IR 05000259/1992019
| ML18036A783 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 07/01/1992 |
| From: | Blake J, Chou R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML18036A781 | List: |
| References | |
| 50-259-92-19, 50-260-92-19, 50-296-92-19, NUDOCS 9207270121 | |
| Download: ML18036A783 (14) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION
REGION II
101 MARIETTASTREET, N.W.
ATLANTA,GEORGIA 30323 r+ +***+
Report Nos.: 50-259/92-19, 50-260/92-19, and 50-296/92-19 Licensee: 'Tennessee Valley Authority
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'B Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 D
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Docket Nos.:
50-.259, 50-260 and 50-296 License Nos.:
DPR-33, DPR-52, and DPR-68 Facility Name:
Browns Ferry 1, 2, and 3 Inspection te 18-22, 1992 Inspect Ri C
ou, Reactor Inspector Date Signed Acco pan ing ersonnel:
Kuo-Sing Chao, Trainee from Atomic Energy Council, Taiwan
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lake, Chief terials and Process Section ngineering Branch Division of Reactor Safety Date Signed SUMMARY Scope:
This routine, unannounced inspection was conducted in the areas of large and small bore piping, tube track steel, platform steel, and pipe stress calculation for the Unit 3 restart activities.
Results:
In the areas inspected, violations or deviations were not identified.
ill During this inspection, the inspector found discrepancies similar to those recorded in Unresolved Item 50-296/92-07-01, which is still pending resolution (para 5.)
Although the licensee and Bechtel reviewed the 95/95 audit program for walkdown packages and concluded that the program is acceptable, the inspector found a higher failure rate than the program predicted.
9207270i2i 92070b PDR ADOCK 05000259
REPORT DETAILS 1. 'ersons Contacted Licensee Employees R. Baird, Unit 3 Principal Engineer M. Bajestani, Technical Support
" P. Baron, Licensing Manager
" G. Campbell, Maintenance and Planning Manager R. Cutsinger, Lead Civil Engineer - Unit 2
" D. Kehoe, Restart Quality Assurance (QA) Manager
" T. Knuettel, Nuclear Engineer
" J. McCarthy, Restart Licensing Manager
" H. McCluckey, Vice President-Restart
" A. Sorrell, Acting Plant Manager
" P. Salas, Compliance Manager J. Scalise, Plant Manager
" G. Turner, Site QA Manager J. Valente, Civil Project Engineer - Unit 3
" O. Zerinque, Vice President-Browns Ferry Operation Other'licensee employee contacted during the inspection included craftsmen, engineers, mechanics, technicians, and administrative personnel.
Other Organizations Bechtel Power Corporation R. Hernandez, Quality Assurance Engineer D. Lindsey, Project Field Quality Control Engineer R. Montgomery, Field Service Manager NRC Personnel
" C. Patterson, Senior Resident Inspector
" B. Bearden, Resident Inspector
" E. Christnot, Resident Inspector
" J. Williams, NRR Project Manager for Browns Ferry
" Attended exit interview
2.
ActivityStatus of Walkdowns, Evaluations, Analyses, and Modifications for Unit 3 The following information shows the status of the licensed activities on the large bore piping, small bore piping, and control rod drive (CRD) systems.
ao Large Bore Piping Stress Analysis (1)
(2)
(3)
(4)
(5)
Walkdown Hanger Loads Issued Calculations Reviewed/Checked Calculations Issued Schedule for next two months 100% complete 90% complete 80% complete 15% (12 of 80)
b.
(a)
18 calculations to be issued (b)
8 hanger loads to be issued Small Bore Piping Program (1)
(2)
(3)
(4)
(5)
Walkdowns Piping Stress Evaluations Pipe Support Evaluations Tube Track Evaluations Schedule for next two months 90% complete (337 of 375)
52%- complete 50% complete 40% complete (4 of 10)
(a)
(b)
(c)
(d)
38 walkdowns to be completed 40 piping stress evaluations to be completed 300 support evaluations to be completed 2 tube track evaluations to be completed c.
Large Bore Piping Support (1)
(2).
(3)
(4)
(5)
(6)
(7)
Walkdowns Hanger Loads Received Calculation Reviewed/Checked DCA Prepared/Checked Calculation Issued DCN Issued Schedule for next two months 100% completed 90% completed 43% complete (774 of 1800)
30% complete 1% complete 1 of 22 (a)
10 DCNs to be issued (b)
350 calculations to be issued
d.
CRD System Frames (1)
Inside Drywell (a)
Stress calculations Issued
'b)
4 Frame Calculations Issued (c)
Stage I DCN In Progress (d)
8 Frame Calculations Issued 100% complete 33% complete 100%, Review Comments
'eing resolved 90% complete
'2)
Outside Drywell (a)
Design Loads Received (b)
Conceptual Design (c)
Analysis of Frames 100% complete 80% complete 20% complete 3.
