ML13312A652
| ML13312A652 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 12/22/1992 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML13312A651 | List: |
| References | |
| NUDOCS 9212310102 | |
| Download: ML13312A652 (3) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION OF THE SECOND TEN-YEAR -INTERVAL INSERVICE INSPECTION PROGRAM PLAN REQUEST FOR RELIEF FOR SOUTHERN CALIFORNIA EDISON COMPANY SAN ONOFRE NUCLEAR GENERATING STATION, UNIT 1 DOCKET NO. 50-206
1.0 INTRODUCTION
Technical Specification 4.7 for San Onofre Nuclear Generating Station, Unit 1 (SONGS 1) states that inservice.inspection and testing of the American Society of Mechanical Engineers (ASME) Code Class 1, 2, and 3 components shall be performed in accordance with Section XI of the ASME Boiler and Pressure Vessel Code and applicable Addenda as required by 10 CFR 50.55a(g), except where specific written relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(i).
Paragraph 10 CFR 50.55a(a)(3) states that alternatives to the requirements of paragraph (g) may be used, when authorized by the NRC, if (i) the proposed alternatives would provide an acceptable level of quality and safety, or (ii) compliance with the specified requirements would result in hardship or unusual difficulties without a compensating increase in the level of quality and safety.
Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1, 2, and 3 components (including supports) shall meet the requirements, except the design and access provisions and the preservice examination requirements, set forth in the ASME Code,Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components," to the extent practical within the limitations of design, geometry, and materials of construction of the components. The regulations require that inservice examination of components and system pressure tests conducted during each ten-year interval comply with the requirements in the latest edition and addenda of Section XI of the ASME Code incorporated by reference in 10 CFR 50.55a(b) on the date twelve months prior to the start of the 120-month inspection interval, subject to the limitations and modifications listed therein. The components (including supports) may meet the requirements set forth in subsequent editions and addenda of the ASME Code incorporated by reference in 10 CFR 50.55a(b) subject to the limitations and modifications listed therein.
9212310102 921222 PDR ADOCK 05000206 P
-2 Pursuant to 10 CFR 50.55a(g)(5), if the licensee determines that conformance with an examination requirement of Section XI of the ASME Code is not practical for its facility, information shall be submitted to the Commission in support of that determination and a request made for relief from the ASME Code requirement. After evaluation of the determination, pursuant to 10 CFR 50.55a(g)(6)(i), the Commission may grant relief and may impose alternative requirements that are determined to be authorized by law, will not endanger life, property, or the common defense and security, and are otherwise in the public interest, giving due consideration to the burden upon the licensee that could result if the requirements were imposed.
By a letter dated November 4, 1992, Southern California Edison Company (licensee) submitted to the NRC a request for relief from the ASME Code requirements that the licensee determined to be impractical to perform during the Second Ten-Year Inservice Inspection Interval for the San Onofre Nuclear Station, Unit 1. The staff has evaluated the licensee's request for relief from the ASME Code,Section XI requirements and the staff's evaluation of the requests for relief are in the sections that follow.
2.0 EVALUATION Request for Relief dated 11/04/92, Hydrostatic Testing of the Component Cooling Water System Code Requirement: Subsection IWD of the ASME Code Section XI defines rules and requirements for inservice inspection of Class 3 pressure-retaining components. Paragraph IWD-2410 in Article IWD-2000 of the Code (1974 Edition, including Summer 1975 Addenda) requires that 100% of the components shall have been tested and examined in accordance with IWA-5000, IWD-5000, and IWD-2600 by the expiration of each inspection interval.
Article IWA-5000 defines the requirements for the system pressure tests including the hydrostatic tests.
Paragraph IWA-5210 of this article requires that the pressure-retaining components shall be visually examined while the system is under the hydrostatic test pressure and temperature. The test pressure and temperature shall be maintained for at least four hours prior to the performance of the examinations. Paragraph IWD-5200 in Article IWD-5000 requires the system test pressure shall be at least 1.10 times the system design pressure.
Licensee's Code Request for Relief: The licensee is requesting relief from the Code requirement to perform hydrostatic tests on portions of the Component Cooling Water System (CCW) as described in four test packages (Test Package Nos. CCW-4, CCW-5, CCW-10 and CCW-11).
For example, Test Package CCW-10 states that boundaries for this test package include outlets from various heat exchangers joining into the common return header which in turn is connected to each CCW pump suction and surge tank.
-3 Licensee's Basis for Requesting Relief: The licensee states that the SONGS 1 Component Water Cooling System is not train separated as it relies heavily on common components and lines, with very few header isolation valves. During normal plant operation, the CCW system is required to continuously transfer heat to salt water cooling system from safety-related and nonsafety-related components that receive heat from the reactor coolant system. Thus, in order to perform the tests the licensee would have to shut down the entire CCW system from service and removing it from service during normal plant operations would impair its safety function. It also serves as a barrier between potentially radioactive systems and the salt water cooling system.
Licensee's Proposed Alternative Examinations: The licensee proposed to perform a leak test at nominal operating pressure and temperature.
Staff Evaluation: The Code requires that 100% inspection of the components shall have been tested and examined in accordance with IWA-5000, IWD-5000, and IWD-2600 at the expiration of each inspection interval.
However, it would be impractical for the licensee to perform these tests while the plant is operating. In order to perform the tests the licensee would have to shut down the entire CCW system from service, and removing it from service during normal plant operations would impair its safety function. The licensee has proposed as an alternative test to perform a leak test at nominal operating pressure and temperature on CCW System components where relief was requested. These alternative examinations should provide reasonable assurance of the structural integrity of the CCW system. Therefore, pursuant to 10 CFR 50.55a(g)(6)(i),
the staff concludes, giving due consideration to the burden of having to shut down the entire CCW system, that the Code requirement for the licensee to perform the required hydrostatic tests for the four packages described in the submittal dated November 4, 1992, is impractical and relief may be granted as requested. Such relief is authorized by law and will not endanger life, property, or the common defense and security, and is otherwise in the public interest.
3.0 CONCLUSION
Paragraph 10 CFR 50.55a(g)(4) requires that components (including supports) that are classified as ASME Code Class 1, 2 and 3 meet the requirements, except design and access provisions and preservice requirements, set forth in applicable editions of ASME Section XI to the extent practical within limitations of design, geometry, and materials of construction of components.
Pursuant to 10 CFR 50.55a(g)(5)(iii), the licensee determined that conformance with certain Code requirements were impractical for its facility and submitted supporting information. The staff concludes that the Code requirements to perform hydrostatic tests on certain components of the CCW System are impractical and that relief may be granted as requested; the licensee's proposed alternative examination will provide a reasonable assurance of the structural integrity of the CCW system.
Principal Contributor:
T. McLellan Date: December 22, 1992