IR 05000260/1989036

Insp Rept 50-260/89-36 on 890828-0901.No Violations Noted. Major Areas Inspected:Small Bore Piping & Instrument Tubing Program

ML20248E721
Person / Time
Site:	Browns Ferry
Issue date:	09/21/1989
From:	Fair J, Terao D Office of Nuclear Reactor Regulation
To:
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ML20248E715	List: IR 05000260/1989036 ML20248E713
References
50-260-89-36, NUDOCS 8910050395
Download: ML20248E721 (19)

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UNITED STATES

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NUCLEAR REGULATORY COMMIS$10N g

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p WASHINGTON, D. C. 20555

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UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF NUCLEAR REACTOR REGULATION TVA PROJECTS DIVISION Report No.:

50-260/89-36 Docket No.:

50-260 Licensee:

Tennessee Valley Authority 6N 38A Lookout Place 1101 Market Street Chattanooga, Tennessee 37402-2801 Facility Name:

Browns Ferry Nuclear Plant, Unit 2 Inspection At:

Browns Ferry Site Inspection Conducted: August 28 through September 1, 1989 MI 9/20/M Inspector:

Q4hn R. Fair Date'

n Approved by:

1. D-

/s 9ko/q

< David (erao,' Chief (l

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Date'

Engineering Branch TVA Prcjects Division

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Office of Nuclear Reactor Regulation l

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8910050395 890921 DR ADOCK 05000260 PNU

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BROWNS FERRY NUCLEAR PLANT, UNIT 2 SMALL BORE PIPING AND INSTRUMENT TUBING PROGRAMS INSPECTION REPORT 50-260/89-36 AUGUST 28 THROUGH SEPTEMBER 1, 1989 1 BACKGROUND INFORMATION The Tennessee Valley Authority's (TVA's) special program for Seismic Class I small bore (less than 21/2 inch diameter) piping was developed to address concerns identified with the application of design criteria, incomplete support details and missing)back-up calculations for typical supports at the Browns Fe Nuclear Plant (BFNP. This program involves the rigorous analysis of a sample of the small bore piping at Browns Ferry and an evaluation of the remaining piping for attributes identified from the sample analyses.

The TVA's special program for Seismic Class I tubing was developed to address concerns identified with the lack of design criteria for the support of capillary tubing and the lack of design criteria for addressing thermally induced stresses in tubing. This program is similar to the small bore piping program in that it involves a rigorous analysis of a sample of the Seismic Class I tubing at Browns Ferry and an evaluation of the remaining tubing for attributes identified from the sample analyses.

The TVA, in Section III.3.7 of the BFNP Nuclear Perfonnance Plan (TVA letter from S. A. White to L. W. Zech dated August 28,1986), stated that programs to address concerns identified with the design and iristallation of small bore piping and instrument tubing were being developed. The details of the small bore piping program were provided in TVA follow-up submittals (References 1, 2 and 3) and the instrument tubing program in a separate TVA submittal (Reference 4). TVA presented the criteria used to select the small bore sample in a meeting with the NRC staff on November 17,1988(Reference 5)andafurther clarification of the scope of the program in a meeting on June 28, 1989 (Reference 6).

The TVA in recent program submittals (References 3, 4) and in a recent meeting with the staff (Reference 6) identified that both the small bore piping program and the instrument tubing program will evaluate the systems identified in the Design Baseline and Verification Program (DBVF) restart scope prior to Browns Ferry Unit 2 restart and the remaining systems after restart. Both programs use restart criteria (interim operability criteria) to determine the modifications required for Browns Ferry Unit 2 restart. TVA's design criteria and restart criteria were reviewed during an inspection of the IE Bulletin 79-14/79-02 program from January 23 through February 3,1989 and the results documented in Inspection Report 50-260/89-15(Reference 7).

The Browns Ferry DBVP implementation has been reviewed by the staff in three team inspections and the results documented in NRC Inspection Reports 50-259, 50-260, 50-296/87-36; 88-07; and 89-07 (References 8, 9,10).

These team inspections included a review of the design criteria and design calculations for small bore piping at Browns Ferry.

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2. INSPECTION SCOPE AND OBJECTIVES The purpose of this inspection was to review TVA's implementation of the small bore piping and instrument tubing programs for Browns Ferry Unit 2.

The review included implementing procedures, quality assurance audit reports, piping and support calculations and the generic attribute evaluations.

3 SUMMARY During the inspection four issues were identified and discussed. The most significant issue, Unresolved Item EMG-029, was the size of the sample of small bore piping rigorously analyzed prior to Browns Ferry Unit 2 restart. Although an agreement for increasing the sample size was reached during the inspection, this issue is considered open pending receipt of TVA's fomal commitment. The open issues identified during this inspection are characterized as unresolved items in Appendix A of the inspection report.

Based on the review of TVA's revised design criteria documents, ten unresolved items from Inspection Report 50-260/89-15 were closed during this inspection.

The closure of these unresolved items is documented in Appendix B of this inspection report.

4 INSPECTION DETAILS 4.1 Small Bore Piping Program TVA's small bore piping program is part of the civil issue program and is described in CEB 8714-10. "Small Bore Piping Qualification Program". The pro-gram is being implemented by Stone and Webster Engineering Corporation (SWEC)

under SWEC Task S013.1. The program scope includes Seismic Class I field routed and supported small bore (2 inch diameter and smaller) piping for Browns Ferry Unit 2.

