HL-5415, Requests Revised Oscillation Power Range Monitor Settings to Eliminate Spurious Alarms
| ML20141C725 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 06/20/1997 |
| From: | Sumner H SOUTHERN NUCLEAR OPERATING CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| HL-5415, NUDOCS 9706250426 | |
| Download: ML20141C725 (13) | |
Text
I Lewis Sumner Southern Nuclear Vice Presidat Operating Company. Inc.
Hatch Project Support '
40 Invemess Parkway l
Post Office Box 1295 Birmingham. Alabama 35201 Tel 205.992.7273 Fax 205.992.0341 SOUTHERN h COMPANY June 20, 1997 Docket Nos. 50-321 HL-5415 50-366 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Edwin I. Hatch Nuclear Plant Oscillation Power Range Monitor Gentlemen:
Southern Nuclear Operating Company (SNC) requests resolution of three issues associated with implementation of the oscillation power range monitor (OPRM),
GE Option III. Plant Hatch Unit 2 is the lead plant for GE Option III. First, preliminary i
results during the monitoring period of the OPRM indicate the response is more sensitive than anticipated. Therefore, SNC is requesting revised OPRM settings to eliminate spurious alarms. Second, in order to validate these settings, SNC requests the OPRM monitoring period for both Units 1 and 2 be increased from 6 months to the stanup of the Units from the next refueling outages. Third, the NRC Safety Evaluation Report (SER) for the power range neutron monitoring Technical Specifications amendments differs slightly from the SNC submittal. SNC requests the SER be revised to reflect the amended bases.
SNC letter dated October 29,1996, and supplemented by letter dated Febmary 19,1997,
[
requested a revision to the Plant Hatch Unit 1 and Unit 2 Technical Specifications. The
/
proposed changes reflected design changes to install a digital upgrade to the power range e
neutron monitoring system that incorporates the long-term stability solution. The SER,
/
dated March 21,1997, for Unit 1 Technical Specifications Amendment No. 205 and Unit 2 Technical Specifications Amendment No.146 approved the average power range monitor (APRM) portion of the submittal. However, the proposed Technical Specifications changes to incorporate the OPRM would be approved pending the results of a 6-month monitoring period (ref. SER section 3.2).
Initial OPRM monitoring data was collected during two Unit 2 startups in late April and early May 1997. Evaluation of the data by SNC and GE indicates the OPRM system successfully implements the stability algorithms; however, the response is more sensitive than anticipated. Using OPRM settings specified in Licensing Topical Report NEDO-32465, two inadvertent alarms have occurred because the system is too sensitive. To correct the sensitivity two settingsjust outside the ranges defined in NEDO-32465 are 9706250426 970620 1 g g lglg; gI g g PDR ADOCK 05000321 1,
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l lL U.S. Nuclear Regulatory Commission Page 2 June 20, 1997 L
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desired. The range settings were based on reactor noise from a few plants. SNC requests that the acceptable values for the tuning parameters be extended from 2.5 Hz to 3.0 Hz for j
the corner frequency and from 100 milliseconds to 50 milliseconds for the period i
tolerance. With the desired settings, the OPRM will continue to detect core wide and regional oscillations and initiate automatic suppression by initiating a full reactor scram prior to violating the minimum critical power ratio (MCPR) safety limit. A summary of the analysis of the initial results and justification to use the desired settings is provided in. The OPRM settings, plant conditions, and tuning data taken during the Unit 2 startups mentioned above are provided in Enclosure 2.
Based upon initial OPRM testing and tuning data, SNC requests the monitoring period for both Units 1 and 2 be extended from 6 months to a complete fuel cycle. While the OPRM successfully implements the stability algorithms, additional monitoring will allow time to assure the sensitivity issue is resolved prior to activating the automatic reactor protection system (RPS) trip. This is consistent with the NRC SER, dated September 5, 1995, for GE Licensing Topical Report (LTR) NEDC-32410, " Nuclear Measurement Analysis and Control Power Range Neutron Monitor (NUMAC-PRNM) Retrofit Plus Option III Stability Trip Function," which approved OPRM monitoring periods up to one fuel cycle (ref. SER section 4.2). As previously stated in the Technical Specifications amendment request, Licensing Topical Report NEDC-32410P is applicable to the OPRM l
implementation at Plant Hatch. If the extension is granted, the existing interim corrective l
actions for determining and mitigating power oscillations will remain in effect during the test period.
