ML17300B030
| ML17300B030 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 08/25/1987 |
| From: | Licitra E Office of Nuclear Reactor Regulation |
| To: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| References | |
| TAC-65920, TAC-65921, TAC-65922, NUDOCS 8709090038 | |
| Download: ML17300B030 (8) | |
Text
QUB 2 5 1987 Docket Nos.:
50-528, 50-529 and 50-530 Mr. E. E.
Van Brunt, Jr.
Executive Vice President Arizona Nuclear Power Project Post Office Box 52034 Phoenix, Arizona 85072-2034 DISTRIBUTION ACRS (la)
'NRC 5 L PDRs MDavis PD5 Plant File LKopp JLee/GKalman GHolahan OGC-Bethesda EJor dan JPartlow
Dear Mr. Van Brunt:
SUBJECT:
REVIEW OF SOFTWARE CHANGES TO THE CORE PROTECTION CALCULATOR-PALO VERDE, UNITS I, 2 AND 3 (TAC NOS. 65920, 65921 AND 65922)
By letter dated July 13, 1987, you requested our approval for certain changes in Core Protection Calculator (CPC) constants, relating to Loss of Flow Protection, to be made with the NRC approved procedure (CEN 39(A)-P, Revision 03-P-A) for such changes.
We have completed our review of your request, and have determined that the proposed changes to the CPC constants are acceptable.
Our detailed evaluation is enclosed.
If you have any questions regarding this letter, please let me know.
Sincerely,
Enclosure:
As stated cc:
See next page Original signed g~r:
E.A. Licitra E. A. Licitra, Senior Project Manager Project Directorate V
Division of Reactor Projects
'III, IV, V and Special Projects DR P/
DV DR
- PDV EALicitra:cd GW ns hton 8/A+87 8/
/87 OFFICIAL RECORD COPY 8709090038 870825 PDR ADOCK 05000528 p
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Hr. E. E.
Van Brunt, Jr.
Arizona Nuclear Power Project Palo Verde CC:
Arthur C. Gehr, Esq.
Snell 5 Wilmer 3100 Valley Center Phoenix, Arizona 85073 Hr. James H. Flenner, Chief Counsel Arizona Corporation Commission 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. Hark Ginsberg Energy Director Office of Economic Planning and Development 1700 West Washington - 5th Floor Phoenix, Arizona 85007 Hr. Wayne Shirley Assistant Attorney General Bataan Memorial Building Santa Fe, New Mexico 87503 Hr. Roy Zimmerman U.S. Nuclear Regulatory Commission P. 0.
Box 239 Arlington, Arizona 85322 Regional Administrator, Region V
U. S. Nuclear Regulatory Commission 1450 Haria Lane Suite 210 Walnut Creek, California 94596 Kenneth Berlin, Esq.
Winston 8 Strawn Suite 500 2550 H Street, NW Washington, DC 20037 Ms. Lynne Bernabei Government Accountability Project of the Institute for Policy Studies 1901 Que Street, NW Washington, DC 20009 Hr. Ron Rayner P. 0.
Box 1509
- Goodyear, AZ 85338 Hr. Charles B. Brinkman, Manager Washington Nuclear Operations Combustion Engineering, Inc.
7910 Woodmont Avenue Suite 1310
- Bethesda, Maryland 20814
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION CORE PROTECTION CALCULATOR SOFTWARE CHANGES PALO VERDE NUCLEAR GENERATING STATION UNITS 1
2 AND 3 ARIZONA NUCLEAR POWER PROJECT
1.0 INTRODUCTION
By letter dated July 13, 19S7 (161-00362-JGH/JRP),
Arizona Nuclear Power Project (ANPP) submitted background information on changes to be made to Core Protection Calculator (CPC) constants related to loss of flow event protection at the Palo Verde Nuclear Generating Station (PVNGS), Units 1, 2 and 3.
These changes will prevent unnecessary reactor trips during a fast bus transfer event.
Although no Technical Specification changes are necessary as a result of these CPC software changes, NRC approval is required as stated in Section 6.8, 1.g of the PVNGS Technical Specifications.
2.0 EVALUATION The loss of coolant flow event was reanalyzed assuming a trip on low reactor coolant pump (RCP) speed rather than the previously assumed trip on projected low DNBR.
A CPC trip is initiated when the RCP shaft speed drops to 95K of its nominal speed.
This modification has been made in other recent CPC plants.
The most limiting loss of flow event, the 4-pump total loss of flow, was the event reanalyzed.
The licensee used an approved methodology to determine the reactor core response.
In addition, a faster (more conservative) flow coastdown curve was used than that assumed in the FSAR analysis.
This revised curve bounds the coastdowns observed during startup testing at PVNGS, Units 1
and 2.
The trip breakers are assumed to open 0.3 seconds after the RCP shaft speed reaches 95< of its nominal speed and the control element assemblies (CEAs) begin to drop 1.25 seconds after the initiation of the event as compared to 1.09 seconds in the previous analysis.
The results indicate that
4 II
the minimum DNBR limit of 1.231 is not violated and the pressures in the reactor coolant and main steam systems remain below 110$ of the design values.
Based on the loss of flow event results and on the fact that the software changes will be made in accordance with the NRC approved software change procedure
{CEN-39(A)-P, Rev. 03-P-A, November 1986), the staff finds the proposed changes to the CPC constants to be acceptable.
- 3. 0 CONCLUSION The staff has reviewed the information on changes to be made to CPC constants related to loss of flow protection and finds the proposed changes acceptable for implementation at PYNGS, Units 1, 2 and 3.
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