ML14138A084
| ML14138A084 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 09/21/1982 |
| From: | Paulson W Office of Nuclear Reactor Regulation |
| To: | Dietch R Southern California Edison Co |
| Shared Package | |
| ML13333B110 | List: |
| References | |
| TASK-03-07.B, TASK-3-7.B, TASK-RR LSO5-82-09-070, LSO5-82-9-70, NUDOCS 8210050300 | |
| Download: ML14138A084 (11) | |
Text
September 21, 1982 Docket No. 50-206 LS05-82 070 Mr. R. Dietch, Vice President Nuclear Engineering and Operations Southern California Edison Company 2244 Walnut Grove Avenue Post Office Box 800 Rosemead, California 91770
Dear Mr. Dietch:
SUBJECT:
SEP TOPIC III-7.1B, DESIGN CODES, DESIGN CRITERIA AND LOAD COMBINATIONS -
SAN ONOFRE 1 Enclosed is a copy of our draft evaluation of SEP Topic III-7.B. The evaluation identifies areas of codes where changes have occurred to decrease safety margins. It also identifies loads applicable to some or all of the structures at San Onofre 1 which haste increased in magnitude.
After reviewing structural drawings of your facility, we concluded that-some code changes of concern were not applicable to yougffacility because the structural elements to which these codesphanges are referring were not found in the structural drawings of San Onofre l) hich-we reviewed.
These changes are identified in Appendix 4 ogWtieehclosure. The evalua tion also concludes that further analysis is required-by you, in order to determine whether the containment is capo4go f withstanding combined seismic and LOCA loads developed in other SEP topics. The report is in draft form and is currently being further reviewed by the staff before 46(Cl}
being finalized. You are to review how these areas of the codes were V)5 applied in the design of San Onofre 1 and the ability of structures to'resist increased loads and assess the current safety margins.
You are requested to examine the facts upon which the staff has based its evaluation and respond by confirming that th, facts are correct or by identifying errors and supplying the correctedinformation. We encourage you to supply any other material that might affect the staff's evaluation of this topic or be significant in the integrated assessment of your facility.
You are requested to respond to the factual correctness of the SER and propose a schedule for resolution of the open -items within 30 days of re ceipt of this letter.
92/ ? 9 Sincerely,
L 1u on DCO khfieldFMi ia 900/82 9
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82 Wand
.7 alt Pauilqnn, Prmnt Manano OFFICE.
SEPB:D L SEPB:DLF 7\\ )^ SEPB:DL perating Reactors Branch lo. 5 SEPB:DL "i e sino a ERE Ki nna""
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flnf o"E-censin~g..................M SURNAME 97/2 9/1Z/82_
9/82 e210050300 820921 PDR ADOCK 05000206 OFFICIAL RECORD COPY USGPO 98i--33e-96a
R. Dietch
-2
Enclosure:
As stated cc w/enclosure:
See next page OFFICE I.
SURNAME....
DATE I............
NRC FORM 318 (10-80) NRCM 0240 OFFICIAL RECORD COPY USGPO: 1981-335-960
Mr. R. Dietch cc Charles R. Kocher, Assistant General Counsel James Beoletto, Esquire Southern California Edison Company Post Office Box 800 Rosemead, California 91770 David R. Pigott Orrick, Herrington & Sutcliffe 600 Montgomery Street San Francisco, California 94111 Harry B. Stoehr San Diego Gas & Electric Company P. 0. Box 1831
.San Diego, California 92112 Resident Inspector/San Onofre NPS c/o U. S. NRC P. 0. Box 4329 San Clemente, California 92672 Mayor City of San Clemente San Clemente, California 92672 Chairman Board of Supervisors County of San Diego San Diego, California 92101 California Department of Health ATTN:
Chief, Environmental Radiation Control Unit Radiological Health Section 714 P Street, Room 498' Sacramento, California 95814 U. S. Environmental Protection Agency Region IX Office ATTN:
Regional Radiation Representative 215 Freemont Street San Francisco, California 94111 Robert H. Engelken, Regional Administrator Nuclear Regulatory Commission, Region V 1450 Maria Lane Walnut Creek, California 94596
SYSTEMATIC EVALUATION PROGRAM TOPIC III-7.B SAN ONOFRE 1 TOPIC:
III-7.B, DESIGN CODES, DESIGN CRITERIA AND LOAD COMBINATIONS I.
INTRODUCTION SEP plants were generally designed and constructed during the time span from the late 1950's to late 1960's. They were designed according to criteria and codes which differ from those accepted by the NRC for new plants.
