ML20057G307
| ML20057G307 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 10/18/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20057G303 | List: |
| References | |
| NUDOCS 9310210262 | |
| Download: ML20057G307 (5) | |
Text
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o UNITED STATES l'
3, NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 N
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SAFETY EVALUATION REPORT BY THE OFFICE NUCLEAR REACTOR REGULATION RELATED TO THE FIRST TEN-YEAR INTERVAL INSERVICE INSPECTION j
PROGRAM PLAN RELIEF RE0 VEST B-12 FOR SOUTHERN CALIFORNIA EDISON COMPANY i
SAN ONOFRE NUCLEAR GENERATING STATION. UNITS NO. 2 AND NO. 3 i
DOCKET NOS. 50-36] AND 50-362
1.0 INTRODUCTION
The Technical Specifications for San Onofre Nuclear Station (SONGS), Units 2 and 3 state that the inservice inspection and testing of American Society of Mechanical Engineers (ASME) Code Class 1, 2, and 3 components shall be 4
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 4
specific written relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(i).
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) 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 A'2E Code,Section XI, " Rules for Inservice Inspection (ISI) of Nuclear Power Plant Components," to the extent practical within the ' imitations of dedgn, geometry, and materials of construction of the components.
The regulations i
require that inservice examination of components and system pressure tests conducted during the second 10-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 12 months prior to the start of the 120-month inspection interval, subject to the limitations and modifications listed therein.
The applicable edition of Section XI of the ASME Code for SONGS 2 and 3 First 10-year ISI Interval is the 1977 Edition, through Summer 1979 Addenda. 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.
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5 9310210262 931018 PDR AEOCM 05000361 P
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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 I
Code requirement. After evaluation of the determination, pursuant to 10 CFR 50.55a(g)(6)(1), 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 l
licensce that could result if the requirements were imposed.
i By letter dated June 16, 1993, Southern California Edison Company (licensee) submitted Relief Request B-12 regarding the hydrostatic testing of certain welds in the 4-inch line from the main steam header to the auxiliary feedwater pump which is unisolable from the steam generator.
The licensee had determined that this Code requirement was impractical to perform at both i
SONGS, Units 2 and 3.
2.0 RELIFF RE0 VEST B-l?
i The licensee is requesting relief from performing a hydrostatic test, as t
required by the ASME Code,Section XI, under IWC-5222(a), on certain welds in the 4-inch line from the main steam header to the auxiliary feedwater pump which will be modified during Cycle 7 outages for both SONGS, Units 2 and 3.
2.1 Code Reauirement IWC-5222(a) requires that the system hydrostatic test pressure shall be at least 1.10 times the system pressure P, for systems with Design Temperature of 200'F(93*C) or less, and at least 1,.25 times the system P,y for systems with Design Temperature above 200'F (93*C).
The system pressure P shall be 1
at the lowest pressure setting among the number of safety or relieE valves provided for overpressure protection within the boundary of the system to be tested.
l 2.2 Licensee's Basis for Recuestina Relief i
The proposed modification will alter the main steam piping to the auxiliary feedwater pump turbine during the Cycle 7 outages in both Units 2 and 3.
This modification, which involves welding connections to the main steam piping and cannot be isolated from the steam generator, will require hydrostatic testing of the modified Class 2 piping under the ASME Section XI program.
The modification will be installed and the majority of welds hydrostatically i
tested to 1.25 times system design pressure in accordance with the ASME Code.
(The system design pressure is substituted for P for systems not provided u
with safety valves.) There are 9 welds which cannot be hydrostatically tested without hydrostatically testing the st'sm generators.
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Figures were provided by the licensee to show the two lines added by this modification. The figures indicate the 9 welds which are subject to this 4
relief request, all other welds will be hydrostatically tested to 1.25 times P.
u To pressurize the steam generator and the associated piping to 1.25 times P,y 1
is not desirable due to the following reasons-l.
The test would need to be performed during plant heat up and would require the safety valves, which are normally set during the outage, to be gagged for this hydrostatic test.
It is the licensee's judgement that this hydrostatic test does not provide measurable benefit over the alternative testing proposed by Relief Request B-12 to justify the cost of performing the hydrostatic i
test and increasing the octage duration by several days.
