IR 05000413/1990025
| ML20058B463 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 10/11/1990 |
| From: | Belisle G, Burnett P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML20058B458 | List: |
| References | |
| 50-413-90-25, 50-414-90-25, NUDOCS 9010300213 | |
| Download: ML20058B463 (8) | |
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/g0CeCg'o UNITED STATES NUCLEAR REGULATORY COMMISSION
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g-Iy 101 MARIETT A STREET.N.W.
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e ATLANTA,oEoRot A 30323
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Report Nos.:
50-413/90-25 and 50-414/90-25 Licensee:
Duke Power Company 422 South Church Street Charlotte, NC 28242 Docket Nos.:
50-413 and 50-414 License Nos.:
NPF-35 and NPF-52 Facility Name:
Catawba 1 and 2 Inspection Conducted:
September 2 28, 1990 Inspector:
/0 / /4 p
P. T. Burnett(/ (/
Date Signed Approved by:
/oI//d'o k
G. A. Belisle, th Wf Date Signed Test Programs Section Engineering Branch Division of Reactor Safety SUMMARY Scope:
This routine, unannounced inspection addressed the areas of post-refueling startup tests. for both units and core performance surveillances performed on Unit 2.
Results:-
Unit 2 startup tests for cycle 4 were. complete and; satisfactory through the end of zero power-testing.
Escalation of Unit 2 to power began after the end of this inspection.
Unit 1 post-refueling startup tests were complete and satisfactory for.all operations through rated thermal power for cycle S.
-An overall improvement.in procedures was noted paragraph 2.
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Core performance surveillances of power distribution, reactivity balance, and end-of-life moderator temperature coefficient were performed with acceptable frequency and results throughout cycle 3 for Unit 2.
No violations or deviations were identified.
i 9010300213 901017 ADOCK0300g3 PDR
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REPORT DETAILS 1.
Persons Contacted Licensee Employees R. G. Blessing, Engineer, Reactor Grouo R. N. Casler, Operations Superintendent
- J. S. Forbes, Technical Services Superintendent
- R.- M. Glover, Performance Manager J. W. Hampton, Station Manager C. L. Hartzell, Compliance Superviser M. W. Hawes, Engineer, Reactor Group
- G. P. Horne, Reactor Engineer
- V. D. King, Compliance D. A. We11baum, Engineer, Reactor Group Other licensee personnel contacted included technicians, operators, engineers and office personnel.
NRC Resident Inspectors W. T. Orders, Senior Resident Inspector
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P. C. Hopkins, Resident Inspector
- J. N. Zeller, Resident. Inspector
- Attanded exit interview on September 28, 1990.
A-list of acronyms and initialisms used in this report is given in the final paragraph.
i 2.
Unit 2 Post-refueling Startup Tests (72700, 61708, 61710)
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Prerequisite Procedures
.r Startup Tests The following prerequi,ite procedures were reviewed or confirmed to be completed satisfactorily prior to startup:
(1) PT/2/A/4600/05E, Refueling ENB Calibration - not reviewed.
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(2)- IP/0/B/3220/01, Enclosure 11.7, RCCA Drop Time Summary, which
was performed on September 9,1990, was reviewed.
The average control' rod drop time to dashpot entry, at operating flow and-temperature,_ was 1.52 seconds. _ All rod drop times fell in the
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range 1.49 to 1.57 seconds;- so the requirements of TS 3.1.3.4 l.
were satisfied for each, b.
Procedures for the Cycle 4 Startup The following completed or in progress procedures were reviewed for technical content and performance:
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(1) PT/2/A/4150/21 ( Approved September 7,1990), Post Refueling Controlling Procer:ra for Startup Testing, was used either to perform specific a*d, or to schedule the performance of other test procedures, mv.t of which are also discussed below.
Since it was last performed, this procedure underwent several significant, approved changes including:
Limit and Precaution 6.9 was added to ensure that Bank D is nearly fully withdrawn (210-220 steps above 20% RTP) during power escalation to reduce the stress on fuel cladding.
- In step 8.2, PRNI high level trips were set down to 25% to assure the LSSS is not violated prior to obtaining a valid heat balance and PRNI power calibration.