The program will evaluate the Seismic Class I piping systems defined by the DBVP restart boundary prior to Browns Ferry Unit 2 restart. According to TVA, the restart scope includes approximately 27,000 feet of piping and approximately 4000 supports (Reference 3). The remaining post restart scope includes an additional 8,000 feet of piping and 1200 supports. The program has resulted in the identification of 598 support modifications and 2184 support repairs as of August 28, 1989. TVA classifies items such as replacing missing hardware, gspping supports, repairing oversize bolt holes, etc. as repairs.

4.1.1 Design Criteria and Implementing Procedures SWEC is using the following TVA design criteria documents in the program implementation:

General Design Criteria No. BFN-50-C-7103, " Structural Analysis a.

and Qualification of Mechanical and Electrical Systems (Piping and Instrument Tubing)," Revision No. 3 March 3, 1989; b.

General Design Criteria No. BFN-50-C-7107, " Design of Class I Seismic Pipe and Tubing Supports," Revision No. 2 April 11,1989;

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Detailed Design Criteria No. BFN-50-C-7303, " Operability Criteria c.

for Pipe and Pipe Supports on Class 1 Seismic Piping," Revision No. 2. February 27, 1989.

I Previous revisions of these documents were reviewed during an inspection

,(Reference 7) at SWEC's Cherry Hill, New Jersey office. Follow-up review of

' cpen items on the design criteria documents is contained in Appendix B of this

. report.

i-SWEC uses the following procedures in the small bore piping program implementation:

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SWEC Project Procedure BFPP 8-9, " Technical. Procedure For Small Bore Piping, Task S013.1,"' Revision 0. December.21, 1987;

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b.

SWEC Project Procedure BFPP 8-9.1, " Piping Run and Support

' Walkdown Procedure Sinall Bore Piping Assessment Task 5013.1 "

Revision 0, October 26, 1987;-

SWEC Project Procedure BFPP 8-9.2, " Prerequisite Data Package c.

Development For Small Bore Piping Assessment Program (Task S013.1) "

Revision 0, December 4, 1987; d.

SWEC Project Procedure BFPP 8-9.3, "Small Bore Piping Analysis and Support Design Requirements Task S013.1," Revision 0, February 22, 1988; SWEC Project Procedure BFPP 8-9.4 " Drawing Preparation and e.

Issuance Procedure for Small Bore Piping Task S013.1," Revision 0 December 4, 1987; f.

SWEC Project Procedure BFPP 8-9.5, " Piping Run and Support Configuration Control Task No. 5013.1," Revision 0. December 21, 1987; SHEC Project Procedure BFPP 8-9.7 " Procedure for Interim and Final g.

Reports for Small Bore Piping Assessment Program Task S013.1,"

Revision 0. December 4, 1987; h.

SWEC Project Procedure BFPP 8-9.8, " Management Plan Fcr Small Bore Piping Assessment Task S013.1," Revision 1. December 11, 1987; i.

SWEC Project Procedure BFPP 8-9.9, " Package Review and Modification Procedure Small Bore Piping Assessment Task 5013.1," Revision 0, January 20, 1989.

SWEC uses the following procedures to perform the detailed "as-built" piping

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and support walkdowns for the detailed analysis portion of the program:

l SWECWalkdownDataPackage(WDP)No.SWEC-003,"PipingWalkdown l

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Procedure," Revision 2, August 10, 1988;

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SWEC WDP No. SWEC-005, " Pipe Support Walkdown Procedure," Revision 4, September 13, 1988.

According to TVA the original walkdowns of the 30 sample problems were started by Gilbert Commonwealth using Browns Ferry Project Instruction BFEP PI 87-40, "Small Bore Reconciliation Program" (Revision I was issued October 22,1987). SWEC reverified all 30 of the walkdowns using the same instruction BFEP PI 87-40.

In addition to BFEP PI 87-40, SWEC issued Project Memorandum No. 007, November 30, 1987 which specified measurement tolerances for the piping walkdowns. SWEC then issued procedures WDP SWEC-003 and WDP SWEC-005 to meet the requirements of TVA Site Director Standard Practice SDSP 9.8 "BFEP Walkdown Program and Construc-tability Surveys", (Revision 7 dated December 8,1988). The SWEC procedures were used for the remaining detailed piping and support walkdowns. The staff requested that TVA identify whether the walkdown tolerances specified in WDP SWEC 003 and SWEC 005 were the same as those specified in BFEP PI 87-40. TVA responded that the SWEC procedures contained more restrictive measurement tolerances than the TVA instruction except for weld size and length. SWEC had used the criteria from the TVA General Construction Specification G-29 for the weld measurements. The staff reviewed the inspection tolerances for welds specified in Section 6.4 of WDP SWEC 005 for weld length and size. For fillet weld size WDP SWEC 005 specifies the value contained in NCIG-01 " Visual Weld Acceptance Criteria for Structural Welding at Nuclear Power Plants," Revision 2 and for weld length WDP SWEC 005 specifies a more conservative criteria. The staff did not i

1!dentify any concerns with these criteria. In addition, the SWEC inspections of pipe support welds had been previously reviewed by an NRC team inspection and the results documented in Inspection Report 50-259/88-13,50-260/88-13, and50-296/88-13(Reference 12).