2.
The ASME Committees are currently reviewing the possibility of relaxing hydrostatic testing requirements following repair or replacement activities.
This relaxation trend can be seen in Code Cases N-498, N-416, and the currently proposed revision to Code i
Case N-416 (416-1).
2.3 Licensee's Proposed Alternative Examination In lieu of the hydrostatic test the following will be performed:
1.
A VT-2 examination will be performed at Mode 3 pressure and temperature conditions (Mode 3 steam pressure is nominally 100 to 150 psi higher than full load steam pressure), and; 2.
The welds that will not receive the ASME Section XI hydrostatic test will be examined by surface examinations using the examination methods in Articles IWA-2220 and IWA-2230 in addition to any required volumetric examinations specified by the repair and replacement article in Section XI, IWA-4000 and IWA-7000.
2.4 Staff Evaluation 1
The staff has reviewed and evaluated the licensee's submittal and finds that the Code requirement to h.ydrostatically test after modification of the 4 inch line welds in the line from the main steam header to the auxiliary pump is t
impractical to perform because:
- 1) the lines are unisolable from the steam generator and would require redesign of the system; and 2) that the j
hydrostatic tests would be required to be performed during plant heat up and would require the safety valves, which are normally set during the outage, to be gagged for this hydrostatic test.
l The licensee's proposed alternatives:
- 1) to perform YT-2 examinations at Mode 3 pressure and temperature; and 2) the welds that will not receive the ASME l
Section XI hydrostatic test will be examined by surface examinations using the
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examination methods in Articles IWA-2220 and IWA-2230, in addition to any required volumetric examinations specified by the repair and replacement article in Section XI, IWA-4000 and IWA-7000, will provide added assurance of structural reliability to the welds in the 4-inch line from the main steam header to the auxiliary feedwater pump.
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 the components.
Pursuant to 10 CFR 50.55a(g)(5)(iii), the licensee determined that conformance with certain Code requirements is impractical for its facility and submitted I
supporting information. The staff has reviewed the licensee's submittal and has concluded that the requirements of the Code are impractical.
Pursuant to 10 CFR 50.55a(g)(6)(i) the staff concluded that relief may be granted for Relief Request B-12 and that the licensee's proposed alternative testing and examinations will ensure the structural integrity of the welds in the 4-inch line from the main steam header to the auxiliary feedwater pump. 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.
The relief has i
been granted giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility.
Principal Contributor:
T. McLellan, EMCB/NRR Date: October 18, 1993
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Messrs. Ray and Guiles San Onofre Nuclear Generating
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Southern California Edison Company Station, Unit Nos. 2 and 3 i
cc:
T. E. Oubre, Esq.
Mr. Robert G. Lacy i
Southern California Edison Company Manager, Nuclear Department Irvine Operations Center San Diego Gas & Electric Company l
23 Parker Street P. O. Box 1831 Irvine, California 92718 San Diego, California 92111 Chairman, Board of Supervisors Mr. Steve Hsu
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County of San Diego Radiologic Health Branch 1600 Pacific Highway, Room 335 State Department of Health Services l
San Diego, California 92101 Post Office Box 942732 Sacremento, California 94234 Mr. Sherwin Harris j
Resource Project Manager Resident Inspector / San Onofre NPS Public Utilities Department c/o U.S. Nuclear Regulatory Commission City of Riverside Post Office Box 4329 r
3900 Main Street San Clemente, California 92674 i
Riverside, California 92522 t
Mayor Mr. Charles B. Brinkman, Manager City of San Clemente t
Washington Nuclear Operations 100 Avenida Presidio ABB Combustion Engineering Nuclear Power San Clemente, California 92672 l
l 12300 Twinbrook Parkway, Suite 330 Rockville, Maryland 20852 Regional Administrator, Region V i
U.S. Nuclear Regulatory Commission Mr. R. W. Krieger, Vice President 1450 Maria Lane, Suite 210 Southern California Edison Company Walnut Creek, California 94596 San Onofre Nuclear Generating Station P. O. Box 128 4
San Clemente, California 92674-0128 t
Mr. Don J. Womeldorf Chief, Environmental Management Branch California Department of Health Services i
i 714 P Street, Room 616 Sacramento, California 95814 L
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