ML20210R668

Forwards Response to NRC RAI Re SCE License Amend Applications 173 & 159 for Songs,Units 2 & 3,proposed Change Number 485,which Requests Addition of SR to TS 3.3.9, CR Isolation Signal

ML20210R668
Person / Time
Site:	San Onofre
Issue date:	08/13/1999
From:	Nunn D SOUTHERN CALIFORNIA EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9908170183
Download: ML20210R668 (5)

Text

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to EDISON "-

Vice President An (.!}] SON INTERNATIONAL

• Company August 13, 1999 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D. C. 20555

Subject:

Docket Nos. 50-361 and 50-362 Response to Request for Additional Information Regarding Proposed Technical Specification Change Number 485 San Onofre Nuclear Generating Station Units 2 and 3

Reference:

Letter dated October 20,1998, from D. E. Nunn (SCE) to Document Control Desk (NRC),

Subject:

Docket Nos 50-361 and 50-362, Proposed Technical Specification Change Number 485, San Onofre Nuclear Generating Station Units 2 and 3 Gentlemen:

Provided as an enclosure is a response to an NRC request for additional information regarding Southern California Edison's (SCE's) license Amendment Applications 173 and 159 for San Onofre Nuclear Generating Station, Units 2 and 3, respectively.

These Amendment Applications consist of Proposed Change Number 485 (PCN 485) to the San Onofre Units 2 and 3 Technical Specifications which requests addition of a Surveillance Requirement to Technical Specification 3.3.9, " Control Room isolation Signal (CRIS)."

If you have any questions on this subject, please contact me or Jack Rainsberry at (949)368-7420.

1 Sincerely, l Enclosure ,

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San Ckwente. CA 92674-0128 949-% 8 1480 Fax 944-368-1490 L

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, . Document Control Desk cc E. W. Merschoff, Regional Administrator, NRC Region IV J. A.'Sloan, NRC Senior Resident inspector, San Onofre Units 2 & 3 L. Raghavan, NRC Project Manager, San Onofre Units 2 and 3 S Y. Hsu, California Department of Health Services l

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E Subscribed on this I day of 1A#/h ( ,1999.

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0 l Respectfully submitted, l SOUTHERN CALIFORNIA EDIS N COMPANY By: b -- -

Dwight E. Nunn Vice President State of California Coun of San Die o )

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~ before me, [NL MllD Mb/K personally appeared f M lMCb N(Lh /A), personally known to me to be l

the person whose name is subscribed to the within instrument and acknowledged to me l that he executed the same in his authorized capacity, and that by his signature on the I instrument the person, or the entity upon behalf of which the person acted, executed l the instrument.

l WITNESS my hand and official seat. ..-- ---- l J

1 MARIANE SANCHEZ Commission #119M

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l ENCLOSURE RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING PROPOSED TECHNICAL SPECIFICATION CHANGE NUMBER 485 l

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NRC Question:

What will the Surveillance Requirement be for response time testing of the Control Room ,

Isolation Signal (CRIS), and what is the basis for acceptability?

Southern California Edison Response:

The response time which will be used in the Licensee Controlled Specification (LCS) 3.3.100 Surveillance Requirement for the CRIS will be two (2) minutes. The surveillance frequency will be 18 months.  ;

l The basis for acceptability is as follows:

The response time is composed of the sample transport time from the control room normal ventilation intake louvers to the radiation monitor detector, the electronic response time of the radiation monitor, and the damper closure time, plus engineering margin.

For transients which generate a Safety injection Actuation Signal (SIAS) initiated CRIS prior to a significant activity release, the Control Room dose calculations may assume that the Control Room will isolate before the radioactive release reaches the control room normal ventilation intake louvers.

For transients which generate a significant activity release prior to a SIAS initiated CRIS, and for transients without a SIAS initiated CRIS, Control Room dose calculations currently assume, if necessary, that the Control Room is isolated on a high radiation initiated CRIS within three (3) minutes.of the radioactive release reaching the control room normal ventilation intake louvers.

The limiting Control Room dose calculation which assumes that the Control Room is isolated within three (3) minutes is currently the Letdown Line Break with a pre-existing iodine spike. The resulting Control Room doses are 25.4 Rem Thyroid,0.7 Rem Beta-Skin, and < 0.1 Rem Whole Body.

LCS Table 3.3.100-2, Emergency Safety Feature Actuation System (ESFAS), response time is planned to be conservatively set at 120 seconds for the electronic response time of the radiation monitor and the damper closure time. The remaining 60 seconds of the three (3) minute required Control Room isolation time is allocated to the sample transport time from the control room normal ventilation intake louvers to the radiation monitor detector. The analysis of record shows the transport time from louvers to radiation detector to be less than 15 seconds, allowing a 45 second margin.

The proposed 18 month surveillance frequency for the CRIS response time test is j consistent with the other CRIS surveillance frequencies.  !

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