Walkdowns Reinspections of Piping Systems and Civil Structures (Unit 3)
a.
Description The licensee uses a team to do walkdown inspections.
A team consists of two pipe support or civil engineers, or a stress engineer and a pipe support engineer.
During the engineering attribute walkdown, one of the engineers in the team inspects and evaluates the piping and associated supports and makes an on-the-spot judgement regarding the acceptability of the system.
The second engineer then independently inspects and verifies the judgement made by the first engineer.
Items requiring repairs, modifications and/or further evaluation to determine acceptability are identified in the
'walkdown packages.
The results of the evaluations are recorded on walkdown checklists along with the proposed repair/modification.
The inspector walked down small bore piping, tubing tracks which support tubing lines, and the upper drywell platform at elevation 604'.
The inspector's walkdown reinspection was completed with assistance from licensee engineers, Bechtel walkdown engineers, and a Bechtel quality control welding inspector.
The piping and supports were partially reinspected against detail drawings or field sketches for configuration, identification, fastener/anchor installation, anchor size, anchor type, marking, anchor edge distance, anchor bolt minimum spacing violation, base plate size and thickness, plate warpage, member size, weld sizes, component identification numbers,
dimensions, oxidation accumulation, interference, maintenance, and damage/protection.
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b. ',.-:;Small Bore Pipirig
'he inspector randomly selected'10 small bore piping supports which had been completed by the,walkdown group.The 10 supports were
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in two systems.
Instruction No. DC-012, Rev."3,.",Engineering Attribute Walkdown Instructions for, Seismic Class I Small Bore Piping, Tubing and Associated Supports", was the walkdown procedure used.
The purpose of a walkdown is to collect information or attributes and compare the field conditions against the existing drawings.
The procedure is to collect information for evaluating existing small bore piping and their associated supports in order to identify discrepancies, based on a screening of certain attributes, as required to satisfy Browns Ferry Nuclear Plant design commitments for Unit 3 restart.
The attributes for piping include source anchor movements, eccentric masses, and span lengths.
The attributes for pipe supports include U-bolts, unistrut type clamps, base plates, pipe to support attachments, structural attachments of supports, and support stiffness.
The supports reinspected are listed below:
Table
Small Bore Su ort Walkdown Support No.
NI-371-77R-00001 12862 Walkdown drawing shows three inches of weld on each side with less than 1/8" fillet weld between the angle steel and the base plate.
Tag No. Discrepancies/Comments/Remedies Walkdown drawing does not show fillet weld between the angle steel and the base plate.
The inspector found 1/4" fillet weld at above location.
NI-371-77R-00002 15563 None
D
Support No.
NI-371-79R-00003" Tag No. Discrepancies/Comments/Remedies 15604
",Weld length location, Note at
.'ection A-A of Page 21 of 24A, RFI No. S-35549 on each side of. angle steel were shown reversed.
NI-377-79R-00004 NI-371-77R-00005 NI-371-77R-00006 NI-371-77R-00007 NI-375-74R-00001 NI-375-74R-00002 15605 15608 15598 The U-bolt shim plate was was 1/2" thick; the walkdown drawing showed it to be 1/4" thick. The licensee will revise the walkdown package to correct this problem.
The weld length at far side at Section A-A of Page 21 of 24A, RFI No. S-35549 was 2" ~
The walkdown drawing showed 2 1/2". The licensee will revise the walkdown package to show the correct weld length.
None None Proposed new support None Small bore primary support Nl-375-61R-00036 has a loose unistrut clamp that was not noted in the walkdown package.
This loose damp will be torqued during the unistrut clamp retorque program.
Nl-374-74R-0003 None
c.
Tube Track The tubing and its associated supports (attached to the tube track)
were walked down and inspected per Instruction No. BC-012,.
"Engineering Attribute Walkdo'wn'Instructions for Seismic Class I
Small Bore Piping, Tubing and Associated Supports".
The tubing supports were attached to or supported by, tube track. The tube track is a continuous angle steel attached to a wall, steel beam, or column.
The tube track is to provide restraint for the tubing since the span for tubing supports is limited to four or five feet.
The licensee also uses
.
Instruction No. BC-005, Rev. 5, "Walkdown Instruction for Piping and Pipe Supports."
The inspector randomly selected six tube track supports in one line for reinspection.
The tube track supports reinspected are listed below:
Table 2 Tube Track S or Reins ection Tube Track Su ort No.
Walkdown Ppkp N
.
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C R
di Detail
Nl-343-54R The unistrut nut was loose.
The licensee will revise the walkdown package to show the loose nut.
G Nl-343-54R Nl-343-54R Nl-343-54R Page 5 of 7 RFI C-1942 None None None Weld between base plate and unistrut was not shown in drawings.
This was a transcription error. The licensee will revise the walkdown package to show the weld size and symbol (cont'd)
Tube Track Su o
No.
Walkdown Ppkp N
.