SWEC uses the following procedure to perfom the generic attribute walkdown and evaluation for the piping systems not evaluated by detailed analysis:

SWEC WDP No. SWEC-006, "Small Bore / Tubing Walkdown Evaluation,"

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Revision 2, March 29, 1989.

4.1.2 Ricorous Analysis Sample TVA originally proposed to perforrI rigorous analysis of a sample of 30 small bore stress problems (Reference 5). Ore additional problem was added to the tample to provide coverage of the Standby Gas Treatment Building. The problem was added because the new amplified resnonse spectra (ARS) for the Standby Gas Treatment Buf1 ding was not enveloped by the Reactor Building ARS. Therefore the rigorous analysis sample consisted cf 31 stress problems and approximately 130 supports.

TVA had originally comitted to rigorously analyze approximately ten percent of the small bore piping scope (References 1, 2). The implementation of TVA's DBYP resulted in the identification of additional Seismic Class I small bore piping within the Browns Ferry Unit 2 restart boundary. As a result, the small bore rigorous analysis sample fell substantially below TVA's original ten percent commitment. Although TVA performed additional rigorous analyses during the implementation of the generic attribute evaluations, the staff felt that additional pipe supports should be rigorously analyzed in order to meet the ten percent comitment. TVA agreed to rigorously analyze an additional 100 pipe-4-

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supports to satisfy the original comitment. This resolution was acceptable to

. the staff pending TVA's confirmation of the commitment (Unresolved Item EMG-029).

According to TVA, the original sample problems were selected to address the following issues:

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High temperature and pressure piping o

Relief valve discharge loads High seismic load areas (High elevations and the Diesel Generator o

Building)

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Eccentric masses l

o Pi)ing which has large attachment movements I

o Sciedule 160 piping o

Seismic /Non-seismic overlap regions -

Specific piping configurations and support details o

The last item cor.tains a number of specific support details including base plates, anchor bolts and welds. Concerns with the qualification of these details had been identified in Significant Condition Report SCR BFNCEB8520. November 6,1985.

Concerns with the qualification of schedule 160 pipe had been identified ir.

Nonconfomance Report NCR BFNMEB8406 R1, issued February 1,1985. A concern with the lack of consideration of relief valve thrust loads had been identified in Significant Condition Report SCR BFNCEB8620 RO, April 14, 1986. Finally, concerns with the evaluation of themal expansion stress range and anchor point displacements resulted in the issuance of CAQR No BFP871113 Revision 0. December 18, 1987.

The selection criteria for the rigorous analysis sample appeared to adequately address these specific issues that were identified at Browns Ferry.

The following rigorous analysis piping and support calculations were reviewed during the inspection:

o Calculation No. CD-Q2075-882275 Revision 1. July 6 '1989 o

Calculation No. CD-Q2075-883002, Revision 1. July 18, 1989 o

Calculation No. CD-Q2075-882276 Revision 1. July 6, 1989 o

Calculation No. CD-Q1067-882101 Revision 1. July 21, 1989 The second calculation was a piping stress analysis of a smell bore line attached f

to Core Spray Pump 2C. The calculation identified that the Browns Ferry Rigorous

' Analysis Handbook nozzle allowable limits had been exceeded for the pump nozzle.

In order to qualify the nozzle, TVA used criteria developed based on earthquake experience data related to the resolution of Unresolved Safety Issue (USI) A-46.

Browns Ferry is subject to the resolution of USI A-46 in accordance with the staff's Generic Letter 87-02 (Reference 13). However, the staff's final safety evaluation for the resolution of USI A-46 has not yet been issued. Since the nozzle loading involves an interface between the rigerously analyted piping

.which must meet the defined Browns Ferry restart criteria and equipment which will be covered in the final USI A-46 resolution, the review questioned whether the use of USI A-46 criteria was appropriate for this interface. This item was considered open pending further staff review of the application of USI A-46 criteria at the piping interface (Unresolved Item EMG 028).

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4.1.3 Generic Attribute Evaluation The rigorous analysis sample resulted in the identification of the following

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attributes which were evaluated on the remaining small bore piping:

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l o-Eccentric masses o

Piping attachment movements o

Piping flexibility in the Drywell and Diesel Generator L

Building In addition, the following attributes were identified for supports:

o U-Bolt with zero gap or oversized bolt holes o

Unistrut clamps as three way restraints or with excessive gaps Base plate anchor bolts damaged, missing or skewed and oversized o

base plate holes o

Pipe and structural attachments missing or loose In order to document the small bore piping program completion SWEC is preparing system calculations for each completed system. The scope of these system calcu-lations included the restart bcundaries established by the Design Baseline and Verification Program. Each system calculation contained the reference docemen-tation for all the piping calculations within the system restart boundary. The documentation included references to rigorous analysis problems evaluated as part of the IE Bulletin 79-14/79-02 program and references to calculations performed tosupportEngineeringChangeNotices(ECNs). According to TVA the ECNs were.

handled as a separate program outside the scope of the small bore program. The small bore piping problems associated with the ECNs are being evaluated for the current design criteria as part of the IE Bulletin 79-14/79-02 program. There-fore, all Seismic Class I small bore piping systems should be covered by the small bore program or the IE Bulletin 79-14/79-02 program with the exception of the CRD insert and withdrawal lines and torus-attached piping. According to TVA, the scope of the ECNs include 38 pipe stress analysis problems and 360 supports.

