IR 05000400/1988035
| ML18005A708 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 11/08/1988 |
| From: | Burnett P, Jape F NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML18005A707 | List: |
| References | |
| 50-400-88-35, NUDOCS 8811230019 | |
| Download: ML18005A708 (9) | |
Text
Report No.:
50-400/88-35 Licensee:
Carolina Power and Light Company P.
0.
Box 1551
.
Raleigh, NC 27602 Docket No.:
50-400 Faci 1 ity Name:
Har ris
License No.: NPf-63 Inspection Conducted:
October 11 - 14, 1988 Inspector:
urne Approved by:
~~ l.c..r ran ape, ie j
Test Programs Section Engineering Branch Division of Reactor Safety SUMMARY g
a e
igne Scope:
Results:
This routine, unannounced inspection addressed the following areas:
,precritical testing, post-refueling startup tests, and beginning-of-cycle power operation.
The SRNIs appear to be operating in too high flux, which prevents
'hem from monitoring the entire approach of criticality, (paragraph 3.a).
The operator requalification program would benefit by the addition of training on operator involvement during startup physics testing, paragraph 4.
Procedures should anticipate RCS temperature reduction when first picking up load and provide advance compensatory measures, paragraph 5.
No violations or deviations were identified.
831I~300I9 BBIIIO PDR ADQCl( 05000400 F'NU
REPORT DETAILS 1.
Persons Contacted Licensee Employees
~R.
T. Biggerstaff, Principal Engineer, On-Site Nuclear Safety J.
M. Collins, Manager, Operations
"J. Garcia, Senior Reactor Engineer
~C.
R. Gibson, Director, Programs and Procedures
~C.
S. Hinnant, Plant General Manager 0.
N.
Hudson, Senior Engineer
~C.
L. McKenzie, Principal equality Assurance Engineer
~J.
H. Smith, Operations Support Supervisor
~F.
E. Strehle, Project equality Assurance Specialist
"D.
L. Tibbets, Director, Regulatory Compliance
~R.
B.
Van Metre, Manager, Technical Support
~M.
G. Wallace, Senior Specialist, Regulatory Compliance
"W.
R. Wilson, Principal Engineer, Technical Support Other licensee employees contacted included shift foremen, engineers, control room operators, and office personnel.
NRC Resident Inspectors W.
H. Bradford, Senior Resident Inspector
"M.
C.
Shannon, Resident Inspector
~Attended exit interview Acronyms and initialisms used throughout this report are listed in the last paragraph.
2.
Pre-Critical Activities (72700)
The following procedures completed prior to criticality to support startup for cycle 2 were reviewed for technical adequacy and performance:
a.
EPT-070 (Revision 0), Reactivity Computer Initial Setup and Calibra-tion,,
was completed, except for restoration, on October 11, 1988.
This was a
bench test checkout with only positive reactivities simulated, but see also the practical checkout of the reactivity computer discussed in paragraph b.
No EST-704 (Revision 4),
Shutdown and Control Rod Drop Test was com-pleted successfully for all rods on October 11, 1988.
A good feature of the procedure is the prerequisite (step 3. 14) that successful statistical reliability tests be performed on the SRNIs prior to pulling rods.
The drop times on all rods were less than the 2.2 seconds to dashpot entry required by TS 4. 1.3.4.
EST-701 (Revision 3),
Shutdown Margin Calculation
-
Mode 2, was performed prior to initiating the startup, and a shutdown margin in excess of the requirement of TS 3.1.1.1 was confirmed.
violations or deviations were identified.
3.
Initial Criticality for Cycle 2 (72700)
The inspector witnessed most of the steps of procedure EPT-069 (Revi-sion 0), Initial Criticality, as they were performed or reviewed the.
completed steps and collected data shortly after performance.
The procedure had three purposes:
a.
Initial criticality for cycle 2 was attained in a well-controlled manner.
Prior to pulling control rods, the operability of the SRNIs was established by performing successful statistical reliability checks, based upon Chi-squared analysis, on each channel.
After establi'shing a
base count rate for each SRNI channel, ICRR was calculated and plotted as the shutdown banks were withdrawn in pred'etermined increments'his process was continued as the control banks were withdrawn in overlap until D bank was withdrawn to 200 steps.
The total flux multiplication during rod withdrawal was about a factor of two.
New base count rates were established for each SRNI channel, and ICRR was monitored and plotted as the RCS boron concen-tration was reduced at a constant dilution rate of -50 gpm.
The licensee did not use every available opportunity to reconfi rm the statistical reliability of the SRNIs, which would have been a desir-able practice.
The inspector did evaluate the new baseline data statistically, and confirmed acceptable operation of the SRNIs.
During the multiplication process, the IRNIs came on scale, and over a decade of overlap was confirmed.
P-6 was reached, and power to the SRNIs terminated before criticality was attained; so the final phase of the approach to criticality was monitored solely by the IRNIs.
This sequence. of events was not the most desirable.
It would have been better if the entire approach to criticality had been monitored by the SRNIs; since their performance had been established to be acceptable; whereas the long term accept-able performance of the IRNIs had not be'en proved.
The initial count rate of the the SRNIs was nearly two-hundred-fold higher than required by Regulatory Guide 1.68. 'he -licensee was asked to consider desensitizing the SRNIs; so they would be on scale during
b.
the entire approach to criticality. It is unlikely that the equi-'ibrium low-leakage core will provide sufficient desensitization.
At the exit interview, management made a
commitment to review and consider methods to. reduce the flux at the SRNIs (inspector followup item 400/88-35-01).