One consequence of the low-leakage core design was that tt
.9ticipated point of adding nuclear heat, in IRN! curr6 units, was reduced to 8.5 E-07 fros 2.5 E-06 amperes, nearly three-fold reduction in leakage and the expe- )d response of all excore nuclear detectors.
- A itew Data Required Step 10.8, was added to capture the HFP critical boron concentration.
Acceptance criterion 11.7 requires that the measured, ARO, HFP C agree within g
50 ppm 8 of the predicted value.
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The application of rod withdrawal limits was clarified.
- Steps were added to improve the accuracy of determination of IRNI setpoints.
Performance of this procedure, through step 12.7.15, began on September 8,1990, and continued until September 13, 1990, when the unit was shutdown for maintenance.
(Power escalation and testing resumed after the close of this inspection).
Tests performed within this procedure were controlled and
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documented by enclosures appended to it.
The following comploted enclosures were reviewed and found satisfactory:
Enclosure 13.1, Rod Control System Logic Check.
- Enclosure 13.2, Shutdown Margin Calculations.
Enclosure 13.7, Source Range and Intermediate Range Overlap Data, assured. that one full decade of overlap existed between SRNIs and IRNIs before P-6 and interruption of power to the SRNI detectors.
Discussions with plant personnel confirmed that criticality had been achieved on the source range before P-6 was invoked.
Historically, criticality has been attained near P-6 in most startups.
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The source and intermediate range chamber carts are fully inserted towards the core.
The licensee will consider the benefit of withdrawing the chambers to provide more margin in time and power between criticality and P-6.
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Enclosure 13.,8, Nuclear Heat Deterniination, was used to determine the point of adding heat by observing a change in
tha reactivi'y trace and NC temperature.
An upper limit of 50% of the point of adding heat was established for the zero power tests to assure that reactivity measurements
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were not invalidated by fuel doppler coef ficient feedback effects.
- Enclosure 13.9, Reactivity Computer Checkout, was used for a dynamic checkout of the reactivity computer.
Positive and negative reactivities were inserted and the reactivity computer solutions were compared with those obtained from measuring reactor period and solving the inhour equation.
The acceptance criterion of 4% agreement was satisfied for reactivities ranging from -40 pcm to +40 pcm.
- Enclosure 13.10, Dif ferential Boron Worth Calculation, was used to calculate the HZP differential boron worth using data obtained during the calibration of the reference control rod bank.
See also procedure PT/0/A/4150/11A, below.
The acceptance criterion that the measured differential boron worth agree within 15% of predicted value was satisfied.
Procedures Driven by the above:
(2) PT/0/A/4150/200 (Approved July 9,1990), Westinghouse Digital Reactivity Computer Checkout, was performed-in its entirety on September 9, 1990.
It was performed in part to confirm the proper computer sof tware and physics constants were loaded on September 11 and 12,1990.
This procedure is an electronic checkout of the computer and not a reactivity comparison test.
(3) PT/2/A/4150/19 (Approved -September 6,1990),1/M Approach to Criticality, was performed during the period September 10 to 12, 1990. _ Good features of the procedure included:
Positive steps to ensure that the VCT was not over diluted during extended operation in the alternate dilute mode.
- Frequent use of the chi-squared test to confirm ope ability of the SRNIs.
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Preplotting of the predicted response of 1/M to dilution for continuing comparison with the actual results during the boron dilution process.
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6 The plotted results indicated that the approach to criticality was well-controlled during both the dilution and rod-withdrawal processes.
(4) PT/2/A/4150/10 (Approved June 4,
1990), Boron Endpoint Measurement, was performed on September 12, 1990, for the ARO configuration.
The result of 1661 ppmB satisfied the acceptance criterion for agreement with the predicted value of 1684 ppmB within 50 ppm.
The procedure was performed again with the reference bank in on September 12 - 13, 1990.
The resulting C was 1560 ppmB which was used in the calculation of differentia $
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boron worth.
