ML13322A549

Requests Licensee Provide Design Mods Which Will Assure Safe Shutdown Can Be Achieved & Maintained Using Onsite Power Source

ML13322A549
Person / Time
Site:	San Onofre
Issue date:	04/13/1979
From:	Lainas G Office of Nuclear Reactor Regulation
To:	Ziemann D Office of Nuclear Reactor Regulation
References
TASK-07-03, TASK-7-3, TASK-RR TAC-48143, NUDOCS 7905240302
Download: ML13322A549 (2)

Text

DISTRIBUTION:

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~9Central files 9r 7 NRC PDR PSB Reading MEMORANDUM FOR: D. Ziemann, Chief, Operating Reactors Branch #2, DOR FROM:

G. Lainas, Chief, Plant Systems Branch, DOR

SUBJECT:

SAN ONOFRE - UNIT 1, FIRE PROTECTION ALTERNATE OFFSITE POWER SOURCE, LICENSEES LETTER OF JANUARY 15, 1979 In the subject letter, the licensee proposed to provide an alternate shutdown capability independent of certain areas where a fire could affect redundant safe shutdown equipment including the onsite power sources. The power source proposed for the alternate capability is an offsite source which is electrically independent and physically separate except for the intertie to the San DiegeoGas and Electric Company's 135 Kv system.

We find that dependence on offsite power alone is unacceptable and that the capability to provide power from an onsite source should be available.

The staff realizes that there are systems which could be used to achieve safe shutdown given that offsite power is available during a fire.

However, the loss of offsite power is assumed for other events which do not affect systems designed to cope with the event.

The staff deems it to be a prudent conservatism to adopt the same criteria for a fire, particularly, since the fire may affect systems designed to cope with its effects.

The loss of offsite power is to be assumed along with the fire without respect to mechanisms through which it can be shown to occur even though such mechanisms do exist. This will assure that at least one source of onsite power is available in the event of a loss of offsite power concurrent with the fire for whatever reason.

Therefore, the staff requests the licensee to provide design modifications which will assure that safe shutdown can be achieved and maintained using an onsite power source.

G. Lainas, Chief Plant Systems Branch Division of Operating Reactors A

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OFFICE, PSB:D SL/PSB:DOR C

DOR SURNAME L

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NRC FORM 318 (9-76)

NRCM 0240 U. S. GOVERNMENT PRINTING OFFICE: 1976 - 626-624

-2 cc:

V. Stello D. Eisenhut G. Lainas D. Ziemann R. Ferguson J. Knight A. Burger T. Wambach Fire Protection Consultants Section C, PSB L. Derderian