The purpose of this topic is to assess the safety margins existing in Category I structures as a result of changes in design codes and criteria.
II. REVIEW GUIDELINES The current licensing criteria which governs the safety issue in this topic is 10 CFR 50, Appendix A, GDC 1, 2, and 4 as interpreted by Standard Review Plan 3.8.
III.
RELATED SAFETY TOPICS The following SEP topics are related to III-7.B:
- 1. 111-2, Wind and Tornado Loadings
- 2. III-3.A, Effects of High Water Level on Structures
- 3. III-4.A, Tornado Missiles
- 4. III-5.A, Effects of High Energy Pipe Breaks Inside Containment
- 5. III-5.B, Effects of High Energy Pipe Breaks Outside Containment
- 6. 111-6, Seismic Design Considerations
- 7. VI-2.D, Mass and Energy Release for Postulated Pipe Break Inside Containment
- 8. VI-3, Containment Pressure and Heat Removal Capability IV. EVALUATION The evaluation is based on a Technical Evaluation Report (TER) prepared by the Franklin Research Center (FRC) in conjunction with the NRC staff.
through contract. The report is entitled, "Design Codes, Design Criteria and Loading Combinations" and is attached to this Safety Evaluation Report as Enclosure (1).
We have compared structural design codes employed in the design of Category I structures at San Onofre 1 to present codes. This was done through generic code versus code comparison without investigating specifically how the original code was applied to the San Onofre 1 design; however, after reviewing drawings of structures at San Onofre 1
-2 we concluded that certain portions of the codes were not applicable to San Onofre 1 because the types of structures to which the codes are referring were non-existent at San Onofre 1. We have compared the loads and loading combinations employed in the design of San Onofre
- 1.
A result of these comparisons is that a number of code changes could potentially impact significantly margins of safety (denoted by scale A and Ax in Enclosure 1).
This can be attributed to several factors such as:
- 1. New codes have imposed stricter limitations than old,
- 2. New codes have included sections governing design of certain types of structures which were not included in the older codes,
- 3. Design loads required today were not included in the plant design, and
- 4. Certain load combinations judged to be significant were not included in plant design.
In Enclosure (1), some items have been judged to potentially impact margins of safety regarding the containment as a result of comparing ASME Section III, Subsection B, 1963 to ASME Section III Subsection NE, 1980.
The code changes of concern from Enclosure (1).are:
Structural Elements to be Code Change Affecting These Elements Examined New Code Old Codes Beams/Columns AISC 1980 AISC 1963 AISC 1971 Hollow circular sections 1.5.1.4.1 1.5.1.4.1 1.5.1.4.1 subject to bending Subpara 7 Composite Beams
- 1. Shear connectors in 1.11.4 1.11.4 NA composite beams
- 2. Composite beams or 1.11.5 girders with formed steel deck Compression Elements AISC 1980 AISC 1963 AISC 1971 With width-to-thickness 1.9.1.2 and 1.9.1 NA ratio higher than speci-Appendix C fied in 1.9.1.2 Hollow circular sections 1.9.2.3 and subject to axial compression Appendix C Tension Members AISC 1980 AISC 1963 AISC 1971 When load is transmitted 1.14.2.2 by bolts or rivets Connections AISC 1980 AISC 1963 AISC 1971
- a. Beam ends with top flange 1.5.1.2.2 coped, if subject to shear
- b. Connections carrying 1.15.5.2 moment or restrained 1.15.5.3 member connection 1.15.5.4
- Double dash (--) indicates that older code had no provisions.
NA indicates not applicable.
7M
-77v.
Structural Elements to be Code Change Affecting These Elements Examined New Code Old Codes Members Designed to Operate AISC 1980 AISC 1963 AISC 1971 in an Inelastic Regime Spacing of lateral bracing 2.9 2.8 NA Short Brackets and Corbels ACI 349-76 ACI 318-63 ACI.318-71 having a shear span-to-11.13 NA depth ratio of unity or less Shear Walls used as a ACI 349-76 ACI 318-63 ACI 318-71 primary load-carrying 11.16 NA member Precast Concrete Structural ACI 349-76 ACI 318-63 ACI 318-71 Elements, where shear is not 11.15 NA a member of diagonal tension Concrete Regions Subject to ACI 349-76 ACI 318-63 ACI 318-71 High Temperatures.