Lastly, the NRC SER for Technical Specifications Amendment Nos. 205 and 146, dated March 21,1997, acknowledges differences between SNC's submittal and LTR NEDC-32410-A. However, SER section 3.3.3 does not reflect the proposed amended Bases submitted in SNC's response to the NRC's Request for Additional Information (RFAI) dated February 19,1997. Specifically, LTR Bases page B 3.3-7 states: "... In addition, j
to provide adequate coverage of the entire core, consistent with the design bases for the APRM Functions 2.a, 2.b, and 2.c, at least [20] LPRM inputs, with at least [three] LPRM inputs from each of the four axial levels at which the LPRMs are located, must be operable for each APRM channel. For the OPRM Upscale, Function 2.f, LPRMs are assigned to " cells" of[4] detectors. A minimum of[later] cells, each with a minimum of
[2] LPRMs, must be OPERABLE for the OPRM Upscale Function 2.f to be OPERABLE."
l In the February 19,1997, response to the RFAI, SNC proposed Bases page B 3.3-7 be amended as follows: "... In addition, to provide adequate coverage of the entire core, consistent with the design bases for APRM Functions 2.a,2.b, and 2.c, at least 17 LPRM inputs, with at least three LPRM inputs from each of the four axial levels at which the LPRMs are located, are required for each APRM channel. For APRM Function 2.f,
~_ -._. - -
U.S. Nuclear Regulatory Commission Page 3 June 20, 1997 OPRM Upscale, LPRMs are assigned to " cells" of 3 detectors with a minimum of I detector per cell. The minimum number of LPRM inputs for APRM Functions 2.a,2.b, and 2.c must be met for the OPRM Upscale Function 2.f to be OPERABLE." The justification for the amended bases is provided in the SNC February 19,1997, letter.
In summary, preliminary testing indicates the OPRM will generate an RPS trip if an instability that could violate the minimum critical power ratio (MCPR) safety limit occurs.
However, extending the test period will allow additional time to resolve the sensitivity issue and ensure the OPRM, once activated, does not cause alarms or trips when the plant has adequate stability margin. Since Plant Hatch is the lead plant for GE Option III, SNC considers the OPRM monitoring extension request to be prudent. If yeu have concerns regarding the matters discussed herein, please coatact this oflice.
Sincerely, 9p -
H. L. Sumner, Jr.
TWM/eb Et closures:
- 1. Response to Request for Information: Oscillation Power Range Monitor i
- 2. OPRM Settings, Plant Conditions, and Tuning Data i
cc: Southern Nuclear Operatine Company l
Mr. P. H. Wells, Nuclear Plant General Manager NORMS U.S. Nuclear Reentatorv Commission. Washington. D.C.
Mr. N. B. Le, Licensing Project Manager - Hatch l
U.S. Nuclear Revulatory Commission. Region 11 Mr. L. A. Reyes, Regional Administrator Mr. B. L. Holbrook, Senior Resident Inspector - Hatch
Analysis ofInitial Results Oscilh. tion Power Range Monitor Background Information Licensing Topical Report (LTR) NEDO-32465-A, "BWR Owners' Group Reactor Stability
. Detect and Suppress Solutions Licensing Basis Methodology," describes the analytical basis for the Option III long term stability solution. The licensing basis for this solution is the period based detection algorithm (PBDA) which relies on the fact the local power range monitors (LPRMs) can be used to distinguish between thermal-hydraulic instabilities and normal reactor operation.
During normal, steady-state reactor operation, the LPRM signals are comprised of two main components: the average power level in the core immediately surrounding the detector and a small component of random (incoherent) noise. The random noise is a broad band of frequencies that are typically present in the BWR reactor system. With the onset of a thermal-hydraulic instability, the LPRM noise component of the signal becomes coherent with a characteristic frequency in the 0.3 to 0.7 Hz range. The PBDA uses this difference in LPRM noise to detect instabilities. Specifically, the oscillation power range monitor (OPRM) system combines signals from a few LPRMs and evaluates the noise component of the combined signal. The PBDA algorithm evaluates each successive pair of maxima and minima in the signal. If the noise is in the specified range (0.3 to 0.7 Hz), it is considered to be a single period confirmation. The system then evaluates the subsequent maxima or minima to determine ifit falls within the specified frequency range. If so, the continuous period confirmation (CPC) count rate in the OPRM is j'
increased by one. This process continues until a maxima or minima in the signal is found to be
[
outside the specified raage. The total CPC count rate prior to resetting is termed the maximum l
continuous period confirmation (MCPC).
