ML13317A627

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Submits Results of Evaluation of Containment post-accident Pressure Reanalysis on Operational Limits,In Response to TMI Action Plan Item II.E.4.2(5).Peak post-accident Pressure & Temp in 770119 Analysis Is Still Applicable
ML13317A627
Person / Time
Site: San Onofre 
Issue date: 06/08/1981
From: Moody W
SOUTHERN CALIFORNIA EDISON CO.
To: Crutchfield D
Office of Nuclear Reactor Regulation
References
TASK-2.E.4.2, TASK-TM TAC-44128, NUDOCS 8106120239
Download: ML13317A627 (2)


Text

Southern California Edison Company P. 0.

BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD. CALIFORNIA 91770 W. C. MOODY TELEPHONES MANAGER, NUCLEAR LICENSING (213) 572-1817 June 8, 1981 (213)1 572-1806 Director, Office of Nuclear Reactor Regulation Attention:

D. M. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing U. S. Nuclear Regulatory Commission Washington, D.C. 20555 O3 Gentlemen:

Subject:

Docket No. 50-206 Clarification of TMI Action Plan Requirements San Onofre Nuclear Generating Station Unit 1 Our April 13, 1981 letter provided information on TMI Action Plans including Containment Isolation Dependability (Item II.E.4.2(5)).

The discussion regarding the containment isolation setpoint identified a discrepancy between the "Containment Post-Accident Pressure Reanalysis" and the operational limits specified in the Technical Specifications. We indicated that the reanalysis would be evaluated to determine the effect of the operational limits. This letter provides the results of the evaluation.

The "Containment Post-Accident Pressure Reanalysis" for San Onofre Unit 1 was transmitted to the NRC by letter dated January 19, 1977. That analysis indicated the post-accident temperature and pressure to be 291oF and 49.4 psig. The initial conditions for that analysis included an initial containment pressure of 14.7 psia or 0 psig. The Technical Specifications for San Onofre Unit 1 contain a limiting condition for operation for the containment sphere. Specification 3.6.C requires that the reactor shall not be made critical nor be allowed to remain critical if the sphere internal pressure is greater than 0.4 psig or is less than -2.0 psig. This allows operation of Unit 1 with an internal sphere pressure between 0.4 and -2.0 psig. Therefore, in the April 13, 1981 letter, we committed to evaluating the containment post-accident pressure utilizing an initial condition of 0.4 psig.

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D. M. Crutchfield, Chief June 8, 1981 The evaluation of the containment post-accident pressure has been performed to determine the effect of utilizing 0.4 psig as an initial condition. This evaluation included an analysis performed in accordance with the Bechtel Topical Report BN-TOP-3, Revision 4, Performance and Sizing of Dry Pressure Containments. The previous analysis utilized Revision 3A of the report. Revision 4 incorporates changes made in response to NRC comments.

The results of the analysis provide a peak post-accident temperature and pressure of 2880F and 48.2 psig. Therefore, the previous peak post-accident pressure and temperature as documented in the January 19, 1977 analysis is still applicable and conservative. Therefore, no further action is deemed necessary at this time.

If you have any questions regarding this matter, please let me know.

Very truly yours,