ML20140C327
| ML20140C327 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry, Sequoyah, 05000000 |
| Issue date: | 03/11/1986 |
| From: | Catlin J, Harwell E, Stevens W TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML082340275 | List: |
| References | |
| I-85-979-SQN, NUDOCS 8603250322 | |
| Download: ML20140C327 (9) | |
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4 TENNESSEE VALLEY AUTHORITY NUCLEAR SAFETY REVIEW STAFF
^
NSRS INVESTIGATION REPORT NO. I-85-979-SQN i
i EMPLOYEE CONCERN:
XX-85-122-033 i
~
SUBJECT:
UNISTRUT ACCEPTABILITY FOR USE ON SEISMIC CATEGORY I SUPPORTS i
i i
DATES OF i
INVESTIGATION:
DECEMBER 20 - FEBRUARY 20, 1986 INVESTIGATOR:
7
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j E.(,HARHELL
/ DME A
REVIEWED BY:
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. C. CATLIN DATE APPROVED BY:
fLl Jjbri
%}lf$r R. D. STEVENS ' DATE l i i hDR DOC P l 0007s
I I. BACKCROUND A Nuclear Safety Review Staff (NSRS) investigation was conducted to determine the validity of an expressed employee concern as received by Quality Technology Company (QTC)/ Employee R3sponse Team (ERT). The concern of record, as summarized on the Employeo Concern Assignment Request Form from QTC and identified as XX-85-122-033, stated: Sequoyah - Unistrut material is used to support instruments, pipe, conduit, control stations and panels, fluid piping on skids, instrument lines, CO2 fire protection lines, fire protection water piping, lighting, etc. Unistrut is unacceptable for use as Seismic Category I supports and items so supported may either fall or become missiles to cause other safety-related equipment to fail. CI has no further info rmation. Anonymous concern via letter. II. SCOPE A. The scope of the investigation was determined from the stated concern to be one specific issue: 1. Is Unistrut material acceptable for seismic category I supports for these features identified? B. During the investigation, USRS reviewed construction specifi-cations, design criteria, regulatory requirements, drawings, construction procedures, nonconforming reports, EN DES calcu-lations, and correspondence with NRC. In addition, a random inspection of Unistrut material was performed in control building. l auxiliary building, and diesel generator building. l III.
SUMMARY
OF FINDINCS l A. Requirements and Commitments l l 1. 10 CFR 50 Appendix B 2. Topical Report TVA-TR75-1A, Section 17.1, "TVA Quality Assurance Program, Program Applicable to Design and Construction" 3. Sequoyah Final Safety Analysis Report, Section 3.7 - Seismic Design, Section 3.8 - Design of Category I Structures; and Section 3.10 - Seismic Design ot Category I Instrumentation and Electrical Equipment l 1
B. Findings 1. During the 1970s, Engineering showed the use of Unistrut material on many of the typical drawings for those features mentioned in the concern. These drawings (47A051 -052, -053 -054, -055, and -056 series) are for Soismic Class I Supports. The allowable loads for the strap-type supports were based on tests performed at Singleton Laboratory in 1975 (Ref. 30). These tests were simple load tests to failure in three directions. In two directions (not parallel to pipe axis), the failure occurred in the bolt. By taking those loads and applying factors to compensate for minimum tensile strength versus ultimate tensile strength and for load conditions such an emergency / faulted or normal / upset, the allowable design loads were established. These design loads woro calculated and tabulated in reference 20. These design loads were later refined for alternate analyzed pipo and rigorously analyzed pipo situations and the new design loads appear in the Sequoyah Pipe Support Design Manual - Volume 3 (Ref. 18). 2. In order to address a Watts Bar Nucicar Plant (WBN) Nonconform-ance Report (NCR) WBN SWP 8237, a detailed analysis was performed to determine the acceptability and justified for use the Unistrut pipe strap, a one hole pipe ur conduit clamp, and a special valve clamp which are subjected to simultaneous loads in more than one direction. This analysis (Ref. 23) used the interaction equation and demonstrated by evaluation that the Unistrut support configurations described above would perform their intended functions and maintain their integrity when subjected to simultaneous loads. This analysis is applicable to supports installed at Sequoyah Nuclear Plant (SQN) prior to issuance of the pipe Support Design Manual, with all being adequate without further ovaluation except extreme cases. 