Section 3.4.1 of NEDO-32465-A of describes the acceptable range of values for two OPRM parameters, period tolerance and corner frequency. Both these parameters can be independently adjusted to tune the OPRM system to each plant's unique LPRM noise characteristics. Within the ranges defined for these parameters, the OPRM system will provide sufficient CPCs of thermal-hydraulic instabilities prior to reaching the PBDA amplitude trip setpoint. The ranges presented in NEDO-32465-A were based on testing the PBDA using data taken with original LPRM l
processing hardware for single LPRM signals from several different plants. Data was taken with a 50-millisecond sample period during stable and unstable reactor operation. A range of parameter values was defined to ensure the OPRM is sensitive enough to detect an instability as it develops at low amplitudes while allowing utilities the flexibility to match the system's response to their plants' noise characteristics during steady-state operation. Matching the noise characteristics is necessary to avoid non-instability-related alarms and reactor scrams.
Normal LPRM noise, which includes frequencies in the 0.3 to 0.7 Hz range, will be detected by the OPRMs as a distribution of MCPCs. The OPRM is tuned based on the MCPC distribution under plant operating conditions which have significant stability margin. Based upon tuning d
HL-5415 El-1
Oscillation Power Range Monitor 3
I criteria proposed by General Electric, a properly tuned OPRM should detect, during a short j
interval of time (e.g.,10 minutes), a fairly high number one and two MCPCs, several three 1
l MCPCs, a few four MCPCs, and very few or no MCPCs of five and greater. During typical 10 j
minute tuning intervals, MCPCs greater than 5 indicate that period tolerance and corner frequency i
j-values are not optimally set and the OPRM is too sensitive.
Hatch-Soecific Information Based on the tuning data collected during the Hatch Unit 2 Cycle 14 startup and the restart from the automatic scram on April 22,1997, it is apparent the OPRMs are too sensitive when the least j
sensitive settings defined by Table 3-1 in NEDO-32465-A are used (a period tolerance of 100 milliseconds and corner frequency of 2.5 Hz). The power range neutron monitoring system 4
(PRNM) system hardware will allow both the period tolerance and corner frequency to be set to even less sensitive values than those defined in the LTR. When these OPRM parameters are set to the least sensitive values allowed by the hardware, the system can be properly tuned to meet the criteria for normal operation (period tolerance of 50 milliseconds and corner frequency of 3.0 Hz).
Several factors may contribute to the Unit 2 OPRMs being more sensitive than anticipated:
i 1.
The range of values for period tolerance and corner frequency defined in the LTR were based primarily on tests of the PBDA for a plant approaching unstable conditions. The LTR testing differs from the NUMAC PRNM implementation of the OPRM as follows:
f a.
The plant data used had a sample frequency of 50 milliseconds. The PRNM provides data every 25 milliseconds. This effectively doubles the sensitivity of the PRNM
]
OPRM and implies that adequate instability detection occurs with a lower period tolerance value.
b.
The plant data used was for single LPRMs rather than an OPRM cell, which, for Plant Hatch, is a combination of three LPRMS, assuming no LPRMs in the cell are bypassed. This effectively provides an additional filter to the data which are analyzed by the PBDA function of the OPRM.
2.
The Hatch Unit 2 noise characteristics may differ from the noise characteristics of the reference plants used to test the algorithm. Specifically, the NUMAC PRNM system has improved accuracy, noise immunity, and LPRM signal filtering. The additional LPRM filtering may increase the sensitivity of the OPRM and produce high MCPC counts when the plant is operating with a large stability margin.
7.
The noise characteristics for Hatch Unit 2 Cycle 14 may differ from the data used to define the range of parameter values.
HL-5415 El-1
Et closure 1 Oscillation Power Range Monitor 4.
Unit 2 reactor conditions, such as power and flow, may differ from the conditions under which the test data were collected.
Conclusion Based upon a review of the Plant Hatch process computer monitoring data for Unit 2, the OPRM is successfully implementing the stability algorithms and is fully expected to produce enough MCPCs to exceed the trip setpoint if a coupled neutronic/ thermal-hydraulic instability occurs.