The reanalysis status of the ECNs was 15 pipe stress calculations and 20 pipe support calculations complete on August 30, 1989. The staff will perfonn additional review of the small bore piping covered by ECNs during a future inspection of the IE Bulletin 79-14/79-02 program.

System Cc1culation CD-Q2003-894393 approved August 26, 1989 was reviewed. This calculation, for the Feedwater System, contained 1S small bore piping packages.

The 18 small bore piping packages documented in the caleclation include;i two small bore problems that mera rigorously analyzed and five small bore problems-that were evaluated for generic attributes., The remaining small bore problems

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referenced in the calculation were evaluated as separate ECNs or as part of the IE Bulletin 79-14/79-02 program. The five small bore problems evaluated for generic attributes resulted in 18 repairs and modifications being identified.

These included checking the bolt torque on unistrut clamps, replacing oversized clamps,addingmissingclamps,andmodifyingexistingclampstoallowaxialpipe A1. modifications and repairs were issued by DCN No. W4525A. At the movement.

time of the inspection the DCN had not been officially closed out as completed.

However, according to TVA the field modifications had been completed. No i

concerns were identified based on the review of the system calculation.

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4.1.4 Technical Audits i

SWEC's Engineering Assurance (EA) group had issued three technical audit reports that covered the small bore piping program as of August 28, 1989:

l SWEC Engineering Assurance Audit Report, " Browns Ferry Nuclear a.

Project - Audit No. 5. January 25, 1988 through February 5, 1988,"

dated February 25, 1988;

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SWEC Engineering Assurance Audit Report, " Browns Ferry Nuclear l

Project - Audit No. 8. June 27 - July 15, 1988," dated

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August 25, 1988; SWEC Engineering Assurance Audit Report, " Browns Ferry Nuclear c.

Project - Audit No.11 June 20-23,1989," dated July 5, 1989.

TVA's Engineering Assurance group had reviewed the small bore piping calcula-tions as part of its review of the DBVP and documented the results in an EA report, " Engineering Assurance Oversight Review Report / Browns Ferry Nuclear Plant - Unit 2/ Design Baseline and Verification Program EA-0R-002", dated December 14, 1988. In addition, TVA had performed a technical audit of the small bore piping effort at SWEC's Decatur office from June 21-23, 1989 and documented the results in report BFN-CEB-89-03. This audit report had not been approved and issued to SWEC at the time of this inspection. The preliminary audit report identified 16 technical findings, 10 programmatic findings, 11 documentational findings and 3 observation findings. The preliminary report also characterized 9 issues as the most significant. During this inspection TVA was requested to provide a SWEC response to three of these issues. The issues selected were:

Run/ branch interface flexibility for piping less than 200"F and at a.

an elevation less than 580 ft.

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Modifications identified for a long unsupported axial run were attributed to eccentric mass.

No thermal flexibility evaluation where multiple in-line 3-way c.

restraints exist on piping less than 200"F.

Item a was concerned with an attribute evaluation perfonned by SWEC. The SWEC response was that specific run/ branch flexibility concerns had not been identi-I fled for these piping systems from the results of the detailed 18mple analysis.

Htxever, SWEC stated the review was performed during the engineering walkdowns and evalbhtions.

Item b identified the concern with attribute evaluation package 02-E56*2-01. SWEC't resper.se was the long axial run involved a penetration which functioned as an enchor for the piping and, therefore, ro concern existed for the axial span. For Item c, the SWEC response was that in-line 3-way restraints had only been escd en dead-ended ambient instrument lines where temperature effects are not significant. At the cima of this inspection, TVA had accepted the SWEC responses on these isnes. The staff will review the final resolution of these issues in a follow-up iuspection of TVA's 79-14/79-02 program to confinn these final positions.

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4.2 In'strument Tubing Program-TVA's instrument tubing program is part of.the civil issue program and is described in CEB-8714-1, " Tubing Support Qualification Program". The program is being implemented by SWEC under SWEC Task S004. The program included all Seismic Class I instrument tubing for Browns Ferry. The program scope originally-

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,specified a 100 percent detailed walkdown and evaluation of all Seismic Class I

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l tubing at Browns Ferry. The scope of this program included 56 tubing problems.

However, as a result of additional. tubing identified during the implementation i

of the DBVP, the program was modified and is being implemented in a similar fashion to the small bore program discussed in Section 4.1 of this report. The additional tubing is being evaluated for generic attributes under SWEC Task S051.

According to TVA the restart scope of the program included 644 supports. The program has resulted in the identification of 175 support modifications and 124 support repairs as 'of August 28, 1989.

4.2.1 Design Criteria and Implementation Procedures For the instrument tubing program SWEC uses the same TVA design criteria docu-ments discussed in Section 4.1.2 of this report. SWEC also uses the following procedures for the instrument tubing program implementation:

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SWEC Project Procedure BFPP 8-1, " Technical Procedure for Field Run Tubing Task S004," Revision 2. January 18, 1988; b.

SWEC Project Procedure BFPP 8-1.3, " Tubing Analysis and Support Design Requirements Task S004 " Revision D November 20, 1987; c; SWEC Project Procedure BFPP 8-1.4 " Drawing Preparation and Issuance Procedure," Revision D. July 24, 1987; d.

SWEC Project Procedure BFPP 8-1.6 " Package Review and Modification Procedure Tubing Assessment Task S051," Revision 0, January 26, 1989.