(5) PT/0/A/4150/12A (Approved August 29, 1990),
Isothermal Temperature Coefficient of Reactivity Measurement, was performed on September 12, 1990, using one cooldown and one heatup of the reactor, each of about 4'F.
There was good agreement between the results, +3.26 and +3.28 pcm/'F, respectively for ITC.
The MTC, based upon the average MTC was +5.11 pcm/*F, which was less than the TS 3.1.1.3 and COLR 2.1.1 limit of +7 pcm/'F.
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The sole formal acceptance criterion in the procedure is the requirement that the measured ITC (corrected to 557'F) be within 2 pcm/'F of the predicted value.
However, step 12.8 contains the stringent requirement that the IT,k from heatup and cooldown agree within 0.4 pcm/'F or else 0 second set up of heatup and cooldown measurement $ must be obtef aed.
No guidance is given on pooling or rejecting data.
The plotter used to display the relationship between reac.ivity I
and temperature provided a much cleaner and interpretable trace than observed for earlier measurements at this facility.
Licensee personnel stated that the improvement came solely from the new plotter and that neither the signal filtering nor the plotter time constant had been increased.
(6) PT/0/A/4150/11A (Approved August 22, 1990), RCCA Bank Worth Measurement by Boration/ Dilution, was performed for the reference bank, control bank C, on September 12-13, 1990, using dilution.
The integral worth of the bank was measured to
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be 905 pcm, which satisfied the acceptance criterion of agreement within 10% of the predicted-value of 910 pcm.
The procedure does not require calculation or plotting of the differential worth curve, which is a departure from earlier versions of this. procedure at this facility.
The' differential worth curve would reveal errors in determining individual
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reactivity increments or systematic' errors in the entire mea-surement with greater sensitivity than provided by the integral
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worth curve.
The licensee was encouraged to return to the l
earlier practice.
(7) PT/0/A/4150/118 (Approv9d August 30, 1990), Control Rod Worth Measurement by Rod Swap, was performed for the balance of the i
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control and safety banks on September 13, 1990.
Agreement between predicted and measured bank worths ranged from -9.5% to
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+3.0% of the predicted values and satisfied the acceptance criterion of agreement within 15% for individual banks.
The total rod worth was 5065 pcm and the predicted total worth was 4940 pcm.
The acceptance criterion of agreement within 10% of the predicted values was satisfied.
(8) PT/0/A/4150/21 (Approved March 28, 1990), Temporary Rod Withdrawal limits, was performed on September 12 - 13, 1990, to implement the procedurally imposed requirement that the operational MTC at BOL be at least 2 pcm/'F less than the i
TS/COLR limit.
Since the measured MTC at ARO nearly satisfied that requirement, imposition of withdrawal limits is not expected to last beyond the time of achieving xenon equilibrium at full power.
The licensee's bases for imposing the 2 pcm/*F conservatism on the operational MTC is to account for measure-ment errors (about 1 pcm/'F in their judgement) and to account for times when the NC average temperature is less than the reference temperature.
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Other Pertinent Documents Reviewed (1) OP/2/A/6700/01, Unit Two Data Book.
(2) CNNE-1553.05-00-008 (revision 3), Startup and Operational Report for Catawba 2, Cycle 4.
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Two significant improvements were noted, across the board, in the procedures used for the Unit 2, Cycle 4 startup.
First, procedure changes were explained in more detail than observ3d previously, either at this facility or at others.
Second, each of the startup test procedures have been augmented by a written addendum termed a Tailgate Document, which provides -a narrative summary of the test, the impact of the test on TS, notes on configuration control, things to watch for, test termination criteria, and expected alarms.
The Tailgate Document should be of direct benefit to the operators and improve communications between operations and engineering.
No violations or deviations were identified.
3.
Unit 1 Post-Refueling Startup Tests (72700, 61702, 61705, 61708, 61710)
Startup testing for Unit 1, Cycle 5 was performed during the period from April 11, to May - 16,1990.
The procedures used for zero power testing were analogous to those discussed for Unit 2 in paragraph 2, above, with similarly acceptable results.
Those completed procedures were reviewed
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in. detail, but will not be addressed further here, because the findings were not significantly different from those already discussed.
