ML17299A590
| ML17299A590 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 08/23/1985 |
| From: | Licitra E Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| TAC-56680, NUDOCS 8509090241 | |
| Download: ML17299A590 (18) | |
Text
NB 88 l888 Docket No.:
50-528 LICENSEE:
Arizona Public Service Company FACILITY:
Palo Verde Unit 1
SUBJECT:
SUMMARY
OF SITE AUDIT FOR THE CORE PROTECTION CALCULATOR A site audit of the Palo Verde Unit 1 core protection calculator (CPC) was conducted on June 24, 1985.
The purpose was to (1) confirm overall system performance and (2) aid in the evaluation of the planned CPC improvement program by the CPC owners group.
A summary of the audit findings, the names of the participants and an outline of the licensee's presentation are included in the attached report.
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Enclosure:
As stated cc:
See next page E. A. Licitra, Project Manager Licensing Branch No.
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Mr.
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Van Brunt, Jr.
Arizona Nuclear Power Project Palo Verde CC:
Arthur C. Gehr, Esq.
Snell 5 Wilmer 3100 Valley Center Phoeni x, Arizona 85073 Mr. James M. Flenner, Chief Counsel Arizona Corporation Cormission 1200 West Washington Phoenix, Arizona 85007 Charles R. Kocher, Esq. Assistant Council James A. Boeletto, Esq.
Southern California Edison Company P. 0.
Box 800
- Rosemead, California 91770 Mr. Mark Ginsberg Energy Director Office of Economic Planning and Development 1700 West Washington - 5th Floor Phoenix, Arizona 85007 Mr. Wayne Shirley Assistant Attorney General Bataan Memorial Building Santa Fe, New Mexico 87503 Mr. Roy Zimmerman U.S. Nuclear Regulatory Commission P. 0.
Box 239 Arlington, Arizona 85322 Ms. Patricia Lee Hourihan 6413 S. 26th Street Phoenix, Arizona 85040 Regional Administrator, Region V
U. S. Nuclear Regulatory Commission 1450 Maria Lane Suite 210 Walnut Creek, California 94596 Kenneth Berlin, Esq.
Winston S. Strawn Suite 500 2550 M Street, NW Washington, DC 20037 Ms. Lynne Bernabei
'overnment Accountability Project of the Institute for Policy Studies 1901 Que Street, NW Washington, DC 20009 Ms. Jill Morrison 522 E. Colgate Tempi, Arizona 85238 Mr. Charles B. Brinkman, Manager Washington Nuclear Operations Combustion Engineering, Inc.
7910 Woodmont Avenue Suite 1310
- Bethesda, Maryland 20814 Mr. Ron Rayner P. 0.
Box 1509,
- Goodyear, AZ 85338
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MEMORANDUM FOR:
Docket Numbers:
50-528, 50-529 and 50-530 FROM:
L. E. Phillips, Leader, Section A
Core Performance
- Branch, DSI LICENSEE:
Arizona Public Service Company FACILITY:
Palo Verde Nuclear Generating Station (PVNGS)
SUBJECT:
CPC START-UP AUDIT FOR PVNGS UNIT 1 On June 24,
- 1985, Laurence E. Phillips, Section Leader in the NRC Core Performance Branch, visited the PVNGS site to review the start up testing program and operator training and procedures relating to the implementation and administrative control of the Core Protection Calculator (CPC) system for PVNGS Unit 1.
The purpose of the meeting was to confirm the PVNGS overall conformance to previously reviewed and approved generic procedures for CPC operation and to obtain feedback on the adequacy of existing operations relative to recently approved Technical Specification modifications and to aid in the evaluation of the CPC improvement program which is planned by a committee of CPC owners (CPC Oversight Committee).
At the time of the meeting, PVNGS Unit I had neared completion of the 20 percent power escalation startup tests but was operating at a reduced power of about 13 percent due to a valve failure requiring bypass of the turbine.
Enclosure I lists the meeting participants. -is an outline of the meeting presentation by Arizona Nuclear Power Project personnel.
After the
- meeting, the control room was visited and the CPC operating data were compared to other plant data outputs.
There were no unexplained discrepancies.
A sample Core Protection Calculator Report was obtained from the plant data logger.
- Also, a periodic test was 'executed on one CPC and the values of addressable constants were obtained.
A subsequent review of these values confirmed that all were within allowable ranges.
A,. CPC Report at the 50 percent power level was. also provided for staff review subsequent to the audit.
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0 erator Trainin Copies of lesson plans and training material describing CPC operations and operator responsibilities in detail were provided for the NRC staff.
The importance of assuring proper input values for addressable constants appears to be appropriately emphasized in training and procedures.
Based on this observation, it is concluded that recent Technical Specification modifications which reduce the restrictions on addressable constant entry have been implemented at Palo, Verde without compromise to CPC reliability.