SWEC uses the following procedure to perform the detailed "as-built" tubing and tubing support walkdowns for the detailed evaluation portion of the program:

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SWEC WDP No. SWEC-004 "Walkdown of Instrumentation Tubing and Supports," Revision 7., June 10, 1988.

SWEC uses the same procedure to perform the generic attribute walkdown and evaluation for tubing syttams not evaluated by detailed analysis at it uses

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for the small bore program:

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SWEC WDP No. SWEC-006 "Small Bore / Tubing Walkdown Evaluation,"

-Revistan 2, March 29, 1989.

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Similar to the small bore piping program, the walkdawns of the original tubing sample were perforted using a Browns Ferry Nuclear Piant Project instruction, BFEP PI 87-56, "Walkdown of Instrumentation Tubing and Supports," Revision 0 September 4, 1987.

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L 4.2.2 Rigorous Analysis Sample-L As discussed previously, the original program involved the as-built walkdown

Land evaluation of the 56 Seismic Class I_ instrument tubing problems at Browns Ferry. According to TVA, 34 of these problems were within the Browns Ferry

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Unit 2 restart boundary.- The remaining restart scope of the instrument tubing

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program was established in Calculation MD-Q0000-88277, "Detennination of Seismic Class ! Tubing.and Capillary Installations at BFNP-Unit 2 and Conmon " Revision 2 May 3, 1989. Since the instrument tubing program originally planned a 100 percent detailed evaluation, the program did not use the same type of methodology to develop the rigorous analysis sample as the small bore program. The concerns that had been identified with instrument tubing at Browns Ferry included two j

Significant Condition Reports SCR BFNEEB8543R1 and SCR BFNEEBB535R2, which questioned the adequacy of the design and installation of tubing at Browns Ferry.

I TVA's instrument tubing program appeared to adequately address the concerns identified.in the Significant Condition Reports.

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The following rigorous analysis calculations were reviewed during the inspection:

o Calculation No. CD-Q3067-88157, Revision 0, November 22, 1987.

o Calculation No. CD-Q3090-88141,' Revision 0, November 30, 1987.

o Calculation No. CD-Q3067-88233 Revision 0, January 13, 1988.

The first calculation involved the tubing to Instrument 3-PCV-67-69. The calculation identified the high stress point at a 90 degree union elbow which formed the transition from 1/4 inch copper tubing to 1/8 inch capillary tubing.

According to SWEC, the joint involves a soldered connection which is shaped like a fillet weld. Therefore, SWEC used the stress intensification factor for a fillet welded connection in the calculation. The calculated stress at allowable limit used for the emergency load the joint was close to the 1.8 Sh combination. The staff requesten that TVA provide test data to demonstrate the adequacy of the soldered joint for the allowable stresses used in the calculation (Unresolved Item EMG 030).

The third calculation. involved a tubing support for the tubing to Instrument 3-PCV-67-69. The support was a framed structure consistirg of tube track with seven attachment points to the tubing run. The member loads for the structure-were generated based on a STRUDL compJter analysis. Based on the staff review of the calculation, it was identified that the frame self excit,ttion seismic loads were not considered in the analysis. SWEC stated that the frame had a nattral_ frequency greater than 20 Hz cod, therefore, was rigid. Accordfrag to

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TVA, SWEC stated that frame self excitation leads were considered when the loads l

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were judged significant by the analyst. The staff requested that TVA verify tJhat calculation (ge seismic leads for the structure were tot significant for the the rigid ran Unresolved Item EMG-031).

Since the tubing rigorous analysis calculations were performed prior to the resolution of design criteria issues, these problems were evaluated for the impact of the current criteria. This evaluation is contained in Calculation No. CD-Q0999-886504, " Impact Assessment of Housner ARS. Design Criteria-9-i

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BFN-50-C-7103, Revision 3 and BFN-50-C-7107.S.evision 2 on Tubing Task S004",

Revision 0, May 19, 1989. According to TVA, this evaluation did not result in

.the identification of any new tubing attributes because the original tubing calculations were done conservatively. The staff reviewed the results of the evaluation of the tubing for Instrument No. 3-PCV-67-69. The new evaluation shows that the stresses are slightly higher than the original calculation (CD-Q3067-88157) but still within the allowable limits.

4.2.3 Generic Attribute Evaluation The generic attributes for the instrument tubing program were developed in Calculation No.'CD-Q0999-890842, " Determination of Attributes Required forThe Walkdown and Evaluation of Tubing Task S051", Revision 0, May 24,1989.

attributes identified were similar to those identified from the small bore piping sample. SWEC is also preparing system calculations for the tubing program to document the calculations within the Design Baseline and Verification Program restart boundary. The following system calculations were reviewed:

o Calculation No. CD-Q0067-89032, Revision 0, July 19, 1989 o Calculation No. CD-Q0023-890833, Revision 0, July 19, 1989 The first calculation compiled the results of five walkdown packages associated with 12 instruments for System 67. Four of the five packages required further These detailed evaluations to demonstrate acceptability of the tubing runs.

further evaluations were performed in the second calculation. Although the second system calculation was for System 23, both systems were connected to the same instrument panel. Attachment A of the second calculation contained two rigorous computer models used to provide bounding results for the four separate line routings. The computer models were developed to evaluate the acceptability of eccentric masses that were identified in the walkdown packages. No open issues were identified during the review of this calculation.