Power escalation activities were controlled by the later sections of PT/1/A/4150/21 (Approved April 11, 1990) Post Refueling Controlling
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Procedure for Startup Testing.
Flux maps were obtained at nominal power levels of 30%, 70%, and 100% RTP.
Prior to proceeding to the next higher power level, the power distribution limits of TS 3/4.a were extrapolated
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to the next higher power to confirm that acceptaole risults were antici-
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pated.
The results of flux maps obtained during powar escal lion were
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reviewed by the inspector.
The acceptance criteria were satisfied in all Cases.
The results of the BOL incore-excore nuclear instrument correlation were I
[i summarized in Enclosure 13.12 to PT/1/A/4600/05A.
Seven flux maps were obtained at or above 99% RTP over a range of axial offsets from -5.7% to
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42.26.
The correlation coefficients for the eight ion chambers each met or exceed 0.99.
The correlation was repaated on July 26, 1990, using eight maps, with equally acceptable results.
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No violations or deviations were identified, i
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Surveillance Activities for Unit 2. Cycle 3 (61702, 61706, 61708)
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Hot Channel Factors
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Nineteen. full core flux maps were obtained over the first 320 EFPD of cycle 3.
Except for the first two, all were made at power Tevels in excess of 90% RTP.
Review of the summary data sheets, Enclosure 13.11 to PT/2/A/4150/05, confirmed that F and F were within The frequency of the measurNNents was satis-
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limits at all times.
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Reactivity Anomaly
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Summary data sheets, Enclosures 13.4 and 13.5 to PT/2/A/4150/04, confirmed that a reactivity balance had been performed with accept-
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able frequency and results through the cycle.
Reactivity deviations ranged from -215 pcm to + 111 pcm and were well within the limit of i 1000 pcm.
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End-of-Life Moderator Temperature Coefficient The measurement made on March 2,1990, was the first performed using the current version of PT/2/A/4150/12B, Moderator Temperature Coefficient of Reactivity Measurement (EOL).
The most significant change was the introduction of a reactivity coefficient, of unknown magnitude, for axial offset into the reactivity balance equations.
That required a solution for two unknowns, the ITC and-the offset coefficient.
Since independent reactivity balance equations could be written for a heatup and a cooldown of the reactor, a solution was possible.
This approach forced the ITCs for heatup and cooldown to be identical and made it inappropriate to have an acceptance
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criterion based upon the agreement between the two measurements, which is.a good check on the quality of the measurements.
However,
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it was possible to ignore the of f set ef fect and obtain two indepen-dent ITCs, which showed acceptable agreement.
The resulting MTC was -20.8 pcm/*F, which was in reasonable agree-ment with predicted values that ranged f rom -22.7 to -23.5 pcm/*F, and was less negative than the limit in Technical Specifications.
No violations or deviations were identified.
5.
Exit Interview (30730)
The inspection scope and findings were summarized on September 27, 1990, with those persons indicated in paragraph I above.
The inspector described the areas inspected and discussed in detail the inspection find-ings.
No dissenting comments were received from the licensee.
Proprie-tary information was reviewed in the course of this inspection, but is not included in this report.
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Acronyms and Initialisms Used in This Report ARO all rods out BOL beginning of life COLR Core Operating Limits Report EFPD effective full power days EOL end of_ life F
nuclear enthalpy hot channel factor dH F
nuclear heat flux hot channel factor HkP hot full power HZP hot zero power IP instrument procedure IRNI intermediate range nuclear instrument ITC isothermal temperature coefficient of reactivity LSSS limiting safety system setting MTC moderator temperature coefficient of reactivity 1/M inverse multiplication NC nuclear (reactor) coolant system NIS-nuclear instrument system OP.
operating procedure P
permissive action-switch pcm percent millirhe, a unit ci reactivity ppmB parts per million boro;i PRNI power. range nuclear i'istrument PT-periodic test.
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-quadrant power tilt ratio RCCA rod cluster control assembly RTP
. rated thermal _ power SRNI'
source enge nuclear instrument TS Technica1' Specification
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VCT volume contro11 tank I
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