From the initial system testing, setting the corner frequency as high as 3.0 Hz and the period tolerance as low as 0.05 seconds (50 milliseconds) provides acceptable OPRM sensitivity. These settings arejust outside the ranges described in NEDO-32465, which were based on data from a few plants with different characteristics than the Hatch Unit 2 PRNM system. The proposed settings of 3.0 Hz and 50 milliseconds provide suflicient period confirmations during stable eactor operation and do not compromise the capability of the OPRM to detect instabilities and initiate an automatic reactor scram prior to violating the MCPR safety limit. Extending the monitoring period from 6 months to the complete fuel cycle for both Units 1 and 2 will provide further opportunity to evaluate the Unit 2 data and validate the desired settings. Also, the Unit I refuel startup scheduled for the Fall of 1997 may corroborate the sensitivity issue. Unless an extension is granted, the Unit 2 OPRM will be activated prior to the Unit I startup.
i l
I l
HL-5415 El-2
OPRM Settings, Plant Conditions, and Tuning Data l
4
I l
Table 1 OPRM Settings t
OPRM Parameter Setpoint Minimum Oscillation Period
- 1.2 seconds Maximum Oscillation Period
- 4.0 seconds Amplitude Threshold Setpoint (SI) 1.15 Amplitude Threshold Setpoint (S2) 0.9 Growth Rate Factor Trip 1.25 Growth Rate Factor Alarm 1.15 Maximum Amplitude Trip 1.27 Maximum Amplitude Alarm 1.17 Confirmation Count Trip 12 Confirmation Count Alami 10 Confirmation Amplitude Trip Setpoint 1.09 Corner Frequency
- *2.0 Hz Period Tolerance
- 100 milliseconds During the latter part of the tuning prceedure, these parameters were reset to 1.4 and 3.3 seconds, respectively.
- Initial settings; these parameters were adjusted during the tuning process.
l l
l t
l HL-5415 E2-1
i Table 2 OPRM Plant Conditions Test Approximate Approximate Core Conditions Power Flow Notes 1
25 %
Minimum recire pump speed 2
64 %
Minimum recirc Just below the 65% load line pump speed Just below the 65% load line at the 3
64 %
51 %
corner of the exclusion region Just below the APRM rod block line at 4
75 %
51 %
the corner of the exclusion region i
5 100 %
100 %
Near rated conditions i
l l
l HL-5415 E2-2
Tatdo 3 OPRM Tuning Data Hatch-2 Beginning of Cyde 14 Core Core Period Comer Case Test Power Flow Tolerance Frequency Number ConRrmation Counts Number Condition Date Time
(%)
(%)
(msec)
(Hz)
OPRM of Ceus 1
2 3
4 5
6 7
8 9
10 Oi8 1
1 04/20/97 16:14 26.18 34.37 100 2.0 A
24 2683 343 29 1
0 0'
O O
O O
B 24 3310 451 26 2
1 0
0 0
0 0
C 24 2508 322 25 1
1 0
0 0
0 0
en D
24 2259 233 31 2
1 0
0 0
0 0
?
2 1
04/20/97 16:42 26.04 34.39 100 2.5 A
. 24 3442 509 25 4
0 0
0 0
0 0
B 24 3321 6%
22 0
0 0
0 0
0 0
C 24 3169 457 23 3
0 0
0 0
0 0
D 24 3207 446 34 2
1 0
0 0
0 0
[
3 2
04/21/97 06:26 33.11 35.0 100 2.5 A
24 3358 652 22 3
1 0
0 0
0
. O B
24 2812 652 11-4 1
0 0
0 Q
0 j
C 24 3198 646 27 2
0 0
0 0
0 0-D 24 4044 722 29 3
0 0
0 0
0 0
4 2
04/21/97 06:41 33.06 35.0 100 2.0 A
24 4089 638 25 7
0 0
0 0
0 0
l B
24 4080 678 32 4
0 0
0 0
0 0
C 24 3692 540 33 4
1 0
0 0
0 0
. h D
24 4484 623 58 7
0 0
0 0
0 0
6 5