3. Honconformance reports were issued for SQN (NCR SQN SWP 8305) and WBN (NCR WBN SWP 8230) stating that Engineering had not provided bolt tightening requirements for miscellaneous steel structures, pipe supports, conduit supports, HVAC supports, and instrumentation line supports. To address the WBN NCR, additional load testing was performed during September 1983 at Singleton Laboratory for various bolt torque values and turn of nut conditions. This additional test data was utilized in performing the engineering analysis (kef. 22) and dotormining acceptability of bolted Unistrut connections at WBN. Sinco prior to 1980 no specific tightening requirements woro given on the drawings, this scenario was also evaluated. Based on the hand tight plus 1/4 to 1/2 turn test data, the ability of the cupports to carry thole design load could bo demonstrated. 2 e
e 4. The SQN NCR SQN SWP 8305 was closed out on February 18, 1986 j (Ref. 31) stating that Sequoyah Contruction Procedures; SNP Inspection Instruction No.1. Inspection of Bolted Connections, and SNP Inspection Instruction No. 66. Inspection of Supports, gave the field instructions for tightening bolted connections not specifically addressed on drawings. However, the issue of construction documents not agreeing with some design assumptions for bolt tightening requirements will be resolved under SCR SQN CEB 8612. J 5. In order to provide the NRC with additional information l concerning the disposition of the various WBN NCRs, a technical meeting was conducted in the Region II office on June 13, 1985, where TVA provide their technical evaluation concerning the acceptability of the Unistrut clamp assembly. In reference 27, the NRC meeting summary stated: It is our opinion that the meeting was beneficial and has provided a better understanding of the technical evaluation performed to support your conclusion of acceptable installation of Unistrut clamp assemblics. 6. In a random walkdown inspection of Unistrut assemblies in the control building, auxiliary building, and diesel generator i building did not reveal any problems of concern. In the i auxiliary building, some clamps wore found loose, but these had been bent where people had stepped on the instrument tubes. In some areas where the Unistrut channel is welded to heavy structural steel, the two side legs would be slightly drawn but not enough that the spring nut would not adequately bridge from les to leg and seat properly in the nut grooves. IV. CONCLUSION:: AND RECOMMENDATIONS A. Conclusions The concern that Unistrut to an unacceptable material for use as i Seismic Category I Supports was not substantiated for the following reasons: 1. Actual load test provides basis for calculating design l allowables. 2. Design allowables have compensated for normal, upset, emergency, and faulted conditions. l i l l i, i 3 e-, ~..,. -. - - -,m.._..
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3. Bolt tightening variations in the field do not void the integrity of the clamp assembly or prevent it from performing l satisfactorily. 4. Apparent acceptance by NRC of TVA's technical evaluations and conclusions concerning use of Unistrut assembly. 4 } } B. Recommendation I-85-979-SQN-01, Resolution of SCR Sequoyah Engineering Project should assure satisfactory resolution and disposition of SCR SQN CEB 8612 and notify the NSRS when this effort is complete. [P3] l i i i 1 t l 2 I a I 4 l l 1 l I I i i l 4
d DOCUMENTS REVIEWED IN INVESTIGATION I-85-879-SQN AND REFERENCES 1. General Construction Specification C-43. Revision 8, " Support and Installation of Piping System in Category I Structures," dated August 8, 1985 2. SNP Construction Procedure No. P-30, Revision 5. " Fabrication and Installation of Seismic Supports," dated May 26, 1981 3. SNP Standard Operating Procedure No. 102, Revision 4. " Conduit Hanger Installations," dated April 21, 1982 4 SNP Construction Procedure No. M-7, Revision 14. " Erection and Documentation Requirements for Piping Systems," dated November 19, 1976 5. SNP Contruction Specification No. N2M-865, Revision 3. " Field Fabrication Assembly Examination, and Tests for Pipe and Duct Systems," dated April 12, 1977 6. NRC Regulatory Guide 1.29 " Seismic Design Classification" 7. NRC Regulatory Guide 1.60, " Design Responso Spectra for Seismic Design of Nuclear Power Plant," Revisicn 1, dated December 1973 j 8. SNP Cencral Design Criteria for Seismically Qualifying Conduit Supports, SQN-DC-V-13.10. Revision 1, dated September 30, 1981 9.* TVA Drawing 45A800, sheets 1 through 7, Electrical Conduit Seismic Support Details, Class I Structures 10. SNP General Design Criteria for Support of Lighting Fixtures in Category I Structures, SQN-DC-V-13.11, Revision 1, dated June 3,1975 11. SNP Construction Procedure No. I-5, Revision 2, " Fabrication, Installation, and Inspection of Seismic Instrumentation Line Supports and Wall-Mounted Panels," dated August 1976 i 12. TVA Drawings 47A051 series, " Mechanical Seismic Supports, Instrument Sensing Lines" 13. TVA Drawings 47A052 series, " Mechanical Seismic Supports. Instrument Sampling, and Radiation Monitoring Lines" 14. TVA Drawings, 47A053 series, " Mechanical Seismic Supports, Process Pipo 2-Inches and Less" 15. TVA Drawings 47A054 series, " Mechanical Seismic Supports, Control Air Lines" 5
