ML13326A776
| ML13326A776 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 05/22/1991 |
| From: | Ray H SOUTHERN CALIFORNIA EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML13326A777 | List: |
| References | |
| NUDOCS 9105300041 | |
| Download: ML13326A776 (3) | |
Text
Southern California Edison Company 23 PARKER STREET IRVINE, CALIFORNIA 92718 HAROLD B. RAY TELEPHONE SENIOR VICE PRESIDENT May 22, 1991 714-45a-4400 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Gentlemen:
Subject:
Docket No. 50-206 Amendment Application No. 192 Containment Testing Pressure and Frequency Request for Exemption from 10CFR50, Appendix J San Onofre Nuclear Generating Station, Unit 1 This letter provides Amendment Application No. 192 which is a request to revise the minimum test pressure for containment integrity testing. In our February 8, 1991 letter we presented the results of our revised analyses which predicted the containment peak pressure following an accident. We stated that the calculated peak pressure had increased to 52.0 psig and that the containment integrity testing required by our existing technical specifications would be performed using this value rather than 49.4 psig as stated in the technical specifications. We also stated that an amendment application to revise the technical specifications would be forwarded within two months of return to service from the Cycle 11 refueling outage.
Amendment Application No. 192 also clarifies the description of the supplemental test performed to verify the accuracy of the integrated leak rate test (ILRT),
updates the Technical Specifications to reflect the current containment design pressure value, and revises the frequency for performing the ILRT.
The change in frequency of the ILRT requires relief from the requirements of Title 10 of the Code of Federal Regulations, Part 50, Appendix J, "Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors."
Therefore, this letter also requests an exemption from 10CFR50, Appendix J.
The amendment application is provided as Enclosure 1 and the exemption request is provided as Enclosure 2.
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Document Control Desk
-2 Amendment Application No. 192 provides a proposed change to decouple the ILRT from the 10 year ISI.
Additionally, the peak testing pressure and the design pressure for the containment sphere are revised as discussed below.
Containment Peak Pressure The minimum test pressure for containment integrity testing in Technical Specification 4.3.1 has been increased from 49.4 psig to 52.0 psig. This change was required due to containment spray system modifications performed during the Cycle 11 refueling outage which necessitated recalculation of the peak containment conditions following a design basis accident. The revised calculations show that the maximum pressure generated inside containment by a design basis accident will be 52.0 psig. The following table provides a summary of the results of the revised calculations which were presented in our February 8, 1991 letter regarding containment pressure.
PEAK PRESSURE PEAK (psig)
TEMPERATURE (OF)
LOCA 51.7 304 MSLB 52.0 413 MSLB1 52.0 387 The ILRT for the Cycle 11 outage was performed using a minimum test pressure of 52.0 psig in accordance with our February 8, 1991 letter. The existing wording of the Technical Specifications states that the current minimum test pressure of 49.4 psig is only a minimum value. No maximum pressure is specified. During conversations with Mr. George Kalman of the NRC staff, it was agreed that the ILRT and ILRT testing would be performed in accordance with the existing technical specifications using a minimum test pressure of 52.0 psig rather than 49.4 psig as currently stated in the Technical Specifications.
Proposed Changes Amendment Application No. 192 revises Technical Specifications 3.6.1, "Containment Sphere," and 4.3.1, "Containment Testing" to include the new peak accident pressure. Amendment Application No. 192 also proposes to revise the description of the supplemental test performed to verify the accuracy of the ILRT, change the frequency of the ILRT to decouple it from the 10 year in service test, and revise the containment design pressure to 52.7 psig.
Document Control Desk
-3 Exemption Request Containment integrated leakage rate test requirements are established in 10 CFR 50, Appendix J. The purpose of the Appendix J test program is to ensure that leakage through the primary reactor containment, systems, and components penetrating primary containment, does not exceed allowable leakage rate values specified within the plant technical specifications.
The containment overall integrated leakage rate test or Type A test, is specifically required by Section III.D of Appendix J. In addition, Appendix J Section III.D specifies a periodic retest schedule for these Type A tests.
The requirements specify that a set of three Type A tests be performed at approximately equal intervals during each 10 year service period. The third test of each set, however, is required to be performed when the plant is shutdown for the 10 year plant Inservice Inspection (ISI).
This requirement is currently imposed by Technical Specification Section 4.3.1.I.C.
However, the requirement to perform the third ILRT coincident with the 10 year ISI has the potential to create schedule conflicts in the event the ISI is extended in accordance with ASME code provisions. For this reason, SCE seeks to decouple the third ILRT from the 10 year ISI and instead perform the test on a 40 +/- 10 month schedule. Therefore, in accordance with the requirements of 10 CFR 50.12, an exemption to the requirements of 10 CFR 50, Appendix J,Section III.D.1(a), is requested by Enclosure 2 to this letter.
If you have any questions in this matter, please let me know.
Very truly yours, Enclosures cc:
George Kalman, NRC Project Manager, San Onofre Unit 1 J. B. Martin, Regional Administrator, NRC Region V C. Caldwell, NRC Senior Resident Inspector, San Onofre Units 1, 2 and 3 C. D. Townsend, NRC Resident Inspector, San Onofre Unit 1 J. H. Hickman, California Department of Health Services