2 04/21/97 06:56 33.02 35.1 150 2.0 A
24 3844 782 67 12 4
1 0
0 0
0 t
B 24 3778 668 62 13 0
1 0
0 0
0 C
24 3434-947 55 19 3
1 0
0 0
0 D
24 4153 863 88 16 3
0 0
0 0
0 6
2 04/21/97 07:13 32.9 34.7 150 2.5 A
24 3208 770 39 14 1
0 0
0 0
0 B
24 2674 726 26 9
0 0
0 0
0 0
C 24 3137 740 34 9
2 0
0 0
0 0
D 24 366:' 943 60 12 3
0 0
0 0
0 7
3 04/21/97 14:00 41.1 52.0 100 2.5 A
24 4747 712 84 10 0
0 0
0 0
0 B
24 4800 750 54 12 1
0 0
0 0
0 C
24 4643 628 75 17 2
0 0
0 0
0 D
24 5103 739 91 15 2
1 0
0 0
0 8
3 04/21/97 14:27 41.4 51.5 100 1.5 A
24 3362 512 73 7
4 0
0 0
0 0
8 24 3549 496 90 20 6
1 0
0 0
0 C
24 2795 -410 69 11 1
0 0
0 0
0 D
24 3520 586 8')
23 3
0 0
0 0
0 1
A m
Tatde 3 CPRM Tuning Dat3 Hatch-2 Bogenmg of Cycle 14 Core Core Period Corner Case Test Power Flow Tolerance Frequency Number Confirmation Counts Number Condrbon Date Trne
(%)
(%)
(msec)
(Hz)
OPRM of C911s 1
2 3
4 5
6 7
8 9
10 9
3 04/21/97 14:57 11.4 52.2 50 3.0 A
24 4508 458 28 2
0 0
0 0
0-0 B
24 4181 476 26 3
0 0
0 0
0 0
C 24 4528 496 17 3
0 0
0 0
0 0
M D
24 4981 559 23 6
0 0
0 0
0 0
S v.
10 4
04/22/97 15:59 76 52.11 100 2.5 A
24 3754 795 120 37 15 3
0 1
1 0
B 24 3816 813 139 31 9
3 2
1 1
0 C
24 3781 834 141 26 9
0 0
1 1
0 D
24 3715 800 134 28 7
0 1
0 0
0 11 4
04/22/97 16:19 75.8 52.2 100 2.5 A
24 3562 766 130 32 4
2 1
0 0
0 B
24 3653 822 124 28 8
2 1
1 0
0 C
24 3627 832 108 34 6
0 1
0 0
0 D
24 3597 767 105 28 7
4 1
1 0
0 12 4
04/22/97 16:42 75.8 52.4 50 3.0 A
24 2890 371 28 2
0 0
0 0
0-0 B
24 2980 362 25 3
0 0
0 0
0 0*
C 24 2985 397 32 7
0 0
0 0
0 0
D 24 2900 382 28 4
0 0
0 0
0 0
13 4*
04/22/97 17:08 72.7 52.9 100 2.5 A
24 3796 802 121 40 4
3 0
1 0
0 h
B 24 3905 853 120 25 7
0 0
0 0
0 g
C 24 3833 820 113 21 7
2 0
0 0
0 D
24 3690 832 114 24 3
2 1
0 0
0 14 4
04/26/97 22:38 76.26 51.83 100 2.5 A
24 4174 788 76 20 0
0 2
0 0
0 B
24 4087 716 92 11 1
0 0
0 0
0 C
24 4249 814 84 12 4
0 0
0 0
0 D
24 4073 744 77 14 4
1 0
0 0
0 l
15 4
04/26/97 22:53 76.12 52.03 100 2.0 A
24 4963 956 199 53 8
3 0
0 0
0 B
24 4917 991 193 54 8
5 1
0 0
0 C
24 4962 992 212 50 12 4
0 0
0 0
D 24 4957 952 190 50 13 1
2 1
0 0
16 4"
04/26/97 23:54 75.56 51.71 100 2.0 A
24 4227 867 164 26 4
2 1
1 0
0 8
24 4253 808 149 33 4
2 0
0 0
0 C
24 4302 871 179 25 14 1
0 0
0 0
D 24 4190 832 163 23 9
0 0
0 0
0 17 4"*
04/27/97 00.08 75.45 51.53 100 2.5 A
24 732 116 35 8
3 0
0 0
0 B
24 691 131 32 6
1 1
0 0
0
[
C 24 713 128 35 9
7 0
0 0
0 1
D 24 663 122 23 12 1
1 0
0 0
[
i
i Table 3 OPRM Tuning Data I
Hatch-2 Beginning of cycm; 14 Core Core Period Comer Case Test Power Flow Tolerance Frequency Numbe' Cordirmation Counts
(%)
(msec)
(Hz)
OPRM of Cens 1
2 4
5
_6 7
8 9
10 M
Number Condition Date Time
(%)
_3 3
.[
18 4"
04/27/97 01:21 74.18 51.78 100 2.5 A
24 M12 660 91 22 5
3 0
1 0
0 3
24 3130 675 119 17 3
0 0
0 0
0 t
G 24 3384 585 110 23' 6
0 0
0 0
0 t
D 24 3057 618 80 20 4
0 0
0 0
0 19 4"
04/27/97 01:36 74.08 52.48 50 3.0 A
24 2538 285 37 4
1 0
0 0
0 0
B 24 2347 285 19 2
0 0
0 0
0 0
C 24 2546 339 25 3
0 0
0 0
0 0
D 24 2375 274 17 3
1 0
0 0
0 0
I li 20 4"
04/27/97 01:49 74.08 52.35 100 3.0 A
24 2531 423 76 12 6
1 0
0 0
0 B
24 2319 449 66 14 4
0 0
0 0
0 C
24 2509 398 51 16 1
1 0
0 0'
O.