~~ DOCUMENTS REVIEWED IN INVESTICATION 1-85-979-SQN AND REFERENCES (continued) 16. TVA Drawings, 47A055 series, " Mechanical Seismic Supports, Heating, Ventilation, and Air Conditioning" 17. TVA Drawings, 47A056 series, " Mechanical Seismic Supports, Condult" 18. Sequoyah Pipe Support Design Manual, Volume 3,'Section No. 9.4, Revision 0, "Unistrut Data," dated April 22, 1983 19. Civil Engineering Branch CEB Report 75-9, Sequoyah and Watts <Bar Nuclear Plants, " Design Data for Support of Category I Stainlesc Steel and Copper Tubing" 20. EN DES Calculations, "Unistrut Pipe Strap Loaa Ratings," Revision O. SWP820728004, dated July 27, 1982; Revision 1, WBP840629002, dated July 6,1984; and Revision 2. WBP840801037 dated August 23, 1984 21. Nonconformance Report WBN SWP 8230 " Tightening Requirements not Specified," SWP821208033 dated December 6, 1982 22. EN DES Calculations, "NCR WBN SWP 8230 Evaluation," WBP831014022 dated November 22, 1983 23. EN DES Calculations, " Evaluation of UCR WBN SWP 8237" Revision 0, SWP830120004 dated January 25. 1983; Revision 1. WBP840629003 dated July 6,1984 24. Nonconformance Report NCR WBN CEB 8501 dated January 24, 1985 (CEB850201009) 25. EN DES Calculations, NCR WBN CEB 8501, " Tightening of P2558 Unistrut Clamp," B41 850305 945, Revision 0, dated March 14, 1985 26. Memo from John A. Raulston, Chief Nuclear Engineer, to J. W. Hufhan, Manager of Licensing and Regulations, "Watto;Bar Nuclear Plant - Unistrut Clamp Assembly Tecting Data and Evaluations," dated June 13, 1985 (B45 850613 269) 27. Letter from Roger D. Walker, NRC Ulrector, Division of Reactor Projects, to H. C. Parris, Manager of Power and Engineering, " Meeting Summary - Watts Dar Nuclear Plant, Unit 1. Docket No. 50-390 " dated July 15, 1985 (A02 850717 002) 28. Nonconformance Report NCR SQN SWP 8305, " Tightening Requirements not Specified." SWP830224038 dated Febeury 18, 1983 29. Condition Adverse to Quality SCR SQN CEB 8612 dated February 18, 1986 6
w DOCUMENTS REVIEWED IN INVESTICATION I-85-979-SQN AND REFERENCES (continued) 30. Memo from R. D. Lane, Civil Engineer, Materials Engineering Section, to G. G. Stack, Project Manager, Sequoyah Nuclear Plant, " Transmittal of Unistrut Clamp Load Test Data." dated July 28, 1975 31. Memo from R. O. Barnett, Chief Civil Engineer, to J. P Vineyard, Project Manager, Sequoyah Engineering Project, " Transmitted Closure of NCR SQN SWP 8305 " dated February 18, 1986 32. Memo from J. P. Vineyard, Project Manager, Sequoyah Engineering Project, to Those listed, " Directing Designers to Include Bolt Tightening Requirements in Drawing Notes," dated February 6,1986 33. ASME Section III Subsection NF e 0115W 7
TVA 54 (03 C 653 (OP WP S 85) I ~ UNITED STATES GOVEllNMENT I ~ Memorandum TENNESSEE VALLEY AUTHORITY TO: H. L. Abercrombie, Gite Director, Sequoyah Nuclear Plant FROM: K. W. dhitt, Director of Nuclear Safety Review Staff E3A8 C-K MAR 1219$8 DATE:
SUBJECT:
NUCLEAR SAFETY REVIEW STAFF INVESTICATION REPORT TRANSMITTAL Transmitted herein is NSRS Report No. I-85-979-SON Subject UNISTRUT ACCEPTABILITY FOR USE ON SEISMIC CATECORY I SUPPORTS Concern No. XX-85-122-033 The attached report contains one Priority 3 [P3] recommendation which requires you to take some form of investigative or corrective action within the next four months (July 11, 1986). No formal response is required for this report unless you disagree with the proposed action. [' Please notify us if actions taken have been completed sooner. Should you have any questions, please contact W. D. Stevens at telephone 6231-X. l Recommend Reportability Determination: Yes No X ~ /. 1 r ?, ', /,frector,NSRS/ Designee WDS:CDM Attachment cc (Attactnent). ) W. C. Bibb, BFN W. T. Cottle, WBN James P. Darling, BLN 7-R. P. Denise, LP6N40A-C G. B. Kirk, SQN h l p D. R. Nichols, E10A14 C-K ( s QTC/ERT, Watts Bar Nuclear Plant -Eric Sliger, LP6N48A-C J. H. Sullivan, SQN ,0594U i l R....Ii C/ca..: nr Rnede I?onularlv an iI,o Pavents Cardene Plan j s}}