Calibration of CPC In ut Si nals A major topic of the audit was the calibration procedures and frequency for those addressable constants which adjust the CPC input signals and calculated parameters to accurately model core conditions.
Extensive testing is done during startup to verify CPC calculations and addressable constants.
If. the CPC core model is not conservative with respect to measurements, addressable constants are updated to reflect test resu'its.
A surveillance program is designed to monitor those parameters which may change during the fuel cycle to assure that values determined during startup remain accurate.
Tests performed during startup include the following.
(a)
Hot functional ultrasonic flow test - performed prior to initial power escalation to determine reactor coolant flow rate, adjust CPC flow calibration constants, and to calibrate RCS pump zp measurement signals vs.
RCS flow.
(b)
Secondary power calibration - performed at 3 percent, 6 percent and 10 percent power plateaus to calibrate neutron flux power from ex-core detectors; adjust neutron flux power calibration constant (KCAL) in CPCs.
At the 20 percent, 50 percent, 80 percent and 100 percent power
, plateaus, both the neutron flux (KCAL) and thermal power (TPC) calibration constants in the CPCs are adjusted.
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(c)
Axial power distribution - at the 20 percent power level, the CPC predicted axial power distribution based on ex-core detector signals is verified to meet specified screening criteria or shape annealing matrix constants are adjusted for better agreement with measurements.
At 50 percent power, axial power shapes are measured over a wide range of power shapes to determine/confirm constants used in axial power synthesis; radial peaking factors and rod and temperature shadowing factors are measured and CPC constants are updated if needed.
CPC constants which are calibrated during the initial startup must again be confirmed and updated as needed after refueling.
The reload startup tests are essentially the same except that hot functional ultrasonic flow measurement and 20 percent axial power calibration tests are omitted.
Reactor coolant pump curves are considered constant from cycle to cycle; hence, flow calibrations are based on the original ap vs flow data.
During plant startups following mid-cycle outages or plant trips, verification of addressable constants is limited to power calibration constants.
The flow calibration procedures received particular attention because of the'se of a pre-startup ultrasonic technique rather than the more conventional periodic flow calibration based on calorimetric heat balances.
Attention was given to the claimed flow measurement uncertainty versus the value used in the approved Statistical Combination of Uncertainties (SCU) analysis.
This issue was resolved in a post-meeting telephone conference between the licensee, Combustion Engineering, and the NRC staff. It was determined that the uncertainty values claimed for the ultrasonic technique, -3.5 percent flow measurement, 0.5 percent calibration method, and 0.162 percent pump speed uncertainty were within the tolerance for the approved System 80 SCU methodology.
Likewise the 3.5 percent ultrasonic measurement accuracy is acceptable to the staff.
Combustion Engineering has evaluated this measurement technique to be more accurate than calorimetric methods.
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Datalink Between Plant Com uter and CPCs The datalink is used primarily during startup and surveillance testing to provide CPC inputs and corresponding calculation results to an off line core analysis program'which can be used to determine the values of CPC addressable constants.
It is also used by engineers to obtain information for assessing CPC calculations.
Summar and Conclusions The staff has reviewed the software implementation and those aspects of operator training and procedures which contribute to the operational reliability of the CPCs at PVNGS.
We conclude that the licensee has demonstrated the capability to operate and maintain the CPCs in a manner that will provide reasonable assurance of their functional reliability.
Technical Specifications relating to the CPCs are adequate in view of the complementary procedures and training program now in place at PVNGS.
- Further, there were no identified deficiencies relating to generic aspects of the CPC implementation which would impact our review of the planned CPC improvement program.
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ENCLOSURE 1
JUNE 24, 1985 NAME ORG POSITION Laurence E. Phillips NRC/CPB SL/Acting Chief Kristin L. McCandless Forrest E. Hicks Cecil A. Anderson Bruce Miller Jeff J. Riedesel Paul M. Keller ANPP ANPP ANPP ANPP ANPP ANPP Licensing TRG Manager Lead Nuclear Inc.
Supervisor Nuclear Fuel Technical Project Engineer Reactor Engineer
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ENCLOSURE 2
Outline/Summar I.
Introduction to CPCs A.
System Description
B.
CPC Function C.
Addressable Constant Uses II.
Start-up Testing Program A.
Initial Startup Testing B.
Subsequent Startups III. Datalink and its uses IV.
Entry of Addressable Constants A.
Administrative Controls B.
Operations Implementation C.
Summary of Procedures V.
Training on CPCs A.
Operator Training B.
Reactor Engineer Training VI.
Functional Test
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MEETING
SUMMARY
DISTRIBUTION Docket"-No(:s.)'.-5O-52B NRC PAR Local PDR NSIC PRC System LB3 Reading
- Attorney, OELD GWKnighton project Manager E.
A. Licitra JLee NRC PARTICIPANTS L.
E. Phillips bcc:
Applicant
& Service List
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