D 24 2372 410 55 13 4
0 0.
0 0
0 i
21 4"
04/27/97 02:01 73.90 52.08 50 2.5 A
24 3633 480 41 -
4 0
0 0
0 0
0 B
24 3501 482 58 5
0 0
0 0
0 0
h.
C 24 3762 522 52 7
0 0
0 0
0 0
D 24 3476 502 59 5
0 0
0 0
0 0
22 5"
05/02/97 12:40 99.98 97.79 100 2.5 A
24 1918 621 55 10 3
1 0
0 0
0 i
B 24 2024 660 60 18 2
0 0
0 0
0 C
24 2012 655 51 15 0
0 0
0 0
0 D
24 2071 659 68 13 1
0 0
0 0
0 23 5"
05/02/97 100 2.0 A
24 2506 806 88 39 2
1 0
0 0
J B
24 2546 870 137 34 10 1
0 1
0 0
C 24 2594 817 118 39 6
1 0
0 0
0 0
24 2519 886 105 35 7
4 2
0 0
0 24 5"
05/02/97 50 2.0
-A 24 2834 624 49 5
1 0
0 0
0 0
B 24 2897 675 59 8
2 0
0 0
0 0
C 24 2943 676 60 10 0
0 0
0 0
0 D
24 2997 670 56 9
1 1
1 0
0 0
25 5"
05/02/97 50 2.5 A
24 2136 433 36 9
0 0
0 0
0 0
0 24 2271 472 36 11 0
0 0
0 0
0 C
24 2366 426 24 6
0 0
0 0
0 0
D 24 2354 453 51 6
0 0
0 0
0 0
Tatde 3 I
OPRM Tuning Data Hatch 2 Beginning of Cycle 14 l
Core Core Period Comer I
Case Test Power Flow Tolerance Frequency Number conrrrn=w N=wn
_0 u
Number Condition Date Time
(%)
(%)
(msec)
(Hz)
OPRM of Ceus 1
2 3
4 5
6 7
8 9
1
~
g m
26 5"
05/02/97 50 3.0 A
24 1521 278 17 1
0 0
0 0
0 0
B 24 1758 279 25 1
0 0
0 0
0 0
C 24 1668 352 15 2
0 0
0 0
0 0
D 24 1737 288 22 4
0 0
0 0
0 0
27 5"
05/02/97 100 3.0 A
24 1447 450 42 11 3
0 0
0 0
0 l
B 24 1559 505 42 11 6
0 0
0 0
0 C
24 1481 443 49 14 3
0 0
0 0
0 D
24 1561 495 42 10 1
0 0
0 0
0 l
r 150 3.0 A
24 1406 498 62 21 1
2 0
0 0
0_
28 5"*
05/02/97 B
24 1506 533 70 20 4-0 0
0 0
O C
24 1451 491 68 17 1
2 1
0 0
0*
D 24 1532 499 65 16 8
2 0
0 0
0 t
IT1Y Ch i
t t
- Data taken during rod insertion to reouce power to beloud the 95% rod line.
" Data taken after osciRation period setpoint changes.
"*Also, three minutes into data coHection, rods inserted to reduce power.
L i
-