLE 4-2 REVISED ANO-2 SCRAM INSERTION I

(USED FOR ANALYSIS OF LOW POWER EVENTS)

Time Position _

Reactivity sec

% Inserted Fraction 0.00 0

0.0

)

0.57 0

0.0 0.85 5

0.0001 Position vs. time is 1.02 10 0.0004 for the slowest CEA 1.18 15 0.0008 measured 5/2/88.

1.32 20 0.0014 1.48 25 0.0028 Reactivity vs. Position 1.62 30 0.0043 Based on space-time 1.77 35 0.0072 calculations done for 1.92 40 0.0117 other plants.

2.05 45 0.0167 2 18 50 0.0250 2.31 55 0.040 2.46 60 0.0617 2.58 65 0.0950 2.70 70 0.1417 2.83 75 0.2083 2.95 80 0.3250 3.07 85 0.4917 3.18 90 0.7767 3.50 100

1. 0 l

i o

w

7 FIGURE 4-2 CEA REACTIVITY VS. TIME i

ANO UNIT 2 CYCLE 7 STARTUP CEA REACTIVITY j

l

1. 0 -

/

/

0.9-m DESIGN c

/

O i

j

0. 8 -

/

1

/

o s.

l l

[

0.7-

/ REVISED

~

l 0.6-I y

l l

F-I l

50.5-l i

F-

/

l g

0.4-f j

W 0.3-f E

i j

0.2-i j

0.1 -

/

/

_s l

0 0

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4

i 1

j ELAPSED TIME (seconds) 4

n 4

f.

?

. TABLE 4-3 EVENTS SENSITIVE T0 DELAY IN SCRAM-TIME T0 CLOSEST APPROACH EVENT TO SAFDL Uncontrolled CEA Withdrawal

~ 2.2 sec,

from a subcritical condition (Table 7.1.6-2 )

Uncontrolled CEA Withdrawal

~ 2.2 sec,

from a critical condition (Table 7.1.6-4 )

(1% power)

CEA Ejection (0% power)

~ 2.5 sec j

(Figure 7.2.1-2 )'

4

• D. Trimble (AP&L) to R. A. Clark (NRC), "Cycle 2 Reload Report", Part 1, February 20, 1981' and Part 2, March 5,.1981.

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