Oi i
C R
Ch Page 5 of 7 RFI C-1942 The weld length at the near side was 1/2" long. The drawing showed 3/4" long.
The licensee will revise the.
walkdown package to show the actual length.
Page 5 or 7 RFI C-1942 View on walkdown drawing should have been west instead of south.
The licensee will revise the walkdown package to reflect the actual view.
d.
Platform The licensee completed the walkdown for all the platforms that were required to be reinspected.
Three modification packages for drywell platforms at EL, 604'nd 628'ad been issued and are in process of modification. Instruction No. BC-001, Rev. 4, "Walkdown Instruction for Seismic Issues (Civil)" was used for the platform walkdown. This walkdown instruction was used to:
Determine the size, location and connection details of structural members supporting IEB 79-14 piping and other Seismic Class I
commodities.
Determine the location and type of attachments to structural members in order to establish applied loadings.
The main attributes checked or collected were dimensions, member sizes, weld size and symbols, detail of connection, piping attachment, and anchorage to the walls, beams or columns.
The inspector randomly selected the Drywell Platform at EL. 604'-0" from Azimith 165'o 270'n the Reactor Building for walkdown reinspection.
e.
Conclusion and Results The discrepancies shown on Table 1 and 2 are similar to the discrepancies found and recorded in the Inspection Report No. 50-296/92-07, which resulted in a Unresolved Item 92-07-01, Large Bore Walkdown Inspection and Document Checking Problem The licensee'used similar inspection techniques and a 95/95 audit program in the inspection of large bore, small bore, miscellaneous steel, cable tray, etc.
For a detail discussion of the previous open item, see Paragraph 5.
No violations or deviations were identified in the areas inspected."
Stress Calculation Review The licensee has completed all the field walkdown for the large bore piping, and 80 percent of the stress calculations have been reanalyzed.
The licensee is in the process of issuing Design Change Notices (DCN) for required modifications.
The inspector randomly selected stress calculation No. CD-03002-920667, Rev. 0, for stress problem No. Nl-302-1R.
The math model in the calculation was used to.confirm the computer input. This calculation was modeled based on as-built walkdown data and evaluated using TVA's TPIPE piping stress analysis computer program.
The calculations used the criteria identified in TVA's Design Criteria BFN-50-C-7103,and Rigorous Analysis Handbook (RAH), to verify piping stress code compliance, component qualifications and summarize pipe support reaction loads for their review and acceptance.
The stress calculation contained:
1) calculation package; 2) math model; 3) Geometry model; 4) static load cases; 5) frequency analysis and dynamic load cases; 6) special post processor; and 7) analysis results.
The inspector partially reviewed the computer input and output for geometry, pressure, temperature, restraint locations, dead weight, seismic factor, stress intensification factor (SIF), member stresses, compliance with code allowable, reaction loads, etc.
The calculated stresses were within the code allowable.
The inspector considered that the stress calculation was of good quality and acceptable.
One input dimension was one foot short but the licensee's engineer evaluated it to be acceptable.
The mistake will be corrected in the stress calculation revision.
No violations or deviations were identified in the areas inspected.
Action on Previous Inspection Findings (92701)
(Open) Unresolved Item 50-296/92-07-01, Large Bore Walkdown Inspection and Document Checking Problems This matter concerned the discrepancies found during an NRC inspector's walkdown reinspection, which revealed several problems existing in the licensee's walkdown reinspections.
The problems included the walkdown accuracy, transcribing errors from the walkdown draft to the final walkdown
schedules or drawings, and 95/95 audit'program efficiency. The inspector discussed the unresolved item with the licensee and Bechtel engineers, QA specialists, and reviewed the information provided: The licensee and Bechtel QA specialists jointly reviewed the program and.found no improvement to be made.
They both were satisfied with the existing 95/95 audit program,
'ven though the NRC inspector found numerous discrepancies during the walkdown reinspection.
During the current inspection on small bore and tube track supports, 8 out of.
17 supports were found to have one or more discrepancies in each support.
The failure rate was very high. The licensee's engineers and QA Specialists claimed that even though numerous discrepancies were found, none were evaluated to have significant impact or cause failure of the support.
TVA and Bechtel pointed out to the inspector that the chart showing the 95/95 Program Results, Quality Trend Analysis Program, Bechtel Job 21042, dated December 20, 1991, showed an overall trend of 98.8 percent (cumulative)
which was better than 95 percent and was therefore acceptable.
Based on the current 95/95 audit method, a support could have five percent defects and still be acceptable since it meets the 95 percent confidence level.
Licensee management agreed to further review the 95/95 audit program.
This item remains open.
No violations or deviations were identified in the area inspected.
6.
Exit Interview The inspection scope and results were summarized on May 22, 1992, with those persons indicated in paragraph 1. The inspector described the areas inspected and discussed in detail the inspection results.
Proprietary information is not contained in this report.
Dissenting comments were not received from the licensee.