Subsequently, the ARO critical boron concentration was measured to be
'764
.ppmB using EPT-067 (Revision 0),
Boron Endpoint Heasurement-All Rods Out.
This was in satisfactory agreement with the predicted value of 1737 ppmB.
Power was increased until nuclear heating effects were observed on the reactivity computer at current levels of 1.5E-6 amps and 1.7E-6 amps on IRNIs
and 36 respectively.
To avoid nuclear heating effects, the zero power testing range was established as 5E-8 to 5E-7 amps on the IRNIs.
The reactivity computer was checked out by comparing its solutions with those obtained by measuring the reactor period by stop watch and solving the inhour equation.
For positive reactivities as great as
pcm and negative reactivities to -64 pcm the agreement between solutions was within 4X, which was acceptable.
This span of reactiv-ity was greater than that subsequently used in the zero power physics tests.
No violations or deviations were identified.
4.
Zero Power Physics Tests (72700, 61708, 61710)
The following tests were reviewed by the inspector:
Moderator Temperature Coefficient Neasurement EST-703 (Revision 3), Moderator Temperature Coefficient -
BOL After Each Refueling, was completed on October 13, 1988, and performance of most of the test was witnessed by the inspector.
The test method used an N-Y recorder with a scaled temperature input to the X-axis and a
scaled reactivity input to the Y-axis.
The slope of the graph was then the ITC.
The ITC was measured from one cooldown and one heatup, each of about 4"F.
Although not a performance criterion of this procedure, the heatup and cooldown results did agree within 1, pcm/"F, which is a
requirement invoked by many other licensees.
The average ITC was -0.82 pcm/"F, which was in reasonable agreement with the predicted value of -0.06 pcm/"F.
The zero power DTC was-1.6 pcm/ F, yielding an MTC of +0.78 pcm/"F.
Neasuring the slope of the recorder trace proved to be difficult because the react>vity signal was noisy and produced a trace about 1-1/4 inches wide while spanning less than 2 inches horizontally and less than 3 inches vertically.
However independent evaluations by several engineers arrived at consistent results.
The technique
was judged to be acceptable; since the slope was clearly much less than the limit corresponding to the limiting NTC of 5 pcm/"F of TS 3. 1. 1.3.
However, a
much less noisy reactivity signal must be used in the future if the HTC is closer to the limit.
b.
Reactivity Morth of Control and Shutdown Rods EPT-068 (Revision 0), Reactivity Morth of the Control and Shutdown Banks Utilizing the Rod Swap Technique, was performed on October 13, 1988.
The inspector independently evaluated the reactivity traces from the reactivity computer for the worth measurement of the refer-ence bank, control bank B.
The SUPERCALC3(Release 2. 1) program was used to manipulate the raw data and to plot the results as a
differential reactivity worth curve.
The results obtained by the inspector and the licensee are shown graphically in Attachment l.
The integral worth of the reference bank differed from prediction by less than 10%
and satisfied the test acceptance criterion.
The reactivity worths of the other control and shutdown banks were determined by rod swap technique and each satisfied the acceptance criterion.
Prior to each of the tests discussed above, the reactor engineer provided a test briefing to the operations shift.
The response to the briefings and observations of communications during the test led the inspector to'he conclusion that more discussion of routine startup tests and the operators'art in them should become part of the operator requalification program prior to the next fuel cycle.
The bases for test acceptance criteria discussed above were found in MCAP-11816, The Nuclear Oesign and Operations Package for Shearon Harris Nuclear Plant Cycle 2 (6/88) (Proprietary).
No violations or deviations were identified.
5.
Observation of Initial Power Operation for Cycle 2 (72700)
The inspector was in the control room when the electrical generator was first synchronized to the grid for cycle 2.
The activities of the opera-tors appeared to be well-controlled and organized.
However, during the initial pickup of load, the average temperature of the RCS dropped below 551"F, placing the unit in a fifteen minute action statement.
The opera-tors recognized the situation.and its limitations immediately and recov-ered temperature in less than fifteen minutes.
However, it appeared that the temperature drop was predictable, and that the unit should have been operated at a higher temperature prior to adding load to prevent entering the action statement.
No violations or deviations were identifie.
Exit Interview The inspection scope and findings were summarized on October 14, 1988, with those persons indicated in paragraph
above.
The inspector described the areas inspected and discussed in detail the inspection findings.
No dissenting comments were received from the licensee.
Proprietary material was reviewed in the course of the inspection, but is not incorporated into this report.
One inspector followup item was identified and confirmed as a licensee commitment:
IFI 50-400/88-35-01:
Review and consider methods to reduce the flux at the SRNIs.
7.
Acronyms and Initialisms Used in this Report ARO BOL DTC EPT EST gpm ICRR-IRNI
-.,
ITC MTC p-6 pcm ppmB-RCS SRNI-TS all rods out beginning-of-life (cycle)
doppler temperature coefficient engineering performance test engineering surveillance test gallon per minute
)nverse count rate ratio intermediate range nuclear instruments isothermal temperature coefficient moderator temperature coefficient permissive 6, flux level measured by IRNs at which power to the SRNIs is removed percent millirho, a unit of reactivity parts per million boron reactor coolant system source range nuclear instrument technical specifications Attachment 1.
Differential Rod Worth Curve
ATTACHMENT
HARRIS CYCLE 2,
. FL'RHNj.K BANIZ B 8'~fferent~ul, 1~Pm tA Cu~e E+- Inspect.tor
~-- Eic:emcee
'78 104 130 f56 EBB 2DB Average Baal< Position (steps)