Time-dependent and Appendix A position-dependent temperature variations Columns with Spliced ACI 349-76 ACI 318-63 ACI 318-71 Reinforcement subject to stress reversals; 7.10.3 805 NA fy in compression to 1/2 fy in tension Steel Embedments used to ACI 349-76 ACI 318-63 ACI 318-71 transmit load to concrete Appendix B Element Subject to ACI 349-76 ACI 318-63 ACI 318-71 Impulsive and Impactive Loads Appendix C whose failure must be precluded Shell Structures with ACI 349-76 ACI 318-63 ACI 318-71 thickness equal to or 19.1 19.1 greater than 12 inches fftqXr"2t~e<
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Structural Elements to be Code Change Affecting These Elements Examined New Code Old Codes Containment Vessels
- 1. Containment vessels of ASME Sec. III, ASME Sec. VIII, materials no longer NE-3112.4 UG-23 listed as code acceptable
- 3. Containment vessels ASME Sec. III, ASME Sec. VIII, designed by formula and NE-3131 subject to substantial loads
UG-29 subject to external pressure
- 5. Different materials ASME Sec. III, ASME Sec. VIII, used for the shell and NE-3133.5(b) stiffening rings
- 6. Vessels with reducer ASME Sec. III, ASME Sec. VIII, section with "reversed" Fig. 3324.11 Fig. UG-36(d) curvature when RL/t < 23 (a) (6)-l
- 7.
Vessels with positive ASME Sec. III, ASME Sec. VIII, locking devices - Quick NE-3327.1 actuating closures
- 8. Pressure indicating ASME Sec. III, ASME Sec. VIII, devices for vessels NE-3327.4 having quick actuating closures Shell Openings and Attachments
UG-36 Provisions for fatigue analysis 77:-
7
Structural Elements to be Code Change Affecting These Elements Examined New Code Old Codes
NE-3334.2 UG-40(c)
-7 Section 10 of Enclosure (1) addresses load and load combination changes which occurred as a result of code changes and identifies specific plant structures for which various load combinations may be significant. Based upon a lack of detailed information on the stress results for loads and load combinations used during design of structures at San Onofre 1, these loads and load combinations may be potentially significant.
Enclosure (2) provides details of an analysis of the containment for combined seismic and LOCA loads performed by our contractor, Lawrence Livermore Laboratory. The conclusion of the report is that a more refined analysis is required in order to determine whether the containment will adequately resist the combined seismic and LOCA loads.
V.
CONCLUSIONS We conclude that after comparing design codes, criteria, loads and load combinations, a number of changes have occurred which could potentially impact margins of safety. These changes are identified above. These differences between plant design and current licensing criteria should be resolved as follows:
- 1. Review Seismic Category I Structures at San Onofre 1 to determine if any of the structural elements for which a concern exists are a part of the facility design of San Onofre 1. For those that are, assess the impact of the code changes on margins of safety on a plant specific basis, 2, Examine on a sampling basis the margins of safety of Seismic Category I Structures for loads and load combinations not covered by another SEP topic and denoted by Ax in Enclosure (1).
(The load tables should be reviewed to assure their technical accuracy concerning applicability of the loads for each of the structures and their significance.
The Category I Structures considered should be reviewed to insure completeness.)
It is concluded that the licensee should pertorm a more refined analysis of the San Onofre 1 containment in order to determine if it is adequate to resist the combined seismic and LOCA loads described in Enclosure (2).
7........71--
z7:
TECHNICAL EVALUATION REPORT DESIGN CODES, DESIGN CRITERIA, AND LOADING COMBINATIONS (SEP, II1-7B)
SOUTHERN CALIFORNIA EDISON AND SAN DIEGO GAS AND ELECTRIC COMPANY SAN ONOFRE NUCLEAR GENERATING STATION UNIT 1 NRC DOCKET NO.
50-206 FRC PROJECT C5257 NRC TAC NO. 41604 FRC ASSIGNMENT 11 NRC CONTRACT NO. NRC-03-79-118 FRC TASK 318 Prepared by Franklin Research Center 20th and Race Street FRC Group Leader:
T. C. Stilwell Philadelphia, PA 19103 Prepared for Nuclear Regulatory Commission Washington, D.C. 20555 Lead NRC Engineer: D. Persinko August 13, 1982 This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, or any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for any third party's use, or the results of such use, of any information, appa ratus, product or process disclosed in this report, or represents that its use by such third party would not infringe privately owned rights.
Franklin Research Center A Division of The Franklin Institute The Benjamin Franklin Parkway, Phila.. Pa. 19103 (215) 448.1000