5 OPEN ITEMS Specific open items identified during this inspection are characterized as unresolved items. Three of the unresolved items EMG-029, EMG-030 and EMG-031 require additional TVA response. A discussion of the unresolved items identi-fied curing the inspection is contained in Appendix A.

6 REVIEW OF PREVIOUS INSPECTION !1 EMS During the inspection, TVA corrective actions to resolve open items from Inspection Report 50-260/89-15 were revinwed. The ten open items reviewed during

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this inspection included the verification of the previous comitments made by l

TVA to revise the piping and pipe support design criteria documents. A discussion of the items closed is provided in Appendix B.

7 MEETING ATTENDEES AND REFERENCES A sumary of attendees at the entrance and exit meetings is provided in Appendix C.

A list of references is provided in Appendix 0.

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APPENDIX A UNRESOLVED ITEMS (0 pen) Unresolved Item EMG-028. USI A-46 Interface Small bore pipe stress Calculation No. CD-Q2075-883002, Revision 1, approved July 18, 1989 contained a letter from SWEC on July 6,1989 which stated that the Core Spray Pump 2C nozzle loads exceeded the allowable limits specified in BFN - RAH 307 Revision 2.

The calculation also contained a TVA response on July 14, 1989 which stated the nozzle loads met the allowable limits in TVA Calculation CD-Q3999-892719 Revision 0, June 26, 1989, This TVA calculation justified higher allowable limits for valve and equipment nozzle loads and valve accelerations for Browns Ferry based, in part, on earthquake experience data used in the resolution of USI A-46. Although Browns Ferry is subject to the resolution of USI A-46 in accordance with the staff's Generic Letter 87-02, the staff questioned the appropriateness of the use of earthquake experience based data at this interface with rigbrously analyzed piping. This item was considered open pending further staff review of the implementation of USI A-46 criteria at this interface.

(0 pen) Unresolved Item EMG-029. Small Bore Piping Program Sample Size TVA's original small bore piping program plan (References 1, 2) speciff ed that a sample of approximately ten percent of the small bore piping program scope would be rigorously analyzed to develop the attributes used in the evaluation of the remaining small bore piping systems at Browns Ferry. In response to staff questions on the small bore program scope (Reference 6), TVA presented additional infomation on the scope of the small bore piping program and the sample size that was rigorously analyzed in a June 30, 1989 submittal (Reference 3). The recent submittal identified that the rigorous analysis sample fell substantially below the estimated ten percent projection. TVA presented data showing that additional small bore piping and supports were rigorously analyzed However, with the during the generic attribute evaluation phase of the program.

inclusion of the additional rigorously analyzed pipe supports, the number of total pipe supports rigorously analyzed was still less than ten percent of the program scope.

During the inspection TVA agreed to rigorously analyze an additional 100 pipe

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supports within the Browns Ferry Unit 2 restart scope. The additional 100 pipe supperts 3nd the associated piping will result in achieving a total rigorous i

analysis of approximately 10 percent of the Browns Farry Unit 2 restart scope.

This item is open pending TVA's written confirmation of the commitment.

10pe d nresolved Item EMG-030. Soldered Joint Allowable Limits Tubing calculation CD-Q3067-88157 Revision 0, November 22, 1987 for Instrument No. 3-PCV-67-69 reported a high stress point at a 90 degree union albow which transitioned from 1/4 inch copper tubing to 1/8 inch capillary tubing. Based on discussions with SWEC it was identified that this joint is a soldered connection.

The calculation used a stress allowable of 1.8 S and a fillet weld based stress g

intensification factor of 1.3 based on the piping design criteria. The staff

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requested that TVA provide test data which supported the use of the piping allowables with a soldered joint. This item is open pending staff review of the supporting test data.

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{0 pen) Unresolved Item EMG-031. Evaluation of Structural Frame Loads Tubing support calculation CD-Q3067-88233, Revision 0, January 13, 1988 associated with Instrument No. 3 PCV-67-69 contained an evaluation of a framed structure containing a tube track with seven separate attachment points to the tubing.

The calculation contained the results of STRUDL computer analysis to obtain the structural member loads. However, the STRUDL analysis did not contain seismic loads due to the frame self weight excitation. Since the frame structure appeared more massive than the tubing it was supporting, the staff requested that TVA verify that the frame self weight excitation loads were not significant. This item is open pending TVA's response to this item.

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APPENDIX B LICENSEE ACTION ON PREVIOUS UNRESOLVED ITEMS (Closed) Unresolved Item EMG-002, SRSS of Inertia and SAM Loa _d_ss Inspection Report B9-15 identified that Section 6.3(d) of TVA's design criteria document BFN-50-C-7103, Revision 2, dated January 20, 1989 had changed the

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criteria for the combination of seismic inertia loads and seismic anchor move-i ment loads from absolute sum to SRSS. TVA's justification for this change was

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I a staff position contained in Section 2.4 of NUREG-1061 which allowed the SRSS of seismic inertia loads and seismic anchor movements for piping system response spectra analysis using the independent support motion method as specified in NUREG-1061. The staff accepted TVA's implementation of this procedure for the independent support motion method of analysis. However, the staff did not consider the method used for the spatial combination for branch connections specified in Section 6.3(b)2 of TVA's design criteria appropriate (Reference 11).

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Revision 3 of BFN-50-C-7103 changed Section 6.3(b)2 to require absolute sum for the branch connection load cases.

In addition Section 6.3(d) was changed to state absolute sum is used for envelope spectra. Based on TVA's revisions to the design criteria, this item is closed.

