ML17298B770
| ML17298B770 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 12/13/1984 |
| From: | Knighton G Office of Nuclear Reactor Regulation |
| To: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| References | |
| NUDOCS 8501030378 | |
| Download: ML17298B770 (9) | |
Text
Docket Nos.:
50-528, 50-529 and 50-530 PEC 13 1984 Mr. E.
E.
Van Brunt, Jr.
Vice President - Nuclear Projects Arizona Public Service Company Post Office Box 21666 Phoenix, Arizona 85036
Dear Mr. Van Brunt:
DISTRIBUTION
~5
.525/529/555 NRC PDR ACRS (16)
LPDR NSIC PRC System LB//3 Reading EALicitra JLee
- Attorney, OELD NGrace EJordan
Subject:
Request for Additional Information - Pressurizer Auxiliary Spray System As a result of the staff's continuing review of the auxiliary spray system for the pressurizer, we have determined the need for (additional information;:..The specific information needed is identified in the enclosed request and has been discussed with Mr. T. Juan of your staff.
We ask that you provide an expeditious response to the enclosed request to permit the staff to complete its review in a timely manner.
If you have any questions about this letter, you should contact Mr. E. Licitra, the Licensing Project Manager.
Sincerely,
Enclosure:
as stated oi iginal aignect by George 7/. Haighton George W. Knighton,,Chief Licensing Branch No.
3 Division of Licensing cc:
See next page DL:LB83 g D
'ALicitra/yt GW 'ton 12/7 /84 12/tg/84 8501030378 84i213 PDR ADOCK 05000528 A
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Palo Verde Mr. E.
E.
Van Brunt, Jr.
Vice President
- Nuclear Projects Arizona Public Service Company P. 0.
Box 21666 Phoenix, Arizona 85036 Arthur C. Gehr, Esq.
Snell 5 Wi lmer 3100 Valley Center Phoenix, Arizona 85073 Mr. James M. Flenner, Chief Counsel Arizona Corporation Commission 1200 West Washington Phoenix, Arizona 85007 Charles R. Kocher, Esq. Assistant Counsel James A. Boelgtto, Esq.
Southern California Edison Company P. 0.
Box 800
- Rosemead, California 91770 Ms. Margaret Walker Deputy Director of Energy Programs Economic Planning and 'Development Office 1700 West Washington Phoenix, Arizona 85007 Mr. Rand L. Greenfield Assistant Attorney General Bataan Memorial Building Santa Fe, New Mexico 87503 Resident Inspector Palo Verde/NPS U.S. Nuclear Regulatory Corwission P. 0.
Box 21324 Phoenix, Arizona 85001 Ms. Patricia Lee Hourihan 6413 S. 26th Street
- Phoenix, Arizona 85040 Kenneth Berlin, Esq.
Winston 5 Strawn Suite 500 2550 M Street, NW Washington, DC 20037 Ms. Lynne Bernabei Government Accountability Project nf the Institute for Policy Studies 1901 gue Street, NW Washington, DC 20009 Ms. Jill Morrison 522 E. Colgate Tempi, Arizona 85238 Regional Administrator - Region V
U. S. Nuclear Regulatory Commission 1450 Maria Lane Suite 210 Walnut Creek, California 94596
Enclosure PALO VERDE REEFER~FR MATER By letter (NRC to CE) dated March 27,
- 1984, the staff expressed concern related to the availability of the auxiliary pressurizer spray (APS) system to perform its required safety functions for CESSAR System 80 plants (Palo Verde, R
WNP-3) which are designed without PORVs.
As noted in the subject letter, the staff considers that the CESSAR System 80 APS should be treated as safety-related in accordance with Appendix A to 10 CFR 50 and 10 CFR 100 since it is required for safe shutdown of the plant and to mitigate the consequences of a SGTR accident should the main pressurizer spray system become unavailable.
APS flow is initiated from the control room by opening at least one of the redundant (parallel) auxiliary spray valves (CH-203 or CH-205) in combination with the closure of the existing loop charging valve (CH-240).
The staff expressed concern that a failure of CH-240 to close would negate the safety function of the APS system.
After being informed of the staff's concern, CE committed (September 18, 1984 letter) to modify CESSAR System 80 to provide a valve in series with the existing loop charging valve (CH-240).
However, discussions with CE revealed that CH-240 and the new series valve would be powered from non-Class 1E buses even though the valves are considered to be safety-related.
The staff finds this unacceptable since these valves are required to perform a safety function
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as discussed above and no analysis has been provided to justify the use of nonsafety-related buses to provide power for operation of the subject valves.
It should be noted that Branch Technical Position RSB 5-1 states that suitable
" redundancy should be provided to assure that for onsite electric power system operation (assuming offsite power is not available) and for offsite electric power system operation (assuming onsite power is not available) the system safety function can be accomplished, assuming a single failure.
It is the staff's position that if equipment (pumps, valves) is required to perform a safety-related function, the mechanical and electrical components including any associated electrical power source should be treated as safety-related and implemented as such.
Thus, the existing loop charging valve (CH-240) and the additional series valve used to isolate normal charging flow should satisfy the single failure criterion and should not be dependent on the use of nonsafety-related equipment including power supplies.
Specifically, each valve should be powered from a separate, electrically independent Class 1E power source, or the use of non-Class lf power to the valves should be justified on some other defined basis.
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It is the staff's understanding that the Palo Verde (first CESSAR System 80 reference plant) applicant has elected to implement CE's proposed design and intends to power the series loop charging valves from nonsafety-related power buses.
Although it is recognized that these-valves will fail closed on loss of power, information provided to date is insufficient to determine that all possible failures or desigp basis events will result in a fail-safe (closed) condition.
Therefore, a failure modes and effects analysis should be performed by the Palo Verde applicant to show that the capability of the subject valves to perform the intended protective functions cannot be degraded below an acceptable level as a result of all possible circumstances (i.e.,
low voltage, low frequency, design basis
- events, etc.) associated with the offsite power supply system and.its associated non-Class lE buses.
Alternately, the staff will consider the implementation of Class 1E electrical protective devices within the non-Class 1E power system as a means to assure that the capability of the valves to perform the intended safety functions is not degraded below an acceptable level.
The applicant should provide for staff review information to describe the results of the required analysis and any non-Class 1E power supply system design changes that may be proposed as a
result of the analysis.
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