(Closed) Unresolved Item EMG-003,1.33 Factor for Hydro Test Inspection Report B9-15 identified that Section 1.4.2.2 of TVA's design criteria document BFN-50-C-7107. Revision 0, dated January 20, 1989, allowed a one-third increase in the normal American Institute of Steel Construction (AISC) allowable stresses for pipe supports for the hydrostatic test condition.

The criteria was not in confomance with the criteria contained in Paragraph 121.1.2(a)ofANSIB31.1.0-1967 which does not allow modification of the allow-able stress for supplementary steel design to AISC specifications for hydrostatic conditions.

Revision 2 of BFN-50-C-7103 specifies no increase for supplementary steel for the hydrostatic condition. However, Revision 2 also contained a change that specified increased allowable limits for standard component supports for the hydrostatic test condition. Although ANSI B31.1.0-1967 allows an increase in allowable stresses for standard component supports for the hydrostatic test condition, the value specified in Revision 2 of BFN-50-C-7107 did not correspond to the code criteria. Cm September 1, 1989, TVA issued a Design Input Memorandou which specified the code criteria shocid not be exceedec. Based on TVA's revisions to the design criteria, this item is closed.

JClosed)UnresolyedItemEMG-004,,SRSSof2PAfor_interfaceAnchort Inspection Report 8015 identified that Section 1.4.2.4 of TVA's design f

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criteria document BFN-50-C-7107. Revision 0, dated J4nuary 20, 1989,

the SRSS of dynamic loads from two sides of a piping system anchcr. The stiff requested that TVA justify the use of $355 methodology for the H91d axial response of a piping syster with an in-If re anc.bor. A SWEC evaluatica of a sample piping problem showed that the SRSS val @ 00uld be exceeded for rigid axial loads. Therefore, TVA agreed to modify this section of the design criteria document to combine the rigid piping axial loads on the anchor by the absolute sum method. Revision 2 of BFN-50-C-7107 contains the absolute sum B-1

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combination for axial loads. Based on TVA's revision to the design criteria this item is closed.

(Closed) Unresolved Item EMG-007. U-bolts on Rigid Supports Inspection Report 89-15 identified that Section 1.4.4.5 of TVA's design criteria document BFN-50-C-7107. Revision 0, dated January 20, 1989 allowed snug tight U-bolts to be evaluated as two-way restraints if the calculated pipe axial move-tent is less than 1/16-inch. The staff agreed with the TVA assessment that movements less than 1/16-inch in the axial direction will not have a significant effect on the U-bolt capacity. However, the staff considered TVA's use of this criteria, in lieu of providing a standard gap, required an additional level of control and verification during the piping analysis effort. Therefore, the staff considered this an open item to be reviewed during TVA's implementation of the aiping analysis effort. Revision 2 of BFN-50-C-7107 states two way U-bolts shall a installed with a 1/16 inch gap. The criteria also states that small bore piping systems with temperatures less than 200'F do not need the gap verified.

The staff did not have a concern with snug tight U-bolts for low temperature small bore piping because these installations are typical industry practice for small bore piping. Based on TVA's revision to the design criteria, which eliminated the additional level of complication in the analysis effort, this item is closed.

(Closed) Unresolved Item ENG-009. Lug Stress Evaluation Inspection Report 89-15 identified that Section 1.4.8 of TVA's design criteria document BFN-50-C-7107. Revision 0, dated January 20, 1989, allows credit to be taken for more than half of the axial shear lugs in the piping analysis if the gap is less than 1/32-inch. Standard industry practice for the analysis is to assume that half of the shear lugs will be effective in the analysis with a standard gap of 1/16-inch. Even if the shear lugs are shimmed to a zero or near-zero gap condition, equal load distribution cannot be achieved unless the supporting structure provides equal bearing stiffness. TVA agreed to modify the design criteria to provide a check on the supporting structure stiffness. Revision 2 of BFN-50-C-7107 contains a requirement to evaluate the load path flexibility when more than half of the lugs are considered effective.

Based on TVA's revision to the design criteria, this item is closed.

',(ClosedLUpresolved Ito EMG-010, StrutjSnubber Lead Sharing Criteria

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Inspection Report 89-15 identified e staff request for TVA's criteria used te l

detersine design loads for double strut &nd snubber supports on horizor.tr.1 pipe i

runs. TVA stated that each double snubber would be designed for 60 percent of the total load, and each double strut would be designed for 75 percent of the load. TVA comitted to revise design criterf e document BFN-50-7107 to add the criteria. Revision 2 of BFN-50-7107 added thase design provisions in Section 1.4.4.10.

Based on TVA's revisien to the design criteria, this issue is closed.

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(Closed) Unresolved Item EMG-012. Restart Criteria

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Inspection Report 89-15 identified the following staff comments on the j

acceptability of the BFNP restart criteria, BFN-50-C-7303, Revision 1, dated

January 20, 1989:

The augmented fatigue evaluation in Section 3.0 was not acceptable; a.

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The criteria for hydraulic snubbers in Section 4.2.2 required justification; c.. The criteria for load sharing in Section 4.2.6 was not acceptable.

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The criteria for spring hangers in a bottomed-out condition in Section 4.2.7 was not acceptable.

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The criteria for localized support flexibility in Section 4.2.8.1 was not acceptable; and f.

The criteria for themal monitoring in Section 4.2.9 was not acceptable.

TVA agreed to revise the restart criteria to reflect the staff's comments.

Revision 2 of BFN-50-C-7303 eliminated the criteria provisions stated above.

Based on TVA's' revision to the restart criteria, this issue is closed.

(Closed) Unresolved Item EMG-014. Pacific Scientific Snubber Load Ratings Inspection Report 89-15 identified that Section 1.4.2.2 of TVA's design criteria document BFN-50-C-7107 contains an allowable value of twice the basic vendor rating for mechanical snubbers in the emergency and faulted load combinations. TVA provided documentation from Pacific Scientific to support these values. The staff requested additional infomation on the basis of Pacific Scientific's allowables. Instead. TVA agreed to revise the design to use the lesser of 1.33 times the basic vendor rating, or the Level C limit for pre-NF snubbers and the Level C limit for post-NF snubbers. The staff accepted l

these allowables. Revision 2 of BFN-50-C-7107 revised the snubber criteria to meet TVA's commitment. Based on TVA's revision to the design criteriz, this issue is closed.

_(Closed) Unresolved Item EMG-021 SAM toads Inspection Report 89-15 identified that Se:tton 6.3(c)2 of Attachment A to TVA's design criteria document BFN-50-C-7103, Revision 2, dated January 20, i

1969. states that the seismic anchor movement (SAM) effects in tha see i

. building do not need to be evaluated. This was not in compliance with TVA's comitw.nts for the reanalysis effort. TVA agreed to revise the design

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criteria to satisfy its previous connitments. Revision 3 of BFN 50-C-7,103 revised the criteria in Section 6.3(c)2 to state SAM effects must be considered or if judged not significant the basis of the judgment must be documented in the analysis. Based on TVA's revision to the design criteria, this item is closed.

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(Closed) Unresolved Item EMG-022, Preload l

Inspection Report 89-15 identified that Section 8.2.3 of Attachment A to

. design criteria document BFN-50-C-7103, Revision 2, dated January 20, 1989, allows preload as a method of reducing nozzle allowable loads. TVA stated that preload was not being used at BFNP and committed to delete this provision l

from the design criteria. Revision 3 of BFN-50-C-7103 eliminated the preload provisions. Based on TVA's revision to the design criteria this item is closed, i

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e APPENDIX C MEETING ATTENDEES C.1 Entrance Meeting - August 28, 1989 NAME ORGANIZATION TITLE John R. Fair NRC Senior Mechanical Engineer Warren Wang SWEC EMD/ Division Alan Chan SWEC Engineering Manager Rick Svarney SWEC Assistant Project Manager

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Alan Johnson SWEC Wayne A. Massie TVA Regulatory Licensing Steve Salowitz SWEC QA Program Administrator Wayne Smathers TVA Engineering Mechanics Group Leader Jon Rupert TVA Lead Civil Chuck Whitehead TVA Program Director Tony Ritter TVA QA Evaluator Gary Lupardus TVA Task Engineer C.2 Exit Meeting - September 1, 1989 John R. Fair NRC Senior Mechanical Engineer Steve Salowitz SWEC QA Program Administrator Alan Chan SWEC Engineering Manager Wayne A. Massie TVA Regulatory Licensing Mark A. Durka SWEC Project Manager / Engineer Jon R. Rupert TVA Lead Civil Chuck Whitehead TVA Program Director Gary Lupardus TVA Task Engineer Wayne Smathers TVA Group Leader Engineering Mechanics Tony Ritter TVA 0A Evaluator Charles Patterson NRC Restart Coordinator Joe McCarthy TVA Regulatory Licensing Supervisor C-1

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I REFERENCES 1.

TVA letter (Gridley to NRC) transmitting the Browns Ferry Small Bore Piping Program dated March 10, 1988.

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TVA letter (Gridley to NRC) transmitting supplemental information on the Browns Ferry Small Bore Piping Program dated April 29, 1988.

3.

TVA letter (Ray to NRC) transmitting supplemental information on the Browns Ferry Unit 2 Small Bore Piping Program dated June 30, 1989.

4.

TVA letter (Ray to NRC) transmitting the Browns Ferry Unit 2 Instrument Tubing Program dated June 13, 1989.

5.

NRC meeting summary of December 13, 1988 meeting on Time History Analysis for Piping Enclosure 2 dated February 1,1989.

6.

NRC meeting summary of June 28, 1989 meeting on the Browns Ferry Unit 2 Seismic Program dated July 31, 1989.

7.

Inspection Report 50-260/89-15, forwarded by B. D. Liaw letter dated May 18, 1989.

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Inspection Report 50-259,260,296/87-36 forwarded by S. D. Richardson letter dated January 21, 1988.

9.

Inspection Report 50-259,260,296/88-07 forwarded by S. D. Richardson letter dated September 8,1989.

10. Inspection Report 50-259,260.296/89-07 forwarded by B. D. Liaw letter dated June 30, 1989.

11. NRC w.eting of February 17, 1989 meeting on Browns Ferry Unit 2 Seismic Istues dated March 22, 1989.

12e Inspection Report 50-259,260,296/88-13 forwarded by S. D. Richardson letter dated October 3, 1988.

13. NRC Generf t Letter 87-02, " Verification of Seismic Adequscy of Mechanical and Electrical Equipment in Operating Reactors, Unresolved Safety Issue (USI) A-46 " dated February 19, 1987.

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